Patent Publication Number: US-11653338-B2

Title: Guard symbols (Ng) tables generation for co-located IAB DU/MT resource transition

Description:
PRIORITY CLAIM 
     This application claims the benefit of priority under 35 U.S.C. 119(e) to the U.S. Provisional Patent Application Ser. No. 62/933,133, filed Nov. 8, 2019, and entitled “METHODS TO GENERATE NG TABLES FOR CO-LOCATED IAB DU/MT RESOURCE TRANSITION,” which provisional patent application is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Aspects pertain to wireless communications. Some aspects relate to wireless networks including 3GPP (Third Generation Partnership Project) networks, 3GPP LTE (Long Term Evolution) networks, 3GPP LTE-A (LTE Advanced) networks, and fifth-generation (5G) networks including 5G new radio (NR) (or 5G-NR) networks and 5G-LTE networks. Other aspects are directed to systems and methods for guard symbols (Ng) tables generation for co-located integrated access and backhaul (IAB) distributed unit (DU) and mobile termination (MT) resource transition. 
     BACKGROUND 
     Mobile communications have evolved significantly from early voice systems to today&#39;s highly sophisticated integrated communication platform. With the increase in different types of devices communicating with various network devices, usage of 3GPP LTE systems has increased. The penetration of mobile devices (user equipment or UEs) in modern society has continued to drive demand for a wide variety of networked devices in a number of disparate environments. Fifth-generation (5G) wireless systems are forthcoming and are expected to enable even greater speed, connectivity, and usability. Next generation 5G networks (or NR networks) are expected to increase throughput, coverage, and robustness and reduce latency and operational and capital expenditures. 5G-NR networks will continue to evolve based on 3GPP LTE-Advanced with additional potential new radio access technologies (RATs) to enrich people&#39;s lives with seamless wireless connectivity solutions delivering fast, rich content and services. As current cellular network frequency is saturated, higher frequencies, such as millimeter wave (mmWave) frequency, can be beneficial due to their high bandwidth. 
     Potential LTE operation in the unlicensed spectrum includes (and is not limited to) the LTE operation in the unlicensed spectrum via dual connectivity (DC), or DC-based LAA, and the standalone LTE system in the unlicensed spectrum, according to which LTE-based technology solely operates in the unlicensed spectrum without requiring an “anchor” in the licensed spectrum, called MulteFire. MulteFire combines the performance benefits of LTE technology with the simplicity of Wi-Fi-like deployments. 
     Further enhanced operation of LTE systems in the licensed as well as unlicensed spectrum is expected in future releases and 5G systems. Such enhanced operations can include techniques for guard symbols (Ng) tables generation for co-located IAB DU and MT resource transition. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       In the figures, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The figures illustrate generally, by way of example, but not by way of limitation, various aspects discussed in the present document. 
         FIG.  1 A  illustrates an architecture of a network, in accordance with some aspects. 
         FIG.  1 B  and  FIG.  1 C  illustrate a non-roaming 5G system architecture in accordance with some aspects. 
         FIG.  2    illustrates a reference diagram of an IAB architecture, in accordance with some aspects. 
         FIG.  3    illustrates a central unit (CU)—distributed unit (DU) split and signaling in an IAB architecture, in accordance with some aspects. 
         FIG.  4    illustrates example resource transitions at co-located MT/DU functions, in accordance with some aspects. 
         FIG.  5    illustrates a block diagram of a communication device such as an evolved Node-B (eNB), a new generation Node-B (gNB), an access point (AP), a wireless station (STA), a mobile station (MS), or a user equipment (UE), in accordance with some aspects. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and the drawings sufficiently illustrate aspects to enable those skilled in the art to practice them. Other aspects may incorporate structural, logical, electrical, process, and other changes. Portions and features of some aspects may be included in or substituted for, those of other aspects. Aspects outlined in the claims encompass all available equivalents of those claims. 
       FIG.  1 A  illustrates an architecture of a network in accordance with some aspects. The network  140 A is shown to include user equipment (UE)  101  and UE  102 . The UEs  101  and  102  are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks) but may also include any mobile or non-mobile computing device, such as Personal Data Assistants (PDAs), pagers, laptop computers, desktop computers, wireless handsets, drones, or any other computing device including a wired and/or wireless communications interface. The UEs  101  and  102  can be collectively referred to herein as UE  101 , and UE  101  can be used to perform one or more of the techniques disclosed herein. 
     Any of the radio links described herein (e.g., as used in the network  140 A or any other illustrated network) may operate according to any exemplary radio communication technology and/or standard. 
     LTE and LTE-Advanced are standards for wireless communications of high-speed data for UE such as mobile telephones. In LTE-Advanced and various wireless systems, carrier aggregation is a technology according to which multiple carrier signals operating on different frequencies may be used to carry communications for a single UE, thus increasing the bandwidth available to a single device. In some aspects, carrier aggregation may be used where one or more component carriers operate on unlicensed frequencies. 
