Patent Publication Number: US-2022240284-A1

Title: Downlink Control Channel Monitoring in New Radio Unlicensed Band

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/US2020/053952, filed Oct. 2, 2020, which claims the benefit of U.S. Provisional Application No. 62/909,416, filed Oct. 2, 2019, each of which is hereby incorporated by reference in its entirety. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Examples of several of the various embodiments of the present disclosure are described herein with reference to the drawings. 
       FIG. 1A  and  FIG. 1B  illustrate example mobile communication networks in which embodiments of the present disclosure may be implemented. 
       FIG. 2A  and  FIG. 2B  respectively illustrate a New Radio (NR) user plane and control plane protocol stack. 
       FIG. 3  illustrates an example of services provided between protocol layers of the NR user plane protocol stack of  FIG. 2A . 
       FIG. 4A  illustrates an example downlink data flow through the NR user plane protocol stack of  FIG. 2A . 
       FIG. 4B  illustrates an example format of a MAC subheader in a MAC PDU. 
       FIG. 5A  and  FIG. 5B  respectively illustrate a mapping between logical channels, transport channels, and physical channels for the downlink and uplink. 
       FIG. 6  is an example diagram showing RRC state transitions of a UE. 
       FIG. 7  illustrates an example configuration of an NR frame into which OFDM symbols are grouped. 
       FIG. 8  illustrates an example configuration of a slot in the time and frequency domain for an NR carrier. 
       FIG. 9  illustrates an example of bandwidth adaptation using three configured BWPs for an NR carrier. 
       FIG. 10A  illustrates three carrier aggregation configurations with two component carriers. 
       FIG. 10B  illustrates an example of how aggregated cells may be configured into one or more PUCCH groups. 
       FIG. 11A  illustrates an example of an SS/PBCH block structure and location. 
       FIG. 11B  illustrates an example of CSI-RSs that are mapped in the time and frequency domains. 
       FIG. 12A  and  FIG. 12B  respectively illustrate examples of three downlink and uplink beam management procedures. 
       FIG. 13A ,  FIG. 13B , and  FIG. 13C  respectively illustrate a four-step contention-based random access procedure, a two-step contention-free random access procedure, and another two-step random access procedure. 
       FIG. 14A  illustrates an example of CORESET configurations for a bandwidth part. 
       FIG. 14B  illustrates an example of a CCE-to-REG mapping for DCI transmission on a CORESET and PDCCH processing. 
       FIG. 15  illustrates an example of a wireless device in communication with a base station. 
       FIG. 16A ,  FIG. 16B ,  FIG. 16C , and  FIG. 16D  illustrate example structures for uplink and downlink transmission. 
       FIG. 17A ,  FIG. 17B  and  FIG. 17C  show examples of MAC subheaders. 
       FIG. 18A  shows an example of a DL MAC PDU. 
       FIG. 18B  shows an example of an UL MAC PDU. 
       FIG. 19  shows an example of multiple LCIDs of downlink. 
       FIG. 20  shows an example of multiple LCIDs of uplink. 
       FIG. 21A  and  FIG. 21B  show examples of SCell activation/deactivation MAC CEs. 
       FIG. 22A ,  FIG. 22B , and  FIG. 22C  show examples of SCell hibernation MAC CEs. 
       FIG. 23  shows an example of BWP management as per an aspect of an embodiment of the disclosure. 
       FIG. 24  shows an example of DRX configuration as per an aspect of an embodiment of the disclosure. 
       FIG. 25  shows an example of one or more DRX timers management as per an aspect of an embodiment of the disclosure. 
       FIG. 26A  and  FIG. 26B  show examples of power saving mechanism as per an aspect of an embodiment of the disclosure. 
       FIG. 27  shows an example of power saving mechanism as per an aspect of an embodiment of the disclosure. 
       FIG. 28  shows an example of search space configuration as per an aspect of an embodiment of the disclosure. 
       FIG. 29  shows an example of control resource set configuration. as per an aspect of an embodiment of the disclosure 
       FIG. 30A  and  FIG. 30B  show examples of search space and control resource set configurations as per an aspect of an embodiment of the disclosure. 
       FIG. 31  shows an example of power saving operation in an unlicensed cell as per an aspect of an embodiment of the disclosure. 
       FIG. 32A  and  FIG. 32B  show examples of power saving operation in an unlicensed cell as per an aspect of an embodiment of the disclosure. 
       FIG. 33  shows an example of PDCCH monitoring on multiple search space and multiple RB sets of a BWP as per an aspect of an embodiment of the disclosure. 
       FIG. 34  is a flowchart of PDCCH monitoring as per an aspect of an example embodiment of the present disclosure. 
       FIG. 35  shows an example of PDCCH monitoring on a search space on multiple RB sets of a BWP as per an aspect of an embodiment of the disclosure. 
       FIG. 36  is a flowchart of PDCCH monitoring as per an aspect of an example embodiment of the present disclosure. 
       FIG. 37  shows an example of PDCCH monitoring on a search space on multiple RB sets of a BWP as per an aspect of an embodiment of the disclosure. 
       FIG. 38  is a flowchart of PDCCH monitoring as per an aspect of an example embodiment of the present disclosure. 
       FIG. 39  shows an example of power saving operation in an unlicensed cell as per an aspect of an embodiment of the disclosure. 
       FIG. 40  shows an example of power saving operation in an unlicensed cell as per an aspect of an embodiment of the disclosure. 
    
    
     DETAILED DESCRIPTION 
     In the present disclosure, various embodiments are presented as examples of how the disclosed techniques may be implemented and/or how the disclosed techniques may be practiced in environments and scenarios. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope. In fact, after reading the description, it will be apparent to one skilled in the relevant art how to implement alternative embodiments. The present embodiments should not be limited by any of the described exemplary embodiments. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and/or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure. Any figures which highlight the functionality and advantages, are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments. 
     Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria are met, for example, in a wireless device, a base station, a radio environment, a network, a combination of the above, and/or the like. Example criteria may be based, at least in part, on for example, wireless device or network node configurations, traffic load, initial system set up, packet sizes, traffic characteristics, a combination of the above, and/or the like. When the one or more criteria are met, various example embodiments may be applied. Therefore, it may be possible to implement example embodiments that selectively implement disclosed protocols. 
     A base station may communicate with a mix of wireless devices. Wireless devices and/or base stations may support multiple technologies, and/or multiple releases of the same technology. Wireless devices may have some specific capability(ies) depending on wireless device category and/or capability(ies). When this disclosure refers to a base station communicating with a plurality of wireless devices, this disclosure may refer to a subset of the total wireless devices in a coverage area. This disclosure may refer to, for example, a plurality of wireless devices of a given LTE or 5G release with a given capability and in a given sector of the base station. The plurality of wireless devices in this disclosure may refer to a selected plurality of wireless devices, and/or a subset of total wireless devices in a coverage area which perform according to disclosed methods, and/or the like. There may be a plurality of base stations or a plurality of wireless devices in a coverage area that may not comply with the disclosed methods, for example, those wireless devices or base stations may perform based on older releases of LTE or 5G technology. 
     In this disclosure, “a” and “an” and similar phrases are to be interpreted as “at least one” and “one or more.” Similarly, any term that ends with the suffix “(s)” is to be interpreted as “at least one” and “one or more.” In this disclosure, the term “may” is to be interpreted as “may, for example.” In other words, the term “may” is indicative that the phrase following the term “may” is an example of one of a multitude of suitable possibilities that may, or may not, be employed by one or more of the various embodiments. The terms “comprises” and “consists of”, as used herein, enumerate one or more components of the element being described. The term “comprises” is interchangeable with “includes” and does not exclude unenumerated components from being included in the element being described. By contrast, “consists of” provides a complete enumeration of the one or more components of the element being described. The term “based on”, as used herein, should be interpreted as “based at least in part on” rather than, for example, “based solely on”. The term “and/or” as used herein represents any possible combination of enumerated elements. For example, “A, B, and/or C” may represent A; B; C; A and B; A and C; B and C; or A, B, and C. 
     If A and B are sets and every element of A is an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B={cell1, cell2} are: {cell1}, {cell2}, and {cell1, cell2}. The phrase “based on” (or equally “based at least on”) is indicative that the phrase following the term “based on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “in response to” (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employing/using” (or equally “employing/using at least”) is indicative that the phrase following the phrase “employing/using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. 
     The term configured may relate to the capacity of a device whether the device is in an operational or non-operational state. Configured may refer to specific settings in a device that effect the operational characteristics of the device whether the device is in an operational or non-operational state. In other words, the hardware, software, firmware, registers, memory values, and/or the like may be “configured” within a device, whether the device is in an operational or nonoperational state, to provide the device with specific characteristics. Terms such as “a control message to cause in a device” may mean that a control message has parameters that may be used to configure specific characteristics or may be used to implement certain actions in the device, whether the device is in an operational or non-operational state. 
     In this disclosure, parameters (or equally called, fields, or Information elements: IEs) may comprise one or more information objects, and an information object may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J. Then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more messages comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages, but does not have to be in each of the one or more messages. 
     Many features presented are described as being optional through the use of “may” or the use of parentheses. For the sake of brevity and legibility, the present disclosure does not explicitly recite each and every permutation that may be obtained by choosing from the set of optional features. The present disclosure is to be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features may be embodied in seven ways, namely with just one of the three possible features, with any two of the three possible features or with three of the three possible features. 
     Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (e.g. hardware with a biological element) or a combination thereof, which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling/simulation program such as Simulink, Stateflow, GNU Octave, or Lab VIEWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and/or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers and microprocessors are programmed using languages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module. 
       FIG. 1A  illustrates an example of a mobile communication network  100  in which embodiments of the present disclosure may be implemented. The mobile communication network  100  may be, for example, a public land mobile network (PLMN) run by a network operator. As illustrated in  FIG. 1A , the mobile communication network  100  includes a core network (CN)  102 , a radio access network (RAN)  104 , and a wireless device  106 . 
     The CN  102  may provide the wireless device  106  with an interface to one or more data networks (DNs), such as public DNs (e.g., the Internet), private DNs, and/or intra-operator DNs. As part of the interface functionality, the CN  102  may set up end-to-end connections between the wireless device  106  and the one or more DNs, authenticate the wireless device  106 , and provide charging functionality. 
     The RAN  104  may connect the CN  102  to the wireless device  106  through radio communications over an air interface. As part of the radio communications, the RAN  104  may provide scheduling, radio resource management, and retransmission protocols. The communication direction from the RAN  104  to the wireless device  106  over the air interface is known as the downlink and the communication direction from the wireless device  106  to the RAN  104  over the air interface is known as the uplink. Downlink transmissions may be separated from uplink transmissions using frequency division duplexing (FDD), time-division duplexing (TDD), and/or some combination of the two duplexing techniques. 
     The term wireless device may be used throughout this disclosure to refer to and encompass any mobile device or fixed (non-mobile) device for which wireless communication is needed or usable. For example, a wireless device may be a telephone, smart phone, tablet, computer, laptop, sensor, meter, wearable device, Internet of Things (IoT) device, vehicle road side unit (RSU), relay node, automobile, and/or any combination thereof. The term wireless device encompasses other terminology, including user equipment (UE), user terminal (UT), access terminal (AT), mobile station, handset, wireless transmit and receive unit (WTRU), and/or wireless communication device. 
     The RAN  104  may include one or more base stations (not shown). The term base station may be used throughout this disclosure to refer to and encompass a Node B (associated with UMTS and/or 3G standards), an Evolved Node B (eNB, associated with E-UTRA and/or 4G standards), a remote radio head (RRH), a baseband processing unit coupled to one or more RRHs, a repeater node or relay node used to extend the coverage area of a donor node, a Next Generation Evolved Node B (ng-eNB), a Generation Node B (gNB, associated with NR and/or 5G standards), an access point (AP, associated with, for example, WiFi or any other suitable wireless communication standard), and/or any combination thereof. A base station may comprise at least one gNB Central Unit (gNB-CU) and at least one a gNB Distributed Unit (gNB-DU). 
     A base station included in the RAN  104  may include one or more sets of antennas for communicating with the wireless device  106  over the air interface. For example, one or more of the base stations may include three sets of antennas to respectively control three cells (or sectors). The size of a cell may be determined by a range at which a receiver (e.g., a base station receiver) can successfully receive the transmissions from a transmitter (e.g., a wireless device transmitter) operating in the cell. Together, the cells of the base stations may provide radio coverage to the wireless device  106  over a wide geographic area to support wireless device mobility. 
     In addition to three-sector sites, other implementations of base stations are possible. For example, one or more of the base stations in the RAN  104  may be implemented as a sectored site with more or less than three sectors. One or more of the base stations in the RAN  104  may be implemented as an access point, as a baseband processing unit coupled to several remote radio heads (RRHs), and/or as a repeater or relay node used to extend the coverage area of a donor node. A baseband processing unit coupled to RRHs may be part of a centralized or cloud RAN architecture, where the baseband processing unit may be either centralized in a pool of baseband processing units or virtualized. A repeater node may amplify and rebroadcast a radio signal received from a donor node. A relay node may perform the same/similar functions as a repeater node but may decode the radio signal received from the donor node to remove noise before amplifying and rebroadcasting the radio signal. 
     The RAN  104  may be deployed as a homogenous network of macrocell base stations that have similar antenna patterns and similar high-level transmit powers. The RAN  104  may be deployed as a heterogeneous network. In heterogeneous networks, small cell base stations may be used to provide small coverage areas, for example, coverage areas that overlap with the comparatively larger coverage areas provided by macrocell base stations. The small coverage areas may be provided in areas with high data traffic (or so-called “hotspots”) or in areas with weak macrocell coverage. Examples of small cell base stations include, in order of decreasing coverage area, microcell base stations, picocell base stations, and femtocell base stations or home base stations. 
     The Third-Generation Partnership Project (3GPP) was formed in 1998 to provide global standardization of specifications for mobile communication networks similar to the mobile communication network  100  in  FIG. 1A . To date, 3GPP has produced specifications for three generations of mobile networks: a third generation (3G) network known as Universal Mobile Telecommunications System (UMTS), a fourth generation (4G) network known as Long-Term Evolution (LTE), and a fifth generation (5G) network known as 5G System (5GS). Embodiments of the present disclosure are described with reference to the RAN of a 3GPP 5G network, referred to as next-generation RAN (NG-RAN). Embodiments may be applicable to RANs of other mobile communication networks, such as the RAN  104  in  FIG. 1A , the RANs of earlier 3G and 4G networks, and those of future networks yet to be specified (e.g., a 3GPP 6G network). NG-RAN implements 5G radio access technology known as New Radio (NR) and may be provisioned to implement 4G radio access technology or other radio access technologies, including non-3GPP radio access technologies. 
       FIG. 1B  illustrates another example mobile communication network  150  in which embodiments of the present disclosure may be implemented. Mobile communication network  150  may be, for example, a PLMN run by a network operator. As illustrated in  FIG. 1B , mobile communication network  150  includes a 5G core network (5G-CN)  152 , an NG-RAN  154 , and UEs  156 A and  156 B (collectively UEs  156 ). These components may be implemented and operate in the same or similar manner as corresponding components described with respect to  FIG. 1A . 
     The 5G-CN  152  provides the UEs  156  with an interface to one or more DNs, such as public DNs (e.g., the Internet), private DNs, and/or intra-operator DNs. As part of the interface functionality, the 5G-CN  152  may set up end-to-end connections between the UEs  156  and the one or more DNs, authenticate the UEs  156 , and provide charging functionality. Compared to the CN of a 3GPP 4G network, the basis of the 5G-CN  152  may be a service-based architecture. This means that the architecture of the nodes making up the 5G-CN  152  may be defined as network functions that offer services via interfaces to other network functions. The network functions of the 5G-CN  152  may be implemented in several ways, including as network elements on dedicated or shared hardware, as software instances running on dedicated or shared hardware, or as virtualized functions instantiated on a platform (e.g., a cloud-based platform). 
     As illustrated in  FIG. 1B , the 5G-CN  152  includes an Access and Mobility Management Function (AMF)  158 A and a User Plane Function (UPF)  158 B, which are shown as one component AMF/UPF  158  in  FIG. 1B  for ease of illustration. The UPF  158 B may serve as a gateway between the NG-RAN  154  and the one or more DNs. The UPF  158 B may perform functions such as packet routing and forwarding, packet inspection and user plane policy rule enforcement, traffic usage reporting, uplink classification to support routing of traffic flows to the one or more DNs, quality of service (QoS) handling for the user plane (e.g., packet filtering, gating, uplink/downlink rate enforcement, and uplink traffic verification), downlink packet buffering, and downlink data notification triggering. The UPF  158 B may serve as an anchor point for intra-/inter-Radio Access Technology (RAT) mobility, an external protocol (or packet) data unit (PDU) session point of interconnect to the one or more DNs, and/or a branching point to support a multi-homed PDU session. The UEs  156  may be configured to receive services through a PDU session, which is a logical connection between a UE and a DN. 
     The AMF  158 A may perform functions such as Non-Access Stratum (NAS) signaling termination, NAS signaling security, Access Stratum (AS) security control, inter-CN node signaling for mobility between 3GPP access networks, idle mode UE reachability (e.g., control and execution of paging retransmission), registration area management, intra-system and inter-system mobility support, access authentication, access authorization including checking of roaming rights, mobility management control (subscription and policies), network slicing support, and/or session management function (SMF) selection. NAS may refer to the functionality operating between a CN and a UE, and AS may refer to the functionality operating between the UE and a RAN. 
     The 5G-CN  152  may include one or more additional network functions that are not shown in  FIG. 1B  for the sake of clarity. For example, the 5G-CN  152  may include one or more of a Session Management Function (SMF), an NR Repository Function (NRF), a Policy Control Function (PCF), a Network Exposure Function (NEF), a Unified Data Management (UDM), an Application Function (AF), and/or an Authentication Server Function (AUSF). 
     The NG-RAN  154  may connect the 5G-CN  152  to the UEs  156  through radio communications over the air interface. The NG-RAN  154  may include one or more gNBs, illustrated as gNB  160 A and gNB  160 B (collectively gNBs  160 ) and/or one or more ng-eNBs, illustrated as ng-eNB  162 A and ng-eNB  162 B (collectively ng-eNBs  162 ). The gNBs  160  and ng-eNBs  162  may be more generically referred to as base stations. The gNBs  160  and ng-eNBs  162  may include one or more sets of antennas for communicating with the UEs  156  over an air interface. For example, one or more of the gNBs  160  and/or one or more of the ng-eNBs  162  may include three sets of antennas to respectively control three cells (or sectors). Together, the cells of the gNBs  160  and the ng-eNBs  162  may provide radio coverage to the UEs  156  over a wide geographic area to support UE mobility. 
     As shown in  FIG. 1B , the gNBs  160  and/or the ng-eNBs  162  may be connected to the 5G-CN  152  by means of an NG interface and to other base stations by an Xn interface. The NG and Xn interfaces may be established using direct physical connections and/or indirect connections over an underlying transport network, such as an internet protocol (IP) transport network. The gNBs  160  and/or the ng-eNBs  162  may be connected to the UEs  156  by means of a Uu interface. For example, as illustrated in  FIG. 1B , gNB  160 A may be connected to the UE  156 A by means of a Uu interface. The NG, Xn, and Uu interfaces are associated with a protocol stack. The protocol stacks associated with the interfaces may be used by the network elements in  FIG. 1B  to exchange data and signaling messages and may include two planes: a user plane and a control plane. The user plane may handle data of interest to a user. The control plane may handle signaling messages of interest to the network elements. 
     The gNBs  160  and/or the ng-eNBs  162  may be connected to one or more AMF/UPF functions of the 5G-CN  152 , such as the AMF/UPF  158 , by means of one or more NG interfaces. For example, the gNB  160 A may be connected to the UPF  158 B of the AMF/UPF  158  by means of an NG-User plane (NG-U) interface. The NG-U interface may provide delivery (e.g., non-guaranteed delivery) of user plane PDUs between the gNB  160 A and the UPF  158 B. The gNB  160 A may be connected to the AMF  158 A by means of an NG-Control plane (NG-C) interface. The NG-C interface may provide, for example, NG interface management, UE context management, UE mobility management, transport of NAS messages, paging, PDU session management, and configuration transfer and/or warning message transmission. 
     The gNBs  160  may provide NR user plane and control plane protocol terminations towards the UEs  156  over the Uu interface. For example, the gNB  160 A may provide NR user plane and control plane protocol terminations toward the UE  156 A over a Uu interface associated with a first protocol stack. The ng-eNBs  162  may provide Evolved UMTS Terrestrial Radio Access (E-UTRA) user plane and control plane protocol terminations towards the UEs  156  over a Uu interface, where E-UTRA refers to the 3GPP 4G radio-access technology. For example, the ng-eNB  162 B may provide E-UTRA user plane and control plane protocol terminations towards the UE  156 B over a Uu interface associated with a second protocol stack. 
     The 5G-CN  152  was described as being configured to handle NR and 4G radio accesses. It will be appreciated by one of ordinary skill in the art that it may be possible for NR to connect to a 4G core network in a mode known as “non-standalone operation.” In non-standalone operation, a 4G core network is used to provide (or at least support) control-plane functionality (e.g., initial access, mobility, and paging). Although only one AMF/UPF  158  is shown in  FIG. 1B , one gNB or ng-eNB may be connected to multiple AMF/UPF nodes to provide redundancy and/or to load share across the multiple AMF/UPF nodes. 
     As discussed, an interface (e.g., Uu, Xn, and NG interfaces) between the network elements in  FIG. 1B  may be associated with a protocol stack that the network elements use to exchange data and signaling messages. A protocol stack may include two planes: a user plane and a control plane. The user plane may handle data of interest to a user, and the control plane may handle signaling messages of interest to the network elements. 
       FIG. 2A  and  FIG. 2B  respectively illustrate examples of NR user plane and NR control plane protocol stacks for the Uu interface that lies between a UE  210  and a gNB  220 . The protocol stacks illustrated in  FIG. 2A  and  FIG. 2B  may be the same or similar to those used for the Uu interface between, for example, the UE  156 A and the gNB  160 A shown in  FIG. 1B . 
       FIG. 2A  illustrates a NR user plane protocol stack comprising five layers implemented in the UE  210  and the gNB  220 . At the bottom of the protocol stack, physical layers (PHYs)  211  and  221  may provide transport services to the higher layers of the protocol stack and may correspond to layer 1 of the Open Systems Interconnection (OSI) model. The next four protocols above PHYs  211  and  221  comprise media access control layers (MACs)  212  and  222 , radio link control layers (RLCs)  213  and  223 , packet data convergence protocol layers (PDCPs)  214  and  224 , and service data application protocol layers (SDAPs)  215  and  225 . Together, these four protocols may make up layer 2, or the data link layer, of the OSI model. 
       FIG. 3  illustrates an example of services provided between protocol layers of the NR user plane protocol stack. Starting from the top of  FIG. 2A  and  FIG. 3 , the SDAPs  215  and  225  may perform QoS flow handling. The UE  210  may receive services through a PDU session, which may be a logical connection between the UE  210  and a DN. The PDU session may have one or more QoS flows. A UPF of a CN (e.g., the UPF  158 B) may map IP packets to the one or more QoS flows of the PDU session based on QoS requirements (e.g., in terms of delay, data rate, and/or error rate). The SDAPs  215  and  225  may perform mapping/de-mapping between the one or more QoS flows and one or more data radio bearers. The mapping/de-mapping between the QoS flows and the data radio bearers may be determined by the SDAP  225  at the gNB  220 . The SDAP  215  at the UE  210  may be informed of the mapping between the QoS flows and the data radio bearers through reflective mapping or control signaling received from the gNB  220 . For reflective mapping, the SDAP  225  at the gNB  220  may mark the downlink packets with a QoS flow indicator (QFI), which may be observed by the SDAP  215  at the UE  210  to determine the mapping/de-mapping between the QoS flows and the data radio bearers. 
     The PDCPs  214  and  224  may perform header compression/decompression to reduce the amount of data that needs to be transmitted over the air interface, ciphering/deciphering to prevent unauthorized decoding of data transmitted over the air interface, and integrity protection (to ensure control messages originate from intended sources. The PDCPs  214  and  224  may perform retransmissions of undelivered packets, in-sequence delivery and reordering of packets, and removal of packets received in duplicate due to, for example, an intra-gNB handover. The PDCPs  214  and  224  may perform packet duplication to improve the likelihood of the packet being received and, at the receiver, remove any duplicate packets. Packet duplication may be useful for services that require high reliability. 
     Although not shown in  FIG. 3 , PDCPs  214  and  224  may perform mapping/de-mapping between a split radio bearer and RLC channels in a dual connectivity scenario. Dual connectivity is a technique that allows a UE to connect to two cells or, more generally, two cell groups: a master cell group (MCG) and a secondary cell group (SCG). A split bearer is when a single radio bearer, such as one of the radio bearers provided by the PDCPs  214  and  224  as a service to the SDAPs  215  and  225 , is handled by cell groups in dual connectivity. The PDCPs  214  and  224  may map/de-map the split radio bearer between RLC channels belonging to cell groups. 
     The RLCs  213  and  223  may perform segmentation, retransmission through Automatic Repeat Request (ARQ), and removal of duplicate data units received from MACs  212  and  222 , respectively. The RLCs  213  and  223  may support three transmission modes: transparent mode (TM); unacknowledged mode (UM); and acknowledged mode (AM). Based on the transmission mode an RLC is operating, the RLC may perform one or more of the noted functions. The RLC configuration may be per logical channel with no dependency on numerologies and/or Transmission Time Interval (TTI) durations. As shown in  FIG. 3 , the RLCs  213  and  223  may provide RLC channels as a service to PDCPs  214  and  224 , respectively. 
     The MACs  212  and  222  may perform multiplexing/demultiplexing of logical channels and/or mapping between logical channels and transport channels. The multiplexing/demultiplexing may include multiplexing/demultiplexing of data units, belonging to the one or more logical channels, into/from Transport Blocks (TB s) delivered to/from the PHYs  211  and  221 . The MAC  222  may be configured to perform scheduling, scheduling information reporting, and priority handling between UEs by means of dynamic scheduling. Scheduling may be performed in the gNB  220  (at the MAC  222 ) for downlink and uplink. The MACs  212  and  222  may be configured to perform error correction through Hybrid Automatic Repeat Request (HARQ) (e.g., one HARQ entity per carrier in case of Carrier Aggregation (CA)), priority handling between logical channels of the UE  210  by means of logical channel prioritization, and/or padding. The MACs  212  and  222  may support one or more numerologies and/or transmission timings. In an example, mapping restrictions in a logical channel prioritization may control which numerology and/or transmission timing a logical channel may use. As shown in  FIG. 3 , the MACs  212  and  222  may provide logical channels as a service to the RLCs  213  and  223 . 
     The PHYs  211  and  221  may perform mapping of transport channels to physical channels and digital and analog signal processing functions for sending and receiving information over the air interface. These digital and analog signal processing functions may include, for example, coding/decoding and modulation/demodulation. The PHYs  211  and  221  may perform multi-antenna mapping. As shown in  FIG. 3 , the PHYs  211  and  221  may provide one or more transport channels as a service to the MACs  212  and  222 . 
       FIG. 4A  illustrates an example downlink data flow through the NR user plane protocol stack.  FIG. 4A  illustrates a downlink data flow of three IP packets (n, n+1, and m) through the NR user plane protocol stack to generate two TBs at the gNB  220 . An uplink data flow through the NR user plane protocol stack may be similar to the downlink data flow depicted in  FIG. 4A . 
     The downlink data flow of  FIG. 4A  begins when SDAP  225  receives the three IP packets from one or more QoS flows and maps the three packets to radio bearers. In  FIG. 4A , the SDAP  225  maps IP packets n and n+1 to a first radio bearer  402  and maps IP packet m to a second radio bearer  404 . An SDAP header (labeled with an “H” in  FIG. 4A ) is added to an IP packet. The data unit from/to a higher protocol layer is referred to as a service data unit (SDU) of the lower protocol layer and the data unit to/from a lower protocol layer is referred to as a protocol data unit (PDU) of the higher protocol layer. As shown in  FIG. 4A , the data unit from the SDAP  225  is an SDU of lower protocol layer PDCP  224  and is a PDU of the SDAP  225 . 
     The remaining protocol layers in  FIG. 4A  may perform their associated functionality (e.g., with respect to  FIG. 3 ), add corresponding headers, and forward their respective outputs to the next lower layer. For example, the PDCP  224  may perform IP-header compression and ciphering and forward its output to the RLC  223 . The RLC  223  may optionally perform segmentation (e.g., as shown for IP packet m in  FIG. 4A ) and forward its output to the MAC  222 . The MAC  222  may multiplex a number of RLC PDUs and may attach a MAC subheader to an RLC PDU to form a transport block. In NR, the MAC subheaders may be distributed across the MAC PDU, as illustrated in  FIG. 4A . In LTE, the MAC subheaders may be entirely located at the beginning of the MAC PDU. The NR MAC PDU structure may reduce processing time and associated latency because the MAC PDU subheaders may be computed before the full MAC PDU is assembled. 
       FIG. 4B  illustrates an example format of a MAC subheader in a MAC PDU. The MAC subheader includes: an SDU length field for indicating the length (e.g., in bytes) of the MAC SDU to which the MAC subheader corresponds; a logical channel identifier (LCID) field for identifying the logical channel from which the MAC SDU originated to aid in the demultiplexing process; a flag (F) for indicating the size of the SDU length field; and a reserved bit (R) field for future use. 
