Patent Publication Number: US-11658793-B2

Title: Downlink control information activating a cell and a bandwidth part

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/171,731, filed Oct. 26, 2018, now U.S. Pat. No. 10,887,073, which claims the benefit of U.S. Provisional Application No. 62/577,239, filed Oct. 26, 2017, which is hereby incorporated by reference in its entirety. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     Examples of several of the various embodiments of the present invention are described herein with reference to the drawings. 
       FIG.  1    is a diagram depicting example sets of OFDM subcarriers as per an aspect of an embodiment of the present disclosure. 
       FIG.  2    is a diagram depicting an example transmission time and reception time for two carriers in a carrier group as per an aspect of an embodiment of the present disclosure. 
       FIG.  3    is a diagram depicting OFDM radio resources as per an aspect of an embodiment of the present disclosure. 
       FIG.  4    is a block diagram of a base station and a wireless device as per an aspect of an embodiment of the present disclosure. 
       FIG.  5 A ,  FIG.  5 B ,  FIG.  5 C  and  FIG.  5 D  are example diagrams for uplink and downlink signal transmission as per an aspect of an embodiment of the present disclosure. 
       FIG.  6    is an example diagram for a protocol structure with multi-connectivity as per an aspect of an embodiment of the present disclosure. 
       FIG.  7    is an example diagram for a protocol structure with CA and DC as per an aspect of an embodiment of the present disclosure. 
       FIG.  8    shows example TAG configurations as per an aspect of an embodiment of the present disclosure. 
       FIG.  9    is an example message flow in a random access process in a secondary TAG as per an aspect of an embodiment of the present disclosure. 
       FIG.  10 A  and  FIG.  10 B  are example diagrams for interfaces between a 5G core network and base stations as per an aspect of an embodiment of the present disclosure. 
       FIG.  11 A ,  FIG.  11 B ,  FIG.  11 C ,  FIG.  11 D ,  FIG.  11 E , and  FIG.  11 F  are example diagrams for architectures of tight interworking between 5G RAN and LTE RAN as per an aspect of an embodiment of the present disclosure. 
       FIG.  12 A ,  FIG.  12 B , and  FIG.  12 C  are example diagrams for radio protocol structures of tight interworking bearers as per an aspect of an embodiment of the present disclosure. 
       FIG.  13 A  and  FIG.  13 B  are example diagrams for gNB deployment scenarios as per an aspect of an embodiment of the present disclosure. 
       FIG.  14    is an example diagram for functional split option examples of the centralized gNB deployment scenario as per an aspect of an embodiment of the present disclosure. 
       FIG.  15    is an example diagram for synchronization signal block transmissions as per an aspect of an embodiment of the present disclosure. 
       FIG.  16    is an example diagram of random access procedure when configured with multiple beam as per an aspect of an embodiment of the present disclosure. 
       FIG.  17    is an example diagram for channel state information reference signal (CSI-RS) transmissions as per an aspect of an embodiment of the present disclosure. 
       FIG.  18    is an example diagram for channel state information reference signal (CSI-RS) transmissions as per an aspect of an embodiment of the present disclosure. 
       FIG.  19    is an example diagram for downlink beam management procedures as per an aspect of an embodiment of the present disclosure. 
       FIG.  20 A  is an example diagram for downlink beam failure scenario in a transmission receiving point (TRP) as per an aspect of an embodiment of the present disclosure. 
       FIG.  20 B  is an example diagram for downlink beam failure scenario in multiple TRPs as per an aspect of an embodiment of the present disclosure. 
       FIG.  21 A  is an example diagram for a secondary activation/deactivation medium access control control element (MAC CE) as per an aspect of an embodiment of the present disclosure. 
       FIG.  21 B  is an example diagram for a secondary activation/deactivation medium access control control element (MAC CE) as per an aspect of an embodiment of the present disclosure. 
       FIG.  22 A  is an example diagram for timing for CSI report when activation of a secondary cell as per an aspect of an embodiment of the present disclosure. 
       FIG.  22 B  is an example diagram for timing for CSI report when activation of a secondary cell as per an aspect of an embodiment of the present disclosure. 
       FIG.  23    is an example diagram for downlink control information (DCI) formats as per an aspect of an embodiment of the present disclosure. 
       FIG.  24    is an example diagram for bandwidth part (BWP) configurations as per an aspect of an embodiment of the present disclosure. 
       FIG.  25    is an example diagram for BWP operation in a secondary cell as per an aspect of an embodiment of the present disclosure. 
       FIG.  26    is an example diagram for BWP operation in a secondary cell as per an aspect of an embodiment of the present disclosure. 
       FIG.  27    is an example diagram for timing management of BWP operation as per an aspect of an embodiment of the present disclosure. 
       FIG.  28    is an example diagram for flowchart of timing management of BWP operation as per an aspect of an embodiment of the present disclosure. 
       FIG.  29    is a flow diagram of an aspect of an embodiment of the present disclosure. 
       FIG.  30    is a flow diagram of an aspect of an embodiment of the present disclosure. 
       FIG.  31    is a flow diagram of an aspect of an embodiment of the present disclosure. 
       FIG.  32    is a flow diagram of an aspect of an embodiment of the present disclosure. 
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Example embodiments of the present invention enable operation of carrier aggregation. Embodiments of the technology disclosed herein may be employed in the technical field of multicarrier communication systems. More particularly, the embodiments of the technology disclosed herein may relate to signal timing in a multicarrier communication system. 
     The following Acronyms are used throughout the present disclosure: 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 ASIC 
                 application-specific integrated circuit 
               
               
                   
                 BPSK 
                 binary phase shift keying 
               
               
                   
                 CA 
                 carrier aggregation 
               
               
                   
                 CSI 
                 channel state information 
               
               
                   
                 CDMA 
                 code division multiple access 
               
               
                   
                 CSS 
                 common search space 
               
               
                   
                 CPLD 
                 complex programmable logic devices 
               
               
                   
                 CC 
                 component carrier 
               
               
                   
                 CP 
                 cyclic prefix 
               
               
                   
                 DL 
                 downlink 
               
               
                   
                 DCI 
                 downlink control information 
               
               
                   
                 DC 
                 dual connectivity 
               
               
                   
                 eMBB 
                 enhanced mobile broadband 
               
               
                   
                 EPC 
                 evolved packet core 
               
               
                   
                 E-UTRAN 
                 evolved-universal terrestrial radio access network 
               
               
                   
                 FPGA 
                 field programmable gate arrays 
               
               
                   
                 FDD 
                 frequency division multiplexing 
               
               
                   
                 HDL 
                 hardware description languages 
               
               
                   
                 HARQ 
                 hybrid automatic repeat request 
               
               
                   
                 IE 
                 information element 
               
               
                   
                 LTE 
                 long term evolution 
               
               
                   
                 MCG 
                 master cell group 
               
               
                   
                 MeNB 
                 master evolved node B 
               
               
                   
                 MIB 
                 master information block 
               
               
                   
                 MAC 
                 media access control 
               
               
                   
                 MAC 
                 media access control 
               
               
                   
                 MME 
                 mobility management entity 
               
               
                   
                 mMTC 
                 massive machine type communications 
               
               
                   
                 NAS 
                 non-access stratum 
               
               
                   
                 NR 
                 new radio 
               
               
                   
                 OFDM 
                 orthogonal frequency division multiplexing 
               
               
                   
                 PDCP 
                 packet data convergence protocol 
               
               
                   
                 PDU 
                 packet data unit 
               
               
                   
                 PHY 
                 physical 
               
               
                   
                 PDCCH 
                 physical downlink control channel 
               
               
                   
                 PHICH 
                 physical HARQ indicator channel 
               
               
                   
                 PUCCH 
                 physical uplink control channel 
               
               
                   
                 PUSCH 
                 physical uplink shared channel 
               
               
                   
                 PCell 
                 primary cell 
               
               
                   
                 PCell 
                 primary cell 
               
               
                   
                 PCC 
                 primary component carrier 
               
               
                   
                 PSCell 
                 primary secondary cell 
               
               
                   
                 pTAG 
                 primary timing advance group 
               
               
                   
                 QAM 
                 quadrature amplitude modulation 
               
               
                   
                 QPSK 
                 quadrature phase shift keying 
               
               
                   
                 RBG 
                 resource block groups 
               
               
                   
                 RLC 
                 radio link control 
               
               
                   
                 RRC 
                 radio resource control 
               
               
                   
                 RA 
                 random access 
               
               
                   
                 RB 
                 resource blocks 
               
               
                   
                 SCC 
                 secondary component carrier 
               
               
                   
                 SCell 
                 secondary cell 
               
               
                   
                 SCG 
                 secondary cell group 
               
               
                   
                 SeNB 
                 secondary evolved node B 
               
               
                   
                 sTAGs 
                 secondary timing advance group 
               
               
                   
                 SDU 
                 service data unit 
               
               
                   
                 S-GW 
                 serving gateway 
               
               
                   
                 SRB 
                 signaling radio bearer 
               
               
                   
                 SC-OFDM 
                 single carrier-OFDM 
               
               
                   
                 SFN 
                 system frame number 
               
               
                   
                 SIB 
                 system information block 
               
               
                   
                 TAI 
                 tracking area identifier 
               
               
                   
                 TAT 
                 time alignment timer 
               
               
                   
                 TDD 
                 time division duplexing 
               
               
                   
                 TDMA 
                 time division multiple access 
               
               
                   
                 TA 
                 timing advance 
               
               
                   
                 TAG 
                 timing advance group 
               
               
                   
                 TTI 
                 transmission time interval 
               
               
                   
                 TB 
                 transport block 
               
               
                   
                 UL 
                 uplink 
               
               
                   
                 UE 
                 user equipment 
               
               
                   
                 URLLC 
                 ultra-reliable low-latency communications 
               
               
                   
                 VHDL 
                 VHSIC hardware description language 
               
               
                   
                 CU 
                 central unit 
               
               
                   
                 DU 
                 distributed unit 
               
               
                   
                 Fs-C 
                 Fs-control plane 
               
               
                   
                 Fs-U 
                 Fs-user plane 
               
               
                   
                 gNB 
                 next generation node B 
               
               
                   
                 NGC 
                 next generation core 
               
               
                   
                 NG CP 
                 next generation control plane core 
               
               
                   
                 NG-C 
                 NG-control plane 
               
               
                   
                 NG-U 
                 NG-user plane 
               
               
                   
                 NR 
                 new radio 
               
               
                   
                 NR MAC 
                 new radio MAC 
               
               
                   
                 NR PHY 
                 new radio physical 
               
               
                   
                 NR PDCP 
                 new radio PDCP 
               
               
                   
                 NR RLC 
                 new radio RLC 
               
               
                   
                 NR RRC 
                 new radio RRC 
               
               
                   
                 NSSAI 
                 network slice selection assistance information 
               
               
                   
                 PLMN 
                 public land mobile network 
               
               
                   
                 UPGW 
                 user plane gateway 
               
               
                   
                 Xn-C 
                 Xn-control plane 
               
               
                   
                 Xn-U 
                 Xn-user plane 
               
               
                   
                 Xx-C 
                 Xx-control plane 
               
               
                   
                 Xx-U 
                 Xx-user plane 
               
               
                   
                   
               
            
           
         
       