     Aspects described herein can be used in the context of any spectrum management scheme including, for example, dedicated licensed spectrum, unlicensed spectrum, (licensed) shared spectrum (such as Licensed Shared Access (LSA) in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz, and further frequencies and Spectrum Access System (SAS) in 3.55-3.7 GHz and further frequencies). 
     Aspects described herein can also be applied to different Single Carrier or OFDM flavors (CP-OFDM, SC-FDMA, SC-OFDM, filter bank-based multicarrier (FBMC), OFDMA, etc.) and in particular 3GPP NR (New Radio) by allocating the OFDM carrier data bit vectors to the corresponding symbol resources. 
     In some aspects, any of the UEs  101  and  102  can comprise an Internet-of-Things (IoT) UE or a Cellular IoT (CIoT) UE, which can comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. In some aspects, any of the UEs  101  and  102  can include a narrowband (NB) IoT UE (e.g., such as an enhanced NB-IoT (eNB-IoT) UE and Further Enhanced (FeNB-IoT) UE). An IoT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity-Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network includes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network. 
     In some aspects, any of the UEs  101  and  102  can include enhanced MTC (eMTC) UEs or further enhanced MTC (FeMTC) UEs. 
     The UEs  101  and  102  may be configured to connect, e.g., communicatively couple, with a radio access network (RAN)  110 . The RAN  110  may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN. The UEs  101  and  102  utilize connections  103  and  104 , respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, connections  103  and  104  are illustrated as an air interface to enable communicative coupling and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code-division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth-generation (5G) protocol, a New Radio (NR) protocol, and the like. 
     In an aspect, the UEs  101  and  102  may further directly exchange communication data via a ProSe interface  105 . The ProSe interface  105  may alternatively be referred to as a sidelink interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH). 
     The UE  102  is shown to be configured to access an access point (AP)  106  via connection  107 . The connection  107  can comprise a local wireless connection, such as, for example, a connection consistent with any IEEE 802.11 protocol, according to which the AP  106  can comprise a wireless fidelity (WiFi®) router. In this example, the AP  106  is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below). 
     The RAN  110  can include one or more access nodes that enable the connections  103  and  104 . These access nodes (ANs) can be referred to as base stations (BSs), NodeBs, evolved NodeBs (eNBs), Next Generation NodeBs (gNBs), RAN nodes, and the like, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). In some aspects, the communication nodes  111  and  112  can be transmission/reception points (TRPs). In instances when the communication nodes  111  and  112  are NodeBs (e.g., eNBs or gNBs), one or more TRPs can function within the communication cell of the NodeBs. The RAN  110  may include one or more RAN nodes for providing macrocells, e.g., macro RAN node  111 , and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node  112 . 
     Any of the RAN nodes  111  and  112  can terminate the air interface protocol and can be the first point of contact for the UEs  101  and  102 . In some aspects, any of the RAN nodes  111  and  112  can fulfill various logical functions for the RAN  110  including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management, and data packet scheduling, and mobility management. In an example, any of the nodes  111  and/or  112  can be a new generation Node-B (gNB), an evolved node-B (eNB), or another type of RAN node. 
     The RAN  110  is shown to be communicatively coupled to a core network (CN)  120  via an S1 interface  113 . In aspects, the CN  120  may be an evolved packet core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN (e.g., as illustrated in reference to  FIGS.  1 B -IC). In this aspect, the S1 interface  113  is split into two parts: the S1-U interface  114 , which carries traffic data between the RAN nodes  111  and  112  and the serving gateway (S-GW)  122 , and the S1-mobility management entity (MME) interface  115 , which is a signaling interface between the RAN nodes  111  and  112  and MMEs  121 . 
     In this aspect, the CN  120  comprises the MMEs  121 , the S-GW  122 , the Packet Data Network (PDN) Gateway (P-GW)  123 , and a home subscriber server (HSS)  124 . The MMEs  121  may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs  121  may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS  124  may comprise a database for network users, including subscription-related information to support the network entities&#39; handling of communication sessions. The CN  120  may comprise one or several HSSs  124 , depending on the number of mobile subscribers, the capacity of the equipment, the organization of the network, etc. For example, the HSS  124  can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc. 
     The S-GW  122  may terminate the S1 interface  113  towards the RAN  110 , and routes data packets between the RAN  110  and the CN  120 . In addition, the S-GW  122  may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities of the S-GW  122  may include a lawful intercept, charging, and some policy enforcement. 