       FIG. 4B  further illustrates MAC control elements (CEs) inserted into the MAC PDU by a MAC, such as MAC  223  or MAC  222 . For example,  FIG. 4B  illustrates two MAC CEs inserted into the MAC PDU. MAC CEs may be inserted at the beginning of a MAC PDU for downlink transmissions (as shown in  FIG. 4B ) and at the end of a MAC PDU for uplink transmissions. MAC CEs may be used for in-band control signaling. Example MAC CEs include: scheduling-related MAC CEs, such as buffer status reports and power headroom reports; activation/deactivation MAC CEs, such as those for activation/deactivation of PDCP duplication detection, channel state information (CSI) reporting, sounding reference signal (SRS) transmission, and prior configured components; discontinuous reception (DRX) related MAC CEs; timing advance MAC CEs; and random access related MAC CEs. A MAC CE may be preceded by a MAC subheader with a similar format as described for MAC SDUs and may be identified with a reserved value in the LCID field that indicates the type of control information included in the MAC CE. 
     Before describing the NR control plane protocol stack, logical channels, transport channels, and physical channels are first described as well as a mapping between the channel types. One or more of the channels may be used to carry out functions associated with the NR control plane protocol stack described later below. 
       FIG. 5A  and  FIG. 5B  illustrate, for downlink and uplink respectively, a mapping between logical channels, transport channels, and physical channels. Information is passed through channels between the RLC, the MAC, and the PHY of the NR protocol stack. A logical channel may be used between the RLC and the MAC and may be classified as a control channel that carries control and configuration information in the NR control plane or as a traffic channel that carries data in the NR user plane. A logical channel may be classified as a dedicated logical channel that is dedicated to a specific UE or as a common logical channel that may be used by more than one UE. A logical channel may also be defined by the type of information it carries. The set of logical channels defined by NR include, for example:
         a paging control channel (PCCH) for carrying paging messages used to page a UE whose location is not known to the network on a cell level;   a broadcast control channel (BCCH) for carrying system information messages in the form of a master information block (MIB) and several system information blocks (SIBs), wherein the system information messages may be used by the UEs to obtain information about how a cell is configured and how to operate within the cell;   a common control channel (CCCH) for carrying control messages together with random access;   a dedicated control channel (DCCH) for carrying control messages to/from a specific the UE to configure the UE; and   a dedicated traffic channel (DTCH) for carrying user data to/from a specific the UE.       

     Transport channels are used between the MAC and PHY layers and may be defined by how the information they carry is transmitted over the air interface. The set of transport channels defined by NR include, for example:
         a paging channel (PCH) for carrying paging messages that originated from the PCCH;   a broadcast channel (BCH) for carrying the MIB from the BCCH;   a downlink shared channel (DL-SCH) for carrying downlink data and signaling messages, including the SIBs from the BCCH;   an uplink shared channel (UL-SCH) for carrying uplink data and signaling messages; and   a random access channel (RACH) for allowing a UE to contact the network without any prior scheduling.       

     The PHY may use physical channels to pass information between processing levels of the PHY. A physical channel may have an associated set of time-frequency resources for carrying the information of one or more transport channels. The PHY may generate control information to support the low-level operation of the PHY and provide the control information to the lower levels of the PHY via physical control channels, known as L1/L2 control channels. The set of physical channels and physical control channels defined by NR include, for example:
         a physical broadcast channel (PBCH) for carrying the MIB from the BCH;   a physical downlink shared channel (PDSCH) for carrying downlink data and signaling messages from the DL-SCH, as well as paging messages from the PCH;   a physical downlink control channel (PDCCH) for carrying downlink control information (DCI), which may include downlink scheduling commands, uplink scheduling grants, and uplink power control commands;   a physical uplink shared channel (PUSCH) for carrying uplink data and signaling messages from the UL-SCH and in some instances uplink control information (UCI) as described below;   a physical uplink control channel (PUCCH) for carrying UCI, which may include HARQ acknowledgments, channel quality indicators (CQI), pre-coding matrix indicators (PMI), rank indicators (RI), and scheduling requests (SR); and   a physical random access channel (PRACH) for random access.       

     Similar to the physical control channels, the physical layer generates physical signals to support the low-level operation of the physical layer. As shown in  FIG. 5A  and  FIG. 5B , the physical layer signals defined by NR include: primary synchronization signals (PSS), secondary synchronization signals (SSS), channel state information reference signals (CSI-RS), demodulation reference signals (DMRS), sounding reference signals (SRS), and phase-tracking reference signals (PT-RS). These physical layer signals will be described in greater detail below. 
       FIG. 2B  illustrates an example NR control plane protocol stack. As shown in  FIG. 2B , the NR control plane protocol stack may use the same/similar first four protocol layers as the example NR user plane protocol stack. These four protocol layers include the PHYs  211  and  221 , the MACs  212  and  222 , the RLCs  213  and  223 , and the PDCPs  214  and  224 . Instead of having the SDAPs  215  and  225  at the top of the stack as in the NR user plane protocol stack, the NR control plane stack has radio resource controls (RRCs)  216  and  226  and NAS protocols  217  and  237  at the top of the NR control plane protocol stack. 
     The NAS protocols  217  and  237  may provide control plane functionality between the UE  210  and the AMF  230  (e.g., the AMF  158 A) or, more generally, between the UE  210  and the CN. The NAS protocols  217  and  237  may provide control plane functionality between the UE  210  and the AMF  230  via signaling messages, referred to as NAS messages. There is no direct path between the UE  210  and the AMF  230  through which the NAS messages can be transported. The NAS messages may be transported using the AS of the Uu and NG interfaces. NAS protocols  217  and  237  may provide control plane functionality such as authentication, security, connection setup, mobility management, and session management. 
     The RRCs  216  and  226  may provide control plane functionality between the UE  210  and the gNB  220  or, more generally, between the UE  210  and the RAN. The RRCs  216  and  226  may provide control plane functionality between the UE  210  and the gNB  220  via signaling messages, referred to as RRC messages. RRC messages may be transmitted between the UE  210  and the RAN using signaling radio bearers and the same/similar PDCP, RLC, MAC, and PHY protocol layers. The MAC may multiplex control-plane and user-plane data into the same transport block (TB). The RRCs  216  and  226  may provide control plane functionality such as: broadcast of system information related to AS and NAS; paging initiated by the CN or the RAN; establishment, maintenance and release of an RRC connection between the UE  210  and the RAN; security functions including key management; establishment, configuration, maintenance and release of signaling radio bearers and data radio bearers; mobility functions; QoS management functions; the UE measurement reporting and control of the reporting; detection of and recovery from radio link failure (RLF); and/or NAS message transfer. As part of establishing an RRC connection, RRCs  216  and  226  may establish an RRC context, which may involve configuring parameters for communication between the UE  210  and the RAN. 
       FIG. 6  is an example diagram showing RRC state transitions of a UE. The UE may be the same or similar to the wireless device  106  depicted in  FIG. 1A , the UE  210  depicted in  FIG. 2A  and  FIG. 2B , or any other wireless device described in the present disclosure. As illustrated in  FIG. 6 , a UE may be in at least one of three RRC states: RRC connected  602  (e.g., RRC_CONNECTED), RRC idle  604  (e.g., RRC_IDLE), and RRC inactive  606  (e.g., RRC_INACTIVE). 
     In RRC connected  602 , the UE has an established RRC context and may have at least one RRC connection with a base station. The base station may be similar to one of the one or more base stations included in the RAN  104  depicted in  FIG. 1A , one of the gNBs  160  or ng-eNBs  162  depicted in  FIG. 1B , the gNB  220  depicted in  FIG. 2A  and  FIG. 2B , or any other base station described in the present disclosure. The base station with which the UE is connected may have the RRC context for the UE. The RRC context, referred to as the UE context, may comprise parameters for communication between the UE and the base station. These parameters may include, for example: one or more AS contexts; one or more radio link configuration parameters; bearer configuration information (e.g., relating to a data radio bearer, signaling radio bearer, logical channel, QoS flow, and/or PDU session); security information; and/or PHY, MAC, RLC, PDCP, and/or SDAP layer configuration information. While in RRC connected  602 , mobility of the UE may be managed by the RAN (e.g., the RAN  104  or the NG-RAN  154 ). The UE may measure the signal levels (e.g., reference signal levels) from a serving cell and neighboring cells and report these measurements to the base station currently serving the UE. The UE&#39;s serving base station may request a handover to a cell of one of the neighboring base stations based on the reported measurements. The RRC state may transition from RRC connected  602  to RRC idle  604  through a connection release procedure  608  or to RRC inactive  606  through a connection inactivation procedure  610 . 
     In RRC idle  604 , an RRC context may not be established for the UE. In RRC idle  604 , the UE may not have an RRC connection with the base station. While in RRC idle  604 , the UE may be in a sleep state for the majority of the time (e.g., to conserve battery power). The UE may wake up periodically (e.g., once in every discontinuous reception cycle) to monitor for paging messages from the RAN. Mobility of the UE may be managed by the UE through a procedure known as cell reselection. The RRC state may transition from RRC idle  604  to RRC connected  602  through a connection establishment procedure  612 , which may involve a random access procedure as discussed in greater detail below. 
     In RRC inactive  606 , the RRC context previously established is maintained in the UE and the base station. This allows for a fast transition to RRC connected  602  with reduced signaling overhead as compared to the transition from RRC idle  604  to RRC connected  602 . While in RRC inactive  606 , the UE may be in a sleep state and mobility of the UE may be managed by the UE through cell reselection. The RRC state may transition from RRC inactive  606  to RRC connected  602  through a connection resume procedure  614  or to RRC idle  604  though a connection release procedure  616  that may be the same as or similar to connection release procedure  608 . 
     An RRC state may be associated with a mobility management mechanism. In RRC idle  604  and RRC inactive  606 , mobility is managed by the UE through cell reselection. The purpose of mobility management in RRC idle  604  and RRC inactive  606  is to allow the network to be able to notify the UE of an event via a paging message without having to broadcast the paging message over the entire mobile communications network. The mobility management mechanism used in RRC idle  604  and RRC inactive  606  may allow the network to track the UE on a cell-group level so that the paging message may be broadcast over the cells of the cell group that the UE currently resides within instead of the entire mobile communication network. The mobility management mechanisms for RRC idle  604  and RRC inactive  606  track the UE on a cell-group level. They may do so using different granularities of grouping. For example, there may be three levels of cell-grouping granularity: individual cells; cells within a RAN area identified by a RAN area identifier (RAI); and cells within a group of RAN areas, referred to as a tracking area and identified by a tracking area identifier (TAI). 
     Tracking areas may be used to track the UE at the CN level. The CN (e.g., the CN  102  or the 5G-CN  152 ) may provide the UE with a list of TAIs associated with a UE registration area. If the UE moves, through cell reselection, to a cell associated with a TAI not included in the list of TAIs associated with the UE registration area, the UE may perform a registration update with the CN to allow the CN to update the UE&#39;s location and provide the UE with a new the UE registration area. 
     RAN areas may be used to track the UE at the RAN level. For a UE in RRC inactive  606  state, the UE may be assigned a RAN notification area. A RAN notification area may comprise one or more cell identities, a list of RAIs, or a list of TAIs. In an example, a base station may belong to one or more RAN notification areas. In an example, a cell may belong to one or more RAN notification areas. If the UE moves, through cell reselection, to a cell not included in the RAN notification area assigned to the UE, the UE may perform a notification area update with the RAN to update the UE&#39;s RAN notification area. 
     A base station storing an RRC context for a UE or a last serving base station of the UE may be referred to as an anchor base station. An anchor base station may maintain an RRC context for the UE at least during a period of time that the UE stays in a RAN notification area of the anchor base station and/or during a period of time that the UE stays in RRC inactive  606 . 
     A gNB, such as gNBs  160  in  FIG. 1B , may be split in two parts: a central unit (gNB-CU), and one or more distributed units (gNB-DU). A gNB-CU may be coupled to one or more gNB-DUs using an F1 interface. The gNB-CU may comprise the RRC, the PDCP, and the SDAP. A gNB-DU may comprise the RLC, the MAC, and the PHY. 
     In NR, the physical signals and physical channels (discussed with respect to  FIG. 5A  and  FIG. 5B ) may be mapped onto orthogonal frequency divisional multiplexing (OFDM) symbols. OFDM is a multicarrier communication scheme that transmits data over F orthogonal subcarriers (or tones). Before transmission, the data may be mapped to a series of complex symbols (e.g., M-quadrature amplitude modulation (M-QAM) or M-phase shift keying (M-PSK) symbols), referred to as source symbols, and divided into F parallel symbol streams. The F parallel symbol streams may be treated as though they are in the frequency domain and used as inputs to an Inverse Fast Fourier Transform (IFFT) block that transforms them into the time domain. The IFFT block may take in F source symbols at a time, one from each of the F parallel symbol streams, and use each source symbol to modulate the amplitude and phase of one of F sinusoidal basis functions that correspond to the F orthogonal subcarriers. The output of the IFFT block may be F time-domain samples that represent the summation of the F orthogonal subcarriers. The F time-domain samples may form a single OFDM symbol. After some processing (e.g., addition of a cyclic prefix) and up-conversion, an OFDM symbol provided by the IFFT block may be transmitted over the air interface on a carrier frequency. The F parallel symbol streams may be mixed using an FFT block before being processed by the IFFT block. This operation produces Discrete Fourier Transform (DFT)-precoded OFDM symbols and may be used by UEs in the uplink to reduce the peak to average power ratio (PAPR). Inverse processing may be performed on the OFDM symbol at a receiver using an FFT block to recover the data mapped to the source symbols. 
       FIG. 7  illustrates an example configuration of an NR frame into which OFDM symbols are grouped. An NR frame may be identified by a system frame number (SFN). The SFN may repeat with a period of 1024 frames. As illustrated, one NR frame may be 10 milliseconds (ms) in duration and may include 10 subframes that are 1 ms in duration. A subframe may be divided into slots that include, for example, 14 OFDM symbols per slot. 
     The duration of a slot may depend on the numerology used for the OFDM symbols of the slot. In NR, a flexible numerology is supported to accommodate different cell deployments (e.g., cells with carrier frequencies below 1 GHz up to cells with carrier frequencies in the mm-wave range). A numerology may be defined in terms of subcarrier spacing and cyclic prefix duration. For a numerology in NR, subcarrier spacings may be scaled up by powers of two from a baseline subcarrier spacing of 15 kHz, and cyclic prefix durations may be scaled down by powers of two from a baseline cyclic prefix duration of 4.7 μs. For example, NR defines numerologies with the following subcarrier spacing/cyclic prefix duration combinations: 15 kHz/4.7 μs; 30 kHz/2.3 μs; 60 kHz/1.2 μs; 120 kHz/0.59 μs; and 240 kHz/0.29 μs. 
     A slot may have a fixed number of OFDM symbols (e.g., 14 OFDM symbols). A numerology with a higher subcarrier spacing has a shorter slot duration and, correspondingly, more slots per subframe.  FIG. 7  illustrates this numerology-dependent slot duration and slots-per-subframe transmission structure (the numerology with a subcarrier spacing of 240 kHz is not shown in  FIG. 7  for ease of illustration). A subframe in NR may be used as a numerology-independent time reference, while a slot may be used as the unit upon which uplink and downlink transmissions are scheduled. To support low latency, scheduling in NR may be decoupled from the slot duration and start at any OFDM symbol and last for as many symbols as needed for a transmission. These partial slot transmissions may be referred to as mini-slot or subslot transmissions. 
       FIG. 8  illustrates an example configuration of a slot in the time and frequency domain for an NR carrier. The slot includes resource elements (REs) and resource blocks (RBs). An RE is the smallest physical resource in NR. An RE spans one OFDM symbol in the time domain by one subcarrier in the frequency domain as shown in  FIG. 8 . An RB spans twelve consecutive REs in the frequency domain as shown in  FIG. 8 . An NR carrier may be limited to a width of 275 RBs or 275×12=3300 subcarriers. Such a limitation, if used, may limit the NR carrier to 50, 100, 200, and 400 MHz for subcarrier spacings of 15, 30, 60, and 120 kHz, respectively, where the 400 MHz bandwidth may be set based on a 400 MHz per carrier bandwidth limit. 
       FIG. 8  illustrates a single numerology being used across the entire bandwidth of the NR carrier. In other example configurations, multiple numerologies may be supported on the same carrier. 
     NR may support wide carrier bandwidths (e.g., up to 400 MHz for a subcarrier spacing of 120 kHz). Not all UEs may be able to receive the full carrier bandwidth (e.g., due to hardware limitations). Also, receiving the full carrier bandwidth may be prohibitive in terms of UE power consumption. In an example, to reduce power consumption and/or for other purposes, a UE may adapt the size of the UE&#39;s receive bandwidth based on the amount of traffic the UE is scheduled to receive. This is referred to as bandwidth adaptation. 
     NR defines bandwidth parts (BWPs) to support UEs not capable of receiving the full carrier bandwidth and to support bandwidth adaptation. In an example, a BWP may be defined by a subset of contiguous RBs on a carrier. A UE may be configured (e.g., via RRC layer) with one or more downlink BWPs and one or more uplink BWPs per serving cell (e.g., up to four downlink BWPs and up to four uplink BWPs per serving cell). At a given time, one or more of the configured BWPs for a serving cell may be active. These one or more BWPs may be referred to as active BWPs of the serving cell. When a serving cell is configured with a secondary uplink carrier, the serving cell may have one or more first active BWPs in the uplink carrier and one or more second active BWPs in the secondary uplink carrier. 
     For unpaired spectra, a downlink BWP from a set of configured downlink BWPs may be linked with an uplink BWP from a set of configured uplink BWPs if a downlink BWP index of the downlink BWP and an uplink BWP index of the uplink BWP are the same. For unpaired spectra, a UE may expect that a center frequency for a downlink BWP is the same as a center frequency for an uplink BWP. 
     For a downlink BWP in a set of configured downlink BWPs on a primary cell (PCell), a base station may configure a UE with one or more control resource sets (CORESETs) for at least one search space. A search space is a set of locations in the time and frequency domains where the UE may find control information. The search space may be a UE-specific search space or a common search space (potentially usable by a plurality of UEs). For example, a base station may configure a UE with a common search space, on a PCell or on a primary secondary cell (PSCell), in an active downlink BWP. 
     For an uplink BWP in a set of configured uplink BWPs, a BS may configure a UE with one or more resource sets for one or more PUCCH transmissions. A UE may receive downlink receptions (e.g., PDCCH or PDSCH) in a downlink BWP according to a configured numerology (e.g., subcarrier spacing and cyclic prefix duration) for the downlink BWP. The UE may transmit uplink transmissions (e.g., PUCCH or PUSCH) in an uplink BWP according to a configured numerology (e.g., subcarrier spacing and cyclic prefix length for the uplink BWP). 
     One or more BWP indicator fields may be provided in Downlink Control Information (DCI). A value of a BWP indicator field may indicate which BWP in a set of configured BWPs is an active downlink BWP for one or more downlink receptions. The value of the one or more BWP indicator fields may indicate an active uplink BWP for one or more uplink transmissions. 
     A base station may semi-statically configure a UE with a default downlink BWP within a set of configured downlink BWPs associated with a PCell. If the base station does not provide the default downlink BWP to the UE, the default downlink BWP may be an initial active downlink BWP. The UE may determine which BWP is the initial active downlink BWP based on a CORESET configuration obtained using the PBCH. 
     A base station may configure a UE with a BWP inactivity timer value for a PCell. The UE may start or restart a BWP inactivity timer at any appropriate time. For example, the UE may start or restart the BWP inactivity timer (a) when the UE detects a DCI indicating an active downlink BWP other than a default downlink BWP for a paired spectra operation; or (b) when a UE detects a DCI indicating an active downlink BWP or active uplink BWP other than a default downlink BWP or uplink BWP for an unpaired spectra operation. If the UE does not detect DCI during an interval of time (e.g., 1 ms or 0.5 ms), the UE may run the BWP inactivity timer toward expiration (for example, increment from zero to the BWP inactivity timer value, or decrement from the BWP inactivity timer value to zero). When the BWP inactivity timer expires, the UE may switch from the active downlink BWP to the default downlink BWP. 
     In an example, a base station may semi-statically configure a UE with one or more BWPs. A UE may switch an active BWP from a first BWP to a second BWP in response to receiving a DCI indicating the second BWP as an active BWP and/or in response to an expiry of the BWP inactivity timer (e.g., if the second BWP is the default BWP). 
     Downlink and uplink BWP switching (where BWP switching refers to switching from a currently active BWP to a not currently active BWP) may be performed independently in paired spectra. In unpaired spectra, downlink and uplink BWP switching may be performed simultaneously. Switching between configured BWPs may occur based on RRC signaling, DCI, expiration of a BWP inactivity timer, and/or an initiation of random access. 
       FIG. 9  illustrates an example of bandwidth adaptation using three configured BWPs for an NR carrier. A UE configured with the three BWPs may switch from one BWP to another BWP at a switching point. In the example illustrated in  FIG. 9 , the BWPs include: a BWP  902  with a bandwidth of 40 MHz and a subcarrier spacing of 15 kHz; a BWP  904  with a bandwidth of 10 MHz and a subcarrier spacing of 15 kHz; and a BWP  906  with a bandwidth of 20 MHz and a subcarrier spacing of 60 kHz. The BWP  902  may be an initial active BWP, and the BWP  904  may be a default BWP. The UE may switch between BWPs at switching points. In the example of  FIG. 9 , the UE may switch from the BWP  902  to the BWP  904  at a switching point  908 . The switching at the switching point  908  may occur for any suitable reason, for example, in response to an expiry of a BWP inactivity timer (indicating switching to the default BWP) and/or in response to receiving a DCI indicating BWP  904  as the active BWP. The UE may switch at a switching point  910  from active BWP  904  to BWP  906  in response receiving a DCI indicating BWP  906  as the active BWP. The UE may switch at a switching point  912  from active BWP  906  to BWP  904  in response to an expiry of a BWP inactivity timer and/or in response receiving a DCI indicating BWP  904  as the active BWP. The UE may switch at a switching point  914  from active BWP  904  to BWP  902  in response receiving a DCI indicating BWP  902  as the active BWP. 
     If a UE is configured for a secondary cell with a default downlink BWP in a set of configured downlink BWPs and a timer value, UE procedures for switching BWPs on a secondary cell may be the same/similar as those on a primary cell. For example, the UE may use the timer value and the default downlink BWP for the secondary cell in the same/similar manner as the UE would use these values for a primary cell. 
     To provide for greater data rates, two or more carriers can be aggregated and simultaneously transmitted to/from the same UE using carrier aggregation (CA). The aggregated carriers in CA may be referred to as component carriers (CCs). When CA is used, there are a number of serving cells for the UE, one for a CC. The CCs may have three configurations in the frequency domain. 
       FIG. 10A  illustrates the three CA configurations with two CCs. In the intraband, contiguous configuration  1002 , the two CCs are aggregated in the same frequency band (frequency band A) and are located directly adjacent to each other within the frequency band. In the intraband, non-contiguous configuration  1004 , the two CCs are aggregated in the same frequency band (frequency band A) and are separated in the frequency band by a gap. In the interband configuration  1006 , the two CCs are located in frequency bands (frequency band A and frequency band B). 
     In an example, up to 32 CCs may be aggregated. The aggregated CCs may have the same or different bandwidths, subcarrier spacing, and/or duplexing schemes (TDD or FDD). A serving cell for a UE using CA may have a downlink CC. For FDD, one or more uplink CCs may be optionally configured for a serving cell. The ability to aggregate more downlink carriers than uplink carriers may be useful, for example, when the UE has more data traffic in the downlink than in the uplink. 
     When CA is used, one of the aggregated cells for a UE may be referred to as a primary cell (PCell). The PCell may be the serving cell that the UE initially connects to at RRC connection establishment, reestablishment, and/or handover. The PCell may provide the UE with NAS mobility information and the security input. UEs may have different PCells. In the downlink, the carrier corresponding to the PCell may be referred to as the downlink primary CC (DL PCC). In the uplink, the carrier corresponding to the PCell may be referred to as the uplink primary CC (UL PCC). The other aggregated cells for the UE may be referred to as secondary cells (SCells). In an example, the SCells may be configured after the PCell is configured for the UE. For example, an SCell may be configured through an RRC Connection Reconfiguration procedure. In the downlink, the carrier corresponding to an SCell may be referred to as a downlink secondary CC (DL SCC). In the uplink, the carrier corresponding to the SCell may be referred to as the uplink secondary CC (UL SCC). 
     Configured SCells for a UE may be activated and deactivated based on, for example, traffic and channel conditions. Deactivation of an SCell may mean that PDCCH and PDSCH reception on the SCell is stopped and PUSCH, SRS, and CQI transmissions on the SCell are stopped. Configured SCells may be activated and deactivated using a MAC CE with respect to  FIG. 4B . For example, a MAC CE may use a bitmap (e.g., one bit per SCell) to indicate which SCells (e.g., in a subset of configured SCells) for the UE are activated or deactivated. Configured SCells may be deactivated in response to an expiration of an SCell deactivation timer (e.g., one SCell deactivation timer per SCell). 
     Downlink control information, such as scheduling assignments and scheduling grants, for a cell may be transmitted on the cell corresponding to the assignments and grants, which is known as self-scheduling. The DCI for the cell may be transmitted on another cell, which is known as cross-carrier scheduling. Uplink control information (e.g., HARQ acknowledgments and channel state feedback, such as CQI, PMI, and/or RI) for aggregated cells may be transmitted on the PUCCH of the PCell. For a larger number of aggregated downlink CCs, the PUCCH of the PCell may become overloaded. Cells may be divided into multiple PUCCH groups. 
       FIG. 10B  illustrates an example of how aggregated cells may be configured into one or more PUCCH groups. A PUCCH group  1010  and a PUCCH group  1050  may include one or more downlink CCs, respectively. In the example of  FIG. 10B , the PUCCH group  1010  includes three downlink CCs: a PCell  1011 , an SCell  1012 , and an SCell  1013 . The PUCCH group  1050  includes three downlink CCs in the present example: a PCell  1051 , an SCell  1052 , and an SCell  1053 . One or more uplink CCs may be configured as a PCell  1021 , an SCell  1022 , and an SCell  1023 . One or more other uplink CCs may be configured as a primary Scell (PSCell)  1061 , an SCell  1062 , and an SCell  1063 . Uplink control information (UCI) related to the downlink CCs of the PUCCH group  1010 , shown as UCI  1031 , UCI  1032 , and UCI  1033 , may be transmitted in the uplink of the PCell  1021 . Uplink control information (UCI) related to the downlink CCs of the PUCCH group  1050 , shown as UCI  1071 , UCI  1072 , and UCI  1073 , may be transmitted in the uplink of the PSCell  1061 . In an example, if the aggregated cells depicted in  FIG. 10B  were not divided into the PUCCH group  1010  and the PUCCH group  1050 , a single uplink PCell to transmit UCI relating to the downlink CCs, and the PCell may become overloaded. By dividing transmissions of UCI between the PCell  1021  and the PSCell  1061 , overloading may be prevented. 
     A cell, comprising a downlink carrier and optionally an uplink carrier, may be assigned with a physical cell ID and a cell index. The physical cell ID or the cell index may identify a downlink carrier and/or an uplink carrier of the cell, for example, depending on the context in which the physical cell ID is used. A physical cell ID may be determined using a synchronization signal transmitted on a downlink component carrier. A cell index may be determined using RRC messages. In the disclosure, a physical cell ID may be referred to as a carrier ID, and a cell index may be referred to as a carrier index. For example, when the disclosure refers to a first physical cell ID for a first downlink carrier, the disclosure may mean the first physical cell ID is for a cell comprising the first downlink carrier. The same/similar concept may apply to, for example, a carrier activation. When the disclosure indicates that a first carrier is activated, the specification may mean that a cell comprising the first carrier is activated. 
     In CA, a multi-carrier nature of a PHY may be exposed to a MAC. In an example, a HARQ entity may operate on a serving cell. A transport block may be generated per assignment/grant per serving cell. A transport block and potential HARQ retransmissions of the transport block may be mapped to a serving cell. 
     In the downlink, a base station may transmit (e.g., unicast, multicast, and/or broadcast) one or more Reference Signals (RSs) to a UE (e.g., PSS, SSS, CSI-RS, DMRS, and/or PT-RS, as shown in  FIG. 5A ). In the uplink, the UE may transmit one or more RSs to the base station (e.g., DMRS, PT-RS, and/or SRS, as shown in  FIG. 5B ). The PSS and the SSS may be transmitted by the base station and used by the UE to synchronize the UE to the base station. The PSS and the SSS may be provided in a synchronization signal (SS)/physical broadcast channel (PBCH) block that includes the PSS, the SSS, and the PBCH. The base station may periodically transmit a burst of SS/PBCH blocks. 