     
     Example embodiments of the invention may be implemented using various physical layer modulation and transmission mechanisms. Example transmission mechanisms may include, but are not limited to: CDMA, OFDM, TDMA, Wavelet technologies, and/or the like. Hybrid transmission mechanisms such as TDMA/CDMA, and OFDM/CDMA may also be employed. Various modulation schemes may be applied for signal transmission in the physical layer. Examples of modulation schemes include, but are not limited to: phase, amplitude, code, a combination of these, and/or the like. An example radio transmission method may implement QAM using BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM and/or the like. Physical radio transmission may be enhanced by dynamically or semi-dynamically changing the modulation and coding scheme depending on transmission requirements and radio conditions. 
       FIG.  1    is a diagram depicting example sets of OFDM subcarriers as per an aspect of an embodiment of the present disclosure. As illustrated in this example, arrow(s) in the diagram may depict a subcarrier in a multicarrier OFDM system. The OFDM system may use technology such as OFDM technology, DFTS-OFDM, SC-OFDM technology, or the like. For example, arrow  101  shows a subcarrier transmitting information symbols.  FIG.  1    is for illustration purposes, and a typical multicarrier OFDM system may include more subcarriers in a carrier. For example, the number of subcarriers in a carrier may be in the range of 10 to 10,000 subcarriers.  FIG.  1    shows two guard bands  106  and  107  in a transmission band. As illustrated in  FIG.  1   , guard band  106  is between subcarriers  103  and subcarriers  104 . The example set of subcarriers A  102  includes subcarriers  103  and subcarriers  104 .  FIG.  1    also illustrates an example set of subcarriers B  105 . As illustrated, there is no guard band between any two subcarriers in the example set of subcarriers B  105 . Carriers in a multicarrier OFDM communication system may be contiguous carriers, non-contiguous carriers, or a combination of both contiguous and non-contiguous carriers. 
       FIG.  2    is a diagram depicting an example transmission time and reception time for two carriers as per an aspect of an embodiment of the present disclosure. A multicarrier OFDM communication system may include one or more carriers, for example, ranging from 1 to 10 carriers. Carrier A  204  and carrier B  205  may have the same or different timing structures. Although  FIG.  2    shows two synchronized carriers, carrier A  204  and carrier B  205  may or may not be synchronized with each other. Different radio frame structures may be supported for FDD and TDD duplex mechanisms.  FIG.  2    shows an example FDD frame timing. Downlink and uplink transmissions may be organized into radio frames  201 . In this example, radio frame duration is 10 msec. Other frame durations, for example, in the range of 1 to 100 msec may also be supported. In this example, each 10 ms radio frame  201  may be divided into ten equally sized subframes  202 . Other subframe durations such as including 0.5 msec, 1 msec, 2 msec, and 5 msec may also be supported. Subframe(s) may comprise of two or more slots (e.g. slots  206  and  207 ). For the example of FDD, 10 subframes may be available for downlink transmission and 10 subframes may be available for uplink transmissions in each 10 ms interval. Uplink and downlink transmissions may be separated in the frequency domain. A slot may be 7 or 14 OFDM symbols for the same subcarrier spacing of up to 60 kHz with normal CP. A slot may be 14 OFDM symbols for the same subcarrier spacing higher than 60 kHz with normal CP. A slot may contain all downlink, all uplink, or a downlink part and an uplink part and/or alike. Slot aggregation may be supported, e.g., data transmission may be scheduled to span one or multiple slots. In an example, a mini-slot may start at an OFDM symbol in a subframe. A mini-slot may have a duration of one or more OFDM symbols. Slot(s) may include a plurality of OFDM symbols  203 . The number of OFDM symbols  203  in a slot  206  may depend on the cyclic prefix length and subcarrier spacing. 
       FIG.  3    is a diagram depicting OFDM radio resources as per an aspect of an embodiment of the present disclosure. The resource grid structure in time  304  and frequency  305  is illustrated in  FIG.  3   . The quantity of downlink subcarriers or RBs may depend, at least in part, on the downlink transmission bandwidth  306  configured in the cell. The smallest radio resource unit may be called a resource element (e.g.  301 ). Resource elements may be grouped into resource blocks (e.g.  302 ). Resource blocks may be grouped into larger radio resources called Resource Block Groups (RBG) (e.g.  303 ). The transmitted signal in slot  206  may be described by one or several resource grids of a plurality of subcarriers and a plurality of OFDM symbols. Resource blocks may be used to describe the mapping of certain physical channels to resource elements. Other pre-defined groupings of physical resource elements may be implemented in the system depending on the radio technology. For example, 24 subcarriers may be grouped as a radio block for a duration of 5 msec. In an illustrative example, a resource block may correspond to one slot in the time domain and 180 kHz in the frequency domain (for 15 KHz subcarrier bandwidth and 12 subcarriers). 
     In an example embodiment, multiple numerologies may be supported. In an example, a numerology may be derived by scaling a basic subcarrier spacing by an integer N. In an example, scalable numerology may allow at least from 15 kHz to 480 kHz subcarrier spacing. The numerology with 15 kHz and scaled numerology with different subcarrier spacing with the same CP overhead may align at a symbol boundary every 1 ms in a NR carrier. 
       FIG.  5 A ,  FIG.  5 B ,  FIG.  5 C  and  FIG.  5 D  are example diagrams for uplink and downlink signal transmission as per an aspect of an embodiment of the present disclosure.  FIG.  5 A  shows an example uplink physical channel. The baseband signal representing the physical uplink shared channel may perform the following processes. These functions are illustrated as examples and it is anticipated that other mechanisms may be implemented in various embodiments. The functions may comprise 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 DFTS-OFDM/SC-FDMA signal for an antenna port, and/or the like. 
     Example modulation and up-conversion to the carrier frequency of the complex-valued DFTS-OFDM/SC-FDMA baseband signal for an antenna port and/or the complex-valued PRACH baseband signal is shown in  FIG.  5 B . Filtering may be employed prior to transmission. 
     An example structure for Downlink Transmissions is shown in  FIG.  5 C . The baseband signal representing a downlink physical channel may perform the following processes. These functions are illustrated as examples and it is anticipated that other mechanisms may be implemented in various embodiments. The functions include scrambling of coded bits in codewords 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. 
     Example modulation and up-conversion to the carrier frequency of the complex-valued OFDM baseband signal for an antenna port is shown in  FIG.  5 D . Filtering may be employed prior to transmission. 
       FIG.  4    is an example block diagram of a base station  401  and a wireless device  406 , as per an aspect of an embodiment of the present disclosure. A communication network  400  may include at least one base station  401  and at least one wireless device  406 . The base station  401  may include at least one communication interface  402 , at least one processor  403 , and at least one set of program code instructions  405  stored in non-transitory memory  404  and executable by the at least one processor  403 . The wireless device  406  may include at least one communication interface  407 , at least one processor  408 , and at least one set of program code instructions  410  stored in non-transitory memory  409  and executable by the at least one processor  408 . Communication interface  402  in base station  401  may be configured to engage in communication with communication interface  407  in wireless device  406  via a communication path that includes at least one wireless link  411 . Wireless link  411  may be a bi-directional link. Communication interface  407  in wireless device  406  may also be configured to engage in a communication with communication interface  402  in base station  401 . Base station  401  and wireless device  406  may be configured to send and receive data over wireless link  411  using multiple frequency carriers. According to some of the various aspects of embodiments, transceiver(s) may be employed. A transceiver is a device that includes both a transmitter and receiver. Transceivers may be employed in devices such as wireless devices, base stations, relay nodes, and/or the like. Example embodiments for radio technology implemented in communication interface  402 ,  407  and wireless link  411  are illustrated are  FIG.  1   ,  FIG.  2   ,  FIG.  3   ,  FIG.  5   , and associated text. 
     An interface may be a hardware interface, a firmware interface, a software interface, and/or a combination thereof. The hardware interface may include connectors, wires, electronic devices such as drivers, amplifiers, and/or the like. A software interface may include code stored in a memory device to implement protocol(s), protocol layers, communication drivers, device drivers, combinations thereof, and/or the like. A firmware interface may include a combination of embedded hardware and code stored in and/or in communication with a memory device to implement connections, electronic device operations, protocol(s), protocol layers, communication drivers, device drivers, hardware operations, combinations thereof, and/or the like. 
     The term configured may relate to the capacity of a device whether the device is in an operational or non-operational state. Configured may also 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 in the device, whether the device is in an operational or non-operational state. 
     According to some of the various aspects of embodiments, a 5G network may include a multitude of base stations, providing a user plane NR PDCP/NR RLC/NR MAC/NR PHY and control plane (NR RRC) protocol terminations towards the wireless device. The base station(s) may be interconnected with other base station(s) (e.g. employing an Xn interface). The base stations may also be connected employing, for example, an NG interface to an NGC.  FIG.  10 A  and  FIG.  10 B  are example diagrams for interfaces between a 5G core network (e.g. NGC) and base stations (e.g. gNB and eLTE eNB) as per an aspect of an embodiment of the present disclosure. For example, the base stations may be interconnected to the NGC control plane (e.g. NG CP) employing the NG-C interface and to the NGC user plane (e.g. UPGW) employing the NG-U interface. The NG interface may support a many-to-many relation between 5G core networks and base stations. 
     A base station may include many sectors for example: 1, 2, 3, 4, or 6 sectors. A base station may include many cells, for example, ranging from 1 to 50 cells or more. A cell may be categorized, for example, as a primary cell or secondary cell. At RRC connection establishment/re-establishment/handover, one serving cell may provide the NAS (non-access stratum) mobility information (e.g. TAI), and at RRC connection re-establishment/handover, one serving cell may provide the security input. This cell may be referred to as the Primary Cell (PCell). In the downlink, the carrier corresponding to the PCell may be the Downlink Primary Component Carrier (DL PCC), while in the uplink, it may be the Uplink Primary Component Carrier (UL PCC). Depending on wireless device capabilities, Secondary Cells (SCells) may be configured to form together with the PCell a set of serving cells. In the downlink, the carrier corresponding to an SCell may be a Downlink Secondary Component Carrier (DL SCC), while in the uplink, it may be an Uplink Secondary Component Carrier (UL SCC). An SCell may or may not have an uplink carrier. 
     A cell, comprising a downlink carrier and optionally an uplink carrier, may be assigned a physical cell ID and a cell index. A carrier (downlink or uplink) may belong to only one cell. The cell ID or Cell index may also identify the downlink carrier or uplink carrier of the cell (depending on the context it is used). In the specification, cell ID may be equally referred to a carrier ID, and cell index may be referred to carrier index. In implementation, the physical cell ID or cell index may be assigned to a cell. A cell ID may be determined using a synchronization signal transmitted on a downlink carrier. A cell index may be determined using RRC messages. For example, when the specification refers to a first physical cell ID for a first downlink carrier, the specification may mean the first physical cell ID is for a cell comprising the first downlink carrier. The same concept may apply to, for example, carrier activation. When the specification indicates that a first carrier is activated, the specification may equally mean that the cell comprising the first carrier is activated. 
     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, 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 may support multiple technologies, and/or multiple releases of the same technology. Wireless devices may have some specific capability(ies) depending on its wireless device category and/or capability(ies). A base station may comprise multiple sectors. 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 wireless devices in a coverage area that may not comply with the disclosed methods, for example, because those wireless devices perform based on older releases of LTE or 5G technology. 
       FIG.  6    and  FIG.  7    are example diagrams for protocol structure with CA and multi-connectivity as per an aspect of an embodiment of the present disclosure. NR may support multi-connectivity operation whereby a multiple RX/TX UE in RRC_CONNECTED may be configured to utilize radio resources provided by multiple schedulers located in multiple gNBs connected via a non-ideal or ideal backhaul over the Xn interface. gNBs involved in multi-connectivity for a certain UE may assume two different roles: a gNB may either act as a master gNB or as a secondary gNB. In multi-connectivity, a UE may be connected to one master gNB and one or more secondary gNBs.  FIG.  7    illustrates one example structure for the UE side MAC entities when a Master Cell Group (MCG) and a Secondary Cell Group (SCG) are configured, and it may not restrict implementation. Media Broadcast Multicast Service (MBMS) reception is not shown in this figure for simplicity. 
     In multi-connectivity, the radio protocol architecture that a particular bearer uses may depend on how the bearer is setup. Three examples of bearers, including, an MCG bearer, an SCG bearer and a split bearer as shown in  FIG.  6   . NR RRC may be located in master gNB and SRBs may be configured as an MCG bearer type and may use the radio resources of the master gNB. Multi-connectivity may also be described as having at least one bearer configured to use radio resources provided by the secondary gNB. Multi-connectivity may or may not be configured/implemented in example embodiments of the disclosure. 
     In the case of multi-connectivity, the UE may be configured with multiple NR MAC entities: one NR MAC entity for master gNB, and other NR MAC entities for secondary gNBs. In multi-connectivity, the configured set of serving cells for a UE may comprise of two subsets: the Master Cell Group (MCG) containing the serving cells of the master gNB, and the Secondary Cell Groups (SCGs) containing the serving cells of the secondary gNBs. For a SCG, one or more of the following may be applied: at least one cell in the SCG has a configured UL CC and one of them, named PSCell (or PCell of SCG, or sometimes called PCell), is configured with PUCCH resources; when the SCG is configured, there may be at least one SCG bearer or one Split bearer; upon detection of a physical layer problem or a random access problem on a PSCell, or the maximum number of NR RLC retransmissions has been reached associated with the SCG, or upon detection of an access problem on a PSCell during a SCG addition or a SCG change: a RRC connection re-establishment procedure may not be triggered, UL transmissions towards cells of the SCG are stopped, a master gNB may be informed by the UE of a SCG failure type, for split bearer, the DL data transfer over the master gNB is maintained; the NR RLC AM bearer may be configured for the split bearer; like PCell, PSCell may not be de-activated; PSCell may be changed with a SCG change (e.g. with security key change and a RACH procedure); and/or a direct bearer type change between a Split bearer and a SCG bearer or simultaneous configuration of a SCG and a Split bearer may or may not supported. 
     With respect to the interaction between a master gNB and secondary gNBs for multi-connectivity, one or more of the following principles may be applied: the master gNB may maintain the RRM measurement configuration of the UE and may, (e.g., based on received measurement reports or traffic conditions or bearer types), decide to ask a secondary gNB to provide additional resources (serving cells) for a UE; upon receiving a request from the master gNB, a secondary gNB may create a container that may result in the configuration of additional serving cells for the UE (or decide that it has no resource available to do so); for UE capability coordination, the master gNB may provide (part of) the AS configuration and the UE capabilities to the secondary gNB; the master gNB and the secondary gNB may exchange information about a UE configuration by employing of NR RRC containers (inter-node messages) carried in Xn messages; the secondary gNB may initiate a reconfiguration of its existing serving cells (e.g., PUCCH towards the secondary gNB); the secondary gNB may decide which cell is the PSCell within the SCG; the master gNB may or may not change the content of the NR RRC configuration provided by the secondary gNB; in the case of a SCG addition and a SCG SCell addition, the master gNB may provide the latest measurement results for the SCG cell(s); both a master gNB and secondary gNBs may know the SFN and subframe offset of each other by OAM, (e.g., for the purpose of DRX alignment and identification of a measurement gap). In an example, when adding a new SCG SCell, dedicated NR RRC signaling may be used for sending required system information of the cell as for CA, except for the SFN acquired from a MIB of the PSCell of a SCG. 
     In an example, serving cells may be grouped in a TA group (TAG). Serving cells in one TAG may use the same timing reference. For a given TAG, user equipment (UE) may use at least one downlink carrier as a timing reference. For a given TAG, a UE may synchronize uplink subframe and frame transmission timing of uplink carriers belonging to the same TAG. In an example, serving cells having an uplink to which the same TA applies may correspond to serving cells hosted by the same receiver. A UE supporting multiple TAs may support two or more TA groups. One TA group may contain the PCell and may be called a primary TAG (pTAG). In a multiple TAG configuration, at least one TA group may not contain the PCell and may be called a secondary TAG (sTAG). In an example, carriers within the same TA group may use the same TA value and/or the same timing reference. When DC is configured, cells belonging to a cell group (MCG or SCG) may be grouped into multiple TAGs including a pTAG and one or more sTAGs. 
       FIG.  8    shows example TAG configurations as per an aspect of an embodiment of the present disclosure. In Example 1, pTAG comprises PCell, and an sTAG comprises SCell1. In Example 2, a pTAG comprises a PCell and SCell1, and an sTAG comprises SCell2 and SCell3. In Example 3, pTAG comprises PCell and SCell1, and an sTAG1 includes SCell2 and SCell3, and sTAG2 comprises SCell4. Up to four TAGs may be supported in a cell group (MCG or SCG) and other example TAG configurations may also be provided. In various examples in this disclosure, example mechanisms are described for a pTAG and an sTAG. Some of the example mechanisms may be applied to configurations with multiple sTAGs. 
     In an example, an eNB may initiate an RA procedure via a PDCCH order for an activated SCell. This PDCCH order may be sent on a scheduling cell of this SCell. When cross carrier scheduling is configured for a cell, the scheduling cell may be different than the cell that is employed for preamble transmission, and the PDCCH order may include an SCell index. At least a non-contention based RA procedure may be supported for SCell(s) assigned to sTAG(s). 
       FIG.  9    is an example message flow in a random access process in a secondary TAG as per an aspect of an embodiment of the present disclosure. An eNB transmits an activation command  900  to activate an SCell. A preamble  902  (Msg1) may be sent by a UE in response to a PDCCH order  901  on an SCell belonging to an sTAG. In an example embodiment, preamble transmission for SCells may be controlled by the network using PDCCH format 1A. Msg2 message  903  (RAR: random access response) in response to the preamble transmission on the SCell may be addressed to RA-RNTI in a PCell common search space (CSS). Uplink packets  904  may be transmitted on the SCell in which the preamble was transmitted. 
     According to some of the various aspects of embodiments, initial timing alignment may be achieved through a random access procedure. This may involve a UE transmitting a random access preamble and an eNB responding with an initial TA command NTA (amount of timing advance) within a random access response window. The start of the random access preamble may be aligned with the start of a corresponding uplink subframe at the UE assuming NTA=0. The eNB may estimate the uplink timing from the random access preamble transmitted by the UE. The TA command may be derived by the eNB based on the estimation of the difference between the desired UL timing and the actual UL timing. The UE may determine the initial uplink transmission timing relative to the corresponding downlink of the sTAG on which the preamble is transmitted. 