     The P-GW  123  may terminate an SGi interface toward a PDN. The P-GW  123  may route data packets between the EPC network  120  and external networks such as a network including the application server  184  (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface  125 . The P-GW  123  can also communicate data to other external networks  131 A, which can include the Internet, IP multimedia subsystem (IPS) network, and other networks. Generally, the application server  184  may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this aspect, the P-GW  123  is shown to be communicatively coupled to an application server  184  via an IP interface  125 . The application server  184  can also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs  101  and  102  via the CN  120 . 
     The P-GW  123  may further be a node for policy enforcement and charging data collection. Policy and Charging Rules Function (PCRF)  126  is the policy and charging control element of the CN  120 . In a non-roaming scenario, in some aspects, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE&#39;s Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with a local breakout of traffic, there may be two PCRFs associated with a UE&#39;s IP-CAN session: a Home PCRF (H-PCRF) within an HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF  126  may be communicatively coupled to the application server  184  via the P-GW  123 . 
     In some aspects, the communication network  140 A can be an IoT network or a 5G network, including a 5G new radio network using communications in the licensed (5G NR) and the unlicensed (5G NR-U) spectrum. One of the current enablers of IoT is the narrowband-IoT (NB-IoT). 
     An NG system architecture can include the RAN  110  and a 5G network core (5GC)  120 . The NG-RAN  110  can include a plurality of nodes, such as gNBs and NG-eNBs. The core network  120  (e.g., a 5G core network or 5GC) can include an access and mobility function (AMF) and/or a user plane function (UPF). The AMF and the UPF can be communicatively coupled to the gNBs and the NG-eNBs via NG interfaces. More specifically, in some aspects, the gNBs and the NG-eNBs can be connected to the AMF by NG-C interfaces, and to the UPF by NG-U interfaces. The gNBs and the NG-eNBs can be coupled to each other via Xn interfaces. 
     In some aspects, the NG system architecture can use reference points between various nodes as provided by 3GPP Technical Specification (TS) 23.501 (e.g., V15.4.0, 2018 December). In some aspects, each of the gNBs and the NG-eNBs can be implemented as a base station, a mobile edge server, a small cell, a home eNB, and so forth. In some aspects, a gNB can be a master node (MN) and NG-eNB can be a secondary node (SN) in a 5G architecture. 
       FIG.  1 B  illustrates a non-roaming 5G system architecture in accordance with some aspects. Referring to FIG. B, there is illustrated a 5G system architecture  140 B in a reference point representation. More specifically. UE  102  can be in communication with RAN  110  as well as one or more other 5G core (5GC) network entities. The 5G system architecture  140 B includes a plurality of network functions (NFs), such as access and mobility management function (AMF)  132 , session management function (SMF)  136 , policy control function (PCF)  148 , application function (AF)  150 , user plane function (UPF)  134 , network slice selection function (NSSF)  142 , authentication server function (AUSF)  144 , and unified data management (UDM)/home subscriber server (HSS)  146 . The UPF  134  can provide a connection to a data network (DN)  152 , which can include, for example, operator services, Internet access, or third-party services. The AMF  132  can be used to manage access control and mobility and can also include network slice selection functionality. The SMF  136  can be configured to set up and manage various sessions according to network policy. The UPF  134  can be deployed in one or more configurations according to the desired service type. The PCF  148  can be configured to provide a policy framework using network slicing, mobility management, and roaming (similar to PCRF in a 4G communication system). The UDM can be configured to store subscriber profiles and data (similar to an HSS in a 4G communication system). 
     In some aspects, the 5G system architecture  140 B includes an IP multimedia subsystem (IMS)  168 B as well as a plurality of IP multimedia core network subsystem entities, such as call session control functions (CSCFs). More specifically, the IMS  168 B includes a CSCF, which can act as a proxy CSCF (P-CSCF)  162 BE, a serving CSCF (S-CSCF)  164 B, an emergency CSCF (E-CSCF) (not illustrated in  FIG.  1 B ), or interrogating CSCF (I-CSCF)  166 B. The P-CSCF  162 B can be configured to be the first contact point for the UE  102  within the IM subsystem (IMS)  168 B. The S-CSCF  164 B can be configured to handle the session states in the network, and the E-CSCF can be configured to handle certain aspects of emergency sessions such as routing an emergency request to the correct emergency center or PSAP. The I-CSCF  166 B can be configured to function as the contact point within an operator&#39;s network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator&#39;s service area. In some aspects, the I-CSCF  166 B can be connected to another IP multimedia network  170 E, e.g. an IMS operated by a different network operator. 
     In some aspects, the UDM/HSS  146  can be coupled to an application server  160 E, which can include a telephony application server (TAS) or another application server (AS). The AS  160 B can be coupled to the IMS  168 B via the S-CSCF  164 B or the I-CSCF  166 B. 