       FIG. 11A  illustrates an example of an SS/PBCH block&#39;s structure and location. A burst of SS/PBCH blocks may include one or more SS/PBCH blocks (e.g., 4 SS/PBCH blocks, as shown in  FIG. 11A ). Bursts may be transmitted periodically (e.g., every 2 frames or 20 ms). A burst may be restricted to a half-frame (e.g., a first half-frame having a duration of 5 ms). It will be understood that  FIG. 11A  is an example, and that these parameters (number of SS/PBCH blocks per burst, periodicity of bursts, position of burst within the frame) may be configured based on, for example: a carrier frequency of a cell in which the SS/PBCH block is transmitted; a numerology or subcarrier spacing of the cell; a configuration by the network (e.g., using RRC signaling); or any other suitable factor. In an example, the UE may assume a subcarrier spacing for the SS/PBCH block based on the carrier frequency being monitored, unless the radio network configured the UE to assume a different subcarrier spacing. 
     The SS/PBCH block may span one or more OFDM symbols in the time domain (e.g., 4 OFDM symbols, as shown in the example of  FIG. 11A ) and may span one or more subcarriers in the frequency domain (e.g., 240 contiguous subcarriers). The PSS, the SSS, and the PBCH may have a common center frequency. The PSS may be transmitted first and may span, for example, 1 OFDM symbol and 127 subcarriers. The SSS may be transmitted after the PSS (e.g., two symbols later) and may span 1 OFDM symbol and 127 subcarriers. The PBCH may be transmitted after the PSS (e.g., across the next 3 OFDM symbols) and may span 240 subcarriers. 
     The location of the SS/PBCH block in the time and frequency domains may not be known to the UE (e.g., if the UE is searching for the cell). To find and select the cell, the UE may monitor a carrier for the PSS. For example, the UE may monitor a frequency location within the carrier. If the PSS is not found after a certain duration (e.g., 20 ms), the UE may search for the PSS at a different frequency location within the carrier, as indicated by a synchronization raster. If the PSS is found at a location in the time and frequency domains, the UE may determine, based on a known structure of the SS/PBCH block, the locations of the SSS and the PBCH, respectively. The SS/PBCH block may be a cell-defining SS block (CD-SSB). In an example, a primary cell may be associated with a CD-SSB. The CD-SSB may be located on a synchronization raster. In an example, a cell selection/search and/or reselection may be based on the CD-SSB. 
     The SS/PBCH block may be used by the UE to determine one or more parameters of the cell. For example, the UE may determine a physical cell identifier (PCI) of the cell based on the sequences of the PSS and the SSS, respectively. The UE may determine a location of a frame boundary of the cell based on the location of the SS/PBCH block. For example, the SS/PBCH block may indicate that it has been transmitted in accordance with a transmission pattern, wherein a SS/PBCH block in the transmission pattern is a known distance from the frame boundary. 
     The PBCH may use a QPSK modulation and may use forward error correction (FEC). The FEC may use polar coding. One or more symbols spanned by the PBCH may carry one or more DMRSs for demodulation of the PBCH. The PBCH may include an indication of a current system frame number (SFN) of the cell and/or a SS/PBCH block timing index. These parameters may facilitate time synchronization of the UE to the base station. The PBCH may include a master information block (MIB) used to provide the UE with one or more parameters. The MIB may be used by the UE to locate remaining minimum system information (RMSI) associated with the cell. The RMSI may include a System Information Block Type 1 (SIB1). The SIB1 may contain information needed by the UE to access the cell. The UE may use one or more parameters of the MIB to monitor PDCCH, which may be used to schedule PDSCH. The PDSCH may include the SIB  1 . The SIB1 may be decoded using parameters provided in the MIB. The PBCH may indicate an absence of SIB  1 . Based on the PBCH indicating the absence of SIB1, the UE may be pointed to a frequency. The UE may search for an SS/PBCH block at the frequency to which the UE is pointed. 
     The UE may assume that one or more SS/PBCH blocks transmitted with a same SS/PBCH block index are quasi co-located (QCLed) (e.g., having the same/similar Doppler spread, Doppler shift, average gain, average delay, and/or spatial Rx parameters). The UE may not assume QCL for SS/PBCH block transmissions having different SS/PBCH block indices. 
     SS/PBCH blocks (e.g., those within a half-frame) may be transmitted in spatial directions (e.g., using different beams that span a coverage area of the cell). In an example, a first SS/PBCH block may be transmitted in a first spatial direction using a first beam, and a second SS/PBCH block may be transmitted in a second spatial direction using a second beam. 
     In an example, within a frequency span of a carrier, a base station may transmit a plurality of SS/PBCH blocks. In an example, a first PCI of a first SS/PBCH block of the plurality of SS/PBCH blocks may be different from a second PCI of a second SS/PBCH block of the plurality of SS/PBCH blocks. The PCIs of SS/PBCH blocks transmitted in different frequency locations may be different or the same. 
     The CSI-RS may be transmitted by the base station and used by the UE to acquire channel state information (CSI). The base station may configure the UE with one or more CSI-RSs for channel estimation or any other suitable purpose. The base station may configure a UE with one or more of the same/similar CSI-RSs. The UE may measure the one or more CSI-RSs. The UE may estimate a downlink channel state and/or generate a CSI report based on the measuring of the one or more downlink CSI-RSs. The UE may provide the CSI report to the base station. The base station may use feedback provided by the UE (e.g., the estimated downlink channel state) to perform link adaptation. 
     The base station may semi-statically configure the UE with one or more CSI-RS resource sets. A CSI-RS resource may be associated with a location in the time and frequency domains and a periodicity. The base station may selectively activate and/or deactivate a CSI-RS resource. The base station may indicate to the UE that a CSI-RS resource in the CSI-RS resource set is activated and/or deactivated. 
     The base station may configure the UE to report CSI measurements. The base station may configure the UE to provide CSI reports periodically, aperiodically, or semi-persistently. For periodic CSI reporting, the UE may be configured with a timing and/or periodicity of a plurality of CSI reports. For aperiodic CSI reporting, the base station may request a CSI report. For example, the base station may command the UE to measure a configured CSI-RS resource and provide a CSI report relating to the measurements. For semi-persistent CSI reporting, the base station may configure the UE to transmit periodically, and selectively activate or deactivate the periodic reporting. The base station may configure the UE with a CSI-RS resource set and CSI reports using RRC signaling. 
     The CSI-RS configuration may comprise one or more parameters indicating, for example, up to 32 antenna ports. The UE may be configured to employ the same OFDM symbols for a downlink CSI-RS and a control resource set (CORESET) when the downlink CSI-RS and CORESET are spatially QCLed and resource elements associated with the downlink CSI-RS are outside of the physical resource blocks (PRBs) configured for the CORESET. The UE may be configured to employ the same OFDM symbols for downlink CSI-RS and SS/PBCH blocks when the downlink CSI-RS and SS/PBCH blocks are spatially QCLed and resource elements associated with the downlink CSI-RS are outside of PRBs configured for the SS/PBCH blocks. 
     Downlink DMRSs may be transmitted by a base station and used by a UE for channel estimation. For example, the downlink DMRS may be used for coherent demodulation of one or more downlink physical channels (e.g., PDSCH). An NR network may support one or more variable and/or configurable DMRS patterns for data demodulation. At least one downlink DMRS configuration may support a front-loaded DMRS pattern. A front-loaded DMRS may be mapped over one or more OFDM symbols (e.g., one or two adjacent OFDM symbols). A base station may semi-statically configure the UE with a number (e.g. a maximum number) of front-loaded DMRS symbols for PDSCH. A DMRS configuration may support one or more DMRS ports. For example, for single user-MIMO, a DMRS configuration may support up to eight orthogonal downlink DMRS ports per UE. For multiuser-MIMO, a DMRS configuration may support up to 4 orthogonal downlink DMRS ports per UE. A radio network may support (e.g., at least for CP-OFDM) a common DMRS structure for downlink and uplink, wherein a DMRS location, a DMRS pattern, and/or a scrambling sequence may be the same or different. The base station may transmit a downlink DMRS and a corresponding PDSCH using the same precoding matrix. The UE may use the one or more downlink DMRSs for coherent demodulation/channel estimation of the PDSCH. 
     In an example, a transmitter (e.g., a base station) may use a precoder matrices for a part of a transmission bandwidth. For example, the transmitter may use a first precoder matrix for a first bandwidth and a second precoder matrix for a second bandwidth. The first precoder matrix and the second precoder matrix may be different based on the first bandwidth being different from the second bandwidth. The UE may assume that a same precoding matrix is used across a set of PRBs. The set of PRBs may be denoted as a precoding resource block group (PRG). 
     A PDSCH may comprise one or more layers. The UE may assume that at least one symbol with DMRS is present on a layer of the one or more layers of the PDSCH. A higher layer may configure up to 3 DMRSs for the PDSCH. 
     Downlink PT-RS may be transmitted by a base station and used by a UE for phase-noise compensation. Whether a downlink PT-RS is present or not may depend on an RRC configuration. The presence and/or pattern of the downlink PT-RS may be configured on a UE-specific basis using a combination of RRC signaling and/or an association with one or more parameters employed for other purposes (e.g., modulation and coding scheme (MCS)), which may be indicated by DCI. When configured, a dynamic presence of a downlink PT-RS may be associated with one or more DCI parameters comprising at least MCS. An NR network may support a plurality of PT-RS densities defined in the time and/or frequency domains. When present, a frequency domain density may be associated with at least one configuration of a scheduled bandwidth. The UE may assume a same precoding for a DMRS port and a PT-RS port. A number of PT-RS ports may be fewer than a number of DMRS ports in a scheduled resource. Downlink PT-RS may be confined in the scheduled time/frequency duration for the UE. Downlink PT-RS may be transmitted on symbols to facilitate phase tracking at the receiver. 
     The UE may transmit an uplink DMRS to a base station for channel estimation. For example, the base station may use the uplink DMRS for coherent demodulation of one or more uplink physical channels. For example, the UE may transmit an uplink DMRS with a PUSCH and/or a PUCCH. The uplink DM-RS may span a range of frequencies that is similar to a range of frequencies associated with the corresponding physical channel. The base station may configure the UE with one or more uplink DMRS configurations. At least one DMRS configuration may support a front-loaded DMRS pattern. The front-loaded DMRS may be mapped over one or more OFDM symbols (e.g., one or two adjacent OFDM symbols). One or more uplink DMRSs may be configured to transmit at one or more symbols of a PUSCH and/or a PUCCH. The base station may semi-statically configure the UE with a number (e.g. maximum number) of front-loaded DMRS symbols for the PUSCH and/or the PUCCH, which the UE may use to schedule a single-symbol DMRS and/or a double-symbol DMRS. An NR network may support (e.g., for cyclic prefix orthogonal frequency division multiplexing (CP-OFDM)) a common DMRS structure for downlink and uplink, wherein a DMRS location, a DMRS pattern, and/or a scrambling sequence for the DMRS may be the same or different. 
     A PUSCH may comprise one or more layers, and the UE may transmit at least one symbol with DMRS present on a layer of the one or more layers of the PUSCH. In an example, a higher layer may configure up to three DMRSs for the PUSCH. 
     Uplink PT-RS (which may be used by a base station for phase tracking and/or phase-noise compensation) may or may not be present depending on an RRC configuration of the UE. The presence and/or pattern of uplink PT-RS may be configured on a UE-specific basis by a combination of RRC signaling and/or one or more parameters employed for other purposes (e.g., Modulation and Coding Scheme (MCS)), which may be indicated by DCI. When configured, a dynamic presence of uplink PT-RS may be associated with one or more DCI parameters comprising at least MCS. A radio network may support a plurality of uplink PT-RS densities defined in time/frequency domain. When present, a frequency domain density may be associated with at least one configuration of a scheduled bandwidth. The UE may assume a same precoding for a DMRS port and a PT-RS port. A number of PT-RS ports may be fewer than a number of DMRS ports in a scheduled resource. For example, uplink PT-RS may be confined in the scheduled time/frequency duration for the UE. 
     SRS may be transmitted by a UE to a base station for channel state estimation to support uplink channel dependent scheduling and/or link adaptation. SRS transmitted by the UE may allow a base station to estimate an uplink channel state at one or more frequencies. A scheduler at the base station may employ the estimated uplink channel state to assign one or more resource blocks for an uplink PUSCH transmission from the UE. The base station may semi-statically configure the UE with one or more SRS resource sets. For an SRS resource set, the base station may configure the UE with one or more SRS resources. An SRS resource set applicability may be configured by a higher layer (e.g., RRC) parameter. For example, when a higher layer parameter indicates beam management, an SRS resource in a SRS resource set of the one or more SRS resource sets (e.g., with the same/similar time domain behavior, periodic, aperiodic, and/or the like) may be transmitted at a time instant (e.g., simultaneously). The UE may transmit one or more SRS resources in SRS resource sets. An NR network may support aperiodic, periodic and/or semi-persistent SRS transmissions. The UE may transmit SRS resources based on one or more trigger types, wherein the one or more trigger types may comprise higher layer signaling (e.g., RRC) and/or one or more DCI formats. In an example, at least one DCI format may be employed for the UE to select at least one of one or more configured SRS resource sets. An SRS trigger type 0 may refer to an SRS triggered based on a higher layer signaling. An SRS trigger type 1 may refer to an SRS triggered based on one or more DCI formats. In an example, when PUSCH and SRS are transmitted in a same slot, the UE may be configured to transmit SRS after a transmission of a PUSCH and a corresponding uplink DMRS. 
     The base station may semi-statically configure the UE with one or more SRS configuration parameters indicating at least one of following: a SRS resource configuration identifier; a number of SRS ports; time domain behavior of an SRS resource configuration (e.g., an indication of periodic, semi-persistent, or aperiodic SRS); slot, mini-slot, and/or subframe level periodicity; offset for a periodic and/or an aperiodic SRS resource; a number of OFDM symbols in an SRS resource; a starting OFDM symbol of an SRS resource; an SRS bandwidth; a frequency hopping bandwidth; a cyclic shift; and/or an SRS sequence ID. 
     An antenna port is defined such that the channel over which a symbol on the antenna port is conveyed can be inferred from the channel over which another symbol on the same antenna port is conveyed. If a first symbol and a second symbol are transmitted on the same antenna port, the receiver may infer the channel (e.g., fading gain, multipath delay, and/or the like) for conveying the second symbol on the antenna port, from the channel for conveying the first symbol on the antenna port. A first antenna port and a second antenna port may be referred to as quasi co-located (QCLed) if one or more large-scale properties of the channel over which a first symbol on the first antenna port is conveyed may be inferred from the channel over which a second symbol on a second antenna port is conveyed. The one or more large-scale properties may comprise at least one of: a delay spread; a Doppler spread; a Doppler shift; an average gain; an average delay; and/or spatial Receiving (Rx) parameters. 
     Channels that use beamforming require beam management. Beam management may comprise beam measurement, beam selection, and beam indication. A beam may be associated with one or more reference signals. For example, a beam may be identified by one or more beamformed reference signals. The UE may perform downlink beam measurement based on downlink reference signals (e.g., a channel state information reference signal (CSI-RS)) and generate a beam measurement report. The UE may perform the downlink beam measurement procedure after an RRC connection is set up with a base station. 
       FIG. 11B  illustrates an example of channel state information reference signals (CSI-RSs) that are mapped in the time and frequency domains. A square shown in  FIG. 11B  may span a resource block (RB) within a bandwidth of a cell. A base station may transmit one or more RRC messages comprising CSI-RS resource configuration parameters indicating one or more CSI-RSs. One or more of the following parameters may be configured by higher layer signaling (e.g., RRC and/or MAC signaling) for a CSI-RS resource configuration: a CSI-RS resource configuration identity, a number of CSI-RS ports, a CSI-RS configuration (e.g., symbol and resource element (RE) locations in a subframe), a CSI-RS subframe configuration (e.g., subframe location, offset, and periodicity in a radio frame), a CSI-RS power parameter, a CSI-RS sequence parameter, a code division multiplexing (CDM) type parameter, a frequency density, a transmission comb, quasi co-location (QCL) parameters (e.g., QCL-scramblingidentity, crs-portscount, mbsfn-subframeconfiglist, csi-rs-configZPid, qcl-csi-rs-configNZPid), and/or other radio resource parameters. 
     The three beams illustrated in  FIG. 11B  may be configured for a UE in a UE-specific configuration. Three beams are illustrated in  FIG. 11B  (beam #1, beam #2, and beam #3), more or fewer beams may be configured. Beam #1 may be allocated with CSI-RS  1101  that may be transmitted in one or more subcarriers in an RB of a first symbol. Beam #2 may be allocated with CSI-RS  1102  that may be transmitted in one or more subcarriers in an RB of a second symbol. Beam #3 may be allocated with CSI-RS  1103  that may be transmitted in one or more subcarriers in an RB of a third symbol. By using frequency division multiplexing (FDM), a base station may use other subcarriers in a same RB (for example, those that are not used to transmit CSI-RS  1101 ) to transmit another CSI-RS associated with a beam for another UE. By using time domain multiplexing (TDM), beams used for the UE may be configured such that beams for the UE use symbols from beams of other UEs. 
     CSI-RSs such as those illustrated in  FIG. 11B  (e.g., CSI-RS  1101 ,  1102 ,  1103 ) may be transmitted by the base station and used by the UE for one or more measurements. For example, the UE may measure a reference signal received power (RSRP) of configured CSI-RS resources. The base station may configure the UE with a reporting configuration and the UE may report the RSRP measurements to a network (for example, via one or more base stations) based on the reporting configuration. In an example, the base station may determine, based on the reported measurement results, one or more transmission configuration indication (TCI) states comprising a number of reference signals. In an example, the base station may indicate one or more TCI states to the UE (e.g., via RRC signaling, a MAC CE, and/or a DCI). The UE may receive a downlink transmission with a receive (Rx) beam determined based on the one or more TCI states. In an example, the UE may or may not have a capability of beam correspondence. If the UE has the capability of beam correspondence, the UE may determine a spatial domain filter of a transmit (Tx) beam based on a spatial domain filter of the corresponding Rx beam. If the UE does not have the capability of beam correspondence, the UE may perform an uplink beam selection procedure to determine the spatial domain filter of the Tx beam. The UE may perform the uplink beam selection procedure based on one or more sounding reference signal (SRS) resources configured to the UE by the base station. The base station may select and indicate uplink beams for the UE based on measurements of the one or more SRS resources transmitted by the UE. 
     In a beam management procedure, a UE may assess (e.g., measure) a channel quality of one or more beam pair links, a beam pair link comprising a transmitting beam transmitted by a base station and a receiving beam received by the UE. Based on the assessment, the UE may transmit a beam measurement report indicating one or more beam pair quality parameters comprising, e.g., one or more beam identifications (e.g., a beam index, a reference signal index, or the like), RSRP, a precoding matrix indicator (PMI), a channel quality indicator (CQI), and/or a rank indicator (RI). 
       FIG. 12A  illustrates examples of three downlink beam management procedures: P 1 , P 2 , and P 3 . Procedure P 1  may enable a UE measurement on transmit (Tx) beams of a transmission reception point (TRP) (or multiple TRPs), e.g., to support a selection of one or more base station Tx beams and/or UE Rx beams (shown as ovals in the top row and bottom row, respectively, of P 1 ). Beamforming at a TRP may comprise a Tx beam sweep for a set of beams (shown, in the top rows of P 1  and P 2 , as ovals rotated in a counter-clockwise direction indicated by the dashed arrow). Beamforming at a UE may comprise an Rx beam sweep for a set of beams (shown, in the bottom rows of P 1  and P 3 , as ovals rotated in a clockwise direction indicated by the dashed arrow). Procedure P 2  may be used to enable a UE measurement on Tx beams of a TRP (shown, in the top row of P 2 , as ovals rotated in a counter-clockwise direction indicated by the dashed arrow). The UE and/or the base station may perform procedure P 2  using a smaller set of beams than is used in procedure P 1 , or using narrower beams than the beams used in procedure P 1 . This may be referred to as beam refinement. The UE may perform procedure P 3  for Rx beam determination by using the same Tx beam at the base station and sweeping an Rx beam at the UE. 
       FIG. 12B  illustrates examples of three uplink beam management procedures: U 1 , U 2 , and U 3 . Procedure U 1  may be used to enable a base station to perform a measurement on Tx beams of a UE, e.g., to support a selection of one or more UE Tx beams and/or base station Rx beams (shown as ovals in the top row and bottom row, respectively, of U 1 ). Beamforming at the UE may include, e.g., a Tx beam sweep from a set of beams (shown in the bottom rows of U 1  and U 3  as ovals rotated in a clockwise direction indicated by the dashed arrow). Beamforming at the base station may include, e.g., an Rx beam sweep from a set of beams (shown, in the top rows of U 1  and U 2 , as ovals rotated in a counter-clockwise direction indicated by the dashed arrow). Procedure U 2  may be used to enable the base station to adjust its Rx beam when the UE uses a fixed Tx beam. The UE and/or the base station may perform procedure U 2  using a smaller set of beams than is used in procedure P 1 , or using narrower beams than the beams used in procedure P 1 . This may be referred to as beam refinement The UE may perform procedure U 3  to adjust its Tx beam when the base station uses a fixed Rx beam. 
     A UE may initiate a beam failure recovery (BFR) procedure based on detecting a beam failure. The UE may transmit a BFR request (e.g., a preamble, a UCI, an SR, a MAC CE, and/or the like) based on the initiating of the BFR procedure. The UE may detect the beam failure based on a determination that a quality of beam pair link(s) of an associated control channel is unsatisfactory (e.g., having an error rate higher than an error rate threshold, a received signal power lower than a received signal power threshold, an expiration of a timer, and/or the like). 
     The UE may measure a quality of a beam pair link using one or more reference signals (RSs) comprising one or more SS/PBCH blocks, one or more CSI-RS resources, and/or one or more demodulation reference signals (DMRSs). A quality of the beam pair link may be based on one or more of a block error rate (BLER), an RSRP value, a signal to interference plus noise ratio (SINR) value, a reference signal received quality (RSRQ) value, and/or a CSI value measured on RS resources. The base station may indicate that an RS resource is quasi co-located (QCLed) with one or more DM-RSs of a channel (e.g., a control channel, a shared data channel, and/or the like). The RS resource and the one or more DMRSs of the channel may be QCLed when the channel characteristics (e.g., Doppler shift, Doppler spread, average delay, delay spread, spatial Rx parameter, fading, and/or the like) from a transmission via the RS resource to the UE are similar or the same as the channel characteristics from a transmission via the channel to the UE. 
     A network (e.g., a gNB and/or an ng-eNB of a network) and/or the UE may initiate a random access procedure. A UE in an RRC_IDLE state and/or an RRC_INACTIVE state may initiate the random access procedure to request a connection setup to a network. The UE may initiate the random access procedure from an RRC_CONNECTED state. The UE may initiate the random access procedure to request uplink resources (e.g., for uplink transmission of an SR when there is no PUCCH resource available) and/or acquire uplink timing (e.g., when uplink synchronization status is non-synchronized). The UE may initiate the random access procedure to request one or more system information blocks (SIBs) (e.g., other system information such as SIB2, SIB3, and/or the like). The UE may initiate the random access procedure for a beam failure recovery request. A network may initiate a random access procedure for a handover and/or for establishing time alignment for an SCell addition. 
       FIG. 13A  illustrates a four-step contention-based random access procedure. Prior to initiation of the procedure, a base station may transmit a configuration message  1310  to the UE. The procedure illustrated in  FIG. 13A  comprises transmission of four messages: a Msg  1   1311 , a Msg  2   1312 , a Msg  3   1313 , and a Msg  4   1314 . The Msg  1   1311  may include and/or be referred to as a preamble (or a random access preamble). The Msg  2   1312  may include and/or be referred to as a random access response (RAR). 
     The configuration message  1310  may be transmitted, for example, using one or more RRC messages. The one or more RRC messages may indicate one or more random access channel (RACH) parameters to the UE. The one or more RACH parameters may comprise at least one of following: general parameters for one or more random access procedures (e.g., RACH-configGeneral); cell-specific parameters (e.g., RACH-ConfigCommon); and/or dedicated parameters (e.g., RACH-configDedicated). The base station may broadcast or multicast the one or more RRC messages to one or more UEs. The one or more RRC messages may be UE-specific (e.g., dedicated RRC messages transmitted to a UE in an RRC_CONNECTED state and/or in an RRC_INACTIVE state). The UE may determine, based on the one or more RACH parameters, a time-frequency resource and/or an uplink transmit power for transmission of the Msg  1   1311  and/or the Msg  3   1313 . Based on the one or more RACH parameters, the UE may determine a reception timing and a downlink channel for receiving the Msg  2   1312  and the Msg  4   1314 . 
     The one or more RACH parameters provided in the configuration message  1310  may indicate one or more Physical RACH (PRACH) occasions available for transmission of the Msg  1   1311 . The one or more PRACH occasions may be predefined. The one or more RACH parameters may indicate one or more available sets of one or more PRACH occasions (e.g., prach-ConfigIndex). The one or more RACH parameters may indicate an association between (a) one or more PRACH occasions and (b) one or more reference signals. The one or more RACH parameters may indicate an association between (a) one or more preambles and (b) one or more reference signals. The one or more reference signals may be SS/PBCH blocks and/or CSI-RSs. For example, the one or more RACH parameters may indicate a number of SS/PBCH blocks mapped to a PRACH occasion and/or a number of preambles mapped to a SS/PBCH blocks. 
     The one or more RACH parameters provided in the configuration message  1310  may be used to determine an uplink transmit power of Msg  1   1311  and/or Msg  3   1313 . For example, the one or more RACH parameters may indicate a reference power for a preamble transmission (e.g., a received target power and/or an initial power of the preamble transmission). There may be one or more power offsets indicated by the one or more RACH parameters. For example, the one or more RACH parameters may indicate: a power ramping step; a power offset between SSB and CSI-RS; a power offset between transmissions of the Msg  1   1311  and the Msg  3   1313 ; and/or a power offset value between preamble groups. The one or more RACH parameters may indicate one or more thresholds based on which the UE may determine at least one reference signal (e.g., an SSB and/or CSI-RS) and/or an uplink carrier (e.g., a normal uplink (NUL) carrier and/or a supplemental uplink (SUL) carrier). 
     The Msg  1   1311  may include one or more preamble transmissions (e.g., a preamble transmission and one or more preamble retransmissions). An RRC message may be used to configure one or more preamble groups (e.g., group A and/or group B). A preamble group may comprise one or more preambles. The UE may determine the preamble group based on a pathloss measurement and/or a size of the Msg  3   1313 . The UE may measure an RSRP of one or more reference signals (e.g., SSBs and/or CSI-RSs) and determine at least one reference signal having an RSRP above an RSRP threshold (e.g., rsrp-ThresholdSSB and/or rsrp-ThresholdCSI-RS). The UE may select at least one preamble associated with the one or more reference signals and/or a selected preamble group, for example, if the association between the one or more preambles and the at least one reference signal is configured by an RRC message. 
     The UE may determine the preamble based on the one or more RACH parameters provided in the configuration message  1310 . For example, the UE may determine the preamble based on a pathloss measurement, an RSRP measurement, and/or a size of the Msg  3   1313 . As another example, the one or more RACH parameters may indicate: a preamble format; a maximum number of preamble transmissions; and/or one or more thresholds for determining one or more preamble groups (e.g., group A and group B). A base station may use the one or more RACH parameters to configure the UE with an association between one or more preambles and one or more reference signals (e.g., SSBs and/or CSI-RSs). If the association is configured, the UE may determine the preamble to include in Msg  1   1311  based on the association. The Msg  1   1311  may be transmitted to the base station via one or more PRACH occasions. The UE may use one or more reference signals (e.g., SSBs and/or CSI-RSs) for selection of the preamble and for determining of the PRACH occasion. One or more RACH parameters (e.g., ra-ssb-OccasionMskIndex and/or ra-OccasionList) may indicate an association between the PRACH occasions and the one or more reference signals. 
     The UE may perform a preamble retransmission if no response is received following a preamble transmission. The UE may increase an uplink transmit power for the preamble retransmission. The UE may select an initial preamble transmit power based on a pathloss measurement and/or a target received preamble power configured by the network. The UE may determine to retransmit a preamble and may ramp up the uplink transmit power. The UE may receive one or more RACH parameters (e.g., PREAMBLE_POWER_RAMPING_STEP) indicating a ramping step for the preamble retransmission. The ramping step may be an amount of incremental increase in uplink transmit power for a retransmission. The UE may ramp up the uplink transmit power if the UE determines a reference signal (e.g., SSB and/or CSI-RS) that is the same as a previous preamble transmission. The UE may count a number of preamble transmissions and/or retransmissions (e.g., PREAMBLE_TRANSMISSION_COUNTER). The UE may determine that a random access procedure completed unsuccessfully, for example, if the number of preamble transmissions exceeds a threshold configured by the one or more RACH parameters (e.g., preambleTransMax). 