     The mapping of a serving cell to a TAG may be configured by a serving eNB with RRC signaling. The mechanism for TAG configuration and reconfiguration may be based on RRC signaling. According to some of the various aspects of embodiments, when an eNB performs an SCell addition configuration, the related TAG configuration may be configured for the SCell. In an example embodiment, an eNB may modify the TAG configuration of an SCell by removing (releasing) the SCell and adding (configuring) a new SCell (with the same physical cell ID and frequency) with an updated TAG ID. The new SCell with the updated TAG ID may initially be inactive subsequent to being assigned the updated TAG ID. The eNB may activate the updated new SCell and start scheduling packets on the activated SCell. In an example implementation, it may not be possible to change the TAG associated with an SCell, but rather, the SCell may need to be removed and a new SCell may need to be added with another TAG. For example, if there is a need to move an SCell from an sTAG to a pTAG, at least one RRC message, for example, at least one RRC reconfiguration message, may be send to the UE to reconfigure TAG configurations by releasing the SCell and then configuring the SCell as a part of the pTAG (when an SCell is added/configured without a TAG index, the SCell may be explicitly assigned to the pTAG). The PCell may not change its TA group and may be a member of the pTAG. 
     The purpose of an RRC connection reconfiguration procedure may be to modify an RRC connection, (e.g. to establish, modify and/or release RBs, to perform handover, to setup, modify, and/or release measurements, to add, modify, and/or release SCells). If the received RRC Connection Reconfiguration message includes the sCellToReleaseList, the UE may perform an SCell release. If the received RRC Connection Reconfiguration message includes the sCellToAddModList, the UE may perform SCell additions or modification. 
     In LTE Release-10 and Release-11 CA, a PUCCH is only transmitted on the PCell (PSCell) to an eNB. In LTE-Release 12 and earlier, a UE may transmit PUCCH information on one cell (PCell or PSCell) to a given eNB. 
     As the number of CA capable UEs and also the number of aggregated carriers increase, the number of PUCCHs and also the PUCCH payload size may increase. Accommodating the PUCCH transmissions on the PCell may lead to a high PUCCH load on the PCell. A PUCCH on an SCell may be introduced to offload the PUCCH resource from the PCell. More than one PUCCH may be configured for example, a PUCCH on a PCell and another PUCCH on an SCell. In the example embodiments, one, two or more cells may be configured with PUCCH resources for transmitting CSI/ACK/NACK to a base station. Cells may be grouped into multiple PUCCH groups, and one or more cell within a group may be configured with a PUCCH. In an example configuration, one SCell may belong to one PUCCH group. SCells with a configured PUCCH transmitted to a base station may be called a PUCCH SCell, and a cell group with a common PUCCH resource transmitted to the same base station may be called a PUCCH group. 
     In an example embodiment, a MAC entity may have a configurable timer timeAlignmentTimer per TAG. The timeAlignmentTimer may be used to control how long the MAC entity considers the Serving Cells belonging to the associated TAG to be uplink time aligned. The MAC entity may, when a Timing Advance Command MAC control element is received, apply the Timing Advance Command for the indicated TAG; start or restart the timeAlignmentTimer associated with the indicated TAG. The MAC entity may, when a Timing Advance Command is received in a Random Access Response message for a serving cell belonging to a TAG and/or if the Random Access Preamble was not selected by the MAC entity, apply the Timing Advance Command for this TAG and start or restart the timeAlignmentTimer associated with this TAG. Otherwise, if the timeAlignmentTimer associated with this TAG is not running, the Timing Advance Command for this TAG may be applied and the timeAlignmentTimer associated with this TAG started. When the contention resolution is considered not successful, a timeAlignmentTimer associated with this TAG may be stopped. Otherwise, the MAC entity may ignore the received Timing Advance Command. 
     In example embodiments, a timer is running once it is started, until it is stopped or until it expires; otherwise it may not be running. A timer can be started if it is not running or restarted if it is running. For example, a timer may be started or restarted from its initial value. 
     Example embodiments of the disclosure may enable operation of multi-carrier communications. Other example embodiments may comprise a non-transitory tangible computer readable media comprising instructions executable by one or more processors to cause operation of multi-carrier communications. Yet other example embodiments may comprise an article of manufacture that comprises a non-transitory tangible computer readable machine-accessible medium having instructions encoded thereon for enabling programmable hardware to cause a device (e.g. wireless communicator, UE, base station, etc.) to enable operation of multi-carrier communications. The device may include processors, memory, interfaces, and/or the like. Other example embodiments may comprise communication networks comprising devices such as base stations, wireless devices (or user equipment: UE), servers, switches, antennas, and/or the like. 
       FIG.  11 A ,  FIG.  11 B ,  FIG.  11 C ,  FIG.  11 D ,  FIG.  11 E , and  FIG.  11 F  are example diagrams for architectures of tight interworking between 5G RAN and LTE RAN as per an aspect of an embodiment of the present disclosure. The tight interworking may enable a multiple RX/TX UE in RRC_CONNECTED to be configured to utilize radio resources provided by two schedulers located in two base stations (e.g. (e)LTE eNB and gNB) connected via a non-ideal or ideal backhaul over the Xx interface between LTE eNB and gNB or the Xn interface between eLTE eNB and gNB. Base stations involved in tight interworking for a certain UE may assume two different roles: a base station may either act as a master base station or as a secondary base station. In tight interworking, a UE may be connected to one master base station and one secondary base station. Mechanisms implemented in tight interworking may be extended to cover more than two base stations. 
     In  FIG.  11 A  and  FIG.  11 B , a master base station may be an LTE eNB, which may be connected to EPC nodes (e.g. to an MME via the S1-C interface and to an S-GW via the S1-U interface), and a secondary base station may be a gNB, which may be a non-standalone node having a control plane connection via an Xx-C interface to an LTE eNB. In the tight interworking architecture of  FIG.  11 A , a user plane for a gNB may be connected to an S-GW through an LTE eNB via an Xx-U interface between LTE eNB and gNB and an S1-U interface between LTE eNB and S-GW. In the architecture of  FIG.  11 B , a user plane for a gNB may be connected directly to an S-GW via an S1-U interface between gNB and S-GW. 
     In  FIG.  11 C  and  FIG.  11 D , a master base station may be a gNB, which may be connected to NGC nodes (e.g. to a control plane core node via the NG-C interface and to a user plane core node via the NG-U interface), and a secondary base station may be an eLTE eNB, which may be a non-standalone node having a control plane connection via an Xn-C interface to a gNB. In the tight interworking architecture of  FIG.  11 C , a user plane for an eLTE eNB may be connected to a user plane core node through a gNB via an Xn-U interface between eLTE eNB and gNB and an NG-U interface between gNB and user plane core node. In the architecture of  FIG.  11 D , a user plane for an eLTE eNB may be connected directly to a user plane core node via an NG-U interface between eLTE eNB and user plane core node. 
     In  FIG.  11 E  and  FIG.  11 F , a master base station may be an eLTE eNB, which may be connected to NGC nodes (e.g. to a control plane core node via the NG-C interface and to a user plane core node via the NG-U interface), and a secondary base station may be a gNB, which may be a non-standalone node having a control plane connection via an Xn-C interface to an eLTE eNB. In the tight interworking architecture of  FIG.  11 E , a user plane for a gNB may be connected to a user plane core node through an eLTE eNB via an Xn-U interface between eLTE eNB and gNB and an NG-U interface between eLTE eNB and user plane core node. In the architecture of  FIG.  11 F , a user plane for a gNB may be connected directly to a user plane core node via an NG-U interface between gNB and user plane core node. 
       FIG.  12 A ,  FIG.  12 B , and  FIG.  12 C  are example diagrams for radio protocol structures of tight interworking bearers as per an aspect of an embodiment of the present disclosure. In  FIG.  12 A , an LTE eNB may be a master base station, and a gNB may be a secondary base station. In  FIG.  12 B , a gNB may be a master base station, and an eLTE eNB may be a secondary base station. In  FIG.  12 C , an eLTE eNB may be a master base station, and a gNB may be a secondary base station. In 5G network, the radio protocol architecture that a particular bearer uses may depend on how the bearer is setup. Three example bearers including an MCG bearer, an SCG bearer, and a split bearer as shown in  FIG.  12 A ,  FIG.  12 B , and  FIG.  12 C . NR RRC may be located in master base station, and SRBs may be configured as an MCG bearer type and may use the radio resources of the master base station. Tight interworking may also be described as having at least one bearer configured to use radio resources provided by the secondary base station. Tight interworking may or may not be configured/implemented in example embodiments of the disclosure. 
     In the case of tight interworking, the UE may be configured with two MAC entities: one MAC entity for master base station, and one MAC entity for secondary base station. In tight interworking, the configured set of serving cells for a UE may comprise of two subsets: the Master Cell Group (MCG) containing the serving cells of the master base station, and the Secondary Cell Group (SCG) containing the serving cells of the secondary base station. For a SCG, one or more of the following may be applied: at least one cell in the SCG has a configured UL CC and one of them, named PSCell (or PCell of SCG, or sometimes called PCell), is configured with PUCCH resources; when the SCG is configured, there may be at least one SCG bearer or one split bearer; upon detection of a physical layer problem or a random access problem on a PSCell, or the maximum number of (NR) RLC retransmissions has been reached associated with the SCG, or upon detection of an access problem on a PSCell during a SCG addition or a SCG change: a RRC connection re-establishment procedure may not be triggered, UL transmissions towards cells of the SCG are stopped, a master base station may be informed by the UE of a SCG failure type, for split bearer, the DL data transfer over the master base station is maintained; the RLC AM bearer may be configured for the split bearer; like PCell, PSCell may not be de-activated; PSCell may be changed with a SCG change (e.g. with security key change and a RACH procedure); and/or neither a direct bearer type change between a Split bearer and a SCG bearer nor simultaneous configuration of a SCG and a Split bearer are supported. 
     With respect to the interaction between a master base station and a secondary base station, one or more of the following principles may be applied: the master base station may maintain the RRM measurement configuration of the UE and may, (e.g., based on received measurement reports, traffic conditions, or bearer types), decide to ask a secondary base station to provide additional resources (serving cells) for a UE; upon receiving a request from the master base station, a secondary base station may create a container that may result in the configuration of additional serving cells for the UE (or decide that it has no resource available to do so); for UE capability coordination, the master base station may provide (part of) the AS configuration and the UE capabilities to the secondary base station; the master base station and the secondary base station may exchange information about a UE configuration by employing of RRC containers (inter-node messages) carried in Xn or Xx messages; the secondary base station may initiate a reconfiguration of its existing serving cells (e.g., PUCCH towards the secondary base station); the secondary base station may decide which cell is the PSCell within the SCG; the master base station may not change the content of the RRC configuration provided by the secondary base station; in the case of a SCG addition and a SCG SCell addition, the master base station may provide the latest measurement results for the SCG cell(s); both a master base station and a secondary base station may know the SFN and subframe offset of each other by OAM, (e.g., for the purpose of DRX alignment and identification of a measurement gap). In an example, when adding a new SCG SCell, dedicated RRC signaling may be used for sending required system information of the cell as for CA, except for the SFN acquired from a MIB of the PSCell of a SCG. 
       FIG.  13 A  and  FIG.  13 B  are example diagrams for gNB deployment scenarios as per an aspect of an embodiment of the present disclosure. In the non-centralized deployment scenario in  FIG.  13 A , the full protocol stack (e.g. NR RRC, NR PDCP, NR RLC, NR MAC, and NR PHY) may be supported at one node. In the centralized deployment scenario in  FIG.  13 B , upper layers of gNB may be located in a Central Unit (CU), and lower layers of gNB may be located in Distributed Units (DU). The CU-DU interface (e.g. Fs interface) connecting CU and DU may be ideal or non-ideal. Fs-C may provide a control plane connection over Fs interface, and Fs-U may provide a user plane connection over Fs interface. In the centralized deployment, different functional split options between CU and DUs may be possible by locating different protocol layers (RAN functions) in CU and DU. The functional split may support flexibility to move RAN functions between CU and DU depending on service requirements and/or network environments. The functional split option may change during operation after Fs interface setup procedure, or may change only in Fs setup procedure (i.e. static during operation after Fs setup procedure). 
       FIG.  14    is an example diagram for different functional split option examples of the centralized gNB deployment scenario as per an aspect of an embodiment of the present disclosure. In the split option example 1, an NR RRC may be in CU, and NR PDCP, NR RLC, NR MAC, NR PHY, and RF may be in DU. In the split option example 2, an NR RRC and NR PDCP may be in CU, and NR RLC, NR MAC, NR PHY, and RF may be in DU. In the split option example 3, an NR RRC, NR PDCP, and partial function of NR RLC may be in CU, and the other partial function of NR RLC, NR MAC, NR PHY, and RF may be in DU. In the split option example 4, an NR RRC, NR PDCP, and NR RLC may be in CU, and NR MAC, NR PHY, and RF may be in DU. In the split option example 5, an NR RRC, NR PDCP, NR RLC, and partial function of NR MAC may be in CU, and the other partial function of NR MAC, NR PHY, and RF may be in DU. In the split option example 6, an NR RRC, NR PDCP, NR RLC, and NR MAC may be in CU, and NR PHY and RF may be in DU. In the split option example 7, an NR RRC, NR PDCP, NR RLC, NR MAC, and partial function of NR PHY may be in CU, and the other partial function of NR PHY and RF may be in DU. In the split option example 8, an NR RRC, NR PDCP, NR RLC, NR MAC, and NR PHY may be in CU, and RF may be in DU. 
     The functional split may be configured per CU, per DU, per UE, per bearer, per slice, or with other granularities. In per CU split, a CU may have a fixed split, and DUs may be configured to match the split option of CU. In per DU split, a DU may be configured with a different split, and a CU may provide different split options for different DUs. In per UE split, a gNB (CU and DU) may provide different split options for different UEs. In per bearer split, different split options may be utilized for different bearer types. In per slice splice, different split options may be applied for different slices. 
     In an example embodiment, the new radio access network (new RAN) may support different network slices, which may allow differentiated treatment customized to support different service requirements with end to end scope. The new RAN may provide a differentiated handling of traffic for different network slices that may be pre-configured, and may allow a single RAN node to support multiple slices. The new RAN may support selection of a RAN part for a given network slice, by one or more slice ID(s) or NSSAI(s) provided by a UE or a NGC (e.g. NG CP). The slice ID(s) or NSSAI(s) may identify one or more of pre-configured network slices in a PLMN. For initial attach, a UE may provide a slice ID and/or an NSSAI, and a RAN node (e.g. gNB) may use the slice ID or the NSSAI for routing an initial NAS signaling to an NGC control plane function (e.g. NG CP). If a UE does not provide any slice ID or NSSAI, a RAN node may send a NAS signaling to a default NGC control plane function. For subsequent accesses, the UE may provide a temporary ID for a slice identification, which may be assigned by the NGC control plane function, to enable a RAN node to route the NAS message to a relevant NGC control plane function. The new RAN may support resource isolation between slices. The RAN resource isolation may be achieved by avoiding that shortage of shared resources in one slice breaks a service level agreement for another slice. 
     A New Radio (NR) system may support both single beam and multi-beam operations. In a multi-beam system, a base station (e.g., gNB) may perform a downlink beam sweeping to provide coverage for downlink Synchronization Signals (SSs) and common control channels. A User Equipment (UE) may perform an uplink beam sweeping for uplink direction to access a cell. In a single beam scenario, a gNB may configure time-repetition transmission for one SS block, which may comprise at least Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Physical Broadcast Channel (PBCH), with a wide beam. In a multi-beam scenario, a gNB may configure at least some of these signals and physical channels in multiple beams. A UE may identify at least OFDM symbol index, slot index in a radio frame and radio frame number from an SS block. 
     In an example, in an RRC_INACTIVE state or RRC_IDLE state, a UE may assume that SS blocks form an SS burst, and an SS burst set. An SS burst set may have a given periodicity. In multi-beam scenarios, SS blocks may be transmitted in multiple beams, together forming an SS burst. One or more SS blocks may be transmitted on one beam. A beam has a steering direction. If multiple SS bursts are transmitted with beams, these SS bursts together may form an SS burst set as shown in  FIG.  15   . A base station  1501  (e.g., a gNB in NR) may transmit SS bursts  1502 A to  1502 H during time periods  1503 . A plurality of these SS bursts may comprise an SS burst set, such as an SS burst set  1504  (e.g., SS bursts  1502 A and  1502 E). An SS burst set may comprise any number of a plurality of SS bursts  1502 A to  1502 H. Each SS burst within an SS burst set may transmitted at a fixed or variable periodicity during time periods  1503 . 
     An SS may be based on Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM). The SS may comprise at least two types of synchronization signals; NR-PSS (Primary synchronization signal) and NR-SSS (Secondary synchronization signal). NR-PSS may be defined at least for initial symbol boundary synchronization to the NR cell. NR-SSS may be defined for detection of NR cell ID or at least part of NR cell ID. NR-SSS detection may be based on the fixed time/frequency relationship with NR-PSS resource position irrespective of duplex mode and beam operation type at least within a given frequency range and CP overhead. Normal CP may be supported for NR-PSS and NR-SSS. 
     The NR may comprise at least one physical broadcast channel (NR-PBCH). When a gNB transmit (or broadcast) the NR-PBCH, a UE may decode the NR-PBCH based on the fixed relationship with NR-PSS and/or NR-SSS resource position irrespective of duplex mode and beam operation type at least within a given frequency range and CP overhead. NR-PBCH may be a non-scheduled broadcast channel carrying at least a part of minimum system information with fixed payload size and periodicity predefined in the specification depending on carrier frequency range. 
     In single beam and multi-beam scenarios, NR may comprise an SS block that may support time (frequency, and/or spatial) division multiplexing of NR-PSS, NR-SSS, and NR-PBCH. A gNB may transmit NR-PSS, NR-SSS and/or NR-PBCH within an SS block. For a given frequency band, an SS block may correspond to N OFDM symbols based on the default subcarrier spacing, and N may be a constant. The signal multiplexing structure may be fixed in NR. A wireless device may identify, e.g., from an SS block, an OFDM symbol index, a slot index in a radio frame, and a radio frame number from an SS block. 
     A NR may support an SS burst comprising one or more SS blocks. An SS burst set may comprise one or more SS bursts. For example, a number of SS bursts within a SS burst set may be finite. From physical layer specification perspective, NR may support at least one periodicity of SS burst set. From UE perspective, SS burst set transmission may be periodic, and UE may assume that a given SS block is repeated with an SS burst set periodicity. 
     Within an SS burst set periodicity, NR-PBCH repeated in one or more SS blocks may change. A set of possible SS block time locations may be specified per frequency band in an RRC message. The maximum number of SS-blocks within SS burst set may be carrier frequency dependent. The position(s) of actual transmitted SS-blocks may be informed at least for helping CONNECTED/IDLE mode measurement, for helping CONNECTED mode UE to receive downlink (DL) data/control in one or more SS-blocks, or for helping IDLE mode UE to receive DL data/control in one or more SS-blocks. A UE may not assume that the gNB transmits the same number of physical beam(s). A UE may not assume the same physical beam(s) across different SS-blocks within an SS burst set. For an initial cell selection, UE may assume default SS burst set periodicity which may be broadcast via an RRC message and frequency band-dependent. At least for multi-beams operation case, the time index of SS-block may be indicated to the UE. 
