WO2022031961A1 - Power saving for nr sidelink communication - Google Patents

Abstract

An apparatus and system to provide power saving in sidelink communications are described. Mechanisms for transition between the power saving state and normal state are based on reception of a triggering signal on the sidelink resources, expiration of a timer, higher layer information received, or changes in the UE. In the PSS, a limited amount of resources in the sidelink pool are selected to monitor and transmit on based on CBR measurements or properties of the UE.

Description

POWER SAVING FOR NR SIDELINK COMMUNICATION PRIORITY CLAIM

[0001] This application claims the benefit of priority to United States Provisional Patent Application Serial No. 63/062,068, filed August 6, 2020, and United States Provisional Patent Application Serial No. 63/062,323, filed August 6, 2020, each of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] Embodiments pertain to fifth generation (5G) wireless communications. In particular, some embodiments relate to sidelink communications in 5G networks.

BACKGROUND

[0003] The use and complexity of wireless systems, which include 4^th generation (4G) and 5^th generation (5G) networks among others, has increased due to both an increase in the types of devices user equipment (UEs) using network resources as well as the amount of data and bandwidth being used by various applications, such as video streaming, operating on these UEs. With the vast increase in number and diversity of communication devices, the corresponding network environment, including routers, switches, bridges, gateways, firewalls, and load balancers, has become increasingly complicated, especially with the advent of next generation (NG) or new radio (NR) systems. As expected, a number of issues abound with the advent, of any new technology.

BRIEF DESCRIPTION OF THE FIGURES

[0004] 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 embodiments discussed in the present document.

[0005] FIG. 1A illustrates an architecture of a network, in accordance with some aspects. [0006] FIG. 1B illustrates a non-roaming 5G system architecture in accordance with some aspects.

[0007] FIG. 1C illustrates a non-roaming 5G system architecture in accordance with some aspects. [0008] FIG. 2 illustrates a block diagram of a communication device in accordance with some embodiments.

[0009] FIG. 3 illustrates sidelink sub-channels in different slots in accordance with some embodiments.

[0010] FIG. 4 illustrates state transitions for determining receive resources in accordance with some embodiments.

[0011] FIG. 5 illustrates state transitions for sleep states in accordance with some embodiments.

[0012] FIG. 6 illustrates sidelink power saving states and transitions in accordance with some embodiments.

DETAILED DESCRIPTION

[0013] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

[0014] FIG. 1A illustrates an architecture of a network in accordance with some aspects. The network 140A includes 3GPP LTE/4G and NG network functions that may be extended to 6G functions. Accordingly, although 5G will be referred to, it is to be understood that this is to extend as able to 6G structures, systems, and functions. A network function can be implemented as a discrete network element, on a dedicated hardware, as a software instance running on dedicated hardware, and/or as a virtualized function instantiated on an appropriate platform, e.g., dedicated hardware or a cloud infrastructure.

[0015] The network 140A is shown to include user equipment (LIE) 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 portable (laptop) or 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.

[0016] Any of the radio links described herein (e.g., as used in the network 140A or any other illustrated network) may operate according to any exemplary radio communication technology and/or standard. 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 other frequencies and Spectrum Access System (SAS) in 3.55-3.7 GHz and other frequencies). Different Single Carrier or Orthogonal Frequency Domain Multiplexing (OFDM) modes (CP-OFDM, SC-FDMA, SC-OFDM, filter bank-based multicarrier (FBMC), OFDMA, etc.), and in particular 3GPP NR, may be used by allocating the OFDM carrier data bit vectors to the corresponding symbol resources.

[0017] In some aspects, any of the UEs 101 and 102 can comprise an Internet-of-Things (loT) UE or a Cellular loT (CIoT) UE, which can comprise a network access layer designed for low-power loT applications utilizing short- lived UE connections. In some aspects, any of the UEs 101 and 102 can include a narrowband (NB) loT UE (e.g., such as an enhanced NB-IoT (eNB-IoT) UE and Further Enhanced (FeNB-IoT) UE). An loT 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 loT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An loT network includes interconnecting loT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The loT UEs may execute background applications (e.g., keep- alive messages, status updates, etc.) to facilitate the connections of the loT network. In some aspects, any of the UEs 101 and 102 can include enhanced MTC (eMTC) UEs or further enhanced MTC (FeMTC) UEs. [0018] 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.

[0019] 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, the 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 5G protocol, a 6G protocol, and the like.

[0020] 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 (SL) 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), a Physical Sidelink Broadcast Channel (PSBCH), and a Physical Sidelink Feedback Channel (PSFCH).

[0021] 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). [0022] 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 transmi ssion/recepti on 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 pow'er (LP) RAN node 112. [0023] 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 gNB, an eNB, or another type of RAN node.

[0024] The RAN 110 is shown to be communicatively coupled to a core network (CN) 120 via an SI interface 113. In aspects, the CN 120 may be an evolved packet core (EPC) network, aNextGen Packet Core (NPC) network, or some other type of CN (e.g., as illustrated in reference to FIGS. 1B-1C). 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.

[0025] 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 handling of communication sessions. The CN 120 may comprise one or several HSSs 124, depending on the number of mobile subscribers, on the capacity of the equipment, on 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. [0026] The S-GW 122 may terminate the SI 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.