     A reference point representation shows that interaction can exist between corresponding NF services. For example,  FIG.  1 B  illustrates the following reference points: N 1  (between the UE  102  and the AMF  132 ), N 2  (between the RAN  110  and the AMF  132 ), N 3  (between the RAN  110  and the UPF  134 ), N 4  (between the SMF  136  and the UPF  134 ), N 5  (between the PCF  148  and the AF  150 , not shown), N 6  (between the UPF  134  and the DN  152 ), N 7  (between the SMF  136  and the PCF  148 , not shown), N 8  (between the UDM  146  and the AMF  132 , not shown), N 9  (between two UPFs  134 , not shown), N 10  (between the UDM  146  and the SMF  136 , not shown), N 11  (between the AMF  132  and the SMF  136 , not shown), N 12  (between the AUSF  144  and the AMF  132 , not shown), N 13  (between the AUSF  144  and the UDM  146 , not shown). N 14  (between two AMFs  132 , not shown), N 15  (between the PCF  148  and the AMF  132  in case of a non-roaming scenario, or between the PCF  148  and a visited network and AMF  132  in case of a roaming scenario, not shown), N 16  (between two SMFs, not shown), and N 22  (between AMF  132  and NSSF  142 , not shown). Other reference point representations not shown in  FIG.  1 B  can also be used. 
       FIG.  1 C  illustrates a 5G system architecture  140 C and a service-based representation. In addition to the network entities illustrated in  FIG.  1 B , system architecture  140 C can also include a network exposure function (NEF)  154  and a network repository function (NRF)  156 . In some aspects, 5G system architectures can be service-based and interaction between network functions can be represented by corresponding point-to-point reference points Ni or as service-based interfaces. 
     In some aspects, as illustrated in  FIG.  1 C , service-based representations can be used to represent network functions within the control plane that enable other authorized network functions to access their services. In this regard, 5G system architecture  140 C can include the following service-based interfaces: Namf  158 H (a service-based interface exhibited by the AMF  132 ), Nsmf  158 I (a service-based interface exhibited by the SMF  136 ), Nnef  158 B (a service-based interface exhibited by the NEF  154 ), Npcf  158 D (a service-based interface exhibited by the PCF  148 ), a Nudm  158 E (a service-based interface exhibited by the UDM  146 ), Naf  158 F (a service-based interface exhibited by the AF  150 ), Nnrf  158 C (a service-based interface exhibited by the NRF  156 ), Nnssf  158 A (a service-based interface exhibited by the NSSF  142 ), Nausf  158 G (a service-based interface exhibited by the AUSF  144 ). Other service-based interfaces (e.g., Nudr, N5g-eir, and Nudsf) not shown in  FIG.  1 C  can also be used. 
     Techniques discussed herein can be performed by a UE, a base station (e.g., any of the UEs or base stations discussed in connection with  FIG.  1 A - FIG.  1 C ), or any of the nodes in the Integrated Access and Backhaul (IAB) communication systems discussed in connection with  FIGS.  2 - 5   . 
     For an IAB node, the IAB distributed unit (DU) function may operate with multiple cells by using multiple component carriers (CCs) and/or multiple antenna panels. On the other hand, the co-located IAB mobile termination (MT) function can work under different CCs with carrier aggregation for a backhaul link. In some aspects, the IAB donor node central unit (CU) function and the parent node can be aware of the multiplexing capability between the MT and the DU functions (e.g., time-division multiplexing (TDM) is required or TDM is not required) of an IAB node for any {MT CC, DU cell} pair. Techniques discussed herein use signaling contents, signaling mechanisms, and detailed signaling methods to communicate an IAB node&#39;s multiplexing capability to the donor CU and the parent node. 
     As illustrated in  FIGS.  2 - 3   , in an IAB network, an IAB node can connect to its parent node (an IAB donor or another IAB node) through a parent backhaul (BH) link, connect to a child user equipment (UE) through a child access (AC) link, and connect to a child IAB node through a child BH link. 
       FIG.  2    shows a reference diagram for IAB in a standalone mode, which contains one IAB donor node  203  and multiple IAB nodes (e.g.,  214 ,  216 ,  218 ,  222 , and  224 ). Referring to  FIG.  2   , the IAB architecture  200  can include a core network (CN)  202  coupled to an IAB donor node  203 . The IAB donor node  203  can include control unit control plane (CU-CP) function  204 , control unit user plane (CU-UP) function  206 , other functions  208 , and distributed unit (DU) functions  210  and  212 . The DU function  210  can be coupled via wireless backhaul links to IAB nodes  214  and  216 . The DU function  212  is coupled via a wireless backhaul link to IAB node  218 . IAB node  214  is coupled to a UE  220  via a wireless access link, and IAB node  216  is coupled to IAB nodes  222  and  224 . The IAB node  222  is coupled to UE  228  via a wireless access link. The IAB node  218  is coupled to UE  226  via a wireless access link. 
     Each of the IAB nodes illustrated in  FIG.  2    can include a mobile termination (MT) function and a DU function. The MT function can be defined as a component of the mobile equipment and can be referred to as a function residing on an IAB-node that terminates the radio interface layers of the backhaul Uu interface toward the IAB-donor or other IAB-nodes. 
     The IAB donor  203  is treated as a single logical node that comprises a set of functions such as gNB-DU, gNB-CU-CP  204 , gNB-CU-UP  206 , and potentially other functions  208 . In deployment, the IAB donor  203  can be split according to these functions, which can all be either collocated or non-collocated as allowed by 3GPP NG-RAN architecture. IAB-related aspects may arise when such a split is exercised. In some aspects, some of the functions presently associated with the IAB-donor may eventually be moved outside of the donor in case it becomes evident that they do not perform IAB-specific tasks. 
       FIG.  3    illustrates a central unit (CU)-distributed unit (DU) split and signaling in an IAB architecture  300 , in accordance with some aspects. Referring to  FIG.  3   , the IAB architecture  300  includes an IAB donor  301 , a parent IAB node  303 , an IAB node  305 , a child IAB node  307 , and a child UE  309 . The IAB donor  301  includes a CU function  302  and a DU function  304 . The parent IAB node  303  includes a parent MT (P-MT) function  306  and a parent DU (P-DU) function  308 . The IAB node  305  includes an MT function  310  and a DU function  312 . The child IAB node  307  includes a child MT (C-MT) function  314  and a child DU (C-DU) function  316 . 