     For CONNECTED and IDLE mode UEs, NR may support network indication of SS burst set periodicity and information to derive measurement timing/duration (e.g., time window for NR-SS detection). A gNB may provide (e.g., via broadcasting an RRC message) one SS burst set periodicity information per frequency carrier to UE and information to derive measurement timing/duration if possible. In case that one SS burst set periodicity and one information regarding timing/duration are indicated, a UE may assume the periodicity and timing/duration for all cells on the same carrier. If a gNB does not provide indication of SS burst set periodicity and information to derive measurement timing/duration, a UE may assume a predefined periodicity, e.g., 5 ms, as the SS burst set periodicity. NR may support set of SS burst set periodicity values for adaptation and network indication. 
     For initial access, a UE may assume a signal corresponding to a specific subcarrier spacing of NR-PSS/SSS in a given frequency band given by a NR specification. For NR-PSS, a Zadoff-Chu (ZC) sequence may be employed as a sequence for NR-PSS. NR may define at least one basic sequence length for a SS in case of sequence-based SS design. The number of antenna port of NR-PSS may be 1. For NR-PBCH transmission, NR may support a fixed number of antenna port(s). A UE may not be required for a blind detection of NR-PBCH transmission scheme or number of antenna ports. A UE may assume the same PBCH numerology as that of NR-SS. For the minimum system information delivery, NR-PBCH may comprise a part of minimum system information. NR-PBCH contents may comprise at least a part of the SFN (system frame number) or CRC. A gNB may transmit the remaining minimum system information in shared downlink channel via NR-PDSCH. 
     In a multi-beam example, one or more of PSS, SSS, or PBCH signals may be repeated for a cell, e.g., to support cell selection, cell reselection, and/or initial access procedures. For an SS burst, an associated PBCH or a physical downlink shared channel (PDSCH) scheduling system information may be broadcasted by a base station to multiple wireless devices. The PDSCH may be indicated by a physical downlink control channel (PDCCH) in a common search space. The system information may comprise a physical random access channel (PRACH) configuration for a beam. For a beam, a base station (e.g., a gNB in NR) may have a RACH configuration which may include a PRACH preamble pool, time and/or frequency radio resources, and other power related parameters. A wireless device may use a PRACH preamble from a RACH configuration to initiate a contention-based RACH procedure or a contention-free RACH procedure. A wireless device may perform a 4-step RACH procedure, which may be a contention-based RACH procedure or a contention-free RACH procedure. The wireless device may select a beam associated with an SS block that may have the best receiving signal quality. The wireless device may successfully detect a cell identifier associated with the cell and decode system information with a RACH configuration. The wireless device may use one PRACH preamble and select one PRACH resource from RACH resources indicated by the system information associated with the selected beam. A PRACH resource may comprise at least one of: a PRACH index indicating a PRACH preamble, a PRACH format, a PRACH numerology, time and/or frequency radio resource allocation, power setting of a PRACH transmission, and/or other radio resource parameters. For a contention-free RACH procedure, the PRACH preamble and resource may be indicated in a DCI or other high layer signaling. 
       FIG.  16    shows an example of a random access procedure (e.g., via a RACH) that may include sending, by a base station, one or more SS blocks. A wireless device  1620  (e.g., a UE) may transmit one or more preambles to a base station  1621  (e.g., a gNB in NR). Each preamble transmission by the wireless device may be associated with a separate random access procedure, such as shown in  FIG.  16   . The random access procedure may begin at step  1601  with a base station  1621  (e.g., a gNB in NR) sending a first SS block to a wireless device  1621  (e.g., a UE). Any of the SS blocks may comprise one or more of a PSS, SSS, tertiary synchronization signal (TSS), or PBCH signal. The first SS block in step  1601  may be associated with a first PRACH configuration. At step  1602 , the base station  1621  may send to the wireless device  1620  a second SS block that may be associated with a second PRACH configuration. At step  1603 , the base station  1621  may send to the wireless device  1620  a third SS block that may be associated with a third PRACH configuration. At step  1604 , the base station  1621  may send to the wireless device  1620  a fourth SS block that may be associated with a fourth PRACH configuration. Any number of SS blocks may be sent in the same manner in addition to, or replacing, steps  1603  and  1604 . An SS burst may comprise any number of SS blocks. For example, SS burst  1610  comprises the three SS blocks sent during steps  1602 - 1604 . 
     The wireless device  1620  may send to the base station  1621  a preamble, at step  1605 , e.g., after or in response to receiving one or more SS blocks or SS bursts. The preamble may comprise a PRACH preamble, and may be referred to as RA Msg 1. The PRACH preamble may be transmitted in step  1605  according to or based on a PRACH configuration that may be received in an SS block (e.g., one of the SS blocks from steps  1601 - 1604 ) that may be determined to be the best SS block beam. The wireless device  1620  may determine a best SS block beam from among SS blocks it may receive prior to sending the PRACH preamble. The base station  1621  may send a random access response (RAR), which may be referred to as RA Msg2, at step  1606 , e.g., after or in response to receiving the PRACH preamble. The RAR may be transmitted in step  1606  via a DL beam that corresponds to the SS block beam associated with the PRACH configuration. The base station  1621  may determine the best SS block beam from among SS blocks it previously sent prior to receiving the PRACH preamble. The base station  1621  may receive the PRACH preamble according to or based on the PRACH configuration associated with the best SS block beam. 
     The wireless device  1620  may send to the base station  1621  an RRCConnectionRequest and/or RRCConnectionResumeRequest message, which may be referred to as RA Msg3, at step  1607 , e.g., after or in response to receiving the RAR. The base station  1621  may send to the wireless device  1620  an RRCConnectionSetup and/or RRCConnectionResume message, which may be referred to as RA Msg4, at step  1608 , e.g., after or in response to receiving the RRCConnectionRequest and/or RRCConnectionResumeRequest message. The wireless device  1620  may send to the base station  1621  an RRCConnectionSetupComplete and/or RRCConnectionResumeComplete message, which may be referred to as RA Msg5, at step  1609 , e.g., after or in response to receiving the RRCConnectionSetup and/or RRCConnectionResume. An RRC connection may be established between the wireless device  1620  and the base station  1621 , and the random access procedure may end, e.g., after or in response to receiving the RRCConnectionSetupComplete and/or RRCConnectionResumeComplete message. 
     A best beam, including but not limited to a best SS block beam, may be determined based on a channel state information reference signal (CSI-RS). A wireless device may use a CSI-RS in a multi-beam system for estimating the beam quality of the links between the wireless device and a base station. For example, based on a measurement of a CSI-RS, a wireless device may report CSI for downlink channel adaption. A CSI parameter may include a precoding matrix index (PMI), a channel quality index (CQI) value, and/or a rank indicator (RI). A wireless device may report a beam index based on a reference signal received power (RSRP) measurement on a CSI-RS. The wireless device may report the beam index in a CSI resource indication (CRI) for downlink beam selection. A base station may transmit a CSI-RS via a CSI-RS resource, such as via one or more antenna ports, or via one or more time and/or frequency radio resources. A beam may be associated with a CSI-RS. A CSI-RS may comprise an indication of a beam direction. Each of a plurality of beams may be associated with one of a plurality of CSI-RSs. A CSI-RS resource may be configured in a cell-specific way, e.g., via common RRC signaling. Additionally or alternatively, a CSI-RS resource may be configured in a wireless device-specific way, e.g., via dedicated RRC signaling and/or layer 1 and/or layer 2 (L1/L2) signaling. Multiple wireless devices in or served by a cell may measure a cell-specific CSI-RS resource. A dedicated subset of wireless devices in or served by a cell may measure a wireless device-specific CSI-RS resource. A base station may transmit a CSI-RS resource periodically, using aperiodic transmission, or using a multi-shot or semi-persistent transmission. In a periodic transmission, a base station may transmit the configured CSI-RS resource using a configured periodicity in the time domain. In an aperiodic transmission, a base station may transmit the configured CSI-RS resource in a dedicated time slot. In a multi-shot or semi-persistent transmission, a base station may transmit the configured CSI-RS resource in a configured period. A base station may configure different CSI-RS resources in different terms for different purposes. Different terms may include, e.g., cell-specific, device-specific, periodic, aperiodic, multi-shot, or other terms. Different purposes may include, e.g., beam management, CQI reporting, or other purposes. 
       FIG.  17    shows an example of transmitting CSI-RSs periodically for a beam. A base station  1701  may transmit a beam in a predefined order in the time domain, such as during time periods  1703 . Beams used for a CSI-RS transmission, such as for CSI-RS 1704 in transmissions  1702 C and/or  1703 E, may have a different beam width relative to a beam width for SS-blocks transmission, such as for SS blocks  1702 A,  1702 B,  1702 D, and  1702 F- 1702 H. Additionally or alternatively, a beam width of a beam used for a CSI-RS transmission may have the same value as a beam width for an SS block. Some or all of one or more CSI-RSs may be included in one or more beams. An SS block may occupy a number of OFDM symbols (e.g.,  4 ), and a number of subcarriers (e.g., 240), carrying a synchronization sequence signal. The synchronization sequence signal may identify a cell. 
       FIG.  18    shows an example of a CSI-RS that may be mapped in time and frequency domains. Each square shown in  FIG.  18    may represent a resource block within a bandwidth of a cell. Each resource block may comprise a number of subcarriers. A cell may have a bandwidth comprising a number of resource blocks. A base station (e.g., a gNB in NR) may transmit one or more Radio Resource Control (RRC) messages comprising CSI-RS resource configuration parameters for one or more CSI-RS. One or more of the following parameters may be configured by higher layer signaling for each CSI-RS resource configuration: CSI-RS resource configuration identity, number of CSI-RS ports, CSI-RS configuration (e.g., symbol and RE locations in a subframe), CSI-RS subframe configuration (e.g., subframe location, offset, and periodicity in a radio frame), CSI-RS power parameter, CSI-RS sequence parameter, CDM type parameter, frequency density, transmission comb, QCL parameters (e.g., QCL-scramblingidentity, crs-portscount, mbsfn-subframeconfiglist, csi-rs-configZPid, qcl-csi-rs-configNZPid), and/or other radio resource parameters. 
       FIG.  18    shows three beams that may be configured for a wireless device, e.g., in a wireless device-specific configuration. Any number of additional beams (e.g., represented by the column of blank squares) or fewer beams may be included. Beam 1 may be allocated with CSI-RS 1 that may be transmitted in some subcarriers in a resource block (RB) of a first symbol. Beam 2 may be allocated with CSI-RS 2 that may be transmitted in some subcarriers in a RB of a second symbol. Beam 3 may be allocated with CSI-RS 3 that may be transmitted in some subcarriers in a RB of a third symbol. All subcarriers in a RB may not necessarily be used for transmitting a particular CSI-RS (e.g., CSI-RS 1) on an associated beam (e.g., beam 1) for that CSI-RS. By using frequency division multiplexing (FDM), other subcarriers, not used for beam 1 for the wireless device in the same RB, may be used for other CSI-RS transmissions associated with a different beam for other wireless devices. Additionally or alternatively, by using time domain multiplexing (TDM), beams used for a wireless device may be configured such that different beams (e.g., beam 1, beam 2, and beam 3) for the wireless device may be transmitted using some symbols different from beams of other wireless devices. 
     Beam management may use a device-specific configured CSI-RS. In a beam management procedure, a wireless device may monitor a channel quality of a beam pair link comprising a transmitting beam by a base station (e.g., a gNB in NR) and a receiving beam by the wireless device (e.g., a UE). When multiple CSI-RSs associated with multiple beams are configured, a wireless device may monitor multiple beam pair links between the base station and the wireless device. 
     A wireless device may transmit one or more beam management reports to a base station. A beam management report may indicate one or more beam pair quality parameters, comprising, e.g., one or more beam identifications, RSRP, PMI, CQI, and/or RI, of a subset of configured beams. 
     A base station and/or a wireless device may perform a downlink L1/L2 beam management procedure. One or more downlink L1/L2 beam management procedures may be performed within one or multiple transmission and receiving points (TRPs), such as shown in  FIG.  20 A  and  FIG.  20 B , respectively. 
       FIG.  19    shows examples of three beam management procedures, P1, P2, and P3. Procedure P1 may be used to enable a wireless device measurement on different transmit (Tx) beams of a TRP (or multiple TRPs), e.g., to support a selection of Tx beams and/or wireless device receive (Rx) beam(s) (shown as ovals in the top row and bottom row, respectively, of P1). Beamforming at a TRP (or multiple TRPs) may include, e.g., an intra-TRP and/or inter-TRP Tx beam sweep from a set of different beams (shown, in the top rows of P1 and P2, as ovals rotated in a counter-clockwise direction indicated by the dashed arrow). Beamforming at a wireless device  1901 , may include, e.g., a wireless device Rx beam sweep from a set of different beams (shown, in the bottom rows of P1 and P3, as ovals rotated in a clockwise direction indicated by the dashed arrow). Procedure P2 may be used to enable a wireless device measurement on different Tx beams of a TRP (or multiple TRPs) (shown, in the top row of P2, as ovals rotated in a counter-clockwise direction indicated by the dashed arrow), e.g., which may change inter-TRP and/or intra-TRP Tx beam(s). Procedure P2 may be performed, e.g., on a smaller set of beams for beam refinement than in procedure P1. P2 may be a particular example of P1. Procedure P3 may be used to enable a wireless device measurement on the same Tx beam (shown as oval in P3), e.g., to change a wireless device Rx beam if the wireless device  1901  uses beamforming. 
     A wireless device  1901  (e.g., a UE) and/or a base station  1902  (e.g., a gNB) may trigger a beam failure recovery mechanism. The wireless device  1901  may trigger a beam failure recovery (BFR) request transmission, e.g., if a beam failure event occurs. A beam failure event may include, e.g., a determination that a quality of beam pair link(s) of an associated control channel is unsatisfactory. A determination of an unsatisfactory quality of beam pair link(s) of an associated channel may be based on the quality falling below a threshold and/or an expiration of a timer. 
     The wireless device  1901  may measure a quality of beam pair link(s) using one or more reference signals (RS). One or more SS blocks, one or more CSI-RS resources, and/or one or more demodulation reference signals (DM-RSs) of a PBCH may be used as a RS for measuring a quality of a beam pair link. Each of the one or more CSI-RS resources may be associated with a CSI-RS resource index (CRI). A quality of a beam pair link may be based on one or more of an RSRP value, reference signal received quality (RSRQ) value, and/or CSI value measured on RS resources. The base station  1902  may indicate that an RS resource, e.g., that may be used for measuring a beam pair link quality, is quasi-co-located (QCLed) with one or more DM-RSs of a control channel. The RS resource and the DM-RSs of the control channel may be QCLed when the channel characteristics from a transmission via an RS to the wireless device  1901 , and the channel characteristics from a transmission via a control channel to the wireless device, are similar or the same under a configured criterion. 
       FIG.  20 A  shows an example of a beam failure event involving a single TRP. A single TRP such as at a base station  2001  may transmit, to a wireless device  2002 , a first beam  2003  and a second beam  2004 . A beam failure event may occur if, e.g., a serving beam, such as the second beam  2004 , is blocked by a moving vehicle  2005  or other obstruction (e.g., building, tree, land, or any object) and configured beams (e.g., the first beam  2003  and/or the second beam  2004 ), including the serving beam, are received from the single TRP. The wireless device  2002  may trigger a mechanism to recover from beam failure when a beam failure occurs. 
       FIG.  20 B  shows an example of a beam failure event involving multiple TRPs. Multiple TRPs, such as at a first base station  2006  and at a second base station  2009 , may transmit, to a wireless device  2008 , a first beam  2007  (e.g., from the first base station  2006 ) and a second beam  2010  (e.g., from the second base station  2009 ). A beam failure event may occur when, e.g., a serving beam, such as the second beam  2010 , is blocked by a moving vehicle  2011  or other obstruction (e.g., building, tree, land, or any object) and configured beams (e.g., the first beam  2007  and/or the second beam  2010 ) are received from multiple TRPs. The wireless device  2008  may trigger a mechanism to recover from beam failure when a beam failure occurs. 
     A wireless device may monitor a PDCCH, such as a New Radio PDCCH (NR-PDCCH), on M beam pair links simultaneously, where M≥1 and the maximum value of M may depend at least on the wireless device capability. Such monitoring may increase robustness against beam pair link blocking. A base station may transmit, and the wireless device may receive, one or more messages configured to cause the wireless device to monitor NR-PDCCH on different beam pair link(s) and/or in different NR-PDCCH OFDM symbol. 
     A base station may transmit higher layer signaling, and/or a MAC control element (MAC CE), that may comprise parameters related to a wireless device Rx beam setting for monitoring NR-PDCCH on multiple beam pair links. A base station may transmit one or more indications of a spatial QCL assumption between a first DL RS antenna port(s) and a second DL RS antenna port(s). The first DL RS antenna port(s) may be for one or more of a cell-specific CSI-RS, device-specific CSI-RS, SS block, PBCH with DM-RSs of PBCH, and/or PBCH without DM-RSs of PBCH. The second DL RS antenna port(s) may be for demodulation of a DL control channel. Signaling for a beam indication for a NR-PDCCH (e.g., configuration to monitor NR-PDCCH) may be via MAC CE signaling, RRC signaling, DCI signaling, or specification-transparent and/or an implicit method, and any combination thereof. 
     For reception of unicast DL data channel, a base station may indicate spatial QCL parameters between DL RS antenna port(s) and DM-RS antenna port(s) of DL data channel. A base station may transmit DCI (e.g., downlink grants) comprising information indicating the RS antenna port(s). The information may indicate the RS antenna port(s) which may be QCLed with DM-RS antenna port(s). A different set of DM-RS antenna port(s) for the DL data channel may be indicated as a QCL with a different set of RS antenna port(s). 
     If a base station transmits a signal indicating a spatial QCL parameters between CSI-RS and DM-RS for PDCCH, a wireless device may use CSI-RSs QCLed with DM-RS for a PDCCH to monitor beam pair link quality. If a beam failure event occurs, the wireless device may transmit a beam failure recovery request, such as by a determined configuration. 
     If a wireless device transmits a beam failure recovery request, e.g., via an uplink physical channel or signal, a base station may detect that there is a beam failure event, for the wireless device, by monitoring the uplink physical channel or signal. The base station may initiate a beam recovery mechanism to recover the beam pair link for transmitting PDCCH between the base station and the wireless device. The base station may transmit one or more control signals, to the wireless device, e.g., after or in response to receiving the beam failure recovery request. A beam recovery mechanism may be, e.g., an L1 scheme, or a higher layer scheme. 
     A base station may transmit one or more messages comprising, e.g., configuration parameters of an uplink physical channel and/or a signal for transmitting a beam failure recovery request. The uplink physical channel and/or signal may be based on at least one of the following: a non-contention based PRACH (e.g., a beam failure recovery PRACH or BFR-PRACH), which may use a resource orthogonal to resources of other PRACH transmissions; a PUCCH (e.g., beam failure recovery PUCCH or BFR-PUCCH); and/or a contention-based PRACH resource. Combinations of these candidate signal and/or channels may be configured by a base station. 
     A gNB may respond a confirmation message to a UE after receiving one or multiple BFR request. The confirmation message may include the CRI associated with the candidate beam the UE indicates in the one or multiple BFR request. The confirmation message may be a L1 control information. 
     Secondary Cell Activation/Deactivation Mechanism 