     The Msg  2   1312  received by the UE may include an RAR. In some scenarios, the Msg  2   1312  may include multiple RARs corresponding to multiple UEs. The Msg  2   1312  may be received after or in response to the transmitting of the Msg  1   1311 . The Msg  2   1312  may be scheduled on the DL-SCH and indicated on a PDCCH using a random access RNTI (RA-RNTI). The Msg  2   1312  may indicate that the Msg  1   1311  was received by the base station. The Msg  2   1312  may include a time-alignment command that may be used by the UE to adjust the UE&#39;s transmission timing, a scheduling grant for transmission of the Msg  3   1313 , and/or a Temporary Cell RNTI (TC-RNTI). After transmitting a preamble, the UE may start a time window (e.g., ra-ResponseWindow) to monitor a PDCCH for the Msg  2   1312 . The UE may determine when to start the time window based on a PRACH occasion that the UE uses to transmit the preamble. For example, the UE may start the time window one or more symbols after a last symbol of the preamble (e.g., at a first PDCCH occasion from an end of a preamble transmission). The one or more symbols may be determined based on a numerology. The PDCCH may be in a common search space (e.g., a Type1-PDCCH common search space) configured by an RRC message. The UE may identify the RAR based on a Radio Network Temporary Identifier (RNTI). RNTIs may be used depending on one or more events initiating the random access procedure. The UE may use random access RNTI (RA-RNTI). The RA-RNTI may be associated with PRACH occasions in which the UE transmits a preamble. For example, the UE may determine the RA-RNTI based on: an OFDM symbol index; a slot index; a frequency domain index; and/or a UL carrier indicator of the PRACH occasions. An example of RA-RNTI may be as follows: 
       RA-RNTI=1 +s _id+14 ×t _id+14×80 ×f _id+14×80×8×ul_carrier_id
 
     where s_id may be an index of a first OFDM symbol of the PRACH occasion (e.g., 0&lt;s_id&lt;14), t_id may be an index of a first slot of the PRACH occasion in a system frame (e.g., 0&lt;t_id&lt;80), f_id may be an index of the PRACH occasion in the frequency domain (e.g., 0&lt;f_id&lt;8), and ul_carrier_id may be a UL carrier used for a preamble transmission (e.g., 0 for an NUL carrier, and 1 for an SUL carrier). 
     The UE may transmit the Msg  3   1313  in response to a successful reception of the Msg  2   1312  (e.g., using resources identified in the Msg  2   1312 ). The Msg  3   1313  may be used for contention resolution in, for example, the contention-based random access procedure illustrated in  FIG. 13A . In some scenarios, a plurality of UEs may transmit a same preamble to a base station and the base station may provide an RAR that corresponds to a UE. Collisions may occur if the plurality of UEs interpret the RAR as corresponding to themselves. Contention resolution (e.g., using the Msg  3   1313  and the Msg  4   1314 ) may be used to increase the likelihood that the UE does not incorrectly use an identity of another the UE. To perform contention resolution, the UE may include a device identifier in the Msg  3   1313  (e.g., a C-RNTI if assigned, a TC-RNTI included in the Msg  2   1312 , and/or any other suitable identifier). 
     The Msg  4   1314  may be received after or in response to the transmitting of the Msg  3   1313 . If a C-RNTI was included in the Msg  3   1313 , the base station will address the UE on the PDCCH using the C-RNTI. If the UE&#39;s unique C-RNTI is detected on the PDCCH, the random access procedure is determined to be successfully completed. If a TC-RNTI is included in the Msg  3   1313  (e.g., if the UE is in an RRC_IDLE state or not otherwise connected to the base station), Msg  4   1314  will be received using a DL-SCH associated with the TC-RNTI. If a MAC PDU is successfully decoded and a MAC PDU comprises the UE contention resolution identity MAC CE that matches or otherwise corresponds with the CCCH SDU sent (e.g., transmitted) in Msg  3   1313 , the UE may determine that the contention resolution is successful and/or the UE may determine that the random access procedure is successfully completed. 
     The UE may be configured with a supplementary uplink (SUL) carrier and a normal uplink (NUL) carrier. An initial access (e.g., random access procedure) may be supported in an uplink carrier. For example, a base station may configure the UE with two separate RACH configurations: one for an SUL carrier and the other for an NUL carrier. For random access in a cell configured with an SUL carrier, the network may indicate which carrier to use (NUL or SUL). The UE may determine the SUL carrier, for example, if a measured quality of one or more reference signals is lower than a broadcast threshold. Uplink transmissions of the random access procedure (e.g., the Msg  1   1311  and/or the Msg  3   1313 ) may remain on the selected carrier. The UE may switch an uplink carrier during the random access procedure (e.g., between the Msg  1   1311  and the Msg  3   1313 ) in one or more cases. For example, the UE may determine and/or switch an uplink carrier for the Msg  1   1311  and/or the Msg  3   1313  based on a channel clear assessment (e.g., a listen-before-talk). 
       FIG. 13B  illustrates a two-step contention-free random access procedure. Similar to the four-step contention-based random access procedure illustrated in  FIG. 13A , a base station may, prior to initiation of the procedure, transmit a configuration message  1320  to the UE. The configuration message  1320  may be analogous in some respects to the configuration message  1310 . The procedure illustrated in  FIG. 13B  comprises transmission of two messages: a Msg  1   1321  and a Msg  2   1322 . The Msg  1   1321  and the Msg  2   1322  may be analogous in some respects to the Msg  1   1311  and a Msg  2   1312  illustrated in  FIG. 13A , respectively. As will be understood from  FIGS. 13A and 13B , the contention-free random access procedure may not include messages analogous to the Msg  3   1313  and/or the Msg  4   1314 . 
     The contention-free random access procedure illustrated in  FIG. 13B  may be initiated for a beam failure recovery, other SI request, SCell addition, and/or handover. For example, a base station may indicate or assign to the UE the preamble to be used for the Msg  1   1321 . The UE may receive, from the base station via PDCCH and/or RRC, an indication of a preamble (e.g., ra-PreambleIndex). 
     After transmitting a preamble, the UE may start a time window (e.g., ra-ResponseWindow) to monitor a PDCCH for the RAR. In the event of a beam failure recovery request, the base station may configure the UE with a separate time window and/or a separate PDCCH in a search space indicated by an RRC message (e.g., recoverySearchSpaceId). The UE may monitor for a PDCCH transmission addressed to a Cell RNTI (C-RNTI) on the search space. In the contention-free random access procedure illustrated in  FIG. 13B , the UE may determine that a random access procedure successfully completes after or in response to transmission of Msg  1   1321  and reception of a corresponding Msg  2   1322 . The UE may determine that a random access procedure successfully completes, for example, if a PDCCH transmission is addressed to a C-RNTI. The UE may determine that a random access procedure successfully completes, for example, if the UE receives an RAR comprising a preamble identifier corresponding to a preamble transmitted by the UE and/or the RAR comprises a MAC sub-PDU with the preamble identifier. The UE may determine the response as an indication of an acknowledgement for an SI request. 
       FIG. 13C  illustrates another two-step random access procedure. Similar to the random access procedures illustrated in  FIGS. 13A and 13B , a base station may, prior to initiation of the procedure, transmit a configuration message  1330  to the UE. The configuration message  1330  may be analogous in some respects to the configuration message  1310  and/or the configuration message  1320 . The procedure illustrated in  FIG. 13C  comprises transmission of two messages: a Msg A  1331  and a Msg B  1332 . 
     Msg A  1331  may be transmitted in an uplink transmission by the UE. Msg A  1331  may comprise one or more transmissions of a preamble  1341  and/or one or more transmissions of a transport block  1342 . The transport block  1342  may comprise contents that are similar and/or equivalent to the contents of the Msg  3   1313  illustrated in  FIG. 13A . The transport block  1342  may comprise UCI (e.g., an SR, a HARQ ACK/NACK, and/or the like). The UE may receive the Msg B  1332  after or in response to transmitting the Msg A  1331 . The Msg B  1332  may comprise contents that are similar and/or equivalent to the contents of the Msg  2   1312  (e.g., an RAR) illustrated in  FIGS. 13A and 13B  and/or the Msg  4   1314  illustrated in  FIG. 13A . 
     The UE may initiate the two-step random access procedure in  FIG. 13C  for licensed spectrum and/or unlicensed spectrum. The UE may determine, based on one or more factors, whether to initiate the two-step random access procedure. The one or more factors may be: a radio access technology in use (e.g., LTE, NR, and/or the like); whether the UE has valid TA or not; a cell size; the UE&#39;s RRC state; a type of spectrum (e.g., licensed vs. unlicensed); and/or any other suitable factors. 
     The UE may determine, based on two-step RACH parameters included in the configuration message  1330 , a radio resource and/or an uplink transmit power for the preamble  1341  and/or the transport block  1342  included in the Msg A  1331 . The RACH parameters may indicate a modulation and coding schemes (MCS), a time-frequency resource, and/or a power control for the preamble  1341  and/or the transport block  1342 . A time-frequency resource for transmission of the preamble  1341  (e.g., a PRACH) and a time-frequency resource for transmission of the transport block  1342  (e.g., a PUSCH) may be multiplexed using FDM, TDM, and/or CDM. The RACH parameters may enable the UE to determine a reception timing and a downlink channel for monitoring for and/or receiving Msg B  1332 . 
     The transport block  1342  may comprise data (e.g., delay-sensitive data), an identifier of the UE, security information, and/or device information (e.g., an International Mobile Subscriber Identity (IMSI)). The base station may transmit the Msg B  1332  as a response to the Msg A  1331 . The Msg B  1332  may comprise at least one of following: a preamble identifier; a timing advance command; a power control command; an uplink grant (e.g., a radio resource assignment and/or an MCS); a UE identifier for contention resolution; and/or an RNTI (e.g., a C-RNTI or a TC-RNTI). The UE may determine that the two-step random access procedure is successfully completed if: a preamble identifier in the Msg B  1332  is matched to a preamble transmitted by the UE; and/or the identifier of the UE in Msg B  1332  is matched to the identifier of the UE in the Msg A  1331  (e.g., the transport block  1342 ). 
     A UE and a base station may exchange control signaling. The control signaling may be referred to as L1/L2 control signaling and may originate from the PHY layer (e.g., layer 1) and/or the MAC layer (e.g., layer 2). The control signaling may comprise downlink control signaling transmitted from the base station to the UE and/or uplink control signaling transmitted from the UE to the base station. 
     The downlink control signaling may comprise: a downlink scheduling assignment; an uplink scheduling grant indicating uplink radio resources and/or a transport format; a slot format information; a preemption indication; a power control command; and/or any other suitable signaling. The UE may receive the downlink control signaling in a payload transmitted by the base station on a physical downlink control channel (PDCCH). The payload transmitted on the PDCCH may be referred to as downlink control information (DCI). In some scenarios, the PDCCH may be a group common PDCCH (GC-PDCCH) that is common to a group of UEs. 
     A base station may attach one or more cyclic redundancy check (CRC) parity bits to a DCI in order to facilitate detection of transmission errors. When the DCI is intended for a UE (or a group of the UEs), the base station may scramble the CRC parity bits with an identifier of the UE (or an identifier of the group of the UEs). Scrambling the CRC parity bits with the identifier may comprise Modulo-2 addition (or an exclusive OR operation) of the identifier value and the CRC parity bits. The identifier may comprise a 16-bit value of a radio network temporary identifier (RNTI). 
     DCIs may be used for different purposes. A purpose may be indicated by the type of RNTI used to scramble the CRC parity bits. For example, a DCI having CRC parity bits scrambled with a paging RNTI (P-RNTI) may indicate paging information and/or a system information change notification. The P-RNTI may be predefined as “FFFE” in hexadecimal. A DCI having CRC parity bits scrambled with a system information RNTI (SI-RNTI) may indicate a broadcast transmission of the system information. The SI-RNTI may be predefined as “FFFF” in hexadecimal. A DCI having CRC parity bits scrambled with a random access RNTI (RA-RNTI) may indicate a random access response (RAR). A DCI having CRC parity bits scrambled with a cell RNTI (C-RNTI) may indicate a dynamically scheduled unicast transmission and/or a triggering of PDCCH-ordered random access. A DCI having CRC parity bits scrambled with a temporary cell RNTI (TC-RNTI) may indicate a contention resolution (e.g., a Msg  3  analogous to the Msg  3   1313  illustrated in  FIG. 13A ). Other RNTIs configured to the UE by a base station may comprise a Configured Scheduling RNTI (CS-RNTI), a Transmit Power Control-PUCCH RNTI (TPC-PUCCH-RNTI), a Transmit Power Control-PUSCH RNTI (TPC-PUSCH-RNTI), a Transmit Power Control-SRS RNTI (TPC-SRS-RNTI), an Interruption RNTI (INT-RNTI), a Slot Format Indication RNTI (SFI-RNTI), a Semi-Persistent CSI RNTI (SP-CSI-RNTI), a Modulation and Coding Scheme Cell RNTI (MCS-C-RNTI), and/or the like. 
     Depending on the purpose and/or content of a DCI, the base station may transmit the DCIs with one or more DCI formats. For example, DCI format 0_0 may be used for scheduling of PUSCH in a cell. DCI format 0_0 may be a fallback DCI format (e.g., with compact DCI payloads). DCI format 0_1 may be used for scheduling of PUSCH in a cell (e.g., with more DCI payloads than DCI format 0_0). DCI format 1_0 may be used for scheduling of PDSCH in a cell. DCI format 1_0 may be a fallback DCI format (e.g., with compact DCI payloads). DCI format 1_1 may be used for scheduling of PDSCH in a cell (e.g., with more DCI payloads than DCI format 1_0). DCI format 2_0 may be used for providing a slot format indication to a group of UEs. DCI format 2_1 may be used for notifying a group of UEs of a physical resource block and/or OFDM symbol where the UE may assume no transmission is intended to the UE. DCI format 2_2 may be used for transmission of a transmit power control (TPC) command for PUCCH or PUSCH. DCI format 2_3 may be used for transmission of a group of TPC commands for SRS transmissions by one or more UEs. DCI format(s) for new functions may be defined in future releases. DCI formats may have different DCI sizes, or may share the same DCI size. 
     After scrambling a DCI with a RNTI, the base station may process the DCI with channel coding (e.g., polar coding), rate matching, scrambling and/or QPSK modulation. A base station may map the coded and modulated DCI on resource elements used and/or configured for a PDCCH. Based on a payload size of the DCI and/or a coverage of the base station, the base station may transmit the DCI via a PDCCH occupying a number of contiguous control channel elements (CCEs). The number of the contiguous CCEs (referred to as aggregation level) may be 1, 2, 4, 8, 16, and/or any other suitable number. A CCE may comprise a number (e.g., 6) of resource-element groups (REGs). A REG may comprise a resource block in an OFDM symbol. The mapping of the coded and modulated DCI on the resource elements may be based on mapping of CCEs and REGs (e.g., CCE-to-REG mapping). 
       FIG. 14A  illustrates an example of CORESET configurations for a bandwidth part. The base station may transmit a DCI via a PDCCH on one or more control resource sets (CORESETs). A CORESET may comprise a time-frequency resource in which the UE tries to decode a DCI using one or more search spaces. The base station may configure a CORESET in the time-frequency domain. In the example of  FIG. 14A , a first CORESET  1401  and a second CORESET  1402  occur at the first symbol in a slot. The first CORESET  1401  overlaps with the second CORESET  1402  in the frequency domain. A third CORESET  1403  occurs at a third symbol in the slot. A fourth CORESET  1404  occurs at the seventh symbol in the slot. CORESETs may have a different number of resource blocks in frequency domain. 
       FIG. 14B  illustrates an example of a CCE-to-REG mapping for DCI transmission on a CORESET and PDCCH processing. The CCE-to-REG mapping may be an interleaved mapping (e.g., for the purpose of providing frequency diversity) or a non-interleaved mapping (e.g., for the purposes of facilitating interference coordination and/or frequency-selective transmission of control channels). The base station may perform different or same CCE-to-REG mapping on different CORESETs. A CORESET may be associated with a CCE-to-REG mapping by RRC configuration. A CORESET may be configured with an antenna port quasi co-location (QCL) parameter. The antenna port QCL parameter may indicate QCL information of a demodulation reference signal (DMRS) for PDCCH reception in the CORESET. 
     The base station may transmit, to the UE, RRC messages comprising configuration parameters of one or more CORESETs and one or more search space sets. The configuration parameters may indicate an association between a search space set and a CORESET. A search space set may comprise a set of PDCCH candidates formed by CCEs at a given aggregation level. The configuration parameters may indicate: a number of PDCCH candidates to be monitored per aggregation level; a PDCCH monitoring periodicity and a PDCCH monitoring pattern; one or more DCI formats to be monitored by the UE; and/or whether a search space set is a common search space set or a UE-specific search space set. A set of CCEs in the common search space set may be predefined and known to the UE. A set of CCEs in the UE-specific search space set may be configured based on the UE&#39;s identity (e.g., C-RNTI). 
     As shown in  FIG. 14B , the UE may determine a time-frequency resource for a CORESET based on RRC messages. The UE may determine a CCE-to-REG mapping (e.g., interleaved or non-interleaved, and/or mapping parameters) for the CORESET based on configuration parameters of the CORESET. The UE may determine a number (e.g., at most 10) of search space sets configured on the CORESET based on the RRC messages. The UE may monitor a set of PDCCH candidates according to configuration parameters of a search space set. The UE may monitor a set of PDCCH candidates in one or more CORESETs for detecting one or more DCIs. Monitoring may comprise decoding one or more PDCCH candidates of the set of the PDCCH candidates according to the monitored DCI formats. Monitoring may comprise decoding a DCI content of one or more PDCCH candidates with possible (or configured) PDCCH locations, possible (or configured) PDCCH formats (e.g., number of CCEs, number of PDCCH candidates in common search spaces, and/or number of PDCCH candidates in the UE-specific search spaces) and possible (or configured) DCI formats. The decoding may be referred to as blind decoding. The UE may determine a DCI as valid for the UE, in response to CRC checking (e.g., scrambled bits for CRC parity bits of the DCI matching a RNTI value). The UE may process information contained in the DCI (e.g., a scheduling assignment, an uplink grant, power control, a slot format indication, a downlink preemption, and/or the like). 
     The UE may transmit uplink control signaling (e.g., uplink control information (UCI)) to a base station. The uplink control signaling may comprise hybrid automatic repeat request (HARQ) acknowledgements for received DL-SCH transport blocks. The UE may transmit the HARQ acknowledgements after receiving a DL-SCH transport block. Uplink control signaling may comprise channel state information (CSI) indicating channel quality of a physical downlink channel. The UE may transmit the CSI to the base station. The base station, based on the received CSI, may determine transmission format parameters (e.g., comprising multi-antenna and beamforming schemes) for a downlink transmission. Uplink control signaling may comprise scheduling requests (SR). The UE may transmit an SR indicating that uplink data is available for transmission to the base station. The UE may transmit a UCI (e.g., HARQ acknowledgements (HARQ-ACK), CSI report, SR, and the like) via a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). The UE may transmit the uplink control signaling via a PUCCH using one of several PUCCH formats. 
     There may be five PUCCH formats and the UE may determine a PUCCH format based on a size of the UCI (e.g., a number of uplink symbols of UCI transmission and a number of UCI bits). PUCCH format 0 may have a length of one or two OFDM symbols and may include two or fewer bits. The UE may transmit UCI in a PUCCH resource using PUCCH format 0 if the transmission is over one or two symbols and the number of HARQ-ACK information bits with positive or negative SR (HARQ-ACK/SR bits) is one or two. PUCCH format 1 may occupy a number between four and fourteen OFDM symbols and may include two or fewer bits. The UE may use PUCCH format 1 if the transmission is four or more symbols and the number of HARQ-ACK/SR bits is one or two. PUCCH format 2 may occupy one or two OFDM symbols and may include more than two bits. The UE may use PUCCH format 2 if the transmission is over one or two symbols and the number of UCI bits is two or more. PUCCH format 3 may occupy a number between four and fourteen OFDM symbols and may include more than two bits. The UE may use PUCCH format 3 if the transmission is four or more symbols, the number of UCI bits is two or more and PUCCH resource does not include an orthogonal cover code. PUCCH format 4 may occupy a number between four and fourteen OFDM symbols and may include more than two bits. The UE may use PUCCH format 4 if the transmission is four or more symbols, the number of UCI bits is two or more and the PUCCH resource includes an orthogonal cover code. 
     The base station may transmit configuration parameters to the UE for a plurality of PUCCH resource sets using, for example, an RRC message. The plurality of PUCCH resource sets (e.g., up to four sets) may be configured on an uplink BWP of a cell. A PUCCH resource set may be configured with a PUCCH resource set index, a plurality of PUCCH resources with a PUCCH resource being identified by a PUCCH resource identifier (e.g., pucch-Resourceid), and/or a number (e.g. a maximum number) of UCI information bits the UE may transmit using one of the plurality of PUCCH resources in the PUCCH resource set. When configured with a plurality of PUCCH resource sets, the UE may select one of the plurality of PUCCH resource sets based on a total bit length of the UCI information bits (e.g., HARQ-ACK, SR, and/or CSI). If the total bit length of UCI information bits is two or fewer, the UE may select a first PUCCH resource set having a PUCCH resource set index equal to “0”. If the total bit length of UCI information bits is greater than two and less than or equal to a first configured value, the UE may select a second PUCCH resource set having a PUCCH resource set index equal to “1”. If the total bit length of UCI information bits is greater than the first configured value and less than or equal to a second configured value, the UE may select a third PUCCH resource set having a PUCCH resource set index equal to “2”. If the total bit length of UCI information bits is greater than the second configured value and less than or equal to a third value (e.g., 1406), the UE may select a fourth PUCCH resource set having a PUCCH resource set index equal to “3”. 
     After determining a PUCCH resource set from a plurality of PUCCH resource sets, the UE may determine a PUCCH resource from the PUCCH resource set for UCI (HARQ-ACK, CSI, and/or SR) transmission. The UE may determine the PUCCH resource based on a PUCCH resource indicator in a DCI (e.g., with a DCI format 1_0 or DCI for 1_1) received on a PDCCH. A three-bit PUCCH resource indicator in the DCI may indicate one of eight PUCCH resources in the PUCCH resource set. Based on the PUCCH resource indicator, the UE may transmit the UCI (HARQ-ACK, CSI and/or SR) using a PUCCH resource indicated by the PUCCH resource indicator in the DCI. 
       FIG. 15  illustrates an example of a wireless device  1502  in communication with a base station  1504  in accordance with embodiments of the present disclosure. The wireless device  1502  and base station  1504  may be part of a mobile communication network, such as the mobile communication network  100  illustrated in  FIG. 1A , the mobile communication network  150  illustrated in  FIG. 1B , or any other communication network. Only one wireless device  1502  and one base station  1504  are illustrated in  FIG. 15 , but it will be understood that a mobile communication network may include more than one UE and/or more than one base station, with the same or similar configuration as those shown in  FIG. 15 . 
     The base station  1504  may connect the wireless device  1502  to a core network (not shown) through radio communications over the air interface (or radio interface)  1506 . The communication direction from the base station  1504  to the wireless device  1502  over the air interface  1506  is known as the downlink, and the communication direction from the wireless device  1502  to the base station  1504  over the air interface is known as the uplink. Downlink transmissions may be separated from uplink transmissions using FDD, TDD, and/or some combination of the two duplexing techniques. 
     In the downlink, data to be sent to the wireless device  1502  from the base station  1504  may be provided to the processing system  1508  of the base station  1504 . The data may be provided to the processing system  1508  by, for example, a core network. In the uplink, data to be sent to the base station  1504  from the wireless device  1502  may be provided to the processing system  1518  of the wireless device  1502 . The processing system  1508  and the processing system  1518  may implement layer 3 and layer 2 OSI functionality to process the data for transmission. Layer 2 may include an SDAP layer, a PDCP layer, an RLC layer, and a MAC layer, for example, with respect to  FIG. 2A ,  FIG. 2B ,  FIG. 3 , and  FIG. 4A . Layer 3 may include an RRC layer as with respect to  FIG. 2B . 
     After being processed by processing system  1508 , the data to be sent to the wireless device  1502  may be provided to a transmission processing system  1510  of base station  1504 . Similarly, after being processed by the processing system  1518 , the data to be sent to base station  1504  may be provided to a transmission processing system  1520  of the wireless device  1502 . The transmission processing system  1510  and the transmission processing system  1520  may implement layer 1 OSI functionality. Layer 1 may include a PHY layer with respect to  FIG. 2A ,  FIG. 2B ,  FIG. 3 , and  FIG. 4A . For transmit processing, the PHY layer may perform, for example, forward error correction coding of transport channels, interleaving, rate matching, mapping of transport channels to physical channels, modulation of physical channel, multiple-input multiple-output (MIMO) or multi-antenna processing, and/or the like. 
     At the base station  1504 , a reception processing system  1512  may receive the uplink transmission from the wireless device  1502 . At the wireless device  1502 , a reception processing system  1522  may receive the downlink transmission from base station  1504 . The reception processing system  1512  and the reception processing system  1522  may implement layer 1 OSI functionality. Layer 1 may include a PHY layer with respect to  FIG. 2A ,  FIG. 2B ,  FIG. 3 , and  FIG. 4A . For receive processing, the PHY layer may perform, for example, error detection, forward error correction decoding, deinterleaving, demapping of transport channels to physical channels, demodulation of physical channels, MIMO or multi-antenna processing, and/or the like. 
     As shown in  FIG. 15 , a wireless device  1502  and the base station  1504  may include multiple antennas. The multiple antennas may be used to perform one or more MIMO or multi-antenna techniques, such as spatial multiplexing (e.g., single-user MIMO or multi-user MIMO), transmit/receive diversity, and/or beamforming. In other examples, the wireless device  1502  and/or the base station  1504  may have a single antenna. 
     The processing system  1508  and the processing system  1518  may be associated with a memory  1514  and a memory  1524 , respectively. Memory  1514  and memory  1524  (e.g., one or more non-transitory computer readable mediums) may store computer program instructions or code that may be executed by the processing system  1508  and/or the processing system  1518  to carry out one or more of the functionalities discussed in the present application. Although not shown in  FIG. 15 , the transmission processing system  1510 , the transmission processing system  1520 , the reception processing system  1512 , and/or the reception processing system  1522  may be coupled to a memory (e.g., one or more non-transitory computer readable mediums) storing computer program instructions or code that may be executed to carry out one or more of their respective functionalities. 
     The processing system  1508  and/or the processing system  1518  may comprise one or more controllers and/or one or more processors. The one or more controllers and/or one or more processors may comprise, for example, a general-purpose processor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) and/or other programmable logic device, discrete gate and/or transistor logic, discrete hardware components, an on-board unit, or any combination thereof. The processing system  1508  and/or the processing system  1518  may perform at least one of signal coding/processing, data processing, power control, input/output processing, and/or any other functionality that may enable the wireless device  1502  and the base station  1504  to operate in a wireless environment. 
     The processing system  1508  and/or the processing system  1518  may be connected to one or more peripherals  1516  and one or more peripherals  1526 , respectively. The one or more peripherals  1516  and the one or more peripherals  1526  may include software and/or hardware that provide features and/or functionalities, for example, a speaker, a microphone, a keypad, a display, a touchpad, a power source, a satellite transceiver, a universal serial bus (USB) port, a hands-free headset, a frequency modulated (FM) radio unit, a media player, an Internet browser, an electronic control unit (e.g., for a motor vehicle), and/or one or more sensors (e.g., an accelerometer, a gyroscope, a temperature sensor, a radar sensor, a lidar sensor, an ultrasonic sensor, a light sensor, a camera, and/or the like). The processing system  1508  and/or the processing system  1518  may receive user input data from and/or provide user output data to the one or more peripherals  1516  and/or the one or more peripherals  1526 . The processing system  1518  in the wireless device  1502  may receive power from a power source and/or may be configured to distribute the power to the other components in the wireless device  1502 . The power source may comprise one or more sources of power, for example, a battery, a solar cell, a fuel cell, or any combination thereof. The processing system  1508  and/or the processing system  1518  may be connected to a GPS chipset  1517  and a GPS chipset  1527 , respectively. The GPS chipset  1517  and the GPS chipset  1527  may be configured to provide geographic location information of the wireless device  1502  and the base station  1504 , respectively. 
       FIG. 16A  illustrates an example structure for uplink transmission. A baseband signal representing a physical uplink shared channel may perform one or more functions. The one or more functions may comprise at least one of: scrambling; modulation of scrambled bits to generate complex-valued symbols; mapping of the complex-valued modulation symbols onto one or several transmission layers; transform precoding to generate complex-valued symbols; precoding of the complex-valued symbols; mapping of precoded complex-valued symbols to resource elements; generation of complex-valued time-domain Single Carrier-Frequency Division Multiple Access (SC-FDMA) or CP-OFDM signal for an antenna port; and/or the like. In an example, when transform precoding is enabled, a SC-FDMA signal for uplink transmission may be generated. In an example, when transform precoding is not enabled, an CP-OFDM signal for uplink transmission may be generated by  FIG. 16A . These functions are illustrated as examples and it is anticipated that other mechanisms may be implemented in various embodiments. 
       FIG. 16B  illustrates an example structure for modulation and up-conversion of a baseband signal to a carrier frequency. The baseband signal may be a complex-valued SC-FDMA or CP-OFDM baseband signal for an antenna port and/or a complex-valued Physical Random Access Channel (PRACH) baseband signal. Filtering may be employed prior to transmission. 
       FIG. 16C  illustrates an example structure for downlink transmissions. A baseband signal representing a physical downlink channel may perform one or more functions. The one or more functions may comprise: scrambling of coded bits in a codeword to be transmitted on a physical channel; modulation of scrambled bits to generate complex-valued modulation symbols; mapping of the complex-valued modulation symbols onto one or several transmission layers; precoding of the complex-valued modulation symbols on a layer for transmission on the antenna ports; mapping of complex-valued modulation symbols for an antenna port to resource elements; generation of complex-valued time-domain OFDM signal for an antenna port; and/or the like. These functions are illustrated as examples and it is anticipated that other mechanisms may be implemented in various embodiments. 