     As illustrated in  FIG.  3   . RRC signaling can be used for communication between the CU function  302  of the IAB donor  301  and the MT functions  306 ,  310 , and  314 , as well as between the CU function  302  and the child UE (C-UE)  309 . 
     Additionally, F1 access protocol (F1AP) signaling can be used for communication between the CU function  302  of the IAB donor  301  and the DU functions of the parent IAB node  303  and the IAB node  305 . 
     As illustrated in  FIGS.  2 - 3   , multiple IAB nodes are connected to a donor node (DN) via a wireless backhaul. A DN or a parent IAB node needs to properly allocate resources for its child IAB node under the half-duplex constraint at the child IAB node. In some aspects, the time-frequency resource allocated to the parent link may be orthogonal to the time-frequency resource allocated to the child or access link. 
     In an IAB network, there may exist resource transition time misalignment for a co-located IAB DU/MT. In some aspects, a parent IAB node can be made aware of the number of guard symbols (Ng) the child IAB node would like the parent IAB node not to use (e.g., desired Ng) at the edge (beginning or end) of a slot when there is a transition between child MT and child DU. Separately or additionally, the child IAB node can be made aware of the number of guard symbols that the parent IAB node will provide (e.g., actual Ng). Disclosed techniques are used for generating Ng tables (including eight resource transition cases) for co-located IAB DU/MT resource transitions. More specifically, some disclosed aspects are associated with generating an Ng table with a given maximum cell radius of 10 km and sub-carrier spacing (SCS) of 15 kHz. Additional aspects are associated with generating other Ng tables. 
     In aspects, new signaling regarding IAB MT/DU resource transition guard symbols is used to fulfill the following two purposes: P 1 : Parent DU to be aware of Ng symbols that an IAB node desires (“desired Ng”); and P 2 : IAB node to be aware of Ng symbols that its parent DU applies (“actual Ng”). Disclosed techniques provide signaling contents, signaling mechanisms, and detailed signaling methods to fulfill these two purposes. 
     In some aspects, the following statements on time-domain resource allocation may be considered by the disclosed techniques: 
     From an MT point-of-view, the following time-domain resources can be indicated for the parent link as in NR Release-15 (D/U/F): Downlink time resource; Uplink time resource: and Flexible time resource. 
     From a DU point-of-view, the child link has the following types of time-domain resources (D/U/F/NA): Downlink time resource; Uplink time resource: Flexible time resource; and Not available (NA) time resources (not to be used for communication on the DU child links). 
     For each of the downlink, uplink, and flexible time-resource types of the DU child link, there are two kinds: hard and soft (H/S). Hard: The corresponding time resource is always available for the DU child link. Soft: The availability of the corresponding time resource for the DU child link is explicitly and/or implicitly controlled by the parent node. 
     In some aspects, for an IAB node, the co-located IAB DU and IAB MT functions have separate semi-static resource configuration from the CU function of the IAB donor node. In addition, the parent DU will conduct dynamical resource scheduling for the IAB MT, while the co-located IAB DU will conduct dynamic resource scheduling for the child links. Several factors may cause potential resource transition time misalignment for the co-located IAB DU/MT: transmission propagation delay for the IAB MT to receive from the parent DU (MT Rx); time advance (TA) is introduced for the IAB MT to transmit to the parent DU (MT Tx): and there exists switching time among any transition among DU Tx, DU Rx, MT Tx, and MT Rx. 
     In some aspects, in one IAB node, the co-located DU and MT functions may have assigned resource transition in the adjacent slots for the DU and MT to transmit (Tx) or receive (Rx). For example, if a resource is assigned for the IAB MT at slot n and a resource is assigned for the co-located IAB DU at slot n−1, the following four resource transition cases may apply: 
     Case A1: MT Rxat slot n→DU Tx at slot n+1; 
     Case A2: MT Rx at slot n→DU Rx at slot n+1; 
     Case A3: MT Tx at slot n→DU Tx at slot n+1; and 
     Case A4: MT Tx at slot n→DU Rx at slot n+1. 
     In the meantime, if a resource is assigned for the IAB DU at slot n and a resource is assigned for the co-located IAB MT at slot n+1, there will be the following four transition cases: 
     Case B1: DU Tx at slot n→MT Tx at slot n+1; 
     Case B2: DU Tx at slot n→MT Rx at slot n+1; 
     Case B3: DU Rx at slot n→MT Tx at slot n+1; and 
     Case B4: DU Rx at slot n→MT Rx at slot n+1. 
     The above eight possible resource transitions are illustrated in  FIG.  4   .  FIG.  4    illustrates diagram  400  of example resource transitions at co-located MT/DU functions, in accordance with some aspects. From  FIG.  4    it may be observed that there exist overlapped resources that cause transmission/receiving conflict for co-located MT/DU functions. Hence, guard symbols (Ng) may need to be added at the edge (beginning or end) of a slot when there is a transition between co-located MT/DU. 
     For example, in Case A1, let T p  denote the propagation delay between the parent node to the MT T MTRx-DUTx  denote the switching time from MT Rx to DU Tx, and T d  is the OFDM symbol duration, then the number of guard symbols N g  can be calculated as 
     