     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”. 
     In an example, 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 an example, 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. 
     In an example, 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. 
     In an example, 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 may be an ongoing random access procedure on the SCell, a wireless device may abort the ongoing random access procedure on the SCell. 
       FIG.  21 A  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’) 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.  21 B  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’) 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.  21 A  and/or  FIG.  21 B , 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.  21 A  and  FIG.  21 B , an R field may indicate a reserved bit. The R field may be set to zero. 
       FIG.  22 A  and  FIG.  22 B  show timeline when a UE receives a MAC activation command. When a UE receives a MAC activation command for a secondary cell in subframe n, the corresponding actions in the MAC layer shall be applied no later than the minimum requirement defined in 3GPP TS 36.133 or TS 38.133 and no earlier than subframe n+8, except for the following: the actions related to CSI reporting and the actions related to the sCellDeactivationTimer associated with the secondary cell, which shall be applied in subframe n+8. When a UE receives a MAC deactivation command for a secondary cell or the sCellDeactivationTimer associated with the secondary cell expires in subframe n, the corresponding actions in the MAC layer shall apply no later than the minimum requirement defined in 3GPP TS 36.133 or TS 38.133, except for the actions related to CSI reporting which shall be applied in subframe n+8. 
     When a UE receives a MAC activation command for a secondary cell in subframe n, the actions related to CSI reporting and the actions related to the sCellDeactivationTimer associated with the secondary cell, are applied in subframe n+8. When a UE receives a MAC deactivation command for a secondary cell or other deactivation conditions are met (e.g. the sCellDeactivationTimer associated with the secondary cell expires) in subframe n, the actions related to CSI reporting are applied in subframe n+8. The UE starts reporting invalid or valid CSI for the Scell at the (n+8) th  subframe, and start or restart the sCellDeactivationTimer when receiving the MAC CE activating the SCell in the n th  subframe. For some UE having slow activation, it may report an invalid CSI (out-of-range CSI) at the (n+8) th  subframe, for some UE having a quick activation, it may report a valid CSI at the (n+8) th  subframe. 
     When a UE receives a MAC activation command for an SCell in subframe n, the UE starts reporting CQI/PMI/RI/PTI for the SCell at subframe n+8 and starts or restarts the sCellDeactivationTimer associated with the SCell at subframe n+8. It is important to define the timing of these actions for both UE and eNB. For example, sCellDeactivationTimer is maintained in both eNB and UE and it is important that both UE and eNB stop, start and/or restart this timer in the same TTI. Otherwise, the sCellDeactivationTimer in the UE may not be in-sync with the corresponding sCellDeactivationTimer in the eNB. Also, eNB starts monitoring and receiving CSI (CQI/PMI/RI/PTI) according to the predefined timing in the same TTI and/or after UE starts transmitting the CSI. If the CSI timings in UE and eNB are not coordinated based on a common standard or air interface signaling the network operation may result in inefficient operations and/or errors. 
     Example of Downlink Control Information (DCI) 
       FIG.  23    shows DCI formats for an example of 20 MHz FDD operation with 2 Tx antennas at the base station and no carrier aggregation in an LTE system. In an example, a gNB may transmit a DCI via a PDCCH for scheduling decision and power-control commends. More specifically, the DCI may comprise at least one of: downlink scheduling assignments, uplink scheduling grants, power-control commands. The downlink scheduling assignments may comprise at least one of: PDSCH resource indication, transport format, HARQ information, and control information related to multiple antenna schemes, a command for power control of the PUCCH used for transmission of ACK/NACK in response to downlink scheduling assignments. The uplink scheduling grants may comprise at least one of: PUSCH resource indication, transport format, and HARQ related information, a power control command of the PUSCH. 
     The different types of control information correspond to different DCI message sizes. For example, supporting spatial multiplexing with noncontiguous allocation of RBs in the frequency domain may require a larger scheduling message in comparison with an uplink grant allowing for frequency-contiguous allocation only. The DCI may be categorized into different DCI formats, where a format corresponds to a certain message size and usage. 
     In an example, a UE may monitor one or more PDCCH to detect one or more DCI with one or more DCI format. The one or more PDCCH may be transmitted in common search space or UE-specific search space. A UE may monitor PDCCH with only a limited set of DCI format, to save power consumption. For example, a normal UE may not be required to detect a DCI with DCI format 6 which is used for an eMTC UE. The more DCI format to be detected, the more power be consumed at the UE. 
     In an example, the information in the DCI formats used for downlink scheduling can be organized into different groups, with the field present varying between the DCI formats, including at least one of: resource information, consisting of: carrier indicator (0 or 3 bits), RB allocation; HARQ process number; MCS, NDI, and RV (for the first TB); MCS, NDI and RV (for the second TB); MIMO related information; PDSCH resource-element mapping and QCI; Downlink assignment index (DAI); TPC for PUCCH; SRS request (1 bit), triggering one-shot SRS transmission; ACK/NACK offset; DCI format 0/1A indication, used to differentiate between DCI format 1A and 0; and padding if necessary. The MIMO related information may comprise at least one of: PMI, precoding information, transport block swap flag, power offset between PDSCH and reference signal, reference-signal scrambling sequence, number of layers, and/or antenna ports for the transmission. 
     In an example, the information in the DCI formats used for uplink scheduling can be organized into different groups, with the field present varying between the DCI formats, including at least one of: resource information, consisting of: carrier indicator, resource allocation type, RB allocation; MCS, NDI (for the first TB); MCS, NDI (for the second TB); phase rotation of the uplink DMRS; precoding information; CSI request, requesting an aperiodic CSI report; SRS request (2 bit), used to trigger aperiodic SRS transmission using one of up to three preconfigured settings; uplink index/DAI; TPC for PUSCH; DCI format 0/1A indication; and padding if necessary. 
     In a NR system, in order to support wide bandwidth operation, a gNB may transmit one or more PDCCH in different control resource sets. A gNB may transmit one or more RRC message comprising configuration parameters of one or more control resource sets. At least one of the one or more control resource sets may comprise at least one of: a first OFDM symbol; a number of consecutive OFDM symbols; a set of resource blocks; a CCE-to-REG mapping; and a REG bundle size, in case of interleaved CCE-to-REG mapping. 
     Example of Bandwidth Part Management 
       FIG.  24    shows example of multiple BWP configuration. A gNB may transmit one or more message comprising configuration parameters of one or more bandwidth parts (BWP). The one or more BWPs may have different numerologies. A gNB may transmit one or more control information for cross-BWP scheduling to a UE. One BWP may overlap with another BWP in frequency domain. 
     A gNB may transmit one or more messages comprising configuration parameters of one or more DL and/or UL BWPs for a cell, with at least one BWP as the active DL or UL BWP, and zero or one BWP as the default DL or UL BWP. For the PCell, the active DL BWP may be the DL BWP on which the UE may monitor one or more PDCCH, and/or receive PDSCH. The active UL BWP is the UL BWP on which the UE may transmit uplink signal. For a secondary cell (SCell) if configured, the active DL BWP may be the DL BWP on which the UE may monitor one or more PDCCH and receive PDSCH when the SCell is activated by receiving a MAC activation/deactivation CE. The active UL BWP is the UL BWP on which the UE may transmit PUCCH (if configured) and/or PUSCH when the SCell is activated by receiving a MAC activation/deactivation CE. Configuration of multiple BWPs may be used to save UE&#39;s power consumption. When configured with an active BWP and a default BWP, a UE may switch to the default BWP if there is no activity on the active BWP. For example, a default BWP may be configured with narrow bandwidth, an active BWP may be configured with wide bandwidth. If there is no signal transmitting or receiving, the UE may switch the BWP to the default BWP, which may reduce power consumption. 
     Switching BWP may be triggered by a DCI or a timer. When a UE receives a DCI indicating DL BWP switching from an active BWP to a new BWP, the UE may monitor PDCCH and/or receive PDSCH on the new BWP. When the UE receives a DCI indicating UL BWP switching from an active BWP to a new BWP, the UE may transmit PUCCH (if configured) and/or PUSCH on the new BWP. A gNB may transmit one or more messages comprising a BWP inactivity timer to a UE. The UE starts the timer when it switches its active DL BWP to a DL BWP other than the default DL BWP. The UE may restart the timer to the initial value when it successfully decodes a DCI to schedule PDSCH(s) in its active DL BWP. The UE may switch its active DL BWP to the default DL BWP when the BWP timer expires. 
     In an example embodiment, a UE configured for operation in bandwidth parts (BWPs) of a serving cell, may be configured by higher layers for the serving cell a set of bandwidth parts (BWPs) for receptions by the UE (DL BWP set) or a set of BWPs for transmissions by the UE (UL BWP set). In an example, for a DL BWP or UL BWP in a set of DL BWPs or UL BWPs, respectively, the UE may be configured at least one of following for the serving cell: a subcarrier spacing for DL and/or UL provided by higher layer parameter, a cyclic prefix for DL and/or UL provided by higher layer parameter, a number of contiguous PRBs for DL and/or UL provided by higher layer parameter, an offset of the first PRB for DL and/or UL in the number of contiguous PRBs relative to the first PRB by higher layer, or Q control resource sets if the BWP is a DL BWP. 
     In an example embodiment, for each serving cell, higher layer signaling may configure a UE with Q control resource sets. In an example, for control resource set q, 0≤q&lt;Q, the configuration may comprise at least one of following: a first OFDM symbol provided by one or more higher layer parameters, a number of consecutive OFDM symbols provided by one or more higher layer parameters, a set of resource blocks provided by one or more higher layer parameters, a CCE-to-REG mapping provided by one or more higher layer parameters, a REG bundle size, in case of interleaved CCE-to-REG mapping, provided by one or more higher layer parameters, or antenna port quasi-collocation provided by higher layer parameter. 
     In an example embodiment, a control resource set may comprise a set of CCEs numbered from 0 to N CCE,q −1 where N CCE,q  may be the number of CCEs in control resource set q. 
     In an example embodiment, the sets of PDCCH candidates that a UE monitors may be defined in terms of PDCCH UE-specific search spaces. A PDCCH UE-specific search space at CCE aggregation level L∈{1, 2, 4, 8} may be defined by a set of PDCCH candidates for CCE aggregation level L. In an example, for a DCI format, a UE may be configured per serving cell by one or more higher layer parameters a number of PDCCH candidates per CCE aggregation level L. 
     In an example embodiment, in non-DRX mode operation, a UE may monitor one or more PDCCH candidate in control resource set q according to a periodicity of W PDCCH,q  symbols that may be configured by one or more higher layer parameters for control resource set q. 
     In an example embodiment, if a UE is configured with higher layer parameter, e.g., cif-InSchedulingCell, the carrier indicator field value may correspond to cif-InSchedulingCell. 
     In an example embodiment, for the serving cell on which a UE may monitor one or more PDCCH candidate in a UE-specific search space, if the UE is not configured with a carrier indicator field, the UE may monitor the one or more PDCCH candidates without carrier indicator field. In an example, for the serving cell on which a UE may monitor one or more PDCCH candidates in a UE-specific search space, if a UE is configured with a carrier indicator field, the UE may monitor the one or more PDCCH candidates with carrier indicator field. 
     In an example embodiment, a UE may not monitor one or more PDCCH candidates on a secondary cell if the UE is configured to monitor one or more PDCCH candidates with carrier indicator field corresponding to that secondary cell in another serving cell. For example, for the serving cell on which the UE may monitor one or more PDCCH candidates, the UE may monitor the one or more PDCCH candidates at least for the same serving cell. 
     In an example embodiment, a UE may receive PDCCH and PDSCH in a DL BWP according to a configured subcarrier spacing and CP length for the DL BWP. A UE may transmit PUCCH and PUSCH in an UL BWP according to a configured subcarrier spacing and CP length for the UL BWP. 
     In an example embodiment, a UE may be configured, by one or more higher layer parameters, a DL BWP from a configured DL BWP set for DL receptions. A UE may be configured by one or more higher layer parameters, an UL BWP from a configured UL BWP set for UL transmissions. If a DL BWP index field is configured in a DCI format scheduling PDSCH reception to a UE, the DL BWP index field value may indicate the DL BWP, from the configured DL BWP set, for DL receptions. If an UL-BWP index field is configured in a DCI format scheduling PUSCH transmission from a UE, the UL-BWP index field value may indicate the UL BWP, from the configured UL BWP set, for UL transmissions. 
     In an example embodiment, for TDD, a UE may expect that the center frequency for the DL BWP is same as the center frequency for the UL BWP. 
     In an example embodiment, a UE may not monitor PDCCH when the UE performs measurements over a bandwidth that is not within the DL BWP for the UE. 
     In an example embodiment, for an initial active DL BWP, UE may identify the bandwidth and frequency of the initial active DL BWP in response to receiving the NR-PBCH. 
     In an example embodiment, a bandwidth of an initial active DL BWP may be confined within the UE minimum bandwidth for the given frequency band. For example, for flexible for DL information scheduling, the bandwidth may be indicated in PBCH, and/or some bandwidth candidates may be predefined. For example, x bits may be employed for indication. This enables. 
     In an example embodiment, a frequency location of initial active DL BWP may be derived from the bandwidth and SS block, e.g. center frequency of the initial active DL BWP. For example, a SS block may have a frequency offset, as the edge of SS block PRB and data PRB boundary may not be aligned. Predefining the frequency location of SS block and initial active DL BWP may reduce the PBCH payload size, additional bits are not needed for indication of frequency location of initial active DL BWP. 
     In an example, for the paired UL BWP, the bandwidth and frequency location may be informed in RMSI. 
     In an example embodiment, for a UE, gNB may configure a set of BWPs by RRC. The UE may transmit or receive in an active BWP from the configured BWPs in a given time instance. For example, an activation/deactivation of DL bandwidth part by means of timer for a UE to switch its active DL bandwidth part to a default DL bandwidth part may be supported. In this case, when the timer at the UE side expires, e.g. the UE has not received scheduling DCI for X ms, the UE may switch to the default DL BWP. 
     In an example, a new timer, e.g., BWPDeactivationTimer, may be defined to deactivate the original BWP and switch to the default BWP. The BWPDeactivationTimer may be started when the original BWP is activated by the activation/deactivation DCI. If PDCCH on the original BWP is received, a UE may restart the BWPDeactivationTimer associated with the original BWP. For example, if the BWPDeactivationTimer expires, a UE may deactivate the original BWP and switch to the default BWP, may stop the BWPDeactivationTimer for the original BWP, and may (or may not) flush all HARQ buffers associated with the original BWP. 
     In an example embodiment, gNB and UE may have different understanding of the starting of the timer since the UE may miss scheduling grants. In an example, the UE may be triggered to switch to the default BWP, but gNB may schedules the UE in the previous active BWP. For example, in the case that the default BWP is nested within other BWPs, gNB may restrict the location of the CORESET of BWP2 to be within BWP1 (e.g., the narrow band BWP1 may be the default BWP). Then the UE may receive CORESET and switch back to BWP2 if it mistakenly switches to the default BWP. 
     In an example embodiment, for a case that the default BWP and the other BWPs are not overlapped in frequency domain, it may not solve a miss switching problem by restricting the location of the CORESET. For example, the gNB may maintain a timer for a UE. When the timer expires, e.g. there is no data scheduling for the UE for Y ms, or gNB has not received feedback from the UE for Y′ ms, the UE may switch to the default BWP to send paging signal or re-schedule the UE in the default BWP. 
     In an example embodiment, gNB may not fix the default bandwidth part to be the same as initial active bandwidth part it. Since the initial active DL BWP may be the SS block bandwidth which is common to UEs in the cell, the traffic load may be very heavy if many UEs fall back to such small bandwidth for data transmission. Configuring the UEs with different default BWPs may help to balance the load in the system bandwidth. 
     In an example embodiment, on a Scell, there may be no initial active BWP since the initial access is performed on the Pcell. For example, the initially activated DL BWP and/or UL BWP when the Scell is activated may be configured or reconfigured by RRC signaling. In an example, the default BWP of the Scell may also be configured or reconfigured by RRC signaling. To strive for a unified design for both Pcell and Scell, the default BWP may be configured or reconfigured by the RRC signalling, and the default BWP may be one of the configured BWPs of the UE. 
     In an example embodiment, gNB may configure UE-specific default DL BWP other than initial active BWP after RRC connection, e.g., for the purpose of load balancing. The default BWP may support other connected mode operations (besides operations supported by initial active BWP) for example fall back and connected mode paging. In this case, the default BWP may comprise common search space, at least the search space needed for monitoring the pre-emption indications. For example, for FDD, the default DL and UL BWPs may be independently configured to the UE. 
     In an example, the initial active DL/UL BWP may be set as default DL/UL BWP. In an example, a UE may return to default DL/UL BWP in some cases. For example, if a UE does not receive control for a long time, the UE may fallback to default BWP. 
     In an example embodiment, gNB may configure UE with multiple BWPs. For example, the multiple BWPs may share at least one CORESET including default BWP. For example, CORESET for RMSI may be shared for all configured BWP. Without going back to another BWP or default BWP, the UE may receive control information via the common CORESET. To minimize the ambiguity of resource allocation, the common CORESET may schedule data within only default BWP. For example, frequency region of default BWP may belong to all the configured BWPs. 
     In an example embodiment, when the configured BWP is associated with a different numerology from default BWP, a semi-static pattern of BWP switching to default BWP may be considered. For example, to check RMSI at least periodically, switching to default BWP may be considered. This may be necessary particularly when BWPs use different numerologies. 
     In an example embodiment, in terms of reconfiguration of default BWP from initial BWP, it may be considered for RRC connected UEs. For RRC IDLE UEs, default BWP may be same as initial BWP (or, RRC IDLE UE may fallback to initial BWP regardless of default BWP). If a UE performs measurement based on SS block, reconfiguration of default BWP outside of initial BWP may become very inefficient due to frequent measurement gap. In this sense, if default BWP is reconfigured to outside of initial BWP, the following conditions may be satisfied: a UE is in CONNECTED mode, and a UE is not configured with SS block based measurement for both serving cell and neighbor cells. 
     In an example embodiment, a DL BWP other than the initial active DL BWP may be configured to a UE as the default DL BWP. The reconfiguring the default DL BWP may be due to load balancing and/or different numerologies employed for active DL BWP and initial active DL BWP. 
     In an example embodiment, a default BWP on Pcell may be an initial active DL BWP for transmission of RMSI, comprising RMSI CORESET with CSS. The RMSI CORESET may comprise USS. The initial active/default BWP may remain active BWP for the user also after UE becomes RRC connected. 
     In an example embodiment, for a paired spectrum, downlink and uplink bandwidth parts may be independently activated while, for an unpaired spectrum downlink and uplink bandwidth parts are jointly activated. In case of bandwidth adaptation, where the bandwidth of the active downlink BWP may be changed, there may, in case of an unpaired spectrum, be a joint activation of a new downlink BWP and new uplink BWP. For example, a new DL/UL BWP pair where the bandwidth of the uplink BWPs may be the same (e.g., no change of uplink BWP). 