       FIG. 16D  illustrates another example structure for modulation and up-conversion of a baseband signal to a carrier frequency. The baseband signal may be a complex-valued OFDM baseband signal for an antenna port. Filtering may be employed prior to transmission. 
     A wireless device may receive from a base station one or more messages (e.g. RRC messages) comprising configuration parameters of a plurality of cells (e.g. primary cell, secondary cell). The wireless device may communicate with at least one base station (e.g. two or more base stations in dual-connectivity) via the plurality of cells. The one or more messages (e.g. as a part of the configuration parameters) may comprise parameters of physical, MAC, RLC, PCDP, SDAP, RRC layers for configuring the wireless device. For example, the configuration parameters may comprise parameters for configuring physical and MAC layer channels, bearers, etc. For example, the configuration parameters may comprise parameters indicating values of timers for physical, MAC, RLC, PCDP, SDAP, RRC layers, and/or communication channels. 
     A timer may begin running once it is started and continue running until it is stopped or until it expires. A timer may be started if it is not running or restarted if it is running. A timer may be associated with a value (e.g. the timer may be started or restarted from a value or may be started from zero and expire once it reaches the value). The duration of a timer may not be updated until the timer is stopped or expires (e.g., due to BWP switching). A timer may be used to measure a time period/window for a process. When the specification refers to an implementation and procedure related to one or more timers, it will be understood that there are multiple ways to implement the one or more timers. For example, it will be understood that one or more of the multiple ways to implement a timer may be used to measure a time period/window for the procedure. For example, a random access response window timer may be used for measuring a window of time for receiving a random access response. In an example, instead of starting and expiry of a random access response window timer, the time difference between two time stamps may be used. When a timer is restarted, a process for measurement of time window may be restarted. Other example implementations may be provided to restart a measurement of a time window. 
     A gNB may transmit one or more MAC PDUs to a wireless device. In an example, a MAC PDU may be a bit string that is byte aligned (e.g., a multiple of eight bits) in length. In an example, bit strings may be represented by tables in which the most significant bit is the leftmost bit of the first line of the table, and the least significant bit is the rightmost bit on the last line of the table. More generally, the bit string may be read from left to right and then in the reading order of the lines. In an example, the bit order of a parameter field within a MAC PDU is represented with the first and most significant bit in the leftmost bit and the last and least significant bit in the rightmost bit. 
     In an example, a MAC SDU may be a bit string that is byte aligned (e.g., a multiple of eight bits) in length. In an example, a MAC SDU may be included in a MAC PDU from the first bit onward. A MAC CE may be a bit string that is byte aligned (e.g., a multiple of eight bits) in length. A MAC subheader may be a bit string that is byte aligned (e.g., a multiple of eight bits) in length. In an example, a MAC subheader may be placed immediately in front of a corresponding MAC SDU, MAC CE, or padding. A MAC entity may ignore a value of reserved bits in a DL MAC PDU. 
     In an example, a MAC PDU may comprise one or more MAC subPDUs. A MAC subPDU of the one or more MAC subPDUs may comprise: a MAC subheader only (including padding); a MAC subheader and a MAC SDU; a MAC subheader and a MAC CE; and/or a MAC subheader and padding. The MAC SDU may be of variable size. A MAC subheader may correspond to a MAC SDU, a MAC CE, or padding. 
     In an example, when a MAC subheader corresponds to a MAC SDU, a variable-sized MAC CE, or padding, the MAC subheader may comprise: an R field with a one bit length; an F field with a one bit length; an LCID field with a multi-bit length; and/or an L field with a multi-bit length. 
       FIG. 17A  shows an example of a MAC subheader with an R field, an F field, an LCID field, and an L field. In the example MAC subheader of  FIG. 17A , the LCID field may be six bits in length, and the L field may be eight bits in length.  FIG. 17B  shows example of a MAC subheader with an R field, a F field, an LCID field, and an L field. In the example MAC subheader of  FIG. 17B , the LCID field may be six bits in length, and the L field may be sixteen bits in length. When a MAC subheader corresponds to a fixed sized MAC CE or padding, the MAC subheader may comprise: an R field with a two bit length and an LCID field with a multi-bit length.  FIG. 17C  shows an example of a MAC subheader with an R field and an LCID field. In the example MAC subheader of  FIG. 17C , the LCID field may be six bits in length, and the R field may be two bits in length. 
       FIG. 18A  shows an example of a DL MAC PDU. Multiple MAC CEs, such as MAC CE 1 and 2, may be placed together. A MAC subPDU comprising a MAC CE may be placed before any MAC subPDU comprising a MAC SDU or a MAC subPDU comprising padding.  FIG. 18B  shows an example of a UL MAC PDU. Multiple MAC CEs, such as MAC CE 1 and 2, may be placed together. A MAC subPDU comprising a MAC CE may be placed after all MAC subPDUs comprising a MAC SDU. In addition, the MAC subPDU may be placed before a MAC subPDU comprising padding. 
     In an example, a MAC entity of a gNB may transmit one or more MAC CEs to a MAC entity of a wireless device.  FIG. 19  shows an example of multiple LCIDs that may be associated with the one or more MAC CEs. The one or more MAC CEs comprise at least one of: a SP ZP CSI-RS Resource Set Activation/Deactivation MAC CE, a PUCCH spatial relation Activation/Deactivation MAC CE, a SP SRS Activation/Deactivation MAC CE, a SP CSI reporting on PUCCH Activation/Deactivation MAC CE, a TCI State Indication for UE-specific PDCCH MAC CE, a TCI State Indication for UE-specific PDSCH MAC CE, an Aperiodic CSI Trigger State Subselection MAC CE, a SP CSI-RS/CSI-IM Resource Set Activation/Deactivation MAC CE, a UE contention resolution identity MAC CE, a timing advance command MAC CE, a DRX command MAC CE, a Long DRX command MAC CE, an SCell activation/deactivation MAC CE (1 Octet), an SCell activation/deactivation MAC CE (4 Octet), and/or a duplication activation/deactivation MAC CE. In an example, a MAC CE, such as a MAC CE transmitted by a MAC entity of a gNB to a MAC entity of a wireless device, may have an LCID in the MAC subheader corresponding to the MAC CE. Different MAC CE may have different LCID in the MAC subheader corresponding to the MAC CE. For example, an LCID given by 111011 in a MAC subheader may indicate that a MAC CE associated with the MAC subheader is a long DRX command MAC CE. 
     In an example, the MAC entity of the wireless device may transmit to the MAC entity of the gNB one or more MAC CEs.  FIG. 20  shows an example of the one or more MAC CEs. The one or more MAC CEs may comprise at least one of: a short buffer status report (BSR) MAC CE, a long BSR MAC CE, a C-RNTI MAC CE, a configured grant confirmation MAC CE, a single entry PHR MAC CE, a multiple entry PHR MAC CE, a short truncated BSR, and/or a long truncated BSR. In an example, a MAC CE may have an LCID in the MAC subheader corresponding to the MAC CE. Different MAC CE may have different LCID in the MAC subheader corresponding to the MAC CE. For example, an LCID given by 111011 in a MAC subheader may indicate that a MAC CE associated with the MAC subheader is a short-truncated command MAC CE. 
     In carrier aggregation (CA), two or more component carriers (CCs) may be aggregated. A wireless device may simultaneously receive or transmit on one or more CCs, depending on capabilities of the wireless device, using the technique of CA. In an example, a wireless device may support CA for contiguous CCs and/or for non-contiguous CCs. CCs may be organized into cells. For example, CCs may be organized into one primary cell (PCell) and one or more secondary cells (SCells). When configured with CA, a wireless device may have one RRC connection with a network. During an RRC connection establishment/re-establishment/handover, a cell providing NAS mobility information may be a serving cell. During an RRC connection re-establishment/handover procedure, a cell providing a security input may be a serving cell. In an example, the serving cell may denote a PCell. In an example, a gNB may transmit, to a wireless device, one or more messages comprising configuration parameters of a plurality of one or more SCells, depending on capabilities of the wireless device. 
     When configured with CA, a base station and/or a wireless device may employ an activation/deactivation mechanism of an SCell to improve battery or power consumption of the wireless device. When a wireless device is configured with one or more SCells, a gNB may activate or deactivate at least one of the one or more SCells. Upon configuration of an SCell, the SCell may be deactivated unless an SCell state associated with the SCell is set to “activated” or “dormant”. 
     A wireless device may activate/deactivate an SCell in response to receiving an SCell Activation/Deactivation MAC CE. In an example, a gNB may transmit, to a wireless device, one or more messages comprising an SCell timer (e.g., sCellDeactivationTimer). In an example, a wireless device may deactivate an SCell in response to an expiry of the SCell timer. 
     When a wireless device receives an SCell Activation/Deactivation MAC CE activating an SCell, the wireless device may activate the SCell. In response to the activating the SCell, the wireless device may perform operations comprising SRS transmissions on the SCell; CQI/PMI/RI/CRI reporting for the SCell; PDCCH monitoring on the SCell; PDCCH monitoring for the SCell; and/or PUCCH transmissions on the SCell. In response to the activating the SCell, the wireless device may start or restart a first SCell timer (e.g., sCellDeactivationTimer) associated with the SCell. The wireless device may start or restart the first SCell timer in the slot when the SCell Activation/Deactivation MAC CE activating the SCell has been received. In an example, in response to the activating the SCell, the wireless device may (re-)initialize one or more suspended configured uplink grants of a configured grant Type 1 associated with the SCell according to a stored configuration. In an example, in response to the activating the SCell, the wireless device may trigger PHR. 
     When a wireless device receives an SCell Activation/Deactivation MAC CE deactivating an activated SCell, the wireless device may deactivate the activated SCell. In an example, when a first SCell timer (e.g., sCellDeactivationTimer) associated with an activated SCell expires, the wireless device may deactivate the activated SCell. In response to the deactivating the activated SCell, the wireless device may stop the first SCell timer associated with the activated SCell. In an example, in response to the deactivating the activated SCell, the wireless device may clear one or more configured downlink assignments and/or one or more configured uplink grants of a configured uplink grant Type 2 associated with the activated SCell. In an example, in response to the deactivating the activated SCell, the wireless device may: suspend one or more configured uplink grants of a configured uplink grant Type 1 associated with the activated SCell; and/or flush HARQ buffers associated with the activated SCell. 
     When an SCell is deactivated, a wireless device may not perform operations comprising: transmitting SRS on the SCell; reporting CQI/PMI/RI/CRI for the SCell; transmitting on UL-SCH on the SCell; transmitting on RACH on the SCell; monitoring at least one first PDCCH on the SCell; monitoring at least one second PDCCH for the SCell; and/or transmitting a PUCCH on the SCell. When at least one first PDCCH on an activated SCell indicates an uplink grant or a downlink assignment, a wireless device may restart a first SCell timer (e.g., sCellDeactivationTimer) associated with the activated SCell. In an example, when at least one second PDCCH on a serving cell (e.g. a PCell or an SCell configured with PUCCH, i.e. PUCCH SCell) scheduling the activated SCell indicates an uplink grant or a downlink assignment for the activated SCell, a wireless device may restart the first SCell timer (e.g., sCellDeactivationTimer) associated with the activated SCell. In an example, when an SCell is deactivated, if there is an ongoing random access procedure on the SCell, a wireless device may abort the ongoing random access procedure on the SCell. 
       FIG. 21A  shows an example of an SCell Activation/Deactivation MAC CE of one octet. A first MAC PDU subheader with a first LCID (e.g., ‘111010’ as shown in  FIG. 19 ) may identify the SCell Activation/Deactivation MAC CE of one octet. The SCell Activation/Deactivation MAC CE of one octet may have a fixed size. The SCell Activation/Deactivation MAC CE of one octet may comprise a single octet. The single octet may comprise a first number of C-fields (e.g. seven) and a second number of R-fields (e.g., one).  FIG. 21B  shows an example of an SCell Activation/Deactivation MAC CE of four octets. A second MAC PDU subheader with a second LCID (e.g., ‘111001’ as shown in  FIG. 19 ) may identify the SCell Activation/Deactivation MAC CE of four octets. The SCell Activation/Deactivation MAC CE of four octets may have a fixed size. The SCell Activation/Deactivation MAC CE of four octets may comprise four octets. The four octets may comprise a third number of C-fields (e.g.,  31 ) and a fourth number of R-fields (e.g.,  1 ). 
     In  FIG. 21A  and/or  FIG. 21B , a C i  field may indicate an activation/deactivation status of an SCell with an SCell index i if an SCell with SCell index i is configured. In an example, when the C i  field is set to one, an SCell with an SCell index i may be activated. In an example, when the C i  field is set to zero, an SCell with an SCell index i may be deactivated. In an example, if there is no SCell configured with SCell index i, the wireless device may ignore the C i  field. In  FIG. 21A  and  FIG. 21B , an R field may indicate a reserved bit. The R field may be set to zero. 
     When configured with CA, a base station and/or a wireless device may employ a hibernation mechanism for an SCell to improve battery or power consumption of the wireless device and/or to improve latency of SCell activation/addition. When the wireless device hibernates the SCell, the SCell may be transitioned into a dormant state. In response to the SCell being transitioned into a dormant state, the wireless device may: stop transmitting SRS on the SCell; report CQI/PMI/RI/PTI/CRI for the SCell according to a periodicity configured for the SCell in a dormant state; not transmit on UL-SCH on the SCell; not transmit on RACH on the SCell; not monitor the PDCCH on the SCell; not monitor the PDCCH for the SCell; and/or not transmit PUCCH on the SCell. In an example, reporting CSI for an SCell and not monitoring the PDCCH on/for the SCell, when the SCell is in a dormant state, may provide the base station an always-updated CSI for the SCell. With the always-updated CSI, the base station may employ a quick and/or accurate channel adaptive scheduling on the SCell once the SCell is transitioned back into active state, thereby speeding up the activation procedure of the SCell. In an example, reporting CSI for the SCell and not monitoring the PDCCH on/for the SCell, when the SCell is in dormant state, may improve battery or power consumption of the wireless device, while still providing the base station timely and/or accurate channel information feedback. In an example, a PCell/PSCell and/or a PUCCH secondary cell may not be configured or transitioned into dormant state. 
     When configured with one or more SCells, a gNB may activate, hibernate, or deactivate at least one of the one or more SCells. In an example, a gNB may transmit one or more RRC messages comprising parameters indicating at least one SCell being set to an active state, a dormant state, or an inactive state, to a wireless device. In an example, when an SCell is in an active state, the wireless device may perform: SRS transmissions on the SCell; CQI/PMI/RI/CRI reporting for the SCell; PDCCH monitoring on the SCell; PDCCH monitoring for the SCell; and/or PUCCH/SPUCCH transmissions on the SCell. 
     When an SCell is in an inactive state, the wireless device may: not transmit SRS on the SCell; not report CQI/PMI/RI/CRI for the SCell; not transmit on UL-SCH on the SCell; not transmit on RACH on the SCell; not monitor PDCCH on the SCell; not monitor PDCCH for the SCell; and/or not transmit PUCCH/SPUCCH on the SCell. When an SCell is in a dormant state, the wireless device may: not transmit SRS on the SCell; report CQI/PMI/RI/CRI for the SCell; not transmit on UL-SCH on the SCell; not transmit on RACH on the SCell; not monitor PDCCH on the SCell; not monitor PDCCH for the SCell; and/or not transmit PUCCH/SPUCCH on the SCell. When configured with one or more SCells, a gNB may activate, hibernate, or deactivate at least one of the one or more SCells. In an example, a gNB may transmit one or more MAC control elements comprising parameters indicating activation, deactivation, or hibernation of at least one SCell to a wireless device. 
     In an example, a gNB may transmit a first MAC CE (e.g., activation/deactivation MAC CE, as shown in  FIG. 21A  or  FIG. 21B ) indicating activation or deactivation of at least one SCell to a wireless device. In  FIG. 21A  and/or  FIG. 21B , a C i  field may indicate an activation/deactivation status of an SCell with an SCell index i if an SCell with SCell index i is configured. In an example, when the C i  field is set to one, an SCell with an SCell index i may be activated. In an example, when the C i  field is set to zero, an SCell with an SCell index i may be deactivated. In an example, if there is no SCell configured with SCell index i, the wireless device may ignore the C i  field. In  FIG. 21A  and  FIG. 21B , an R field may indicate a reserved bit. In an example, the R field may be set to zero. 
     In an example, a gNB may transmit a second MAC CE (e.g., hibernation MAC CE) indicating activation or hibernation of at least one SCell to a wireless device. In an example, the second MAC CE may be associated with a second LCID different from a first LCID of the first MAC CE (e.g., activation/deactivation MAC CE). In an example, the second MAC CE may have a fixed size. In an example, the second MAC CE may consist of a single octet containing seven C-fields and one R-field.  FIG. 22A  shows an example of the second MAC CE with a single octet. In another example, the second MAC CE may consist of four octets containing 31 C-fields and one R-field.  FIG. 22B  shows an example of the second MAC CE with four octets. In an example, the second MAC CE with four octets may be associated with a third LCID different from the second LCID for the second MAC CE with a single octet, and/or the first LCID for activation/deactivation MAC CE. In an example, when there is no SCell with a serving cell index greater than 7, the second MAC CE of one octet may be applied, otherwise the second MAC CE of four octets may be applied. 
     In an example, when the second MAC CE is received, and the first MAC CE is not received, C i  may indicate a dormant/activated status of an SCell with SCell index i if there is an SCell configured with SCell index i, otherwise the MAC entity may ignore the C i  field. In an example, when C i  is set to “1”, the wireless device may transition an SCell associated with SCell index i into a dormant state. In an example, when C i  is set to “0”, the wireless device may activate an SCell associated with SCell index i. In an example, when C i  is set to “0” and the SCell with SCell index i is in a dormant state, the wireless device may activate the SCell with SCell index i. In an example, when C i  is set to “0” and the SCell with SCell index i is not in a dormant state, the wireless device may ignore the C i  field. 
     In an example, when both the first MAC CE (activation/deactivation MAC CE) and the second MAC CE (hibernation MAC CE) are received, two C i  fields of the two MAC CEs may indicate possible state transitions of the SCell with SCell index i if there is an SCell configured with SCell index i, otherwise the MAC entity may ignore the C i  fields. In an example, the C, fields of the two MAC CEs may be interpreted according to  FIG. 22C . 
     When configured with one or more SCells, a gNB may activate, hibernate, or deactivate at least one of the one or more SCells. In an example, a MAC entity of a gNB and/or a wireless device may maintain an SCell deactivation timer (e.g., sCellDeactivationTimer) per configured SCell (except the SCell configured with PUCCH/SPUCCH, if any) and deactivate the associated SCell upon its expiry. 
     In an example, a MAC entity of a gNB and/or a wireless device may maintain an SCell hibernation timer (e.g., sCellHibernationTimer) per configured SCell (except the SCell configured with PUCCH/SPUCCH, if any) and hibernate the associated SCell upon the SCell hibernation timer expiry if the SCell is in active state. In an example, when both the SCell deactivation timer and the SCell hibernation timer are configured, the SCell hibernation timer may take priority over the SCell deactivation timer. In an example, when both the SCell deactivation timer and the SCell hibernation timer are configured, a gNB and/or a wireless device may ignore the SCell deactivation timer regardless of the SCell deactivation timer expiry. 
     In an example, a MAC entity of a gNB and/or a wireless device may maintain a dormant SCell deactivation timer (e.g., dormantSCellDeactivationTimer) per configured SCell (except the SCell configured with PUCCH/SPUCCH, if any), and deactivate the associated SCell upon the dormant SCell deactivation timer expiry if the SCell is in dormant state. 
     In an example, when a MAC entity of a wireless device is configured with an activated SCell upon SCell configuration, the MAC entity may activate the SCell. In an example, when a MAC entity of a wireless device receives a MAC CE(s) activating an SCell, the MAC entity may activate the SCell. In an example, the MAC entity may start or restart the SCell deactivation timer associated with the SCell in response to activating the SCell. In an example, the MAC entity may start or restart the SCell hibernation timer (if configured) associated with the SCell in response to activating the SCell. In an example, the MAC entity may trigger PHR procedure in response to activating the SCell. 
     In an example, when a MAC entity of a wireless device receives a MAC CE(s) indicating deactivating an SCell, the MAC entity may deactivate the SCell. In an example, in response to receiving the MAC CE(s), the MAC entity may: deactivate the SCell; stop an SCell deactivation timer associated with the SCell; and/or flush all HARQ buffers associated with the SCell. In an example, when an SCell deactivation timer associated with an activated SCell expires and an SCell hibernation timer is not configured, the MAC entity may: deactivate the SCell; stop the SCell deactivation timer associated with the SCell; and/or flush all HARQ buffers associated with the SCell. 
     In an example, when a first PDCCH on an activated SCell indicates an uplink grant or downlink assignment, or a second PDCCH on a serving cell scheduling an activated SCell indicates an uplink grant or a downlink assignment for the activated SCell, or a MAC PDU is transmitted in a configured uplink grant or received in a configured downlink assignment, the MAC entity may: restart the SCell deactivation timer associated with the SCell; and/or restart the SCell hibernation timer associated with the SCell if configured. In an example, when an SCell is deactivated, an ongoing random access procedure on the SCell may be aborted. 
     In an example, when a MAC entity is configured with an SCell associated with an SCell state set to dormant state upon the SCell configuration, or when the MAC entity receives MAC CE(s) indicating transitioning the SCell into a dormant state, the MAC entity may: transition the SCell into a dormant state; transmit one or more CSI reports for the SCell; stop an SCell deactivation timer associated with the SCell; stop an SCell hibernation timer associated with the SCell if configured; start or restart a dormant SCell deactivation timer associated with the SCell; and/or flush all HARQ buffers associated with the SCell. In an example, when the SCell hibernation timer associated with the activated SCell expires, the MAC entity may: hibernate the SCell; stop the SCell deactivation timer associated with the SCell; stop the SCell hibernation timer associated with the SCell; and/or flush all HARQ buffers associated with the SCell. In an example, when a dormant SCell deactivation timer associated with a dormant SCell expires, the MAC entity may: deactivate the SCell; and/or stop the dormant SCell deactivation timer associated with the SCell. In an example, when an SCell is in dormant state, ongoing random access procedure on the SCell may be aborted. 
     A base station (gNB) may configure a wireless device (UE) with uplink (UL) bandwidth parts (BWPs) and downlink (DL) BWPs to enable bandwidth adaptation (BA) on a PCell. If carrier aggregation is configured, the gNB may further configure the UE with at least DL BWP(s) (i.e., there may be no UL BWPs in the UL) to enable BA on an SCell. For the PCell, an initial active BWP may be a first BWP used for initial access. For the SCell, a first active BWP may be a second BWP configured for the UE to operate on the SCell upon the SCell being activated. In paired spectrum (e.g. FDD), a gNB and/or a UE may independently switch a DL BWP and an UL BWP. In unpaired spectrum (e.g. TDD), a gNB and/or a UE may simultaneously switch a DL BWP and an UL BWP. 
     In an example, a gNB and/or a UE may switch a BWP between configured BWPs by means of a DCI or a BWP inactivity timer. When the BWP inactivity timer is configured for a serving cell, the gNB and/or the UE may switch an active BWP to a default BWP in response to an expiry of the BWP inactivity timer associated with the serving cell. The default BWP may be configured by the network. In an example, for FDD systems, when configured with BA, one UL BWP for each uplink carrier and one DL BWP may be active at a time in an active serving cell. In an example, for TDD systems, one DL/UL BWP pair may be active at a time in an active serving cell. Operating on the one UL BWP and the one DL BWP (or the one DL/UL pair) may improve UE battery consumption. BWPs other than the one active UL BWP and the one active DL BWP that the UE may work on may be deactivated. On deactivated BWPs, the UE may: not monitor PDCCH; and/or not transmit on PUCCH, PRACH, and UL-SCH. 
     In an example, a serving cell may be configured with at most a first number (e.g., four) of BWPs. In an example, for an activated serving cell, there may be one active BWP at any point in time. In an example, a BWP switching for a serving cell may be used to activate an inactive BWP and deactivate an active BWP at a time. In an example, the BWP switching may be controlled by a PDCCH indicating a downlink assignment or an uplink grant. In an example, the BWP switching may be controlled by a BWP inactivity timer (e.g., bwp-InactivityTimer). In an example, the BWP switching may be controlled by a MAC entity in response to initiating a Random Access procedure. Upon addition of an SpCell or activation of an SCell, one BWP may be initially active without receiving a PDCCH indicating a downlink assignment or an uplink grant. The active BWP for a serving cell may be indicated by RRC and/or PDCCH. In an example, for unpaired spectrum, a DL BWP may be paired with a UL BWP, and BWP switching may be common for both UL and DL. 
       FIG. 23  shows an example of BWP switching on an SCell. In an example, a UE may receive RRC message comprising parameters of a SCell and one or more BWP configuration associated with the SCell. The RRC message may comprise: RRC connection reconfiguration message (e.g., RRCReconfiguration); RRC connection reestablishment message (e.g., RR CR establishment); and/or RRC connection setup message (e.g., RRCSetup). Among the one or more BWPs, at least one BWP may be configured as the first active BWP (e.g., BWP 1), one BWP as the default BWP (e.g., BWP 0). The UE may receive a MAC CE to activate the SCell at n th  slot. The UE may start a SCell deactivation timer (e.g., sCellDeactivationTimer), and start CSI related actions for the SCell, and/or start CSI related actions for the first active BWP of the SCell. The UE may start monitoring a PDCCH on BWP 1 in response to activating the SCell. 
     In an example, the UE may start restart a BWP inactivity timer (e.g., bwp-InactivityTimer) at m th  slot in response to receiving a DCI indicating DL assignment on BWP 1. The UE may switch back to the default BWP (e.g., BWP 0) as an active BWP when the BWP inactivity timer expires, at s th  slot. The UE may deactivate the SCell and/or stop the BWP inactivity timer when the sCellDeactivationTimer expires. 
     In an example, a MAC entity may apply normal operations on an active BWP for an activated serving cell configured with a BWP comprising: transmitting on UL-SCH; transmitting on RACH; monitoring a PDCCH; transmitting PUCCH; receiving DL-SCH; and/or (re-) initializing any suspended configured uplink grants of configured grant Type 1 according to a stored configuration, if any. 
     In an example, on an inactive BWP for each activated serving cell configured with a BWP, a MAC entity may: not transmit on UL-SCH; not transmit on RACH; not monitor a PDCCH; not transmit PUCCH; not transmit SRS, not receive DL-SCH; clear any configured downlink assignment and configured uplink grant of configured grant Type 2; and/or suspend any configured uplink grant of configured Type 1. 
     In an example, if a MAC entity receives a PDCCH for a BWP switching of a serving cell while a Random Access procedure associated with this serving cell is not ongoing, a UE may perform the BWP switching to a BWP indicated by the PDCCH. In an example, if a bandwidth part indicator field is configured in DCI format 1_1, the bandwidth part indicator field value may indicate the active DL BWP, from the configured DL BWP set, for DL receptions. In an example, if a bandwidth part indicator field is configured in DCI format 0_1, the bandwidth part indicator field value may indicate the active UL BWP, from the configured UL BWP set, for UL transmissions. 
     In an example, for a primary cell, a UE may be provided by a higher layer parameter Default-DL-BWP a default DL BWP among the configured DL BWPs. If a UE is not provided a default DL BWP by the higher layer parameter Default-DL-BWP, the default DL BWP is the initial active DL BWP. In an example, a UE may be provided by higher layer parameter bwp-InactivnyTimer, a timer value for the primary cell. If configured, the UE may increment the timer, if running, every interval of 1 millisecond for frequency range 1 or every 0.5 milliseconds for frequency range 2 if the UE may not detect a DCI format 1_1 for paired spectrum operation or if the UE may not detect a DCI format 1_1 or DCI format 0_1 for unpaired spectrum operation during the interval. 
     In an example, if a UE is configured for a secondary cell with higher layer parameter Default-DL-BWP indicating a default DL BWP among the configured DL BWPs and the UE is configured with higher layer parameter bwp-InactivnyTimer indicating a timer value, the UE procedures on the secondary cell may be same as on the primary cell using the timer value for the secondary cell and the default DL BWP for the secondary cell. 
     In an example, if a UE is configured by higher layer parameter Active-BWP-DL-SCell a first active DL BWP and by higher layer parameter Active-BWP-UL-SCell a first active UL BWP on a secondary cell or carrier, the UE may use the indicated DL BWP and the indicated UL BWP on the secondary cell as the respective first active DL BWP and first active UL BWP on the secondary cell or carrier. 