       
         
           
             
               
                 N 
                 g 
               
               = 
               
                 
                   
                     T 
                     
                       MTRx 
                       - 
                       DUTx 
                     
                   
                   + 
                   
                     T 
                     p 
                   
                 
                 
                   T 
                   d 
                 
               
             
             . 
           
         
       
     
     This N g  guard symbols can be added at the end of the MT Rx or the beginning of the DU Tx. 
     In some aspects, the following functionalities may also be used in connection with disclosed techniques. A parent IAB node can be made aware of the number of symbols Ng the child IAB node would like the parent IAB node not to use at the edge (beginning or end) of a slot when there is a transition between child MT and child DU. Separately or additionally, the child IAB node can be made aware of the number of guard symbols that the parent IAB node will provide. 
     In some aspects, one or more guard symbols Ng can be provided for each of the possible transitions with potential overlap as illustrated in the following NG table (labeled as Table 1): 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
            
               
                   
                 MT to DU 
                 DL Tx 
                 UL Rx 
               
               
                   
                   
               
               
                   
                 DL Rx 
               
               
                   
                 UL Tx 
               
               
                   
                   
               
               
                   
                 DU to MT 
                 DL Rx 
                 UL Tx 
               
               
                   
                   
               
               
                   
                 DL Tx 
               
               
                   
                 UL Rx 
               
               
                   
                   
               
            
           
         
       
     
     In some aspects, if Ng is not provided, it is assumed to be 0. 
     Disclosed techniques relate to different methods to generate the above Ng tables for co-located IAB DU/MT resource transitions. 
     Methods to Generate Ng Tables for Co-located IAB DU/MT Resource Transitions 
     There are several factors related to Ng calculation and range: 
     (a) Transmission propagation delay T p  from parent DU to the IAB MT (MT Rx); 
     (b) TA is applied for the IAB MT for UL transmission to the parent DU (MT Tx); 
     (c) There exists switching time between any transitions among DU Tx, DU Rx, MT Tx, and MT Rx; and 
     (d) The OFDM symbol duration T d . 
     To decide the value of the propagation delay T p , one reference is the range of N TA *T c  where N TA *T A ·16*64/2 μ  and T A =0, 1, 2, . . . , 3846 as defined in TS38.213. However, the maximum N TA *T c  value can be up to 2 ms, which is in the level of slots and designed for large cell size. To derive Ng, we need to have a more reasonable assumption on the IAB cell range. In some aspects, one reasonable assumption is to use 10 km as a maximum inter-IAB node distance. 
     An example of IAB maximum cell radius of 10 km and SCS 15 kHz (with the OFDM symbol T d =66.7 μs) scenario is provided herein. The one-way transmission propagation delay is T p ≤33.3 μs and in the [0,0.5] symbol range. The TA which is (N TA +N TA,offset )*T c  defined TS38.213 can be considered as 2*T p +N TA,offset *T c , where N TA,offset  is defined in TS38.133 Table 7.1.2-2. Hence, the TA is in the [0,1.5] symbol range. In some aspects, N TA,offset *T c  is a reference for switching time between different transitions between DU/MT, which is 10.0.51 symbol range. In some aspects, the number of guard symbols (Ng) for the eight possible resource transitions are provided in the following Table 2. 
     