     In an example embodiment, there may be an association of DL BWP and UL BWP in RRC configuration. For example, in case of TDD, a UE may not retune the center frequency of channel BW between DL and UL. In this case, since the RF is shared between DL and UL in TDD, a UE may not retune the RF BW for every alternating DL-to-UL and UL-to-DL switching. 
     In an example embodiment, making an association between DL BWP and UL BWP may allow that one activation/deactivation command may switch both DL and UL BWPs at once. Otherwise, separate BWP switching commands may be necessary. 
     In an example embodiment, a DL BWP and a UL BWP may be configured to the UE separately. Pairing of the DL BWP and the UL BWP may impose constrains on the configured BWPs, e.g., the paired DL BWP and UL BWP may be activated simultaneously. For example, gNB may indicate a DL BWP and a UL BWP to a UE for activation in a FDD system. In an example, gNB may indicate a DL BWP and a UL BWP with the same center frequency to a UE for activation in a TDD system. Since the activation/deactivation of the BWP of the UE is instructed by gNB, no paring or association of the DL BWP and UL BWP may be mandatory even for TDD system. It may be up to gNB implementation 
     In an example embodiment, the association between DL carrier and UL carrier within a serving cell may be done by carrier association. For example, for TDD system, UE may not be expected to retune the center frequency of channel BW between DL and UL. To achieve it, an association between DL BWP and UL BWP may be needed. For example, a way to associate them may be to group DL BWP configurations with same center frequency as one set of DL BWPs and group UL BWP configurations with same center frequency as one set of UL BWPs. The set of DL BWPs may be associated with the set of UL BWPs sharing the same center frequency. 
     For an FDD serving cell, there may be no association between DL BWP and UL BWP if the association between DL carrier and UL carrier within a serving cell may be done by carrier association. 
     In an example embodiment, UE may identify a BWP identity from DCI to simplify the indication process. The total number of bits for BWP identity may depend on the number of bits that may be employed within the scheduling DCI (or switching DCI) and the UE minimum BW. The number of BWPs may be determined by the UE supported minimum BW along with the network maximum BW. For instance, in a similar way, the maximum number of BWP may be determined by the network maximum BW and the UE minimum BW. In an example, if 400 MHz is the network maximum BW and 50 MHz is the UE minimum BW, 8 BWP may be configured to the UE which means that 3 bits may be needed within the DCI to indicate the BWP. In an example, such a split of the network BW depending on the UE minimum BW may be useful for creating one or more default BWPs from the network side by distributing UEs across the entire network BW, e.g., load balancing purpose. 
     In an example embodiment, at least 2 DL and 2 UL BWP may be supported by a UE for a BWP adaption. For example, the total number of BWP supported by a UE may be given by 2&lt;Number of DL/UL BWP≤floor (Network maximum BW/UE minimum DL/UL BW). For example, a maximum number of configured BWPs may be 4 for DL and UL respectively. For example, a maximum number of configured BWPs for UL may be 2. 
     In an example embodiment, different sets of BWPs may be configured for different DCI formats/scheduling types respectively. For example, some larger BWPs may be configured for non-slot-based scheduling than that for slot-based scheduling. If different DCI formats are defined for slot-based scheduling and non-slot-based scheduling, different BWPs may be configured for different DCI formats. This may provide flexibility between different scheduling types without increasing DCI overhead. The 2-bit bitfield may be employed to indicate a BWP among the four for the DCI format. For example, 4 DL BWPs or [2 or 4] UL BWPs may be configured for each DCI formats. Same or different BWPs may be configured for different DCI formats. 
     In an example embodiment, a required maximum number of configured BWPs (may be not comprising the initial BWP) may depend on the flexibility needed for a BWP functionality. For example, in the minimal case of supporting bandlimited devices, it may be sufficient to be able to configure one DL BWP and one UL BWP (or a single DL/UL BWP pair in case of unpaired spectrum). For example, to support bandwidth adaptation, there may be a need to configure (at least) two DL BWPs and a single uplink BWP for paired spectrum (or two DL/UL BWP pairs for unpaired spectrum). For example, to support dynamic load-balancing between different parts of the spectrum, there may be a need to configure one or more DL (UL) BWPs that jointly cover different parts of the downlink (uplink) carrier. In an example, for dynamic load balancing, it may be sufficient with two bandwidth parts. In addition to the two bandwidth parts, two additional bandwidth parts may be needed for bandwidth adaptation. For example, a Maximum number of configured BWPs may be four DL BWPs and two UL BWPs for a paired spectrum. For example, a Maximum number of configured BWPs may be four DL/UL BWP pairs for an unpaired spectrum. 
     In an example embodiment, UE may monitor for RMSI and broadcast OSI which may be transmitted by the gNB within the common search space (CSS) on the PCell. In an example, RACH response and paging control monitoring on the PCell may be transmitted within the CSS. In an example, when a UE is allowed to be on an active BWP configured with UE-specific search space (USSS or USS), the UE may not monitor the common search space. 
     In an example, for a PCell, at least one of configured DL bandwidth parts may comprise at least one CORESET with a CSS type. For example, to monitor RMSI and broadcast OSI, UE may periodically switch to the BWP containing the CSS. In an example, the UE may periodically switch to the BWP containing the CSS for RACH response and paging control monitoring on the PCell. 
     In an example, if BWP switching to monitor the CSS happens frequently, it may result in increasing overhead. In an example, the overhead due to the CSS monitoring may depends on overlapping in frequency between any two BWPs. In an example, in a nested BWP configuration where one BWP is a subset of another BWP, the same CORESET configuration may be employed across the BWPs. In this case, unless reconfigured otherwise, a default BWP may be the one containing the CSS, and another BWP may contain the CSS. In an example, the BWPs may be partially overlapping. If the overlapping region is sufficient, a CSS may be across a first BWP and a second BWP. In an example, two non-overlapping BWP configurations may exist. 
     In an example embodiment, there may be one or more benefits of configuring the same CORESET containing the CSS across BWPs. For example, RMSI and broadcast OSI monitoring may be handled without necessitating BWP switching. In an example, RACH response and paging control monitoring on the PCell may also be handled without switching. For example, if CORESET configuration is the same across BWPs, robustness for BWP switching may improve, because even if gNB and UE are out-of-sync as to which BWP is currently active, the DL control channel may work. In an example, one or more constraints on BWP configuration may not be too much, considering that BWP may be for power saving, even the nested configuration may be very versatile for different applications. 
     In an example embodiment, for the case where the BWP configurations are non-overlapping in frequency, there may not be spec mandate for UE to monitor RMSI and broadcast OSI in the CSS. It may be left to implementation to handle this case. 
     In an example embodiment, NR may support group-common search space (GCSS). For example, the GCSS may be employed as an alternative to CSS for certain information. In an example, gNB may configure GCSS within a BWP for a UE, and information such as RACH response and paging control may be transmitted on GCSS. For example, the UE may monitor GCSS instead of switching to the BWP containing the CSS for such information. 
     In an example embodiment, for pre-emption indication and other group-based commands on a serving cell, gNB may transmit the information on GCSS. UE may monitor the GCSS for the information. For example, for SCell which may not have CSS. 
     In an example embodiment, NR may configure a CORESET without using a BWP. For example, NR support to configure a CORESET based on a BWP to reduce signaling overhead. In an example, a first CORESET for a UE during an initial access may be configured based on its default BWP. In an example, a CORESET for monitoring PDCCH for RAR and paging may be configured based on a DL BWP. In an example, the CORESET for monitoring group common (GC)-PDCCH for SFI may be configured based on a DL BWP. In an example, the CORESET for monitoring GC-DCI for pre-emption indication may be configured based on a DL BWP. In an example, the BWP index may be indicated in the CORESET configuration. In an example, the default BWP index may not be indicated in the CORESET configuration. 
     In an example embodiment, the contention-based random access (CBRA) RACH procedure may be supported via an initial active DL and UL BWPs since the UE identity is unknown to the gNB. In an example, the contention-free random access (CFRA) RACH procedure may be supported via the USS configured in an active DL BWP for the UE. For example, in this case, an additional CSS for RACH purpose may not need to be configured per BWP. For example, idle mode paging may be supported via an initial active DL BWP and the connected mode paging may be supported via a default BWP. No additional configurations for the BWP for paging purposes may not be needed for paging. For the case of pre-emption, a configured BWP (on a serving cell) may have the CSS configured for monitoring the pre-emption indications. 
     In an example embodiment, for a configured DL BWP, a group-common search space may be associated with at least one CORESET configured for the same DL BWP. For example, depending on the monitoring periodicity of different group-common control information types, it may not be practical for the UE to autonomously switch to a default BWP where a group-common search space is available to monitor for such DCI. In this case, if there is at least one CORESET configured on a DL BWP, it may be possible to configure a group-common search space in the same CORESET. 
     In an example embodiment, a center frequency of the activated DL BWP may not be changed. In an example, the center frequency of the activated DL BWP may be changed. For example, For TDD, if the center frequency of the activated DL BWP and deactivated DL BWP is not aligned, the active UL BWP may be switched implicitly. 
     In an example embodiment, BWPs with different numerologies may be overlapped, and rate matching for CSI-RS/SRS of another BWP in the overlapped region may be employed to achieve dynamic resource allocation of different numerologies in FDM/TDM fashion. In an example, for the CSI measurement within one BWP, if the CSI-RS/SRS is collided with data/RS in another BWP, the collision region in another BWP may be rate matched. For example, CSI information over the two BWPs may be known at a gNB side by UE reporting. Dynamic resource allocation with different numerologies in a FDM manner may be achieved by gNB scheduling. 
     In an example embodiment, PUCCH resources may be configured in a configured UL BWP, in a default UL BWP and/or in both. For instance, if the PUCCH resources are configured in the default UL BWP, UE may retune to the default UL BWP for transmitting an SR. for example, the PUCCH resources are configured per BWP or a BWP other than the default BWP, the UE may transmit an SR in the current active BWP without retuning. 
     In an example embodiment, if a configured SCell is activated for a UE, a DL BWP may be associated with an UL BWP at least for the purpose of PUCCH transmission, and a default DL BWP may be activated. If the UE is configured for UL transmission in same serving cell, a default UL BWP may be activated. 
     In an example embodiment, at least one of configured DL BWPs comprises one CORESET with common search space (CSS) at least in primary component carrier. The CSS may be needed at least for RACH response (msg2) and pre-emption indication. 
     In an example, for the case of no periodic gap for RACH response monitoring on Pcell, for Pcell, one of configured DL bandwidth parts may comprise one CORESET with the CSS type for RMSI &amp; OSI. For Pcell, a configured DL bandwidth part may comprise one CORESET with the CSS type for RACH response &amp; paging control for system information update. For a serving cell, a configured DL bandwidth part may comprise one CORESET with the CSS type for pre-emption indication and other group-based commands. 
     In an example, for the case of a presence of periodic gap for RACH response monitoring on Pcell, for Pcell, one of configured DL bandwidth parts may comprise one CORESET with CSS type for RMSI, OSI, RACH response &amp; paging control for system information update. For a serving cell, a configured DL bandwidth part may comprise one CORESET with the CSS type for pre-emption indication and other group-based commands. 
     In an example embodiment, BWPs may be configured with respect to common reference point (PRB 0) on a NW carrier. In an example, the BWPs may be configured using TYPE1 RA as a set of contiguous PRBs, with PRB granularity for the START and LENGTH, and the minimum length may be determined by the minimum supported size of a CORESET. 
     In an example embodiment, a CSS may be configured on a non-initial BWP for RAR and paging. 
     In an example embodiment, to monitor (group) common channel for RRC CONNECTED UE, an initial DL BWP may comprise control channel for RMSI, OSI and paging and UE switches BWP to monitor such channel. In an example, a configured DL BWP may comprise control channel for Msg2. In an example, a configured DL BWP may comprise control channel for SFI. In an example, a configured DL BWP may comprise pre-emption indication and other group common indicators like power control. 
     In an example embodiment, a DCI may explicitly indicate activation/deactivation of BWP. 
     For example, a DCI without data assignment may comprise an indication to activate/deactivate BWP. In an example, UE may receive a first indication via a first DCI to activate/deactivate BWP. In order for the UE to start receiving data, a second DCI with a data assignment may be transmitted by the gNB. A UE may receive the first DCI in a target CORESET in a target BWP. In an example, until there is CSI feedback provided to a gNB, the gNB scheduler may make conservative scheduling decisions. 
     In an example, a DCI without scheduling for active BWP switching may be transmitted to measure the CSI before scheduling. It may be taken as an implementation issue of DCI with scheduling, for example, the resource allocation field may be set to zero, which means no data may be scheduled. Other fields in this DCI may comprise one or more CSI/SRS request fields. 
     In an example embodiment, support for a single scheduling DCI to trigger active BWP switching may be motivated by dynamic BWP adaptation for UE power saving during active state (which may comprise ON duration and when inactivity timer is running when C-DRX is configured). For example, with a C-DRX enabled, a UE may consume significant amount of power monitoring PDCCH without decoding any grant. To reduce the power consumption during PDCCH monitoring, two BWPs may be configured: a narrower BWP for PDCCH monitoring, and a wider BWP for scheduled data. In such a case, the UE may switch back-and-forth between the narrower BWP and the wider BWP, depending on the burstiness of the traffic. For example, the UE may be revisiting a BWP that it has dwelled on previously. For this case, combining a BWP switching indication and a scheduling grant may result in low latency and reduced signalling overhead for BWP switching. 
     In an example embodiment, a SCell activation and deactivation may trigger the corresponding action for its configured BWP. In an example, a SCell activation and deactivation may not trigger the corresponding action for its configured BWP. 
     In an example embodiment, a dedicated BWP activation/deactivation DCI may impact a DCI format. For example, a scheduling DCI with a dummy grant may be employed. the dummy grant may be constructed by invalidating one or some of the fields, for example, the resource allocation field. In an example, it may be feasible to leverage a fallback scheduling DCI format (which contains a smaller payload) to improve the robustness for BWP DCI signalling, without incurring extra work on introducing a new DCI format. 
     In an example embodiment, a DCI with data assignment may comprise an indication to activate/deactivate BWP along with a data assignment. For example, a UE may receive a combined data allocation and BWP activation/deactivation message. For example, a DCI format may comprise a field to indicate BWP activation/deactivation along with a field indicating UL/DL grant. In this case, the UE may start receiving data with a single DCI. In this case, the DCI may need indicate one or more target resources of a target BWP. A gNB scheduler may have little knowledge of the CSI in the target BW and may have to make conservative scheduling decisions. 
     In an example embodiment, for the DCI with data assignment, the DCI may be transmitted on a current active BWP and scheduling information may be for a new BWP. For example, there may be a single active BWP. There may be one DCI in a slot for scheduling the current BWP or scheduling another BWP. The same CORESET may be employed for the DCI scheduling the current BWP and the DCI scheduling another BWP. For example, to reduce the number of blind decoding, the DCI payload size for the DCI scheduling current BWP and the scheduling DCI for BWP switching may be the same. 
     In an example embodiment, to support the scheduling DCI for BWP switching, a BWP group may be configured by gNB, in which a numerology in one group may be the same. In an example, the BWP switching for the BWP group may be configured, in which BIF may be present in the CORESETs for one or more BWPs in the group. For example, scheduling DCI for BWP switching may be configured per BWP group, in which an active BWP in the group may be switched to any other BWP in the group. 
     In an example, embodiment, a DCI comprising scheduling assignment/grant may not comprise active-BWP indicator. For a paired spectrum, a scheduling DCI may switch UEs active BWP for the transmission direction that the scheduling is valid for. For an unpaired spectrum, a scheduling DCI may switch the UEs active DL/UL BWP pair regardless of the transmission direction that the scheduling is valid for. There may be a possibility for downlink scheduling assignment/grant with “zero” assignment, in practice allowing for switch of active BWP without scheduling downlink or uplink transmission 
     In an example embodiment, a timer-based activation/deactivation BWP may be supported. For example, a timer for activation/deactivation of DL BWP may reduce signalling overhead and may enable UE power savings. The activation/deactivation of a DL BWP may be based on an inactivity timer (referred to as a BWP inactive (or inactivity) timer). For example, a UE may start and reset a timer upon reception of a DCI. When the UE is not scheduled for the duration of the timer, the timer may expire. In this case, the UE may activate/deactivate the appropriate BWP in response to the expiry of the timer. For example, the UE may activate for example the Default BWP and may deactivate the source BWP. 
     For example, a BWP inactivity timer may be beneficial for power saving for a UE switching to a default BWP with smaller BW and fallback for a UE missing DCI based activation/deactivation signaling to switch from one BWP to another BWP 
     In an example embodiment, triggering conditions of the BWP inactivity timer may follow the ones for the DRX timer in LTE. For example, an On-duration of the BWP inactivity timer may be configured, and the timer may start when a UE-specific PDCCH may be successfully decoded indicating a new transmission during the On-duration. The timer may restart when a UE-specific PDCCH is successfully decoded indicating a new transmission. The timer may stop once the UE is scheduled to switch to the default DL BWP. 
     In an example embodiment, for fallback, the BWP inactivity timer may start once the UE switches to a new DL BWP. The timer may restart when a UE-specific PDCCH is successfully decoded, wherein the UE-specific PDCCH may be associated with a new transmission, a retransmission or some other purpose, e.g., SPS activation/deactivation if supported. 
     In an example embodiment, a UE may switch to a default BWP if the UE does not receive any control/data from the network during a BWP inactivity timer running. The timer may be reset upon reception of any control/data. For example, the timer may be triggered when UE receives a DCI to switch its active DL BWP from the default BWP to another. For example, the timer may be reset when a UE receives a DCI to schedule PDSCH(s) in the BWP other than the default BWP. 
     In an example embodiment, a DL BWP inactivity timer may be defined separately from a UL BWP inactivity timer. For example, there may be some ways to set the timer, e.g., independent timer for DL BWP and UL BWP, or a joint timer for DL and UL BWP. In an example, for the separate timers, assuming both DL BWP and UL BWP are activated, if there is DL data and UL timer expires, UL BWP may not be deactivated since PUCCH configuration may be affected. For example, for the uplink, if there is UL feedback signal related to DL transmission, the timer may be reset (Or, UL timer may not be set if there is DL data). On the other hand, if there is UL data and the DL timer expires, there may be no issue if the DL BWP is deactivated since UL grant is transmitted in the default DL BWP. 
     In an example embodiment, a BWP inactivity-timer may enable the fallback to default BWP on Pcell and Scell. 
     In an example embodiment, a timer-based activation/deactivation of BWP may be similar to a UE DRX timer. For example, there may not be a separate inactivity timer for BWP activation/deactivation for the UE DRX timer. For example, one of the UE DRX inactivity timer may trigger BWP activation/deactivation. 