     In an example, a set of PDCCH candidates for a wireless device to monitor is defined in terms of PDCCH search space sets. A search space set comprises a CSS set or a USS set. A wireless device monitors PDCCH candidates in one or more of the following search spaces sets: a Type0-PDCCH CSS set configured by pdcch-ConfigSIB1 in MIB or by searchSpaceSIB1 in PDCCH-ConfigCommon or by searchSpaceZero in PDCCH-ConfigCommon for a DCI format with CRC scrambled by a SI-RNTI on the primary cell of the MCG, a Type0A-PDCCH CSS set configured by searchSpaceOtherSystemInformation in PDCCH-ConfigCommon for a DCI format with CRC scrambled by a SI-RNTI on the primary cell of the MCG, a Type1-PDCCH CSS set configured by ra-SearchSpace in PDCCH-ConfigCommon for a DCI format with CRC scrambled by a RA-RNTI or a TC-RNTI on the primary cell, a Type2-PDCCH CSS set configured by pagingSearchSpace in PDCCH-ConfigCommon for a DCI format with CRC scrambled by a P-RNTI on the primary cell of the MCG, a Type3-PDCCH CSS set configured by SearchSpace in PDCCH-Config with searchSpaceType=common for DCI formats with CRC scrambled by INT-RNTI, SFI-RNTI, TPC-PUSCH-RNTI, TPC-PUCCH-RNTI, or TPC-SRS-RNTI and, only for the primary cell, C-RNTI, MCS-C-RNTI, or CS-RNTI(s), and a USS set configured by SearchSpace in PDCCH-Config with searchSpaceType=ue-Specific for DCI formats with CRC scrambled by C-RNTI, MCS-C-RNTI, SP-CSI-RNTI, or CS-RNTI(s). 
     In an example, a wireless device determines a PDCCH monitoring occasion on an active DL BWP based on one or more PDCCH configuration parameters comprising: a PDCCH monitoring periodicity, a PDCCH monitoring offset, and a PDCCH monitoring pattern within a slot. For a search space set (SS s), the wireless device determines that a PDCCH monitoring occasion(s) exists in a slot with number n s,f   μ  in a frame with number n f  if (n f ·N slot   frame, μ +n s,f   μ −o s ) mod k s =0. N slot   frame,μ  is a number of slot in a frame when numerology μ is configured. o s  is a slot offset indicated in the PDCCH configuration parameters. k s  is a PDCCH monitoring periodicity indicated in the PDCCH configuration parameters. The wireless device monitors PDCCH candidates for the search space set for T s  consecutive slots, starting from slot n s,f   μ , and does not monitor PDCCH candidates for search space set s for the next k s −T s  consecutive slots. In an example, a USS at CCE aggregation level L∈{1, 2, 4, 8, 16} is defined by a set of PDCCH candidates for CCE aggregation level L. If a wireless device is configured with CrossCarrierSchedulingConfig for a serving cell, the carrier indicator field value corresponds to the value indicated by CrossCarrierSchedulingConfig. 
     In an example, a wireless device decides, for a search space set s associated with CORESET p, CCE indexes for aggregation level L corresponding to PDCCH candidate m s,n     CI    of the search space set in slot n s,f   μ  for an active DL BWP of a serving cell corresponding to carrier indicator field value n CI  as 
     
       
         
           
             
               
                 
                   
                     
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     where, 
     Y p,n     s,f       μ   =0 for any CSS; Y p,n     s,f       μ   =(A p ·Y p,n     s,f       μ     −1 ) mod D for a USS, Y p,−1 =n RNTI ≠0, A p =39827 for p mod 3=0, A p =39829 for p mod 3=1, A p =39839 for p mod 3=2, and D=65537; i=0, . . . , L−1; N CCE,p  is the number of CCEs, numbered from 0 to N CCE,p −1, in CORESET p; n CI  is the carrier indicator field value if the wireless device is configured with a carrier indicator field by CrossCarrierSchedulingConfig for the serving cell on which PDCCH is monitored; otherwise, including for any CSS, n CI =0; m s,n     CI   =0, . . . , M s,n     CI     (L) −1, where M s,n     CI     (L)  is the number of PDCCH candidates the wireless device is configured to monitor for aggregation level L of a search space set s for a serving cell corresponding to n CI ; for any CSS, M s,max   (L) =M s,0   (L) ; for a USS, M s,max   (L)  is the maximum of M s,n     CI     (L)  over all configured n CI  values for a CCE aggregation level L of search space set s; and the RNTI value used for n RNTI  is the C-RNTI. 
     In an example, DRX operation may be used by a UE to improve UE battery lifetime. With DRX configured, UE may discontinuously monitor downlink control channel, e.g., PDCCH or EPDCCH. A base station may configure DRX operation with a set of DRX parameters, e.g., using RRC configuration. The set of DRX parameters may be selected based on the application type such that the wireless device may reduce power and resource consumption. In response to DRX being configured/activated, a UE may receive data packets with an extended delay, since the UE may be in DRX Sleep/Off state at the time of data arrival at the UE and the base station may wait until the UE transitions to the DRX ON state. 
     In an example, during a DRX mode, the UE may power down most of its circuitry when there are no packets to be received. The UE may monitor PDCCH discontinuously in the DRX mode. The UE may monitor the PDCCH continuously when a DRX operation is not configured. During this time the UE listens to the downlink (DL) (or monitors PDCCHs) which is called DRX Active state. In a DRX mode, a time during which UE doesn&#39;t listen/monitor PDCCH is called DRX Sleep state. 
       FIG. 24  shows an example of the embodiment. A gNB may transmit an RRC message comprising one or more DRX parameters of a DRX cycle. The one or more parameters may comprise a first parameter and/or a second parameter. The first parameter may indicate a first time value of the DRX Active state (e.g., DRX On duration) of the DRX cycle. The second parameter may indicate a second time of the DRX Sleep state (e.g., DRX Off duration) of the DRX cycle. The one or more parameters may further comprise a time duration of the DRX cycle. During the DRX Active state, the UE may monitor PDCCHs for detecting one or more DCIs on a serving cell. During the DRX Sleep state, the UE may stop monitoring PDCCHs on the serving cell. When multiple cells are in active state, the UE may monitor all PDCCHs on (or for) the multiple cells during the DRX Active state. During the DRX off duration, the UE may stop monitoring all PDCCH on (or for) the multiple cells. The UE may repeat the DRX operations according to the one or more DRX parameters. 
     In an example, DRX may be beneficial to the base station. In an example, if DRX is not configured, the wireless device may be transmitting periodic CSI and/or SRS frequently (e.g., based on the configuration). With DRX, during DRX OFF periods, the UE may not transmit periodic CSI and/or SRS. The base station may assign these resources to the other UEs to improve resource utilization efficiency. 
     In an example, the MAC entity may be configured by RRC with a DRX functionality that controls the UE&#39;s downlink control channel (e.g., PDCCH) monitoring activity for a plurality of RNTIs for the MAC entity. The plurality of RNTIs may comprise at least one of: C-RNTI; CS-RNTI; INT-RNTI; SP-CSI-RNTI; SFI-RNTI; TPC-PUCCH-RNTI; TPC-PUSCH-RNTI; Semi-Persistent Scheduling C-RNTI; eIMTA-RNTI; SL-RNTI; SL-V-RNTI; CC-RNTI; or SRS-TPC-RNTI. In an example, in response to being in RRC_CONNECTED, if DRX is configured, the MAC entity may monitor the PDCCH discontinuously using the DRX operation; otherwise the MAC entity may monitor the PDCCH continuously. 
     In an example, RRC may control DRX operation by configuring a plurality of timers. The plurality of timers may comprise: a DRX On duration timer (e.g., drx-onDurationTimer); a DRX inactivity timer (e.g., drx-InactivityTimer); a downlink DRX HARQ RTT timer (e.g., drx-HARQ-RTT-TimerDL); an uplink DRX HARQ RTT Timer (e.g., drx-HARQ-RTT-TimerUL); a downlink retransmission timer (e.g., drx-RetransmissionTimerDL); an uplink retransmission timer (e.g., drx-RetransmissionTimerUL); one or more parameters of a short DRX configuration (e.g., drx-ShortCycle and/or drx-ShortCycleTimer)) and one or more parameters of a long DRX configuration (e.g., drx-LongCycle). In an example, time granularity for DRX timers may be in terms of PDCCH subframes (e.g., indicated as psf in the DRX configurations), or in terms of milliseconds. 
     In an example, in response to a DRX cycle being configured, the Active Time may include the time while at least one timer is running. The at least one timer may comprise drx-onDuration Timer, drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransrnissionTimerUL, or mac-ContentionResolutionTimer. 
     In an example, drx-Inactivity-Timer may specify a time duration for which the UE may be active after successfully decoding a PDCCH indicating a new transmission (UL or DL or SL). This timer may be restarted upon receiving PDCCH for a new transmission (UL or DL or SL). The UE may transition to a DRX mode (e.g., using a short DRX cycle or a long DRX cycle) in response to the expiry of this timer. In an example, drx-ShortCycle may be a first type of DRX cycle (e.g., if configured) that needs to be followed when UE enters DRX mode. In an example, a DRX-Config IE indicates the length of the short cycle. drx-ShortCycleTimer may be expressed as multiples of shortDRX-Cycle. The timer may indicate the number of initial DRX cycles to follow the short DRX cycle before entering the long DRX cycle. drx-onDurationTimer may specify the time duration at the beginning of a DRX Cycle (e.g., DRX ON). drx-onDurationTimer may indicate the time duration before entering the sleep mode (DRX OFF). drx-HARQ-RTT-TimerDL may specify a minimum duration from the time new transmission is received and before the UE may expect a retransmission of a same packet. This timer may be fixed and may not be configured by RRC. drx-RetransrnissionTimerDL may indicate a maximum duration for which UE may be monitoring PDCCH when a retransmission from the eNodeB is expected by the UE. 
     In response to a DRX cycle being configured, the Active Time may comprise the time while a Scheduling Request is sent on PUCCH and is pending. In an example, in response to a DRX cycle being configured, the Active Time may comprise the time while an uplink grant for a pending HARQ retransmission can occur and there is data in the corresponding HARQ buffer for synchronous HARQ process. In response to a DRX cycle being configured, the Active Time may comprise the time while a PDCCH indicating a new transmission addressed to the C-RNTI of the MAC entity has not been received after successful reception of a Random Access Response for the preamble not selected by the MAC entity. 
     A DL HARQ RTT Timer may expire in a subframe and the data of the corresponding HARQ process may not be successfully decoded. The MAC entity may start the drx-RetransmissionTimerDL for the corresponding HARQ process. An UL HARQ RTT Timer may expire in a subframe. The MAC entity may start the drx-RetransmissionTimerUL for the corresponding HARQ process. A DRX Command MAC control element or a Long DRX Command MAC control element may be received. The MAC entity may stop drx-onDuration Timer and stop drx-InactivityTimer. In an example, drx-InactivityTimer may expire or a DRX Command MAC control element may be received in a subframe. In an example, in response to Short DRX cycle being configured, the MAC entity may start or restart drx-ShortCycleTimer and may use Short DRX Cycle. Otherwise, the MAC entity may use the Long DRX cycle. 
     In an example, drx-ShortCycleTimer may expire in a subframe. The MAC entity may use the Long DRX cycle. In an example, a Long DRX Command MAC control element may be received. The MAC entity may stop drx-ShortCycleTimer and may use the Long DRX cycle. 
     In an example, if the Short DRX Cycle is used and [(SFN*10)+subframe number] modulo (drx-ShortCycle)=(drxStartOffset) modulo (drx-ShortCycle), the wireless device may start drx-onDurationTimer. In an example, if the Long DRX Cycle is used and [(SFN*10)+subframe number] modulo (drx-longCycle)=drxStartOffset, the wireless device may start drx-onDuration Timer. 
       FIG. 25  shows example of DRX operation. A base station may transmit an RRC message comprising configuration parameters of DRX operation. A base station may transmit a DCI for downlink resource allocation via a PDCCH, to a UE. the UE may start the drx-InactivityTimer during which, the UE may monitor the PDCCH. After receiving a transmission block (TB) when the drx-InactivityTimer is running, the UE may start a HARQ RTT Timer (e.g., drx-HARQ-RTT-TimerDL), during which, the UE may stop monitoring the PDCCH. The UE may transmit a NACK to the base station upon unsuccessful receiving the TB. When the HARQ RTT Timer expires, the UE may monitor the PDCCH and start a HARQ retransmission timer (e.g., drx-RetransmissionTimerDL). When the HARQ retransmission timer is running, the UE may receive a second DCI indicating a DL grant for the retransmission of the TB. If not receiving the second DCI before the HARQ retransmission timer expires, the UE may stop monitoring the PDCCH. 
       FIG. 26A  show example of a power saving mechanism based on wake-up. A gNB may transmit one or more messages comprising parameters of a wake-up duration (e.g., a power saving duration, or a Power Saving Channel (PSCH) occasion), to a UE. The wake-up duration may be located a number of slots (or symbols) before a DRX On duration of a DRX cycle. The number of slots (or symbols), or, referred to as a gap between a wakeup duration and a DRX on duration, may be configured in the one or more RRC messages or predefined as a fixed value. The gap may be used for at least one of: synchronization with the gNB; measuring reference signals; and/or retuning RF parameters. The gap may be determined based on a capability of the UE and/or the gNB. In an example, the parameters of the wake-up duration may be pre-defined without RRC configuration. In an example, the wake-up mechanism may be based on a wake-up indication via a PSCH. The parameters of the wake-up duration may comprise at least one of: a PSCH channel format (e.g., numerology, DCI format, PDCCH format); a periodicity of the PSCH; a control resource set and/or a search space of the PSCH. When configured with the parameters of the wake-up duration, the UE may monitor the wake-up signal or the PSCH during the wake-up duration. When configured with the parameters of the PSCH occasion, the UE may monitor the PSCH for detecting a wake-up indication during the PSCH occasion. In response to receiving the wake-up signal/channel (or a wake-up indication via the PSCH), the UE may wake-up to monitor PDCCHs according to the DRX configuration. In an example, in response to receiving the wake-up indication via the PSCH, the UE may monitor PDCCHs in the DRX active time (e.g., when drx-onDurationTimer is running). The UE may go back to sleep if not receiving PDCCHs in the DRX active time. The UE may keep in sleep during the DRX off duration of the DRX cycle. In an example, if the UE doesn&#39;t receive the wake-up signal/channel (or a wake-up indication via the PSCH) during the wake-up duration (or the PSCH occasion), the UE may skip monitoring PDCCHs in the DRX active time. 
     In an example, a power saving mechanism may be based on a go-to-sleep indication via a PSCH.  FIG. 26B  shows an example of a power saving based on go-to-sleep indication. In response to receiving a go-to-sleep indication via the PSCH, the UE may go back to sleep and skip monitoring PDCCHs during the DRX active time (e.g., next DRX on duration of a DRX cycle). In an example, if the UE doesn&#39;t receive the go-to-sleep indication via the PSCH during the wake-up duration, the UE monitors PDCCHs during the DRX active time, according to the configuration parameters of the DRX operation. This mechanism may reduce power consumption for PDCCH monitoring during the DRX active time. 
     In an example, a power saving mechanism may be implemented by combining  FIG. 26A  and  FIG. 26B . A base station may transmit a power saving indication, in a DCI via a PSCH, indicating whether the wireless device wake up for next DRX on duration or skip next DRX on duration. The wireless device may receive the DCI via the PSCH. In response to the power saving indication indicating the wireless device wake up for next DRX on duration, the wireless device may wake up for next DRX on duration. The wireless device monitors PDCCH in the next DRX on duration in response to the waking up. In response to the power saving indication indicating the wireless device skip (or go to sleep) for next DRX on duration, the wireless device goes to sleep or skip for next DRX on duration. The wireless device skips monitoring PDCCH in the next DRX on duration in response to the power saving indication indicating the wireless device shall go to sleep for next DRX on duration. 
       FIG. 27  shows an example embodiment of power saving mechanism. A base station (e.g., gNB) may transmit to a wireless device (e.g., UE), one or more RRC messages comprising first configuration parameters of a power saving channel (PSCH) and second configuration parameters of a power saving (PS) operation. The first configuration parameters of the PSCH may comprise at least one of: one or more first search spaces (SSs) and/or one or more first control resource sets (COREST) on which the UE monitors the PSCH, one or more first DCI formats with which the UE monitors the PSCH, a radio network temporary identifier (RNTI) dedicated for monitoring the PSCH (e.g., PS-RNTI different from 3GPP existing RNTI values configured for the wireless device). The second configuration parameters of the PS operation may comprise at least one of: one or more second SSs and/or one or more second CORESTs on which the UE monitors PDCCHs in the PS operation, one or more first DCI formats with which the UE monitors PDCCHs in the PS operation, one or more MIMO parameters indicating a first maximum number of antenna (layers, ports, TRPs, panels, and/or the like) based on which the UE perform MIMO processing (transmission or reception) in the PS operation, one or more first cross-slot scheduling indicator indicating whether cross-slot scheduling is configured when the UE is in the PS operation, a BWP index indicating on which the UE transmit or receive data packet in the PS operation, and/or a cell index indicating on which the UE transmit or receive data packet in the PS operation. The one or more RRC messages may further comprise third configuration parameters of a normal function operation (e.g., full function, non-PS, or the like). The third configuration parameters may comprise at least one of: one or more third SSs and/or one or more third CORESTs on which the UE monitors PDCCHs in the non-PS operation, one or more second DCI formats with which the UE monitors PDCCHs in the non-PS operation, one or more MIMO parameters indicating a second maximum number of antenna (layers, ports, TRPs, panels, and/or the like) based on which the UE perform MIMO processing (transmission or reception) in the non-PS operation, one or more second cross-slot scheduling indicator indicating whether cross-slot scheduling is configured when the UE is in the non-PS operation, and/or the like. The UE, based on cross-slot scheduling being configured, may switch off some receiver modules (e.g., data buffering, RF chain, channel tracking, etc.) after receiving a DCI indicating a cross-slot scheduling and before receiving a data packet based on the DCI, for the purpose of power saving. In an example, the one or more second SSs and/or the one or more second CORESTs may occupy smaller radio resources than the one or more third SSs and/or the one or more third CORESTs, e.g., for the purpose of power saving. The first maximum number may be smaller than the second maximum number, e.g., for the purpose of power saving. 
     As shown in  FIG. 27 , when configured with the parameters of the PSCH and PS operation, the UE may monitor the PSCH (e.g., on the 1st SS/CORESET) for detecting a DCI (e.g., with CRC scrambled by the PS-RNTI) during the PSCH monitoring occasions. In an example, the DCI may be received with a second RNTI and a second DCI format (e.g., DCI format 0_0/0_0/0_2/1_0/1_1/1_2/2_0/2_1/2_2/2_3, etc.). Based on the PSCH monitoring, the UE may detect a PS indication contained in the DCI. In an example, the DCI may or may not indicate an active BWP switching. In response to receiving the PS indication via the PSCH, the UE may start performing a PS operation based on the one or more second configuration parameters of the PS operation. 
     In an example, based on receiving a DCI comprising a PS indication, a wireless device may perform a PS operation comprising at least one of: monitoring PDCCHs on 2nd PDCCH occasions and on 2nd SSs/CORESETs, refraining from monitoring the PSCH on 1st SSs/CORESETs, refraining from monitoring PDCCHs on 3rd PDCCH occasions and on 3rd SSs/CORESETs, transmitting or receiving data packets with the 1st maximum number of antenna (layers, ports, TRPs, panels, and/or the like), and/or transmitting or receiving data packets with cross-slot scheduling based on the one or more first cross-slot scheduling indicator. In an example, based on a PS indication in the DCI, the wireless device may switch from first SS(s) to second SS(s) for PDCCH monitoring on the BWP. 
     In an example, performing the PS operation may further comprise switching an active BWP of one or more cells (e.g., a PCell/SCell, or a cell group) to a dormant BWP of the one or more cells. The UE may monitor the PDCCHs on 2nd PDCCH occasions and on 2nd SSs/CORESETs continuously when DRX operation is not configured. The UE may monitor the PDCCHs on 2nd PDCCH occasions and on 2nd SSs/CORESETs discontinuously in a DRX active time (e.g., next DRX on duration) when DRX operation is configured. The UE, based on the monitoring the PDCCH on 2nd PDCCH occasions, may transmit or receive data packets or TB s in response to receiving a DCI indicating an uplink grant or a downlink assignment. 
     In an example, in response to receiving the PS indication via the PSCH, the UE may transition a SCell from an active state to a dormant state, based on the PS indication indicating a state transition of the SCell. A dormant state of a SCell may be a time period duration which the wireless device may: stop monitoring PDCCH(s) on/for the SCell, stop receiving PDSCH(s) on the SCell, stop transmitting uplink signals (PUSCH, PUCCH, PRACH, DMRS, and/or PRACH) on the SCell, and/or transmit CSI report for the SCell. The wireless device may maintain the dormant state of the SCell until receiving a second indicator indicating a transition of the SCell from the dormant state to the active state. 
     As shown in  FIG. 27 , when configured with the parameters of the PSCH and PS operation, the UE may monitor the PSCH (e.g., on the 1st SS/CORESET) during the PSCH monitoring occasions. The UE may not detect a PS indication via the PSCH, e.g., when a base station determines that the UE shall stay in a full function mode, or a non-PS mode. In response to not receiving the PS indication via the PSCH, the UE may start performing operations in a full function mode based on the one or more third configuration parameters. In an example, a base station may transmit a PS indication indicating whether the wireless device shall stay in a full function mode. The wireless device may receive the PS indication via a PSCH. In response to the PS indication indicating the wireless shall stay in a full function mode, the wireless device may start performing operations in the full function mode based on the one or more third configuration parameters. 
     In an example, performing operations in a full function mode based on the one or more third configuration parameters may comprise at least one of: monitoring PDCCHs on 3rd PDCCH occasions and on 3rd SSs/CORESETs, refraining from monitoring the PSCH on 1st SSs/CORESETs, refraining from monitoring PDCCHs on 2nd PDCCH occasions and on 2nd SSs/CORESETs, transmitting or receiving data packets with the 2nd maximum number of antenna (layers, ports, TRPs, panels, and/or the like), transmitting or receiving data packets with same-slot scheduling based on the one or more second cross-slot scheduling indicator indicating same-slot scheduling is configured. The UE may monitor the PDCCHs on 3rd PDCCH occasions and on 3rd SSs/CORESETs continuously when DRX operation is not configured. The UE may monitor the PDCCHs on 3rd PDCCH occasions and on 3rd SSs/CORESETs discontinuously in a DRX active time when DRX operation is configured. The UE, based on the monitoring the PDCCH on 3rd PDCCH occasions, may transmit or receive data packets or TBs in response to receiving a DCI indicating an uplink grant or a downlink assignment. 
     In an example, a UE may monitor a set of PDCCH candidates according to configuration parameters of a search space set comprising a plurality of search spaces (SSs). The UE may monitor a set of PDCCH candidates in one or more CORESETs for detecting one or more DCIs. Monitoring may comprise decoding one or more PDCCH candidates of the set of the PDCCH candidates according to the monitored DCI formats. Monitoring may comprise decoding a DCI content of one or more PDCCH candidates with possible (or configured) PDCCH locations, possible (or configured) PDCCH formats (e.g., number of CCEs, number of PDCCH candidates in common SSs, and/or number of PDCCH candidates in the UE-specific SSs) and possible (or configured) DCI formats. The decoding may be referred to as blind decoding. 
       FIG. 28  shows an example of configuration of a SS. In an example, one or more SS configuration parameters of a SS may comprise at least one of: a SS ID (searchSpaceId), a control resource set ID (controlResourceSetId), a monitoring slot periodicity and offset parameter (monitoringSlotPeriodicityAndOffset), a SS time duration value (duration), a monitoring symbol indication (monitoringSymbolsWithinSlot), a number of candidates for an aggregation level (nrofCandidates), and/or a SS type indicating a common SS type or a UE-specific SS type (searchSpaceType). The monitoring slot periodicity and offset parameter may indicate slots (e.g. in a radio frame) and slot offset (e.g., related to a starting of a radio frame) for PDCCH monitoring. The monitoring symbol indication may indicate on which symbol(s) of a slot a wireless device may monitor PDCCH on the SS. The control resource set ID may identify a control resource set on which a SS may be located. 
       FIG. 29  shows an example of configuration of a control resource set (CORESET). In an example, a base station may transmit to a wireless device one or more configuration parameters of a CORESET. The configuration parameters may comprise at least one of: a CORESET ID identifying the CORESET, a frequency resource indication, a time duration parameter indicating a number of symbols of the CORESET, a CCE-REG mapping type indicator, a plurality of TCI states, an indicator indicating whether a TCI is present in a DCI, and the like. The frequency resource indication, comprising a number of bits (e.g., 45 bits), indicates frequency domain resources, each bit of the indication corresponding to a group of 6 RBs, with grouping starting from the first RB group in a BWP of a cell (e.g., SpCell, SCell). The first (left-most/most significant) bit corresponds to the first RB group in the BWP, and so on. A bit that is set to 1 indicates that a RB group, corresponding to the bit, belongs to the frequency domain resource of this CORESET. Bits corresponding to a group of RBs not fully contained in the BWP within which the CORESET is configured are set to zero. 
     In an example embodiment, Listen-before-talk (LBT) may be implemented for transmission in a cell configured in unlicensed band (referred to as a LAA cell and/or a NR-U cell for the sake of convenience, for example, an LAA cell and NR-U cell may be interchangeable and may refer any cell operating in unlicensed band. The cell may be operated as non-standalone with an anchor cell in a licensed band or standalone without an anchor cell in licensed band). The LBT may comprise a clear channel assessment. For example, in an LBT procedure, equipment may apply a clear channel assessment (CCA) check before using the channel. For example, the CCA comprise at least energy detection that determines the presence (e.g., channel is occupied) or absence (e.g., channel is clear) of other signals on a channel. A regulation of a country may impact on the LBT procedure. For example, European and Japanese regulations mandate the usage of LBT in the unlicensed bands, for example in 5 GHz unlicensed band. Apart from regulatory requirements, carrier sensing via LBT may be one way for fair sharing of the unlicensed spectrum. 
     In an example embodiment, discontinuous transmission on an unlicensed carrier with limited maximum transmission duration may be enabled. Some of these functions may be supported by one or more signals to be transmitted from the beginning of a discontinuous downlink transmission in the unlicensed band Channel reservation may be enabled by the transmission of signals, by an NR-U node, after or in response to gaining channel access based on a successful LBT operation. Other nodes may receive the signals (e.g., transmitted for the channel reservation) with an energy level above a certain threshold that may sense the channel to be occupied. Functions that may need to be supported by one or more signals for operation in unlicensed band with discontinuous downlink transmission may comprise one or more of the following: detection of the downlink transmission in unlicensed band (including cell identification) by wireless devices; time and frequency synchronization of a wireless devices. 
     In an example embodiment, DL transmission and frame structure design for an operation in unlicensed band may employ subframe, (mini-)slot, and/or symbol boundary alignment according to carrier aggregation timing relationships across serving cells aggregated by CA. This may not imply that the base station transmissions start at the subframe, (mini-)slot, and/or symbol boundary. Unlicensed cell operation (e.g., LAA and/or NR-U) may support transmitting PDSCH, for example, when not all OFDM symbols are available for transmission in a subframe according to LBT. Delivery of necessary control information for the PDSCH may be supported. 
     An LBT procedure may be employed for fair and friendly coexistence of 3GPP system (e.g., LTE and/or NR) with other operators and technologies operating in unlicensed spectrum. For example, a node attempting to transmit on a carrier in unlicensed spectrum may perform a clear channel assessment (e.g., as a part of one or more LBT procedures) to determine if the channel is free for use. An LBT procedure may involve at least energy detection to determine if the channel is being used. For example, regulatory requirements in some regions, e.g., in Europe, specify an energy detection threshold such that if a node receives energy greater than this threshold, the node assumes that the channel is not free. While nodes may follow such regulatory requirements, a node may optionally use a lower threshold for energy detection than that specified by regulatory requirements. A radio access technology (e.g., LTE and/or NR) may employ a mechanism to adaptively change the energy detection threshold. For example, NR-U may employ a mechanism to adaptively lower the energy detection threshold from an upper bound. Adaptation mechanism may not preclude static or semi-static setting of the threshold. In an example Category 4 LBT (CAT4 LBT) mechanism or other type of LBT mechanisms may be implemented. 
     Various example LBT mechanisms may be implemented. In an example, for some signals, in some implementation scenarios, in some situations, and/or in some frequencies no LBT procedure may be performed by the transmitting entity. In an example, Category 1 (CAT1, e.g., no LBT) may be implemented in one or more cases. For example, a channel in unlicensed band may be hold by a first device (e.g., a base station for DL transmission), and a second device (e.g., a wireless device) takes over the for a transmission without performing the CAT1 LBT. In an example, Category 2 (CAT2, e.g. LBT without random back-off and/or one-shot LBT) may be implemented. The duration of time determining that the channel is idle may be deterministic (e.g., by a regulation). A base station may transmit an uplink grant indicating a type of LBT (e.g., CAT2 LBT) to a wireless device. CAT1 LBT and CAT2 LBT may be employed for COT sharing. For example, a base station (a wireless device) may transmit an uplink grant (resp. uplink control information) comprising a type of LBT. For example, CAT1 LBT and/or CAT2 LBT in the uplink grant (or uplink control information) may indicate, to a receiving device (e.g., a base station, and/or a wireless device) to trigger COT sharing. In an example, Category 3 (CAT3, e.g. LBT with random back-off with a contention window of fixed size) may be implemented. The LBT procedure may have the following procedure as one of its components. The transmitting entity may draw a random number N within a contention window. The size of the contention window may be specified by the minimum and maximum value of N. The size of the contention window may be fixed. The random number N may be employed in the LBT procedure to determine the duration of time that the channel is sensed to be idle before the transmitting entity transmits on the channel. In an example, Category 4 (CAT4, e.g. LBT with random back-off with a contention window of variable size) may be implemented. The transmitting entity may draw a random number N within a contention window. The size of contention window may be specified by the minimum and maximum value of N. The transmitting entity may vary the size of the contention window when drawing the random number N. The random number N may be used in the LBT procedure to determine the duration of time that the channel is sensed to be idle before the transmitting entity transmits on the channel. 