       
         
           
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Ng calculation and range for IAB maximum cell radius 10 km and SCS 15 kHz. 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 MT to DU 
                 DL Tx 
                 UL Rx 
               
               
                   
               
               
                 DL Rx 
                           N   g     =     ⌈         T     MTRx   -   DUTx       +     T   p         T   d       ⌉         
   Ng range: [1] 
                           N   g     =     ⌈         T     MTRx   -   DURx       +     T     DURx   -   DUTx       +     T   p         T   d       ⌉         
   Ng range: [1, 2] 
               
               
                   
               
               
                 UL Tx 
                           N   g     =     ⌈         T     MTTx   -   DUTx       +     T   p     -   TA       T   d       ⌉         
   Ng range: [0, 1] 
                           N   g     =     ⌈         T     MTTx   -   DURx       +     T     DURx   -   DUTx       +     T   p     -   TA       T   d       ⌉         
   Ng range: [0, 1] 
               
               
                   
               
               
                 DU to MT 
                 DL Rx 
                 UL Tx 
               
               
                   
               
               
                 DL Tx 
                           N   g     =     ⌈         T     DUTx   -   MTRx       -     T   p         T   d       ⌉         
   Ng range: [0, 1] 
                           N   g     =     ⌈         T     DUTx   -   MTTx       +   TA   -     T   p         T   d       ⌉         
   Ng range: [1, 2] 
               
               
                   
               
               
                 UL Rx 
                           N   g     =     ⌈         T     DURx   -   MTRx       -     T     DURx   -   DUTx       +     T   p         T   d       ⌉         
   Ng range: [0, 1] 
                           N   g     =     ⌈         T     DURx   -   MTTx       -     T     DURx   -   DUTx       +   TA   -     T   p         T   d       ⌉         
   Ng range: [1, 2] 
               
               
                   
               
            
           
         
       
     