     For example, there may be a separate inactivity timer for BWP activation/deactivation for the UE DRX timer. For example, the DRX timers may be defined in a MAC layer, and the BWP timer may be defined in a physical layer. In an example, If the same DRX inactivity timer is employed for BWP activation/deactivation, UE may stay in a wider BWP for as long as the inactivity timer is running, which may be a long time. For example, the DRX inactivity timer may be set to a large value of 100-200 milliseconds for C-DRX cycle of 320 milliseconds, larger than the ON duration (10 milliseconds). This may imply that power saving due to narrower BWP may not be achievable. To realize potential of UE power saving promised by BWP switching, a new timer may be defined, and it may be configured to be smaller than the DRX inactivity timer. From the point of view of DRX operation, BWP switching may allow UE to operate at different power levels during the active state, effectively providing some more intermediate operating points between the ON and OFF states. 
     In an example embodiment, with a DCI explicit activation/deactivation of BWP, a UE and a gNB may not be synchronized with respect to which BWP is activated/deactivated. The gNB scheduler may not have CSI information related to a target BWP for channel-sensitive scheduling. The gNB may be limited to conservative scheduling for one or more first several scheduling occasions. The gNB may rely on periodic or aperiodic CSI-RS and associated CQI report to perform channel-sensitive scheduling. Relying on periodic or aperiodic CSI-RS and associated CQI report may delay channel-sensitive scheduling and/or lead to signaling overhead (e.g. in the case where we request aperiodic CQI). To mitigate a delay in acquiring synchronization and channel state information, a UE may transmit an acknowledgement upon receiving an activation/deactivation of BWP. For example, a CSI report based on the provided CSI-RS resource may be transmitted after activation of a BWP and is employed as acknowledgment of activation/deactivation. 
     In an example embodiment, a gNB may provide a sounding reference signal for a target BWP after a UE tunes to a new bandwidth. In an example, the UE may report the CSI, which is employed as an acknowledgement by the gNB to confirm that the UE receive an explicit DCI command and activates/deactivates the appropriate BWPs. In an example, for the case of an explicit activation/deactivation via DCI with data assignment, a first data assignment may be carried out without a CSI for the target BWP 
     In an example embodiment, a guard period may be defined to take RF retuning and the related operations into account. For example, a UE may neither transmit nor receive signals in the guard period. A gNB may need to know the length of the guard period. For example, the length of the guard period may be reported to the gNB as a UE capability. The length of the guard period may be closely related on the numerologies of the BWPs and the length of the slot. For example, the length of the guard period for RF retuning may be reported as a UE capability. In an example, the UE may report the absolute time in μs. in an example, the UE may report the guard period in symbols. 
     In an example embodiment, after the gNB knows the length of the guard period by UE reporting, the gNB may want to keep the time domain position of guard period aligned between the gNB and the UE. For example, the guard period for RF retuning may be predefined for time pattern triggered BWP switching. In an example, for the BWP switching triggered by DCI and timer, the guard period for DCI and timer based BWP switching may be an implementation issue. In an example, for BWP switching following some time pattern, the position of the guard period may be defined. For example, if the UE is configured to switch periodically to a default BWP for CSS monitoring, the guard period may not affect the symbols carrying CSS. 
     In an example embodiment, a single DCI may switch the UE&#39;s active BWP form one to another (of the same link direction) within a given serving cell. A separate field may be employed in the scheduling DCI to indicate the index of the BWP for activation, such that UE may determine the current DL/UL BWP according to a detected DL/UL grant without requiring any other control information. In case the BWP change does not happen during a certain time duration, the multiple scheduling DCIs transmitted in this duration may comprise the indication to the same BWP. During the transit time when potential ambiguity may happen, gNB may send scheduling grants in the current BWP or together in the other BWPs containing the same target BWP index, such that UE may obtain the target BWP index by detecting the scheduling DCI in either one of the BWPs. The duplicated scheduling DCI may be transmitted K times. When UE receive one of the K times transmissions, UE may switch to the target BWP and start to receive or transmit (UL) in the target BWP according to the BWP indication field. 
     In an example embodiment, switching between BWPs may not introduce large time gaps when UE may not be able to receive due to re-tuning, neither after detecting short inactivity (Case 1) or when data activity is reactivated (Case 2). For example, in Case 2, long breaks of several slots may severely impact the TCP ramp up as UE may not be able to transmit and receive during those slots, impacting obtained RTT and data rate. Case 1 may be seen less problematic at first glance but similarly long break in reception may make UE out of reach from network point of view reducing network interest to utilize short inactivity timer. 
     In an example, if BWP switching takes significant time, and UE requires new reference symbols to update AGC, channel estimation etc., the system may have less possibilities/motivation to utilize active BWP adaption in the UE. This may be achieved by preferring configuration where BWP center frequency remains the same when switching between BWPs. 
     In an example embodiment, a frequency location of UE RF bandwidth may be indicated by gNB. For example, considering the UE RF bandwidth capability, the RF bandwidth of the UE may be usually smaller than the carrier bandwidth. The supported RF bandwidth for a UE is usually a set of discrete values (e.g., 10 MHz, 20 MHz, 50 MHz and so on), for energy saving purpose, the UE RF bandwidth may be determined as the minimum available bandwidth supporting the BWP bandwidth. But the granularity of BWP bandwidth is PRB level, which is decoupled with UE RF bandwidth and more flexible. As a result, in most cases the UE RF bandwidth is larger than the BWP bandwidth. The UE may receive the signal outside the carrier bandwidth, especially if the configured BWP is configured near the edge of the carrier bandwidth. And the inter-system interference or the interference from the adjacent cell outside the carrier bandwidth may impact the receiving performance of the BWP. Thus, to keep the UE RF bandwidth in the carrier bandwidth, it is necessary to indicate the frequency location of the UE RF bandwidth by gNB. 
     In an example embodiment, in terms of measurement gap configuration, the gap duration may be determined based on the measurement duration and necessary retuning gap. For example, different retuning gap may be needed depending on the cases. For example, if a UE does not need to switch its center, the retuning may be small such as 20 us. For the case that the network may not know whether the UE needs to switch its center or not to perform measurement, a UE may indicate the necessary retuning gap for a measurement configuration. 
     In an example embodiment, the necessary gap may depend on the current active BWP which may be dynamically switched via switching mechanism. In this case, for example, UEs may need to dynamically indicate the necessary gap. 
     In an example embodiment, the measurement gap may be implicitly created, wherein the network may configure a certain gap (which may comprise the smallest retuning latency, for example, the network may assume small retuning gap is necessary if both measurement bandwidth and active BWP may be included within UE maximum RF capability assuming center frequency of current active BWP is not changed). In this case, for example, if a UE needs more gap than the configured, the UE may skip receiving or transmitting. 
     In an example embodiment, different measurement gap and retuning latency may be assumed for RRM and CSI respectively. For CSI measurement, if periodic CSI measurement outside of active BWP is configured, a UE may need to perform its measurement periodically per measurement configuration. For RRM, it may be up to UE implementation where to perform the measurement as long as it satisfies the measurement requirements. In this case, for example, the worst-case retuning latency for a measurement may be employed. In an example, as the retuning latency may be different between intra-band and inter-band retuning, separate measurement gap configuration between intra-band and inter-band measurement may be considered. 
     In an example embodiment, for multiple DCI formats with the same DCI size of a same RNTI, a respective DCI format may comprise an explicit identifier to distinguish them. For example, a same DCI size may come from a few (but not a large number of) zero-padding bits at least in UE-specific search space. 
     In an example embodiment, when there is a BWP switching, a DCI in the current BWP may need to indicate resource allocation in the next BWP that the UE is expected to switch. For example, the resource allocation may be based on the UE-specific PRB indexing, which may be per BWP. A range of the PRB indices may change as the BWP changes. In an example, the DCI to be transmitted in current BWP may be based on the PRB indexing for the current BWP. The DCI may need to indicate the RA in the new BWP, which may arouse a conflict. To resolve the conflict without significantly increasing UEs blind detection overhead, the DCI size and bit fields may not change per BWP for a given DCI type. 
     In an example embodiment, as the range of the PRB indices may change as the BWP changes, one or more employed bits among the total bit field for RA may be dependent on the employed BWP. For example, UE may employ the indicated BWP ID that the resource allocation is intended to identify the resource allocation bit field. 
     In an example embodiment, a DCI size of the BWP may consider two cases. One case may be a normal DCI detection without BWP retuning, and the other case may be a DCI detection during the BWP retuning. 
     For example, in some cases, a DCI format may be independent of the BW of the active DL/UL BWP (which may be called as fallback DCI). In an example, at least one of DCI formats for DL may be configured to have the same size to a UE for one or more configured DL BWPs of a serving cell. In an example, at least one of the DCI formats for UL may be configured to have the same size to a UE for one or more configured UL BWPs of a serving cell. In an example embodiment, a BWP-dependent DCI format may be monitored at the same time (which may be called as normal DCI) for both active DL BWP and active UL BWP. For example, UE may be configured to monitor both DCI formats at the same time. During the BWP activation/deactivation, gNB may assign the fallback DCI format to avoid ambiguity during the transition period. 
     In an example embodiment, if a UE is configured with multiple DL or UL BWPs in a serving cell, an inactive DL/UL BWP may be activated by a DCI scheduling a DL assignment or UL grant respectively in this BWP. As the UE is monitoring the PDCCH on the currently active DL BWP, the DCI may comprise an indication to a target BWP that the UE may switch to for PDSCH reception or UL transmission. A BWP indication may be inserted in the UE-specific DCI format for this purpose. The bit width of this field may depend on either the maximum possible or presently configured number of DL/UL BWPs. Similar to CIF, it may be simpler to set the BWP indication field to a fixed size based on the maximum number of configured BWPs. 
     In an example, a DCI format size may match the BW of the BWP in which the PDCCH is received. To avoid an increase in the number of blind decodes, the UE may identify the RA field based on the scheduled BWP. For example, for a transition from a small BWP to a larger BWP, the UE may identify the RA field as being the LSBs of the required RA field for scheduling the larger BWP. 
     In an example embodiment, a same DCI size for scheduling different BWPs may be defied by keeping a same size of resource allocation field for one or more configured BWPs. For example, gNB may not be aware of whether UE switches BWPs if gNB does not receive at least one response from the UE (e.g., gNB may be aware of if UE switches BWPs based on a reception of ACK/NACK from the UE). In an example, to avoid such a mismatch between gNB and UE, NR may define fallback mechanism. For example, if there is no response from the UE, gNB may transmit the scheduling DCI for previous BWPs and that for newly activated BWP since the UE may receive the DCI on either BWP. When the gNB receives a response from the UE, the gNB may confirm that the active BWP switching is completed. In an example, if a same DCI size for scheduling different BWPs is considered and COREST configuration is also the same for different BWPs, gNB may not transmit multiple DCIs. 
     In an example embodiment, DCI format(s) may be configured user-specifically per cell, e.g., not per BWP. For example, after the UE syncs to the new BWP, the UE may start to monitor pre-configured search-space on the CORESET. If the DCI formats may be configured per cell to keep the number of DCI formats, the corresponding header size in DCI may be small. 
     In an example embodiment, a size of DCI format in different BWPs may vary and may change at least due to different size of RA bitmap on different BWPs. For example, the size of DCI format configured in a cell for a UE may be dependent on BWP it schedules. 
     In an example embodiment, the monitored DCI format size on a search-space of a CORESET may be configurable with the sufficiently fine granularity (the granularity may be predefined). For example, the monitored DCI format size with sufficient granularity may be beneficial when a gNB may have the possibility to set freely the monitoring DCI format size on a search-spaces of a CORESET, such that it may accommodate the largest actual DCI format size variant among one or more BWPs configured in a serving cell. 
     In an example embodiment, for a UE-specific serving cell, one or more DL BWPs and one or more UL BWPs may be configured by dedicated RRC for a UE. For the case of PCell, this may be done as part of the RRC connection establishment procedure. For the SCell, this may be done via RRC configuration which may indicate the SCell parameters. 
     In an example embodiment, when a UE receives SCell activation command, there may be a default DL and/or UL BWP which may be activated since there may be at least one DL and/or UL BWP which may be monitored by the UE depending on the properties of the SCell (DL only or UL only or both). This BWP which may be activated upon receiving SCell activation command, may be informed to the UE via the a RRC configuration which configured the BWP on this serving cell. 
     For example, for SCell, RRC signalling for SCell configuration/reconfiguration may be employed to indicate which DL BWP and/or which UL BWP may be activated when the SCell activation command is received by the UE. The indicated BWP may be the initially active DL/UL BWP on the SCell. Therefore, SCell activation command may activate DL and/or UL BWP. 
     In an example embodiment, for a SCell, RRC signaling for the SCell configuration/reconfiguration may be employed for indicating a default DL BWP on the SCell which may be employed for fall back purposes. For example, the default DL BWP may be same or different from the initially activated DL/UL BWP which is indicated to UE as part of the SCell configuration. In an example, a default UL BWP may be configured to UE for the case of transmitting PUCCH for SR (as an example), in case the PUCCH resources are not configured in every BWP for the sake of SR. 
     In an example, a Scell may be for DL only. For the Scell for DL only, UE may keep monitoring an initial DL BWP (initial active or default) until UE receives SCell deactivation command. 
     In an example, a Scell may be for UL only. For the Scell for UL only, when UE receives a grant, UE may transmit on the indicated UL BWP. In an example, the UE may not maintain an active UL BWP if UE does not receive a grant. In an example, not mainlining the active UL BWP due to no grant receive may not deactivate the SCell. 
     In an example, a Scell may be for UL and DL. For the Scell for UL and DL, a UE may keep monitoring an initial DL BWP (initial active or default) until UE receives SCell deactivation command and. The UL BWP may be employed when there is a relevant grant or an SR transmission. 
     In an example, a BWP deactivation may not result in a SCell deactivation. For example, when the UE receives the SCell deactivation command, the active DL and/or UL BWPs may be considered deactivated. 
     In an example embodiment, if the SCell has its associated UL and/or a UE is expected to perform RACH procedure on SCell during activation, activation of UL BWP may be needed. For example, at SCell activation, DL only (only active DL BWP) or DL/UL (both DL/UL active BWP) may be configured. Regarding SUL band as a SCell, a UE may select default UL BWP based on measurement or the network configures which one in its activation. 
     In an example embodiment, one or more BWPs are semi-statically configured via UE-specific RRC signaling. In a CA system, if a UE maintains RRC connection with the primary component carrier (CC), the BWP in secondary CC may be configured via RRC signaling in the primary CC. 
     In an example embodiment, one or more BWPs may be semi-statically configured to a UE via RRC signaling in PCell. A DCI transmitted in SCell may indicate a BWP among the one or more configured BWP, and grant detailed resource based on the indicated BWP. 
     In an example embodiment, for a cross-CC scheduling, a DCI transmitted in PCell may indicate a BWP among the one or more configured BWPs, and grants detailed resource based on the indicated BWP. 
     In an example embodiment, when a SCell is activated, a DL BWP may be initially activated for configuring CORESET for monitoring the first PDCCH in Scell. The DL BWP may serve as a default DL BWP in the SCell. In an example, since the UE performs initial access via a SS block in PCell, the default DL BWP in SCell may not be derived from SS block for initial access. The default DL BWP in Scell may be configured by RRC signaling in the PCell. 
     In an example embodiment, when an Scell is activated, an indication indicating which DL BWP and/or which UL BWP are active may be in RRC signalling for Scell configuration/reconfiguration. For example, the RRC signalling for Scell configuration/reconfiguration may be employed for indicating which DL BWP and/or which UL BWP are initially activated when the Scell is activated. 
     In an example embodiment, when an Scell is activated, an indication indicating which DL BWP and/or which UL BWP are active may be in Scell activation signaling. For example, Scell activation signaling may be employed for indicating which DL BWP and/or which UL BWP are initially activated when the Scell is activated. 
     In an example embodiment, for PCells and pSCells, an initial default bandwidth parts for DL and UL (e.g., for RMSI reception and PRACH transmission) may be valid until at least one bandwidth part is configured for the DL and UL via RRC UE-specific signaling, respectively, at what time the initial default DL/UL bandwidth parts may become invalid and new default DL/UL bandwidth parts may take effect. In an example, for an Scell, the SCell configuration may comprise default DL/UL bandwidth parts 
     In an example embodiment, an initial BWP on Pcell may be defined by MIB. In an example, an initial BWP and default BWP may be separately configurable for the Scell. For an Scell if the Scell is activated, an initial BWP may be the widest configured BWP of the Scell. For example, after the traffic burst is served, and an inactivity timer expires, a UE may retune to default BWP which may be the narrow BWP, for power savings, keeping the Scell active and may be ready to be opened briskly when additional data burst arrives. 
     In an example embodiment, a BWP on Scell may be activated by means of cross-cell scheduling DCI, if cross-cell scheduling is configured to a UE. In this case, the gNB may activate a BWP on the Scell by indicating CIF and BWPI in the scheduling DCI. 
     In an example embodiment, UE and/or gNB may perform synchronization tracking within an active DL BWP without SS block. For example, TRS along with DL BWP configuration may be configured. For example, a DL BWP with SS block or TRS may be configured as a reference for synchronization tracking, which may be similar to the design of CSS monitoring when the BWP does not comprise a common CORESET. 
     In an example embodiment, SS-block based RRM measurements may be decoupled with BWP framework. For example, measurement configurations for each RRM and CSI feedback may be independently configured from bandwidth part configurations. CSI and SRS measurements/transmissions may be performed within the BWP framework. 
     In an example embodiment, for a MCS assignment of the first one or more DL data packets after active DL BWP switching, the network may assign robust MCS to a UE for the first one or more DL data packets based on RRM measurement reporting. In an example, for a MCS assignment of the first one or more DL data packets after active DL BWP switching, the network may signal to a UE by active DL BWP switching DCI to trigger aperiodic CSI measurement/reporting to speed up link adaptation convergence. For a UE, periodic CSI measurement outside the active BWP in a serving cell may not supported. For a UE, RRM measurement outside active BWP in a serving cell may be supported. For a UE, RRM measurement outside configured BWPs in a serving cell may be supported. 
     In an example embodiment, the RRM measurements may be performed on a SSB and/or CSI-RS. The RRM/RLM measurements may be independent of BWPs. 