     In an unlicensed band, a type of LBT (CAT1, CAT2, CAT3, and/or CAT4) may be configured via control messages (RRC, MAC CE, and/or DCI) per a cell. In an example, a type of LBT (CAT1, CAT2, CAT3, and/or CAT4) may be configured via control messages (RRC, MAC CE, and/or DCI) per BWP. For example, a type of LBT (CAT1, CAT2, CAT3, and/or CAT4) may be determined at least based on a numerology configured in a BWP. In this case, BWP switching may change a type of LBT. 
     In an example, a wireless device may employ uplink (UL) LBT. The UL LBT may be different from a downlink (DL) LBT (e.g. by using different LBT mechanisms or parameters) for example, since the NR-U UL may be based on scheduled access which affects a wireless device&#39;s channel contention opportunities. Other considerations motivating a different UL LBT comprise, but are not limited to, multiplexing of multiple wireless devices in a subframe (slot, and/or mini-slot). 
     In an example, DL transmission burst(s) may be a continuous (unicast, multicast, broadcast, and/or combination thereof) transmission by a base station (e.g., to one or more wireless devices) on a carrier component (CC). UL transmission burst(s) may be a continuous transmission from one or more wireless devices to a base station on a CC. In an example, DL transmission burst(s) and UL transmission burst(s) on a CC in an unlicensed spectrum may be scheduled in a TDM manner over the same unlicensed carrier. Switching between DL transmission burst(s) and UL transmission burst(s) may require an LBT (e.g., CAT1 LBT, CAT2 LBT, CAT3 LBT, and/or CAT4 LBT). For example, an instant in time may be part of a DL transmission burst and/or an UL transmission burst. 
     Channel occupancy time (COT) sharing may be employed in a radio access technology (e.g., LTE and or NR). COT sharing may be a mechanism that one or more wireless devices share a channel that is sensed as idle by at least one of the one or more wireless devices. For example, one or more first devices occupy a channel an LBT (e.g., the channel is sensed as idle based on CAT4 LBT) and one or more second devices shares it using an LBT (e.g., 25 us LBT) within a maximum COT (MCOT) limit. For example, the MOCT limit may be given per priority class, logical channel priority, and/or wireless device specific. COT sharing may allow a concession for UL in unlicensed band. For example, a base station may transmit an uplink grant to a wireless device for a UL transmission. For example, a base station may occupy a channel and transmit, to one or more wireless devices a control signal indicating that the one or more wireless devices may use the channel. For example, the control signal may comprise an uplink grant and/or a particular LBT type (e.g., CAT1 LBT and/or CAT2 LBT). The one or more wireless device may determine COT sharing based at least on the uplink grant and/or the particular LBT type. The wireless device may perform UL transmission(s) with dynamic grant and/or configured grant (e.g., Type 1, Type2, autonomous UL) with a particular LBT (e.g., CAT2 LBT such as 25 us LBT) in the configured period, for example, if a COT sharing is triggered. A COT sharing may be triggered by a wireless device. For example, a wireless device performing UL transmission(s) based on a configured grant (e.g., Type 1, Type2, autonomous UL) may transmit an uplink control information indicating the COT sharing (UL-DL switching within a (M)COT). A starting time of DL transmission(s) in the COT sharing triggered by a wireless device may be indicated by one or more ways. For example, one or more parameters in the uplink control information indicate the starting time. For example, resource configuration(s) of configured grant(s) configured/activated by a base station may indicate the starting time. For example, a base station may be allowed to perform DL transmission(s) after or in response to UL transmission(s) on the configured grant (e.g., Type 1, Type 2, and/or autonomous UL). There may be a delay (e.g., at least 4 ms) between the uplink grant and the UL transmission. The delay may be predefined, semi-statically configured (via a RRC message) by a base station, and/or dynamically indicated (e.g., via an uplink grant) by a base station. The delay may not be accounted in the COT duration. 
     In an example, initial active DL/UL BWP may be 20 MHz (or approximately) for a first unlicensed band, e.g., in a 5 GHz unlicensed band. An initial active DL/UL BWP in one or more unlicensed bands may be similar (e.g., approximately 20 MHz in a 5 GHz and/or 6 GHz unlicensed spectrum), for example, if similar channelization is used in the one or more unlicensed bands (e.g., by a regulation). For a wideband case, a base station may configure the wideband with one or more BWP. For example, for 80 MHz case, a base station may configure four BWPs; each BWP may be configured with about 20 MHz. An active BWP (DL and/or UL) may be switched one to another at least based on BWP switching mechanism. For example, a base station may configure the wideband with one or more subbands when the cell comprises a single BWP. For example, for 80 MHz case, a base station may configure four subbands; each subband may be configured with about 20 MHz. For example, a wireless device may perform an LBT subband by subband, and may transmit data via scheduled resources on one or more subbands where the LBT indicates idle. 
     In an example, carrier aggregation between PCell configured on a licensed band and SCell configured on unlicensed band may be supported. In an example, SCell may have both DL and UL, or DL-only. In an example, dual connectivity between PCell (e.g., LTE cell) configured on a licensed band and PSCell (e.g., NR-U cell) configured on unlicensed band may be supported. In an example, Stand-alone operation on an unlicensed band, where all carriers are in one or more unlicensed bands, may be supported. In an example, a cell with DL in unlicensed band and UL in a licensed band or vice versa may be supported. In an example, dual connectivity between PCell (e.g., NR cell) on a licensed band and PSCell (e.g., NR-U cell) on unlicensed band may be supported. 
     In an example, a radio access technology (e.g., LTE and/or NR) operating bandwidth may be an integer multiple of 20 MHz, for example, if absence of Wi-Fi cannot be guaranteed (e.g. by regulation) in an unlicensed band (e.g., 5 GHz, 6 GHZ, and/or sub-7 GHz) where the radio access technology (e.g., LTE and/or NR) is operating. In an example, a wireless device may perform one or more LBTs in units of 20 MHz. In an example, receiver assisted LBT (e.g., RTS/CTS type mechanism) and/or on-demand receiver assisted LBT (e.g., for example receiver assisted LBT enabled only when needed) may be employed. In an example, techniques to enhance spatial reuse may be used. 
     In an example, wideband carrier with more than one channels (e.g., subbands) is supported on in an unlicensed band. In an example, there may be one active BWP in a carrier. In an example, a BWP with one or more channels may be activated. In an example, when absence of Wi-Fi cannot be guaranteed (e.g. by regulation), LBT may be performed in units of 20 MHz. In this case, there may be multiple parallel LBT procedures for this BWP. The actual transmission bandwidth may be subject to subband with LBT success, which may result in dynamic bandwidth transmission within this active wideband BWP. 
     In an example, one or more active BWPs may be supported. To improve the BWP utilization efficiency, the BWP bandwidth may be the same as the bandwidth of subband for LBT, e.g., LBT may be carried out on each BWP. The network may activate/deactivate the BWPs based on data volume to be transmitted. In an example, one or more non-overlapped BWPs may be activated for a wireless device within a wide component carrier, which may be similar as carrier aggregation. To improve the BWP utilization efficiency, the BWP bandwidth may be the same as the bandwidth of subband for LBT, i.e. LBT may be a carrier out on each BWP. When more than one subband LBT success, it requires a wireless device to have the capability to support one or more narrow RF or a wide RF which may comprise the one or more activated BWPs. 
     In an example, a single wideband BWP may be activated for a wireless device within a component carrier. The bandwidth of wideband BWP may be in the unit of subband for LBT. A subband may comprise a plurality of RBs. The plurality of RBs may be referred to as an RB set. In this specification, an RB set may be equally referred to as a subband. For example, if the subband for LBT is 20 MHz in 5 GHz band, the wideband BWP bandwidth may comprise multiple 20 MHz. The actual transmission bandwidth may be subject to subband with LBT success, which may result in dynamic bandwidth transmission within this active wideband BWP. 
     In an example, with wideband (e.g., 80 MHz) configuration on a BWP, frequency resources of a SS (or CORESET) may be spread within the BWP. Frequency resources of a SS (or CORESET) may be confined within a subband of the BWP. A subband may be in unit of 20 MHz, e.g., for LBT procedure in a NR-U cell.  FIG. 30A  and  FIG. 30B  show two SS/CORESET configurations in frequency domain in a BWP of a plurality of BWPs of a cell, or in a cell (in case of a single BWP configured on the cell). 
       FIG. 30A  shows an example of SS/CORESET configuration in a BWP. In an example, a frequency resource indication of 1st SS or 1st CORESET configuration may indicate frequency resources spread on a number of RB groups in the BWP, the number of RB groups not being confined or within a subband (e.g., 20 MHz) of the BWP. Spreading the frequency resources within the BWP may enable a base station to flexibly distribute PDCCH resources for different UEs, or different signalling purpose (e.g., common, or UE-specific). 
       FIG. 30B  show an example of SS/CORESET configuration in a BWP. In an example, a frequency resource indication of 1st SS or 1st CORESET configuration may indicate frequency resources are confined in a bandwidth (e.g., 20 MHz) of a subband (a frequency partition, a RB set, an LBT subband, or an LBT bandwidth, and the like) of the BWP. To maintain UE&#39;s capability of CORESETs/SSs configuration (e.g., at most 40 SSs per cell, or at most 12 or 20 CORESETs per cell) same (or similarly) as in case of operating in a licensed cell, a CORESET, identified by a CORESET ID, may be allocated with a same number of RBs (or RB groups) in each subband of the BWP. The same number of RBs (or RB groups) may be located in the same frequency locations (e.g., relative to a starting frequency location of each subband) of each subband of the BWP. 
     In an example, a BWP may comprise a number (e.g., 4) of LBT subbands, each LBT subband occupying a number of RBs (or RB groups) of the BWP. A first LBT subband may overlap in frequency domain with a second LBT subband. A first LBT subband may not overlap in frequency domain with a second LBT subband. In response to the frequency resource of 1st CORESET being confined in a bandwidth of a subband of the BWP, the wireless device may monitor PDCCH on the 1st SS of the 1st CORESET on each subband of the number of subbands of the BWP. Confining frequency resources of a CORESET within a bandwidth of a subband of a BWP may increase signalling transmission robustness. In an example, a base station may perform LBT procedure per subband of the BWP. In response to the LBT procedure being successful on one of the subbands of the BWP, the base station may transmit DCI via a PDCCH on the one of the subbands of the BWP. 
     In an example, a wireless device, before receiving a DCI, may not be aware of on which subband a base station may succeed an LBT procedure (e.g., when the LBT procedure indicates channel is clear on a subband), and may not be aware of on which subband the base station may transmit the DCI. When configured with multiple LBT subbands on a BWP, the wireless device may monitor PDCCH on the multiple LBT subbands for receiving the DCI. 
     In existing technologies, a wireless device, when configured with an unlicensed cell (or a NR-U cell), may monitor PDCCHs on a SS of a CORESET on multiple subbands of a plurality of subbands of a cell (or an active BWP of the cell when the cell comprises a plurality of BWPs). The monitoring the PDCCH on multiple subbands may increase power consumption of a wireless device. When a wireless device is working in a power saving mode (or state) for achieving power saving gain, e.g., in case of a power level of battery being lower than a threshold, the existing technologies may result in loss of the power saving gain. In an example, when the wireless device is communicating with a base station for latency-tolerant services (e.g., MTC, IoT, NR light, wireless sensor data transmission, and the like), always monitoring PDCCH on each subband may not be power efficient, or cost efficient, e.g., when the wireless device is required with long battery life time (e.g., months or years). There is a need to improve power consumption of a wireless device when operation on a wideband NR-U cell. Example embodiments disclose methods to improve power efficiency for operation on a wideband NR-U cell. The methods may comprise monitoring search spaces or CORESETs in a reduced number of subbands, from a plurality of subbands configured on a BWP/cell, based on at least one of: a power saving indication, a DCI format, a service type, a cell type, a link type, a search space type, and the like. Example embodiments may improve power consumption of a wireless device for PDCCH monitoring on a wideband NR-U cell. 
       FIG. 31  shows an example of power saving in a NR-U cell. In an example, a base station may transmit to a wireless device one or more RRC messages comprising configuration parameters of a cell. The cell may be a primary cell, or a secondary cell (or a PUCCH secondary cell). The cell may comprise a plurality of BWPs, each BWP being configured with a number of radio blocks within frequency resources of a cell. A wireless device may activate a first BWP of the plurality of BWPs, on which the wireless device may monitor PDCCHs on a CORESET configured on the first BWP. The wireless device may deactivate the first BWP based on receiving a DCI for deactivating the first BWP, or an expiry of a BWP time (e.g., BWP inactivity timer). In response to the first BWP being deactivated, the wireless device may stop monitoring PDCCHs on the first BWP. In an example, the cell may comprise a single BWP, the single BWP occupying the whole bandwidth of the cell. When a base station or a wireless device does not support BWP management (e.g., activation/deactivation/switching), the base station may not configure BWP management on the cell in which case a BWP and a cell are equivalent. 
     In an example, a BWP of a cell (or a cell when comprising a single BWP), may be partitioned into a number of subbands (or LBT subbands), each subband occupying a number of frequency resources of the BWP. In an example, a subband may have a bandwidth of 20 MHz, for aligning with a bandwidth for performing an LBT procedure in unlicensed frequency band. A wireless device, when configured with the number of subbands on the BWP, may monitor PDCCHs on the number of subbands based on configuration, receive PDSCH on the number of subbands, and/or transmit uplink signals (PUCCH/PUSCH) on the number of subbands of the BWP, if the BWP is an uplink BWP. In an example, in response to the BWP being activated, all subbands of the BWP are activated. Different from BWP switching, where a wireless device activates a new BWP and deactivates an old BWP at a time in response to switching an active BWP, the wireless device may activate all subbands of a BWP, without switching a first subband to a second subband based on command (e.g., DCI or timer). Not explicit subband switching command may simplify implementation cost and reduce latency of activation/deactivation of a subband. 
     In an example, the configuration parameters of a BWP may indicate configurations of a plurality of SSs and a plurality of CORESETs. A CORESET of the plurality of CORESETs may be configured with frequency radio resources confined in a subband of the plurality of subbands of the BWP. The CORESET may be associated with one or more SSs of the plurality of SSs, where the association between a SS and a CORESET comprise a CORESET ID, in configuration parameters of the SS, identifying the CORESET. The configurations of the plurality of SSs and the plurality of CORESETs may be implemented by examples of  FIG. 28  and/or  FIG. 29 . 
     As shown in  FIG. 31 , the wireless device may receive a command indicating activation of a first BWP (1st BWP) of the cell. In response to activating the first BWP, the wireless device may monitor a SS with multiple monitoring frequency locations one or more of the plurality of subbands, each of the multiple monitoring frequency locations corresponding to one of the one or more of the plurality of subbands of the first BWP. The multiple frequency locations may be configured in the configuration parameters of the SS. In an example, when 4 subbands are configured on a BWP, the configuration parameters of the SS may comprise a 4-bit bitmap, each bit of the bitmap corresponding to a subband of the 4 subbands. A bit, of the bitmap, corresponding to a subband, may indicate whether the wireless device monitor the SS on the CORESET on the subband. A bit, of the bitmap, with a first value (e.g., 1), may indicate the wireless monitors the subband corresponding to the bit. A bit, of the bitmap, with a second value (e.g., 0), may indicate the wireless does not monitor the subband corresponding to the bit. When all bits of the bitmap are set to a first value “1”, the wireless device shall monitor the SS on the CORESET on all subbands. 
     In an example, first configuration parameters of a CORESET may comprise a frequency domain resource indicator, as shown in  FIG. 29 . The frequency domain resource indicator may indicate frequency resources of the CORESET are confined within a subband, as shown in  FIG. 30B . Frequency resources of a CORESET may be confined within a subband when RB groups belonging to the CORESET are located within a bandwidth of a subband. In an example, the frequency domain resource indicator may indicate frequency resources of the CORESET are not confined within a subband, as shown in  FIG. 30A . Second configuration parameters of a SS (e.g., associated with the CORESET) may comprise a frequency monitoring occasion bitmap. A bit of the bitmap may indicate whether a wireless device monitors the SS on a subband corresponding to the bit. In an example, when the frequency domain resource indicator of the CORESET indicates frequency resources of the CORESET are not confined within a subband, the wireless device may ignore the frequency monitoring occasion bitmap (if configured) of configuration parameters of the SS, the SS being associated with the CORESET. The wireless device may, based on the ignoring the frequency monitoring occasion bitmap, monitor the SS on the BWP based on the frequency domain resource indicator of the CORESET. In an example, when the frequency domain resource indicator of the CORESET indicates frequency resources of the CORESET are confined within a subband, the wireless device may monitor a SS, associated with the CORESET, on one or more subbands of the BWP, based on the frequency monitoring occasion bitmap of configuration parameters of the SS. The wireless device may monitor the SS on a first subband, in response to a bit of the bitmap, corresponding to the first subband, indicating the wireless device monitors the SS on the first subband. The wireless device may skip monitoring the SS on a second subband, in response to a bit of the bitmap, corresponding to the second subband, indicating the wireless device does not monitor the SS on the second subband. 
     In an example, when a base station determines radio resources of a CORESET are confined within a subband of a BWP, the base station may transmit configuration parameters of a SS associated with the CORESET, the configuration parameters comprising a frequency monitoring occasion bitmap indicating one or more subbands in the BWP for monitoring the SS. When the base station determines radio resources of the CORESET are not confined within a subband of a BWP, the base station may transmit configuration parameters of a SS associated with the CORESET, the configuration parameters not comprising the frequency monitoring occasion bitmap indicating one or more subbands for monitoring the SS, or the frequency monitoring occasion bit map may be absent in the configuration parameters of the SS. In an example, the base station may determine whether to confine radio resources of a CORESET within a subband of a BWP based on control channel load condition, service type, and/or interference from other system (e.g., WiFi, Bluetooth, or other unlicensed systems). 
     In an example, based on the monitoring the PDCCH on a SS of a CORESET on one or more subbands of the BWP, the wireless device may receive a DCI via the PDCCH on one of the one or more subbands of the BWP, the one of the one or more subbands being a subband on which the base station succeed a LBT procedure indicating a clear channel. Monitoring more than one subband for DCI reception may improve DCI delivery robustness, e.g., in case of an LBT procedure not being successful on a subband. 
     In an example, when there is no transport block available for transmission, the wireless device may switch to a power saving (PS) mode. The base station may transmit a power saving indication (e.g., PS indication) to the wireless device. The wireless device may switch to the PS mode in response to an expiry of power saving timer. In response to receiving the PS indication, or an expiry of the PS timer, the wireless device may continue monitoring the SS of the CORESET on a first subband of the one or more subbands of the BWPs, and stop monitoring the SS on second subbands of the one or more subbands of the BWPs. The one or more subbands maybe subbands on which the wireless device monitor PDCCH before receiving the PS indication or an expiry of PS timer. In an example, the first subband may be a subband with a lowest subband index, of the one or more subbands. The first subband may be a subband with a lowest frequency location, of the one or more subbands. The first subband may be subband on which the wireless device receives PS indication. The first subband may be a subband on which the wireless device receives a group common DCI (e.g., DCI for COT sharing, or slot format indication). In an example, the wireless device may perform one or more PS operations by implementing examples of  FIG. 26A ,  FIG. 26B  and/or  FIG. 27 . 
     In response to receiving the PS indication, or an expiry of the PS timer, the wireless device may determine whether to reduce PDCCH monitoring frequency locations for a SS on subbands of an active BWP, based on at least one of: a search space type of the SS, a DCI format configured on the SS, a RNTI for monitoring on the SS, a cell type (e.g., PCell, PSCell, SCell, or PUCCH SCell), a link type (e.g., cellular link between a wireless device and a base station, sidelink between wireless devices, unmanned aerial vehicle link between drones, and the like), and/or a service/device type (e.g., MTC device, URLLC device, IoT device, and/or drones). 
     In an example, the wireless device may continue monitoring PDCCH on a SS on a configured number of subbands of an active BWP, in response to receiving the PS indication and the SS being a first SS type (e.g., type0-PDCCH CSS, type0A-PDCCH CSS, type1-PDCCH CSS, type2-PDCCH CSS, type3-PDCCH CSS, and/or a USS). In an example, the wireless device may stop monitoring PDCCH on the SS on the configured number of subbands of an active BWP, or restrict monitoring PDCCH on the SS on a single subband of the configured number of subbands of the active BWP, in response to receiving the PS indication and the SS being a second SS type (e.g., type0-PDCCH CSS, type0A-PDCCH CSS, type1-PDCCH CSS, type2-PDCCH CSS, type3-PDCCH CSS, and/or a USS). 
     In an example, the wireless device may continue monitoring PDCCH on a SS on a configured number of subbands of an active BWP, in response to receiving the PS indication and a DCI format configured on the SS being a first DCI format (e.g., DCI format 0_0/0_1/1_1/1_2/2_0/2_1/2_2/2_3). In an example, the wireless device may stop monitoring PDCCH on the SS on the configured number of subbands of an active BWP, or restrict monitoring PDCCH on the SS on a single subband of the configured number of subbands of the active BWP, in response to receiving the PS indication and the DCI format configured on the SS being a second DCI format (e.g., DCI format 0_0/0_1/1_1/1_2/2_0/2_1/2_2/2_3). 
     In an example, the wireless device may continue monitoring PDCCH for receiving a DCI with a first RNTI (e.g., P-RNTI, SI-RNTI, RA-RNTI, C-RNTI, MCS-C-RNTI, CS-RNTI, TPC-PUCCH/PUSCH-RNTI, TPC-SRS-RNTI, INT-RNTI, SFI-RNTI, SP-CSI-RNTI) on a SS on a configured number of subbands of an active BWP, in response to receiving the PS indication. In an example, the wireless device may stop monitoring PDCCH for receiving the DCI with a second RNTI (e.g., P-RNTI, SI-RNTI, RA-RNTI, C-RNTI, MCS-C-RNTI, CS-RNTI, TPC-PUCCH/PUSCH-RNTI, TPC-SRS-RNTI, INT-RNTI, SFI-RNTI, SP-CSI-RNTI) on the SS on the configured number of subbands of an active BWP, or restrict monitoring PDCCH for receiving a DCI with the second RNTI on the SS on a single subband of the configured number of subbands of the active BWP, in response to receiving the PS indication. 
     In an example, the wireless device may continue monitoring PDCCH on a SS on a configured number of subbands of an active BWP of a cell with a first cell type (e.g., PCell/PSCell, SCell, PUCCH SCell), in response to receiving the PS indication. In an example, the wireless device may stop monitoring PDCCH on the SS on the configured number of subbands of an active BWP of a cell with a second cell type (e.g., PCell/PSCell, SCell, PUCCH SCell), or restrict monitoring PDCCH on the SS on a single subband of the configured number of subbands of the active BWP of the cell with the second cell type, in response to receiving the PS indication. 
     In an example, a wireless device may monitor a first SS of a first CORESET on one or more first subbands of a BWP, when the wireless is in a full power state (e.g., non-PS state). In response to receiving the PS indication or an expiry of a PS timer, the wireless device may stop monitoring the first SS of the first CORESET on the one or more first subbands of the BWP. In response to receiving the PS indication or an expiry of a PS timer, the wireless device may start monitoring a second SS of a second CORESET on one or more second subbands of the BWP. In an example, the second SS, the second CORESET, and/or the one or more second subbands, may be configured (in an RRC message) for the PS operation on the BWP. The first SS, the first CORESET, and/or the one or more first subbands, may be configured (in an RRC message) for the non-PS operation on the BWP. In an example, the wireless device may perform one or more non-PS operations by implementing examples of  FIG. 26A ,  FIG. 26B  and/or  FIG. 27 . 
     In an example, a wireless device may monitor a second SS of a second CORESET on one or more second subbands of the BWP in a power saving state. In an example, the second SS, the second CORESET, and/or the one or more second subbands, may be configured (in an RRC message) for the PS operation on the BWP. The wireless device may switch to a non-PS state in response to receiving a DCI indicating the switching, or an expiry of second power saving timer. In response to switching to the non-PS state, the wireless device may start monitoring a first SS of a first CORESET on one or more first subbands of the BWP. In response to switching to the non-PS state, the wireless device may stop monitoring the second SS of the second CORESET on the one or more second subbands of the BWP. In response to switching to the non-PS state, the wireless device may continue monitoring the second SS of the second CORESET on the one or more second subbands of the BWP. The first SS, the first CORESET, and/or the one or more first subbands, may be configured (in an RRC message) for the non-PS operation on the BWP. In an example, the wireless device may perform one or more non-PS operations by implementing examples of  FIG. 26A ,  FIG. 26B  and/or  FIG. 27 . 
     By example embodiments of  FIG. 31 , the wireless device may dynamically adapt PDCCH monitoring locations in frequency domain for a power saving operation. Example embodiments may improve power consumption of a wireless device and reduce implementation cost of the wireless device. 
       FIG. 32A  and  FIG. 32B  show examples of dynamical PDCCH monitoring on multiple subbands of a BWP. In an example, a base station may transmit to a wireless device, a DCI, comprising one or more power saving indication, indicating whether PDCCH monitoring adaptation within a cell is applied, or PDCCH monitoring adaptation within a BWP is applied. 
       FIG. 32A  shows an example of a DCI with a DCI format indicating dynamical PDCCH monitoring on multiple subbands of a BWP. The DCI, when indicating PDCCH monitoring adaptation within a cell (switching BWPs of the cell), may comprise a BWP indicator (e.g., 2 bits) indicating a BWP the wireless device switches to for reducing PDCCH monitoring or increasing PDCCH monitoring. The wireless device, based on configuration parameters of PDCCH, may monitor PDCCH on different BWPs (when activated) with different PDCCH monitoring periodicity (in time domain), different number of search spaces or CORESETs. In an example, the DCI, when indicating PDCCH monitoring adaptation within a BWP, may comprise a subband indicator (e.g., 2 bits) indicating a subband on which the wireless device monitors PDCCHs. The DCI may further comprise one or more DCI fields indicating power saving parameters comprising: maximum MIMO layers, maximum processing time for PDCCH/PDSCH/PUSCH/HARQ-ACK, cross slot scheduling indication. In an example, the DCI, when indicating PDCCH monitoring adaptation within a cell, may be CRC scrambled with a first RNTI. The DCI, when indicating PDCCH monitoring adaptation within a BWP, may be CRC scrambled with a second RNTI. The first RNTI and/or the second RNTI may be different from C-RNTI. In an example, the DCI may comprise an indication bit indicating whether the DCI indicates PDCCH monitoring adaptation within a cell (e.g., switching BWPs) or the DCI indicates PDCCH monitoring adaptation within a BWP (one or more subbands of the BWP). 
       FIG. 32B  shows an example of power saving operation in a cell. In an example, the cell may comprise a number of BWPs, each BWP comprising a number of subbands (or LBT subbands). The wireless device may activate a first BWP of the cell. The wireless device may receive a DCI indicating a power saving operation. The DCI may indicate whether the power saving operation is implemented as BWP switching, or the power saving operation is implemented as reducing PDCCH monitoring frequency locations within an active BWP. In response to the DCI indicating BWP switching for power saving, the wireless device may switch from the first BWP to the second BWP, the second BWP being indicated by the BWP indicator of the DCI. The wireless device may reduce power consumption on the second BWP when PDCCH monitoring occasions on the second BWP are less than the PDCCH monitoring occasions on the first BWP. In response to the DCI indicating power saving within an active BWP, the wireless device may monitor PDCCH in a subband of the BWP, the subband being indicated by the subband indicator of the DCI. 
     In an example, a base station may transmit to a wireless device a DCI comprising a bitmap (e.g., indicating frequency monitoring occasion), each bit of the bitmap corresponding to a subband of a plurality of subbands of an active BWP. In an example, the DCI may be one of DCI formats comprising DCI format 0_0/0_1/0_2/1_0/1_1/1_2/2_0/2_1/2_2/2_3, etc. In an example, a bit, of the bitmap, with a first value (e.g., “1”), indicates the wireless device monitor PDCCH on a subband corresponding to the bit. A bit, of the bitmap, with a second value (e.g., “0”), indicates the wireless device does not monitor PDCCH on a subband corresponding to the bit. When 4 subbands are configured on a BWP, the bitmap may have a length of 4 bits, each bit corresponding to a subband of the 4 subbands. In response to receiving the DCI, the wireless device may adapt PDCCH monitoring based on the bitmap of the DCI. The wireless device may monitor PDCCH on a first subband in response to a first bit, of the bitmap, corresponding to the first subband, indicating PDCCH monitoring. The wireless device may skip monitoring PDCCH on a second subband in response to a second bit, of the bitmap, corresponding to the second subband, indicating skipping the PDCCH monitoring. 
     In an example, based on existing technologies, a wireless device may not dynamically reduce power consumption for PDCCH monitoring when multiple search spaces are configured and multiple subbands (or RB sets) are configured in a BWP. Different search spaces may be configured on different subbands of the BWP. In an example, different search spaces may be for reception of DCIs for different purposes. Some search space may require more and complexed blind decoding for detecting a DCI. Some search space may require less blind decoding. The wireless device, by using existing technologies, may not dynamically reduce power consumption for PDCCH monitoring on different search spaces on different subbands of the BWP. There is a need to improve power consumption of a wireless device for PDCCH monitoring when configured with multiple search spaces and multiple subbands on a BWP. 