     In some aspects, the value of Ng may depend on switching time, propagation delay T p , and OFDM symbol duration T d , which could have different values depending on carrier frequency and SCS. In some aspects, the following three methods to generate the Ng tables: 
     Method 1: Use a Single Ng Table for all Carrier Frequencies and SCSs. 
     In some aspects, the same switching time, T p  value and T d  value is used for all carrier frequency ranges and SCS values. For example, the T d  value can be calculated based on a reference SCS (e.g., 15 kHz). Another possibility is to let switching time and T p  value proportionally scale with respect to T d , so that the Ng table can remain the same. 
     Method 2: Generate Two Tables for FR1 and FR2, Respectively. 
     In some aspects, switching time and T p  can use different values for FR1 and FR2. In some aspects, different reference SCSs can be used for frequency range 1 (FR1) and FR2 to calculate the reference T d  values (e.g., 15 kHz for FR1, 60 kHz for FR2). 
     Method 3: Generate Four tables for SCS={15 kHz, 30 kHz, 60 kHz, 120 kHz}, respectively. 
     In some aspects, switching time, T p  value and T d  value can be individually decided for each SCSs. 
       FIG.  5    illustrates a block diagram of a communication device such as an evolved Node-B (eNB), a next generation Node-B (gNB), an access point (AP), a wireless station (STA), a mobile station (MS), or a user equipment (UE), in accordance with some aspects and to perform one or more of the techniques disclosed herein. In alternative aspects, the communication device  500  may operate as a standalone device or may be connected (e.g., networked) to other communication devices. 
     Circuitry (e.g., processing circuitry) is a collection of circuits implemented in tangible entities of the device  500  that include hardware (e.g., simple circuits, gates, logic, etc.). Circuitry membership may be flexible over time. Circuitries include members that may, alone or in combination, perform specified operations when operating. In an example, the hardware of the circuitry may be immutably designed to carry out a specific operation (e.g., hardwired). In an example, the hardware of the circuitry may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) including a machine-readable medium physically modified (e.g., magnetically, electrically, moveable placement of invariant massed particles, etc.) to encode instructions of the specific operation. 
     In connecting the physical components, the underlying electrical properties of a hardware constituent are changed, for example, from an insulator to a conductor or vice versa. The instructions enable embedded hardware (e.g., the execution units or a loading mechanism) to create members of the circuitry in hardware via the variable connections to carry out portions of the specific operation when in operation. Accordingly, in an example, the machine-readable medium elements are part of the circuitry or are communicatively coupled to the other components of the circuitry when the device is operating. For example, any of the physical components may be used in more than one member of more than one circuitry. For example, under operation, execution units may be used in a first circuit of a first circuitry at one point in time and reused by a second circuit in the first circuitry, or by a third circuit in a second circuitry at a different time. Additional examples of these components with respect to the device  500  follow. 
     In some aspects, the device  500  may operate as a standalone device or may be connected (e.g., networked) to other devices. In a networked deployment, the communication device  500  may operate in the capacity of a server communication device, a client communication device, or both in server-client network environments. In an example, the communication device  500  may act as a peer communication device in a peer-to-peer (P2P) (or other distributed) network environment. The communication device  500  may be a UE, eNB, PC, a tablet PC, an STB, a PDA, a mobile telephone, a smartphone, a web appliance, a network router, switch or bridge, or any communication device capable of executing instructions (sequential or otherwise) that specify actions to be taken by that communication device. Further, while only a single communication device is illustrated, the term “communication device” shall also be taken to include any collection of communication devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), and other computer cluster configurations. 
     Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client, or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. For example, the software may reside on a communication device-readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations. 
     Accordingly, the term “module” is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor configured using the software, the general-purpose hardware processor may be configured as respective different modules at different times. The software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time. 
     The communication device (e.g., UE)  500  may include a hardware processor  502  (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory  504 , a static memory  506 , and a storage device  507  (e.g., hard drive, tape drive, flash storage, or other block or storage devices), some or all of which may communicate with each other via an interlink (e.g., bus)  508 . 
     The communication device  500  may further include a display device  510 , an alphanumeric input device  512  (e.g., a keyboard), and a user interface (UI) navigation device  514  (e.g., a mouse). In an example, the display device  510 , input device  512 , and UI navigation device  514  may be a touchscreen display. The communication device  500  may additionally include a signal generation device  518  (e.g., a speaker), a network interface device  520 , and one or more sensors  521 , such as a global positioning system (GPS) sensor, compass, accelerometer, or another sensor. The communication device  500  may include an output controller  528 , such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.). 
     The storage device  507  may include a communication device-readable medium  522 , on which is stored one or more sets of data structures or instructions  524  (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. In some aspects, registers of the processor  502 , the main memory  504 , the static memory  506 , and/or the storage device  507  may be, or include (completely or at least partially), the device-readable medium  522 , on which is stored the one or more sets of data structures or instructions  524 , embodying or utilized by any one or more of the techniques or functions described herein. In an example, one or any combination of the hardware processor  502 , the main memory  504 , the static memory  506 , or the mass storage  516  may constitute the device-readable medium  522 . 
     As used herein, the term “device-readable medium” is interchangeable with “computer-readable medium” or “machine-readable medium”. While the communication device-readable medium  522  is illustrated as a single medium, the term “communication device-readable medium” may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store one or more instructions  524 . The term “communication device-readable medium” is inclusive of the terms “machine-readable medium” or “computer-readable medium”, and may include any medium that is capable of storing, encoding, or carrying instructions (e.g., instructions  524 ) for execution by the communication device  500  and that cause the communication device  50  to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting communication device-readable medium examples may include solid-state memories and optical and magnetic media. Specific examples of communication device-readable media may include non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Random Access Memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, communication device-readable media may include non-transitory communication device-readable media. In some examples, communication device-readable media may include communication device-readable media that is not a transitor propagating signal. 
     The instructions  524  may further be transmitted or received over a communications network  526  using a transmission medium via the network interface device  520  utilizing any one of a number of transfer protocols. In an example, the network interface device  520  may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network  526 . In an example, the network interface device  520  may include a plurality of antennas to wirelessly communicate using at least one of single-input-multiple-output (SIMO), MIMO, or multiple-input-single-output (MISO) techniques. In some examples, the network interface device  520  may wirelessly communicate using Multiple User MIMO techniques. 
     The term “transmission medium” shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the communication device  500 , and includes digital or analog communications signals or another intangible medium to facilitate communication of such software. In this regard, a transmission medium in the context of this disclosure is a device-readable medium. 
     Although an aspect has been described with reference to specific exemplary aspects, it will be evident that various modifications and changes may be made to these aspects without departing from the broader scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This Detailed Description, therefore, is not to betaken in a limiting sense, and the scope of various aspects is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.