     In an example embodiment, UE may not be configured with aperiodic CSI reports for non-active DL BWPs. For example, the CSI measurement may be obtained after the BW opening and the wide-band CQI of the previous BWP may be employed as starting point for the other BWP on the NW carrier. 
     In an example embodiment, UE may perform CSI measurements on the BWP before scheduling. For example, before scheduling on a new BWP, the gNB may intend to find the channel quality on the potential new BWPs before scheduling the user on that BWP. In this case, the UE may switch to a different BWP and measure channel quality on the BWP and then transmit the CSI report. There may be no scheduling needed for this case. 
       FIG.  25    shows example of BWP switching associated with BWP inactivity timer. A UE may receive RRC message comprising parameters of at least one SCell and one or more BWP configuration associated with the at least one SCell. Among the one or more BWPs, at least one BWP may be configured as the first active BWP (e.g., BWP 1 in the figure), one BWP as the default BWP (e.g., BWP 0 in the figure). The UE may receive a MAC CE to activate the Scell at the n th  subframe. The UE may start the sCellDeactivationTimer, and start reporting CSI for the SCell, and/or start reporting CSI for the first active BWP of the SCell at the (n+8) th  subframe. The UE may start the BWP inactivity timer when receiving a DCI indicating switching BWP from BWP 1 to BWP 2, at the (n+8+k) th  subframe. The gap k between receiving the DCI and starting the BWP inactivity timer may be configured or predefined, to allow the UE switch to the new BWP. When receiving a PDCCH indicating DL scheduling on BWP 2, for example, at the (n+8+k+m) th  subframe, the UE may restart the BWP inactivity timer. The UE may switch back to the default BWP (0) when the BWP inactivity timer expires, at the (n+8+k+m+1) th  subframe. The UE may deactive the SCell when the sCellDeactivationTimer expires. Employing the BWP inactivity timer may further reduce UE&#39;s power consumption when the UE is configured with multiple cells with each cell having wide bandwidth (e.g., 1 GHz). The UE may only transmit on or receive from a narrow-bandwidth BWP (e.g., 5 MHz) on the PCell or SCell when there is no activity on an active BWP. 
     In an example, a UE may receive one or more RRC messages configuring a first active BWP and a default BWP for a SCell. These two BWPs may be different, for example, as shown in  FIG.  25   , the first active BWP is BWP 0, and the default BWP is BWP 1. When receiving a MAC CE activating the SCell, the UE may activate the first active BWP (BWP 1), e.g., by monitoring one or more PDCCH and/or transmitting uplink signals on the first active DL or UL BWP. In an example, the UE may stay on the first active BWP (BWP 1) until receiving a DCI indicating active BWP change, and starting the BWP inactivity timer. In this case, it may be not power efficient, since the UE may keep monitoring the PDCCH on the first active BWP, even though there may be no activity on the first active BWP until receiving a DCI indicating a BWP change. It&#39;s necessary to have mechanism to reduce the power consumption for a UE when a SCell activated with multiple BWPs. 
       FIG.  26    shows an example of the embodiment. A UE may receive one or more RRC message comprise at least configuration parameters of a plurality of cells, the plurality of cells comprising a PCell and at least one SCell. The configuration parameters of the at least one SCell may comprise at least one of: one or more BWPs associated with one or more radio resource configuration (e.g., frequency location, bandwidth, subcarrier spacing, cyclic prefix, one or more CSI-RS resource configuration); at least a first BWP identifier indicating a first active BWP; a second BWP identifier indicating a default BWP; a BWP inactivity timer with a timer value; a SCell deactivation timer with a timer value. The BWP inactivity timer value may be configured per cell or per base station in a RRC message, or may be a pre-defined value. The SCell deactivation timer may be configured for each SCell with a different/same value. In an example, the SCell deactivation timer may be configured for all SCells with a same value in a RRC message, or as a pre-defined value. The UE may receive a SCell activation/deactivation MAC CE comprising parameters indicating activation or deactivation of the at least one SCell at the n th  subframe. In an example, a UE may receive a SCell activation/deactivation DCI indicating activation or deactivation of the at least one SCell at the n th  subframe. The UE may start or restart the SCell deactivation timer at the (n+k) th  subframe, in response to receiving the SCell activation/deactivation MAC CE or DCI. In an example, the UE may start the BWP inactivity timer at the (n+k+m) th  subframe, in response to receiving the SCell activation/deactivation MAC CE or DCI, if the first active BWP is different from the default BWP. In an example, the UE may start CSI report for the first active BWP at the (n+k) th  subframe. In another example, the UE may start CSI report for the first active BWP at the (n+k+m) th  subframe. The first time offset (e.g., k value) between receiving the SCell activation/deactivation MAC CE or DCI and starting the SCell deactivation timer may be configured in a RRC message, or preconfigured as a fixed value. The second time offset (e.g., m value) between starting the SCell deactivation timer and starting the BWP inactivity timer may be configured in a RRC message, or predefined as a fixed value. For example, the first time offset may be configured as zero if a DCI is used to activate a SCell in case that a UE is capable of activating the SCell quickly. The second time offset may be predefined or configured as zero if the time for SCell activation is same as the time for BWP activation, then the UE may start the SCell deactivation timer and BWP inactivity timer (if the first active BWP is different from the default BWP) in the same time. With the embodiment, when activating a SCell with multiple BWPs, the UE may switch to the default BWP when the BWP inactivity timer expires, even without receiving a DCI indicating BWP change, therefore reducing the power consumption. The configurable or predefined time offset for SCell activation and BWP activation may give the gNB more flexibility on controlling SCell activation and BWP activation, and allow different UEs with different capability (e.g., on BWP switch) to change BWP correctly. 
     In an example, when receiving a second DCI indicating an active BWP change, a UE may start or restart the BWP inactivity timer depending on whether the new active BWP is the default BWP. For example, in  FIG.  26   , a UE may receive the second DCI indicating active BWP change from BWP 1 to BWP 2, at the (n+k+m+l) th  subframe. The UE may start or restart the BWP timer if the new active BWP is not the default BWP. In some case, when the UE may have a quick BWP switch, the UE may start or restart the BWP inactivity timer at the same subframe, i.e., the (n+k+m+l) th  subframe. In another example, when the UE may have a slow BWP switch, the UE may start or restart the BWP inactivity timer at the (n+k+m+l+o) th  subframe. The time offset (e.g., o value) between receiving the second DCI and starting BWP inactivity timer may be configured or predefined. The time offset may be a transition gap. The transition gap may be a time period between a first time when receiving the second DCI and a second time when the wireless device completes BWP switching from BWP 1 to BWP 2. With the configurable time offset between receiving BWP change DCI and starting the BWP inactivity timer, it may give the gNB more flexibility on controlling BWP change, and allow different UEs with different capability (e.g., on BWP switch) to change BWP correctly. 
     In an example, a UE may receive the second DCI indicating active BWP change from an active BWP to a default BWP, for example, in  FIG.  26   , a UE may receive the second DCI indicating active BWP change from BWP 1 to BWP 0. The UE may stop the BWP inactivity timer, in response to receiving the second DCI. With the embodiment, stopping the BWP inactivity timer when switching an active BWP to the default BWP may avoid unnecessary BWP inactivity timer management at the gNB and the UE. 
       FIG.  27    shows an example of the embodiment. A UE may receive, from a base station, one or more RRC message comprise at least configuration parameters of a cell. The configuration parameters of the cell may comprise at least one of: one or more BWPs associated with one or more radio resource configuration (e.g., frequency location, bandwidth, subcarrier spacing, cyclic prefix, one or more CSI-RS resource configuration); at least a first BWP identifier indicating a first active BWP; a second BWP identifier indicating a default BWP; a BWP inactivity timer with a timer value. In an example, the UE may communicate with the base station via the first active BWP (e.g., BWP 1 in  FIG.  27   ). The UE may receive a first DCI indicating an active BWP switching from the first active BWP to a second BWP (e.g., BWP 2 in  FIG.  27   ) at slot n. The wireless device may finish the active BWP switching in a transition gap (with a length k, as shown  FIG.  27   ) in response to the first DCI. The wireless device may start the BWP inactivity timer at slot n+k. During the BWP inactivity timer being running, the wireless device may monitor a PDCCH on the second BWP which is an active BWP after the active BWP switching. The wireless device may receive a second DCI indicating an active BWP switching from the second BWP to the default BWP. In response to the second DCI, the wireless device may stop the BWP inactivity timer at the same slot when receiving the second DCI. In response to the second DCI, the wireless device may stop the BWP inactivity timer at a second slot the transition gap after a first slot when receiving the second DCI. 
       FIG.  28    shows an example of flowchart of the embodiment. At  2810 , a wireless device may receive one or more messages comprising configuration parameters of a first active BWP and a default BWP of a cell. At  2820 , the wireless device may activate the first active BWP of the cell in response to at least one of: activation of the cell; receiving a DCI indicating downlink assignment or uplink grant. At  2830 , the wireless device may transmit or receive data packets on the first active BWP in response to activating the first active BWP. At  2840 , the wireless device may receive a first DCI indicating an active BWP switching to a second BWP at a first slot. At  2850 , in response to the first DCI, the wireless device may switch to the second BWP as the active BWP and start a BWP inactivity timer at a second slot. At  2860 , the wireless device may receive a second DCI indicating switching to the default BWP as the active BWP. At  2870 , in response to the second DCI, the wireless device may switch to the default BWP and stop the BWP inactivity timer. 
     In an example, a wireless device may receive one or more RRC message comprising: configuration parameters of a plurality of cells, the plurality of cells comprising a primary cell and at least one secondary cell, wherein configuration parameters of the at least one secondary cell comprising at least one of: one or more BWPs associated with one or more radio resource configuration (e.g., frequency location, bandwidth, subcarrier spacing, cyclic prefix, one or more CSI-RS resource configuration); a first active BWP from the one or more BWPs; a default BWP from the one or more BWPs; and a timer value for a first BWP inactivity timer. The wireless device may receive a MAC CE or DCI activating/deactivating the at least one secondary cell. The wireless device may start the first BWP inactivity timer, in response to receiving the MAC CE or DCI, if the first active BWP is different from the default BWP, for the at least one secondary cell. In an example, the wireless device may start the first BWP inactivity timer after a predefined time offset, or a configured time offset. In another example, the wireless device may not start the first BWP inactivity timer, if the first active BWP is same as the default BWP. 
     According to various embodiments, a device such as, for example, a wireless device, off-network wireless device, a base station, a core network device, and/or the like, may comprise one or more processors and memory. The memory may store instructions that, when executed by the one or more processors, cause the device to perform a series of actions. Embodiments of example actions are illustrated in the accompanying figures and specification. Features from various embodiments may be combined to create yet further embodiments. 
       FIG.  29    is a flow diagram of an aspect of an embodiment of the present disclosure. At  2910 , a wireless device may receive from a base station, one or more messages comprising configuration parameters of a cell. The configuration parameters may comprise bandwidth part (BWP) parameters of a first BWP and a second BWP. The configuration parameters may comprise a timer value associated with a BWP inactivity timer. At  2920 , a first downlink control information may be received at a first slot. The first downlink control information may indicate switching to the second BWP as an active BWP. At  2930 , in response to the first downlink control information, the first BWP may switch to the second BWP as the active BWP. In response to the first downlink control information, the BWP inactivity timer may be started at a second slot based on the timer value. The second slot may occur after the first slot by an amount of time determined based on a time offset value. At  2940 , a default BWP may be switched to in response to an expiry of the BWP inactivity timer. 
     According to an example embodiment, the time offset value may be indicated in the configuration parameters. According to an example embodiment, the time offset value may be a fixed value. According to an example embodiment, the cell may be a primary cell of a plurality of cells. According to an example embodiment, the cell may be a secondary cell of a plurality of cells. According to an example embodiment, the BWP parameters of the first BWP or the second BWP indicate at least one of: a frequency location; a bandwidth; a value of subcarrier spacing; a cyclic prefix; or one or more reference signal resource configuration. 
     According to an example embodiment, the first BWP may be activated in response to receiving a second downlink control information indicating a downlink assignment or an uplink grant. According to an example embodiment, the BWP inactivity timer may be started in response to the second downlink control information. According to an example embodiment, the first BWP may be activated in response to receiving a command indicating an activation of the cell. According to an example embodiment, the command may be a medium access control control element. According to an example embodiment, the command may be a downlink control information. According to an example embodiment, the BWP inactivity timer may be started based on the timer value in response to the command. According to an example embodiment, the activation of the first BWP may comprise monitoring a downlink control channel on the first BWP. According to an example embodiment, switching from the first BWP to the second BWP as the active BWP may comprise stopping monitoring a first downlink control channel on the first BWP. According to an example embodiment, switching from the first BWP to the second BWP as the active BWP may comprise monitoring a second downlink control channel on the second BWP. 
     According to an example embodiment, a second downlink control information may be received at a third slot. The second downlink control information may indicate switching to a default BWP as the active BWP. According to an example embodiment, in response to the second downlink control information, the active BWP may be switched to the default BWP. According to an example embodiment, in response to the second downlink control information, the BWP inactivity timer may be stopped. 
     According to an example embodiment, the default BWP may be different from the second BWP. According to an example embodiment, the switching of the active BWP to the default BWP may comprise monitoring a downlink control channel on the default BWP. According to an example embodiment, the stopping the BWP inactivity timer may comprise stopping the BWP inactivity timer at the third slot. According to an example embodiment, the time offset value may be based on a capability of the wireless device. According to an example embodiment, a first bandwidth of the first BWP may be less than a second bandwidth of the cell. According to an example embodiment, the BWP inactivity timer may be stopped in response to receiving a command indicating a deactivation of the cell. 
       FIG.  30    is a flow diagram of an aspect of an embodiment of the present disclosure. At  3010 , a wireless device may receive from a base station, one or more messages comprising configuration parameters of a cell. The configuration parameters may comprise bandwidth part (BWP) parameters of a first BWP, a default BWP; and a value associated with a BWP inactivity timer. At  3020 , a first downlink control information (DCI) indicating downlink assignments may be received. An uplink grant on the first BWP may be received. At  3030 , the BWP inactivity timer may be started with the value in response to the first DCI. At  3040 , a second DCI indicating switching an active BWP from the first BWP to the default BWP may be received. At  3050 , the active BWP may be switched to the default BWP in response to the second DCI. The BWP inactivity timer may be stopped in response to the second DCI. 
       FIG.  31    is a flow diagram of an aspect of an embodiment of the present disclosure. At  3110 , a wireless device may receive from a base station, one or more messages comprising configuration parameters of bandwidth parts (BWPs) a cell. The configuration parameters may indicate: a first BWP identifier indicating a first active BWP; a second BWP identifier indicating a default BWP; and a value for a BWP inactivity timer. At  3120 , a command indicating an activation of the cell may be received. At  3130 , in response to the command, the BWP inactivity timer may be started with the value. At  3140 , a downlink control channel may monitor the first active BWP for a downlink control information while the BWP inactivity timer is running. At  3150 , the wireless device may switch to the default BWP in response to an expiry of the BWP inactivity timer. According to an example embodiment, the command may comprise a medium access control control element. According to an example embodiment, the command may comprise a downlink control information. 
       FIG.  32    is a flow diagram of an aspect of an embodiment of the present disclosure. At  3210 , a wireless device may receive from a base station, one or more messages comprising configuration parameters of bandwidth parts (BWPs) a cell. The configuration parameters may indicate: a first BWP identifier indicating a first active BWP; a second BWP identifier indicating a default BWP; and a time value. At  3210 , a command indicating an activation of the cell may be received. At  3210 , monitoring a downlink control channel may be monitored for a downlink control information on the first active BWP. At  3210 , the wireless device may switch to the default BWP in response to a period of time starting from the receiving the command. The period of time may be based on the time value. 
     In this disclosure, “a” and “an” and similar phrases are to be interpreted as “at least one” or “one or more.” Similarly, any term that ends with the suffix “(s)” is to be interpreted as “at least one” or “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 to one or more of the various embodiments. If A and B are sets and every element of A is also 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” 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” 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 terms “including” and “comprising” should be interpreted as meaning “including, but not limited to”. 
     In this disclosure, various embodiments are disclosed. Limitations, features, and/or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure. 
     In this disclosure, parameters (Information elements: IEs) may comprise one or more objects, and each of those objects 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. 
     Furthermore, many features presented above 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. However, 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 different ways, namely with just one of the three possible features, with any two of the three possible features or with all 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 isolatable 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 (i.e. hardware with a biological element) or a combination thereof, all of which are 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 LabVIEWMathScript. Additionally, 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. Finally, it needs to be emphasized that the above mentioned technologies are often used in combination to achieve the result of a functional module. 
     The disclosure of this patent document incorporates material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, for the limited purposes required by law, but otherwise reserves all copyright rights whatsoever. 
     While various embodiments have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made therein without departing from the scope. In fact, after reading the above description, it will be apparent to one skilled in the relevant art(s) how to implement alternative embodiments. Thus, the present embodiments should not be limited by any of the above described exemplary embodiments. 
     In addition, it should be understood that 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. 
     Further, the purpose of the Abstract of the Disclosure is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The Abstract of the Disclosure is not intended to be limiting as to the scope in any way. 
     Finally, it is the applicant&#39;s intent that only claims that include the express language “means for” or “step for” be interpreted under 35 U.S.C. 112. Claims that do not expressly include the phrase “means for” or “step for” are not to be interpreted under 35 U.S.C. 112.