     One of example embodiments, based on one or more examples above and/or combination of one or more examples above (e.g., examples of  FIG. 27 ,  FIG. 32  A and/or  FIG. 32B ), may comprise transmitting by a base station and/or receiving by a wireless device, a DCI indicating search space switching on a BWP and subband indication on the BWP. In response to receiving the DCI, the wireless device may switch from a first search space to a second search space and monitor the second search space on one or more subbands of the BWP, the one or more subbands determined based on the subband indication in the DCI. Based on example embodiment, by receiving the DCI indicating both search space switching and subband indication, the wireless device may reduce power consumption for PDCCH monitoring when multiple search spaces and multiple subbands are configured. Based on example embodiment, the base station by transmitting the DCI indicating both search space switching and subband indication, may reduce signaling overhead. Otherwise, by using existing technologies, the base station may transmit a first DCI indicating a search space switching and a second DCI indicating one or more subbands, e.g., for PDCCH monitoring, on the BWP. Existing technologies, by transmitting or receiving the two DCIs indicating search space switching and subband indication, may increase power consumption of a wireless device and/or increase signaling overhead for a base station. 
     One of example embodiments, based on one or more examples above and/or combination of one or more examples above (e.g., examples of  FIG. 27 ,  FIG. 32  A and/or  FIG. 32B ), may comprise transmitting by a base station and/or receiving by a wireless device, a DCI with an existing DCI format (e.g., DCI format 2_0 indicating slot format indication). The DCI may comprise a new DCI field indicating one or more subbands of a BWP. Based on whether the DCI comprises the new DCI field indicating one or more subbands of the BWP, the wireless device may determine on which subband(s) the wireless device monitors the PDCCH on a search space. In an example, when the DCI is a legacy DCI format (e.g., without the new DCI field indicating the one or more subbands of the DCI), the wireless device may monitor the PDCCH on the search space in one or more first subbands indicated in a frequency monitor location bitmap associated with the search space, where the frequency monitor location bitmap is configured in a RRC message. In an example, when the DCI is a new DCI format (e.g., with the new DCI field indicating the one or more subbands of the DCI), the wireless device may monitor the PDCCH on the search space in one or more second subbands determined based on the frequency monitor location bitmap associated with the search space and the new DCI field. By determining on which subband(s) the wireless device monitors PDCCH on a SS based on a DCI format, the wireless device may reduce power consumption for PDCCH monitoring when the search space is configured on multiple subbands. 
       FIG. 33  shows an example embodiment of PDCCH monitoring when multiple search spaces and multiple subbands are configured on a BWP. In an example, a base station may transmit to a wireless device one or more RRC messages comprising configuration parameters of a cell comprising a plurality of BWPs. The configuration parameters may indicate a plurality of search spaces (e.g., 1st SS and 2nd SS as shown in  FIG. 33 ) on a BWP of the cell. A BWP may comprise a plurality of resource block (RB) sets (or subbands). In an example, a subband may be equally referred to as an RB set in this specification. The configuration parameters may comprise a first frequency monitor location indication bitmap, associated with 1st SS, indicating that frequency resources of 1st SS are mapped to one or more first RB sets (e.g., 1st RB set and 2nd RB set as shown in  FIG. 33 ). The configuration parameters may comprise a second frequency monitor location indication bitmap, associated with 2nd SS, indicating that frequency resources of 2nd SS are mapped to one or more second RB sets (e.g., 3rd RB set and 4th RB set as shown in  FIG. 33 ). 
     In an example, based on the first frequency monitor location indication bitmap, the wireless device may monitor PDCCH on the first SS in the 1st RB set and 2nd RB set of the BWP. The wireless device, by monitoring the PDCCH, may attempt to detect a DCI with a DCI format on the 1st RB set and 2nd RB set. In an example, based on the first frequency monitor location indication bitmap, the wireless device may not monitor PDCCH on the first SS in the 3rd RB set or 4th RB set of the BWP, when the first frequency monitor location indication bitmap indicates the first SS is not mapped to the 3rd RB set or 4th RB set of the BWP. 
     In an example, the wireless device may receive a DCI during the monitoring the PDCCH on the first SS in the 1st RB set and 2nd RB set of the BWP. The DCI may be a DCI format 2_0 indicating slot format indication for one or more cells. The DCI may be a group common DCI addressed to a group of wireless devices comprising the wireless device. The DCI may indicate a power saving information and RB set indication. In an example, the power saving information may indicate refraining from PDCCH monitoring on the 1st SS and starting monitoring PDCCH on the 2nd SS. Or simply, the power saving information may indicate switching PDCCH monitoring from the 1st SS to the 2nd SS. In an example, the RB set indication in the DCI may comprise a RB set indication bitmap, each bit of the RB set indication bitmap indicating whether a corresponding RB set, of the plurality of RB sets of the BWP, is available (or occupied by the base station, acquired by the base station, etc.,) for downlink reception. A first bit of the RB set indication bitmap may correspond to a first RB set of the plurality of RB sets. A second bit of the RB set indication bitmap may correspond to a second RB set of the plurality of RB sets, etc. In an example, a bit of the RB set indication bitmap, being set to a first value (e.g., 0), may indicate that a corresponding RB set, of the plurality of RB sets of the BWP, is unavailable for downlink reception. In an example, a bit of the RB set indication bitmap, being set to a second value (e.g., 1), may indicate that a corresponding RB set, of the plurality of RB sets of the BWP, is available for downlink reception. In an example, the RB set indication bitmap may indicate a third RB set (e.g., 3rd RB set as shown in  FIG. 33 ) is available. 
     In an example, the wireless device, based on search space switching indication, the wireless device may stop monitoring the PDCCH on the 1st SS. The wireless device may stop monitoring the PDCCH on the 1st SS in the 1st RB set and 2nd RB set. Based on search space switching indication, the wireless device may start to monitor the 2nd SS. In an example, the wireless device may determine one or more RB sets of the plurality of RB sets of the BWP for PDCCH monitoring on the 2nd SS based on the RB set indication bitmap of the DCI and the second frequency monitor location indication bitmap. In an example, the wireless device may monitor PDCCH on the 2nd SS in a 3rd RB set of the plurality of RB sets of the BWP, in response to the 3rd RB set being available based on the RB set indication bitmap in the DCI and the 2nd SS being mapped to the 3rd RB set based on the second frequency monitor location indication bitmap. Based on example embodiment, by receiving the DCI indicating both search space switching and RB set(s) indication, the wireless device may reduce power consumption for PDCCH monitoring when multiple search spaces and multiple RB sets are configured. Based on example embodiment, a base station by transmitting the DCI indicating both search space switching and RB set(s) indication, may reduce signaling overhead. 
     In an example, during monitoring the PDCCH on 2nd SS in the 3rd RB set, the wireless device may receive a second DCI indicating an uplink grant or a downlink assignment. The wireless device may transmit uplink TB based on the second DCI indicating the uplink grant. The wireless device may receive downlink TB based on the second DCI indicating the downlink assignment. 
       FIG. 34  shows an example flowchart of PDCCH monitoring switching on multiple RB sets of a BWP. At  3410 , a wireless device receives from a base station, configuration parameters of a bandwidth part of a cell. The bandwidth part comprises resource block sets. The configuration parameters indicate that a first search space is mapped on one or more first resource block set of the resource block sets. The configuration parameters indicate that a second search space is mapped on one or more second resource block sets of the resource block sets. At  3420 , the wireless device monitors, in the one or more first resource block sets, a PDCCH in the first search space. At  3430 , the wireless device receives a DCI indicating: refraining from monitoring the PDCCH on the first search space, monitoring the PDCCH on the second search space, and that at least one of the one or more second resource block sets is available. At  3440 , based on the DCI, the wireless device skips monitoring the PDCCH on the first search space and monitors the PDCCH on the second search space in the at least one of the one or more second resource block sets. 
     In an example, a wireless device monitors a PDCCH on a first search space in a bandwidth part comprising resource block sets. The wireless device receives a downlink control information indicating: refraining from monitoring the PDCCH on the first search space, monitoring the PDCCH on a second search space of the bandwidth part and that one or more resource block set of the resource block sets is available. The wireless device, based on the downlink control information, skips monitoring the PDCCH on the first search space and monitors the PDCCH on the second search space in at least one of the one or more resource block set. 
     According to an example embodiment, each of the resource block sets of the bandwidth part comprises a plurality of resource blocks in frequency domain of the bandwidth part. 
     According to an example embodiment, the wireless device receives, via the PDCCH, the DCI during the monitoring the PDCCH on the first search space. 
     According to an example embodiment, the DCI does not comprise a bandwidth part identifier of a second bandwidth part of a cell, wherein the DCI does not indicate an active bandwidth part switching from the bandwidth part to the second bandwidth part. 
     According to an example embodiment, the DCI is a DCI format 2_0 comprising slot format indications of one or more cells. The DCI is received with cyclic redundancy check bits being scrambled by a slot format indication radio network temporary identifier. 
     According to an example embodiment, the DCI comprises an available resource block set indication bitmap, wherein each bit of the available resource block set indication bitmap corresponds to a respective one of the resource blocks. In an example, each bit of the available resource block set indication bitmap indicates whether a resource block, of the resource blocks, corresponding to the bit, is available for downlink reception on the bandwidth part. 
     According to an example embodiment, the wireless device may receive a second DCI during the monitoring the PDCCH via the second SS, wherein the second DCI indicating an uplink grant or a downlink assignment. The wireless device may receive a downlink transport block based on the second DCI in response to the second DCI indicating the downlink assignment for the downlink transport block. The wireless device may transmit an uplink transport block based on the second DCI in response to the second DCI indicating the uplink grant for the uplink transport block. 
     According to an example embodiment, the wireless device may receive a radio resource control message comprising a first frequency monitoring location bitmap of the first search space, each bit of the first frequency monitoring location bitmap indicating whether frequency resources of the first search space, are mapped to a respective one of the resource block sets. The radio resource control message comprises configuration parameters of the cell comprising a plurality of bandwidth parts comprising the bandwidth part. The radio resource control message further comprises configuration parameters of the first search space, the configuration parameters comprising at least one of: a first search space index identifying the first search space, a control resource set index identifying a control resource set associated with the first search space, one or more time domain resource allocation parameters of the first search space and a number of aggregation levels for the first search space. 
     According to an example embodiment, the wireless device monitors the PDCCH on the first search space on one or more first RB sets of the RB sets, wherein the one or more first RB sets are determined based on the first frequency monitoring location bitmap. The wireless device determines the one or more first RB sets based on one or more bits, of the first frequency monitoring location bitmap, corresponding to the one or more first RB sets, being set to a first value indicating that the frequency resources for the first search space are mapped to the one or more first RB set. 
     According to an example embodiment, a radio resource control message further comprises a second frequency monitoring location bitmap of the second search space, each bit of the second frequency monitoring location bitmap indicating whether frequency resources of the second search space, are mapped to a respective one of the RB sets. 
     According to an example embodiment, the wireless device monitors the PDCCH on the second search space in the at least one of the one or more resource block set, wherein the at least one of the one or more resource block set is determined based on: one or more bits of the second frequency monitoring location bitmap indicating the frequency resources of the second search space are mapped to the at least one of the one or more resource block set, and the at least one of the one or more resource block set being available for downlink reception on the bandwidth part. 
     In an example, a wireless device monitors a downlink control channel on a first search space (SS) in a first resource block (RB) set of RB sets of a bandwidth part. The wireless device receives, via the first SS, a DCI indicating switching from the first SS to a second SS of the bandwidth part and comprising an RB set indication indicating at least one second RB set of the RB sets is available. Based on the DCI, the wireless device skips monitoring the downlink control channel on the first SS and monitors, based on the RB set indication, the downlink control channel on the second SS in at least one of the at least one second RB set. 
     In an example, based on existing technologies, a wireless device may not dynamically reduce power consumption for PDCCH monitoring when a search space is configured on multiple RB sets in a BWP. Different RB sets may have different interference and loading condition. In some time, a first RB set may have light interference and/or loading. In another time, the first RB may have heavy interference and loading, and a second RB set may become light-loaded and/or light-interfered. In an example, the wireless device may monitor PDCCH on a SS in one or more first RB sets based on a frequency monitor location bitmap associated with the SS, the frequency monitor location bitmap being configured in a RRC message. The wireless device may receive a DCI indicating one or more second RB sets are available for reception. The one or more first RB sets may be different from the one or more second RB sets. Based on existing technologies, the wireless device may have difficulties in determining on which RB set(s) the wireless device monitor PDCCH on the SS, after receiving the DCI. Based on existing technologies, the wireless device may have difficulties in determining whether on the one or more first RB sets or on the one or more second RB set the wireless device shall monitor PDCCH. The wireless device, by using existing technologies, may not dynamically reduce power consumption for PDCCH monitoring on a search space on different RB sets of the BWP. There is a need to improve power consumption of a wireless device for PDCCH monitoring a search space is configured on multiple RB sets of a BWP. 
     One of example embodiments, based on one or more examples above and/or combination of one or more examples above (e.g., examples of  FIG. 31 ,  FIG. 32  A and/or  FIG. 32B ), may comprise transmitting by a base station and receiving by a wireless device, a RRC message comprising a first bitmap of frequency monitor location indication of a SS, and a DCI comprising a second bitmap of RB set indication bitmap. Based on the first bitmap and the second bitmap, the wireless device may determine one or more RB sets for PDCCH monitoring on a SS. In an example, the first bitmap indicates that frequency resources of the SS are mapped to the one or more first RB sets. The second bitmap indicates that the one or more RB second sets are available. The wireless device may determine that the one or more first RB sets and the one or more second RB sets both comprise the one or more RB sets. The wireless device may determine that the one or more RB sets may be a subset of first RB sets associated with the SS based on the first bitmap. The wireless device may determine that the one or more RB sets may be a subset of second RB sets indicated by the second bitmap, as available. In an example, the wireless device may determine that the one or more RB set may be intersection of the first RB sets and the second RB sets. Based on example embodiments, by determining RB sets for PDCCH monitoring based on a DCI and a RRC message, the wireless device may reduce power consumption for PDCCH monitoring when a SS is configured on multiple RB sets. 
       FIG. 35  shows an example embodiment of PDCCH monitoring on multiple RB sets of a BWP of a cell. In an example, a base station may transmit to a wireless device one or more RRC messages comprising configuration parameters of a cell. The cell comprises a plurality of BWPs. Each BWP may comprise a plurality of RB sets. The configuration parameters may comprise a first bitmap (e.g., 1st bitmap as shown in  FIG. 35 ), of a search space (SS), indicating a frequency monitor location indication for the SS. Each bit of the first bitmap may correspond to a respective one of the plurality of RB sets of the BWP. Each bit of the first bitmap may indicate whether frequency resources of the SS are mapped to the corresponding RB set of the plurality of RB sets. In an example, 1st bit of the 1st bitmap may indicate whether the SS is mapped to 1st RB set, 2nd bit of the 1st bitmap may indicate whether the SS is mapped to 2nd RB set. A bit, of the 1st bitmap, being set to a first value (e.g., 0), may indicate that the SS is not mapped to a corresponding RB set. A bit, of the 1st bitmap, being set to a second value (e.g., 1), may indicate that the SS is mapped to a corresponding RB set. In an example, the 1st bitmap may indicate the SS are mapped to one or more first RB sets of the plurality of RB sets of the BWP. 
     In an example, the wireless device may receive a 1st DCI (e.g., with DCI format 2_0) comprising a 2nd bitmap of RB set indication. Each bit of the 2nd bitmap may correspond to a respective RB set of the plurality of RB sets of the BWP. Each bit of the 2nd bitmap may indicate whether a corresponding RB set is available for downlink reception (or uplink transmission). In an example, 1st bit of the 2nd bitmap may indicate whether 1st RB set is available for downlink reception, 2nd bit of the 2nd bitmap may indicate whether 2nd RB set is available for downlink reception. A bit, of the 2nd bitmap, being set to a first value (e.g., 0), may indicate that a corresponding RB set is unavailable. A bit, of the 2nd bitmap, being set to a second value (e.g., 1), may indicate that a corresponding RB set is available. In an example, the 2nd bitmap may indicate one or more second RB sets of the plurality of RB sets of the BWP are available. 
     In an example, the one or more first RB sets may be different from the one or more second RB sets. The one or more first RB sets may overlap (partially or fully) with the one or more second RB sets. In an example, when the one or more first RB sets overlaps fully with the one or more second RB sets, the one or more first RB sets belong to the one or more second RB sets, or the one or more the second RB sets belong to the one or more first RB sets. In an example, when the one or more first RB sets overlap partially with the one or more second RB sets, a first subset of the one or more first RB sets is same as a second subset of the one or more second RB sets. 
     In an example, based on the 1st DCI comprising the 2nd bitmap and the RRC message comprising the 1st bitmap, the wireless device may determine one or more RB sets for PDCCH monitoring on the SS. In an example, the one or more RB sets may be an intersection of the one or more first RB sets and the one or more second RB sets, wherein the one or more first RB sets are determined based on the 1st bitmap and the one or more second RB sets are determined based on the 2nd bitmap. In an example, the wireless device may monitor PDCCH on the SS in the one or more RB sets, wherein the SS is mapped to the one or more RB sets based on the 1st bitmap and the one or more RB sets are available based on the 2nd bitmap. 
     In an example, based on monitoring the PDCCH on the one or more RB sets, the wireless device may receive a second DCI. The second DCI may indicate an uplink grant or a downlink assignment. The wireless device may transmit uplink TB based on the second DCI indicating the uplink grant. The wireless device may receive downlink TB based on the second DCI indicating the downlink assignment. 
       FIG. 36  shows an example flowchart of PDCCH monitoring on multiple RB sets of a BWP. At  3610 , a wireless device receives a first bitmap of frequency allocation of a search space (SS). In an example, each bit of the first bitmap indicates whether frequency resources of the SS are mapped to a respective resource block (RB) set of RB sets of a bandwidth part. At  3620 , the wireless device receives a first downlink control information (DCI) comprising a second bitmap of RB set indication. In an example, each bit of the second bitmap indicates whether a respective RB set, of the RB sets, is available for reception. At  3630 , the wireless device monitors, based on the first bitmap and the second bitmap, a downlink control channel on the SS in one or more RB set of the RB sets, wherein the one or more RB set is determined based on the first bitmap and the second bitmap. At  3640 , the wireless device may receive a second DCI during the monitoring the downlink control channel on the one or more RB set. 
     According to an example embodiment, the wireless device determines the one or more RB set based on: one or more first bit, of the first bitmap, corresponding to the one or more RB set, being set to a first value indicating that frequency resources for the SS are mapped to the one or more RB set, and one or more second bit, of the second bitmap, corresponding to the one or more RB set, being set to a second value indicating that the one or more RB set is available for downlink reception. 
     According to an example embodiment, the wireless device receives one or more radio resource control messages comprising configuration parameters of a cell comprising a plurality of bandwidth parts comprising the bandwidth part. The one or more radio resource control messages comprise the first bitmap of frequency allocation of the search space 
     According to an example embodiment, the wireless device skips monitoring the downlink control channel on the SS in one or more second RB set of the RB sets, in response to: one or more first bit, of the first bitmap, corresponding to the one or more second RB set, being set to a first value indicating that frequency resources for the SS are not mapped to the one or more second RB set, one or more second bit, of the second bitmap, corresponding to the one or more second RB set, being set to a second value indicating that the one or more second RB set is unavailable for downlink reception. 
     According to an example embodiment, each of the resource block sets of the bandwidth part comprises a plurality of resource blocks in frequency domain of the bandwidth part. 
     According to an example embodiment, the first DCI is a DCI format 2_0 comprising slot format indications of one or more cells. The first DCI is with cyclic redundancy check bits being scrambled by a slot format indication radio network temporary identifier configured in one or more radio resource control messages. 
     According to an example embodiment, the wireless device receives a downlink transport block based on the second DCI in response to the second DCI indicating a downlink assignment for the downlink transport block. 
     According to an example embodiment, the wireless device transmits an uplink transport block based on the second DCI in response to the second DCI indicating an uplink grant for the uplink transport block. 
     According to an example embodiment, the wireless device receives one or more radio resource control messages comprising configuration parameters of the SS, the configuration parameters comprising the first bitmap and at least one of: an SS index identifying the SS, a control resource set index identifying a control resource set associated with the SS, one or more time domain resource allocation parameters of the SS and a number of aggregation levels for the SS. 
       FIG. 37  shows an example embodiment of PDCCH monitoring on multiple RB sets of a BWP of a cell. In an example, a base station may transmit to a wireless device one or more RRC messages comprising configuration parameters of a cell. The cell comprises a plurality of BWPs. Each BWP may comprise a plurality of RB sets. The configuration parameters may comprise a first bitmap (e.g., 1st bitmap as shown in  FIG. 37 ), of a SS, indicating a frequency monitor location indication for the SS. Each bit of the first bitmap may correspond to a respective one of the plurality of RB sets of the BWP. Each bit of the first bitmap may indicate whether frequency resources of the SS are mapped to the corresponding RB set of the plurality of RB sets. In an example, 1st bit of the 1st bitmap may indicate whether the SS is mapped to 1st RB set, 2nd bit of the 1st bitmap may indicate whether the SS is mapped to 2nd RB set. A bit, of the 1st bitmap, being set to a first value (e.g., 0), may indicate that the SS is not mapped to a corresponding RB set. A bit, of the 1st bitmap, being set to a second value (e.g., 1), may indicate that the SS is mapped to a corresponding RB set. In an example, the 1st bitmap may indicate the SS are mapped to one or more first RB sets of the plurality of RB sets of the BWP. 
     In an example, the wireless device may receive a 1st DCI (e.g., a legacy DCI format 2_0 indicating slot format configuration of one or more cells). In an example, based on the 1st DCI being the legacy DCI format 2_0, the wireless device may monitor PDCCH on the SS in one or more first RB sets, of the plurality of RB sets of the BWP, based on the 1st bitmap indicating the SS is mapped to the one or more first RB sets. 
     In an example, the wireless device may receive a 2nd DCI (e.g., with DCI format 2_0 comprising a new DCI field). The new DCI field in the 2nd DCI may comprise a 2nd bitmap indicating whether one or more RB sets are available. Each bit of the 2nd bitmap may correspond to a respective RB set of the plurality of RB sets of the BWP. Each bit of the 2nd bitmap may indicate whether a corresponding RB set is available for downlink reception (or uplink transmission). In an example, 1st bit of the 2nd bitmap may indicate whether 1st RB set is available for downlink reception, 2nd bit of the 2nd bitmap may indicate whether 2nd RB set is available for downlink reception. A bit, of the 2nd bitmap, being set to a first value (e.g., 0), may indicate that a corresponding RB set is unavailable. A bit, of the 2nd bitmap, being set to a second value (e.g., 1), may indicate that a corresponding RB set is available. In an example, the 2nd bitmap may indicate one or more second RB sets of the plurality of RB sets of the BWP are available. 
     In an example, in response to the 2nd DCI comprising the 2nd bitmap, the wireless device may determine one or more RB sets for PDCCH monitoring on the SS based on the 2nd bitmap comprised in the 2nd DCI and the 1st bitmap comprised in the RRC message. The wireless device may determine the one or more RB sets based on example of  FIG. 35 . 
     In an example, based on example of  FIG. 37 , the wireless device may determine one or more RB sets for PDCCH monitoring on an SS based on a DCI format. In response to the DCI comprising an available RB set indication, the wireless device may determine the one or more RB sets based on a first bitmap associated with the SS and the available RB set indication. In response to the DCI not comprising the available RB set indication, the wireless device may determine the one or more RB set based on the first bitmap associated with the SS. 
       FIG. 38  show an example flowchart of PDCCH monitoring on multiple RB sets of a BWP. At  3810 , a wireless device monitors a downlink control channel on a search space in a first resource block (RB) set and a second RB set, wherein the first RB set and the second RB set are in a bandwidth part of a cell. At  3820 , the wireless device receiving a downlink control information comprising an RB set field indicating the first RB set is unavailable and the second RB set is available. At  3830 , the wireless device skips monitoring the downlink control channel on the search space on the first RB set. At  3840 , the wireless device monitors the downlink control channel on the search space on the second RB set. 
       FIG. 39  shows an example of power saving in a NR-U cell. In an example, a base station may transmit to a wireless device one or more RRC messages comprising configuration parameters of a cell. The configuration parameters may be implemented by examples of  FIG. 31 . The wireless device may receive a command indicating activation of a first BWP (1st BWP) of the cell. In response to activating the first BWP, the wireless device may monitor a SS on a CORESET with multiple monitoring frequency locations one or more of the plurality of subbands, each of the multiple monitoring frequency locations corresponding to one of the one or more of the plurality of subbands of the first BWP. 
     In an example, based on monitoring the PDCCH on a SS of a CORESET on one or more subbands of the BWP, a wireless device may receive a DCI via the PDCCH on a first subband (e.g., 1st LBT subband) of the one or more subbands of the BWP. In an example, the first subband is a subband on which the base station succeeds a LBT procedure indicating a clear channel. 
     In an example, in response to receiving the DCI via the first subband, the wireless device may monitor the PDCCH on a SS on the first subband, and stop monitoring the PDCCH on the SS on other subbands of an active BWP. Monitoring PDCCH on a subband on which a recent DCI is received may reduce power consumption of a wireless device. 
     In an example, in response to receiving the DCI via the first subband, the wireless device may monitor the PDCCH on a SS on a group of subbands, the group of subbands being associated with the first band. The association between the first band and the group of subbands may be indicated in an RRC message, or predefined. In an example, a first subband (with subband index 0) may be associated with a second subband (with subband index 1) and a third subband (subband index 2). The association may be based on frequency locations of the subbands. When the first subband, the second subband, and the third subband are within a bandwidth threshold (e.g., a value greater than a first number (e.g., 20 MHz) and less than a second number (e.g., 60 MHz)), the base station and/or the wireless device may determine the first subband, the second subband, and the third subband are associated. Monitoring PDCCH on a group of subbands, associated with a subband on which a recent DCI is received, may reduce power consumption of a wireless device. 
       FIG. 40  shows an example of power saving in a NR-U cell. In an example, a wireless device may activate a first BWP of the wideband NR-U cell. In response to activating the first BWP, the wireless device may monitor a SS on a CORESET with multiple monitoring frequency locations one or more of the plurality of subbands, each of the multiple monitoring frequency locations corresponding to one of the one or more of the plurality of subbands of the first BWP. 
     In an example, based on monitoring the PDCCH on a SS of a CORESET on one or more subbands of the BWP, the wireless device may receive a DCI via the PDCCH on a first subband (e.g., 1st LBT subband) of the one or more subbands of the BWP. In an example, the first subband is a subband on which the base station succeeds an LBT procedure indicating a clear channel. 
     As shown in  FIG. 40 , in response to receiving the DCI via the first subband, the wireless device may, within a first time duration, keep monitoring the PDCCH on the first subband, and stop monitoring the PDCCH on the SS on other subbands of an active BWP. The first time duration may be configured or predefined for maintaining PDCCH monitoring on the first subband. The first time duration may start at a time when receiving the DCI. The first time duration may start at a time when the wireless device transmits uplink signals. The wireless device may monitor the one or more subbands of the BWP after the first time duration or an expiry of the first time duration. 
     In an example, a wireless device my receive configuration parameters of at least one SS on a BWP of a cell, the configuration parameters indicating the BWP comprising a plurality of subbands and radio resources of the at least one SS being confined (or within) in a subband of the plurality of subbands. The wireless device may monitor PDCCH on the at least one SS on the plurality of subbands of the BWP. The wireless device may receive, via the PDCCH, a first DCI indicating transitioning to a power saving state. The wireless device may transition to the power saving state based on an expiry of a power saving timer. The wireless device may determine a first subband of the plurality of subbands for PDCCH monitoring in the power saving state. The wireless device may monitor, in response to transitioning to the power saving state, the PDCCH on the at least one SS on the first subband of the BWP. The cell may be in an unlicensed band. The wireless device may stop, in response to transitioning to the power saving state, monitoring the PDCCH on the at least one SS on at least a second subband of the plurality of subbands, the at least second subband being different from the first subband. The wireless device may determine the first subband based on a SS type of the at least one SS, a DCI format of the first DCI, a DCI content, a subband index of a subband. 
     In an example, a wireless device may monitor PDCCH on a SS of a CORESET on a plurality of subbands of a BWP of a cell in an active state. The wireless device may switch to a power saving state. The wireless device may determine a first subband of the plurality of subbands for PDCCH monitoring in the power saving state. The wireless device may monitor, in response to the switching to the power saving state, the PDCCH on the SS of the CORESET on the first subband of the BWP. 
     In an example, a wireless device may monitor PDCCH on a SS of a CORESET on a plurality of subbands of a BWP of a cell in an active state. The wireless device may receive, via the PDCCH, a power saving indication comprising a subband index indicating a first subband, of the plurality of subbands, for PDCCH monitoring in the cell in a power saving state. The wireless device may monitor, in response to the power saving indication, the PDCCH on the SS of the CORESET on the first subband of the BWP in the power saving state.