[0027] 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 131A, 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. [0028] 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'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'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. [0029] In some aspects, the communication network 140A can be an loT network or a 5G or 6G network, including 5G new radio network using communications in the licensed (5G NR) and the unlicensed (5G NR-U) spectrum. One of the current enablers of loT is the narrow'band-loT (NB-IoT). Operation in the unlicensed spectrum may include dual connectivity (DC) operation and the standalone LTE system in the unlicensed spectrum, according to which LTE-based technology solely operates in unlicensed spectrum without the use of an “anchor" in the licensed spectrum, called MulteFire. 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 sidelink resource allocation and UE processing behaviors for NR si delink V2X communications.

[0030] An NG system architecture (or 6G 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/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. [0031] In some aspects, the NG system architecture can use reference points between various nodes. 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.

[0032] FIG. IB illustrates a non-roaming 5G system architecture in accordance with some aspects. In particular, FIG. IB illustrates a 5G system architecture 140B in a reference point representation, which may be extended to a 6G system architecture. More specifically, UE 102 can be in communication with RAN 110 as well as one or more other 5GC network entities. The 5G system architecture 140B includes a plurality of network functions (NFs), such as an AMF 132, session management function (SMF) 136, policy control function (PCF) 148, application function (AF) 150, UPF 134, network slice selection function (NSSF) 142, authentication server function ( AUSF) 144, and unified data management (UDM)/home subscriber server (HSS) 146.

[0033] 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 AMF 132 may provide UE-based authentication, authorization, mobility management, etc., and may be independent of the access technologies. The SMF 136 can be configured to set up and manage various sessions according to network policy. The SMF 136 may thus be responsible for session management and allocation of IP addresses to UEs. The SMF 136 may also select and control the UPF 134 for data transfer. The SMF 136 may be associated with a single session of a UE 101 or multiple sessions of the UE 101. This is to say that the UE 101 may have multiple 5G sessions. Different SMFs may be allocated to each session. The use of different SMFs may permit each session to be individually managed. As a consequence, the functionalities of each session may be independent of each other.

[0034] The UPF 134 can be deployed in one or more configurations according to the desired service type and may be connected with a data network. 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 profdes and data (similar to an HSS in a 4G communication system).

[0035] The AF 150 may provide information on the packet flow to the PCF 148 responsible for policy control to support a desired QoS. The PCF 148 may set mobility and session management policies for the UE 101. To this end, the PCF 148 may use the packet flow information to determine the appropriate policies for proper operation of the AMF 132 and SMF 136. The AUSF 144 may store data for UE authentication. [0036] In some aspects, the 5G system architecture 140B includes an IP multimedia subsystem (IMS) 168B as well as a plurality of IP multimedia core network subsystem entities, such as call session control functions (CSCFs). More specifically, the IMS 168B includes a CSCF, which can act as a proxy CSCF (P-CSCF) 162BE, a serving CSCF (S-CSCF) 164B, an emergency CSCF (E-CSCF) (not illustrated in FIG. IB), or interrogating CSCF (I-CSCF) 166B.

The P-CSCF 162B can be configured to be the first contact point for the UE 102 within the IM subsystem (IMS) 168B. The S-CSCF 164B 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 166B can be configured to function as the contact point within an operator's network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator's service area. In some aspects, the I-CSCF 166B can be connected to another IP multimedia network 170E, e.g. an IMS operated by a different network operator.

[0037] In some aspects, the UDM/HSS 146 can be coupled to an application server 160E, which can include a telephony application server (TAS) or another application server (AS). The AS 160B can be coupled to the IMS 168B via the S-CSCF 164B or the I-CSCF 166B.

[0038] A reference point representation shows that interaction can exist between corresponding NF services. For example, FIG. IB illustrates the following reference points: N1 (between the UE 102 and the AMF 132), N2 (between the RAN 110 and the AMF 132), N3 (between the RAN 110 and the UPF 134), N4 (between the SMF 136 and the UPF 134), N5 (between the PCF 148 and the AF 150, not shown), N6 (between the UPF 134 and the DN 152), N7 (between the SMF 136 and the PCF 148, not shown), N8 (between the UDM 146 and the AMF 132, not shown), N9 (between two UPFs 134, not. shown), N10 (between the UDM 146 and the SMF 136, not shown), N11 (between the AMF 132 and the SMF 136, not shown), N12 (between the AUSF 144 and the AMF 132, not shown), N13 (between the AUSF 144 and the UDM 146, not shown), N14 (between two AMFs 132, not shown), N15 (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), N16 (between two SMFs, not shown), and N22 (between AMF 132 and NSSF

142, not shown). Other reference point representations not shown in FIG. IB can also be used.

[0039] FIG. 1C illustrates a 5G system architecture 140C and a servicebased representation. In addition to the network entities illustrated in FIG. IB, system architecture 140C 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.

[0040] In some aspects, as illustrated in FIG. 1C, sendee-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 140C can include the following service- based interfaces: Namf 158H (a sendee-based interface exhibited by the AMF 132), Nsmf 1581 (a sendee-based interface exhibited by the SMF 136), Nnef 158B (a sendee-based interface exhibited by the NEF 154), Npcf 158D (a sendee-based interface exhibited by the PCF 148), a Nudm 158E (a sendee- based interface exhibited by the UDM 146), Naf 158F (a service-based interface exhibited by the AF 150), Nnrf 158C (a sendee-based interface exhibited by the NRF 156), Nnssf 158A (a sendee-based interface exhibited by the NSSF 142), Nausf 158G (a sendee-based interface exhibited by the AUSF 144). Other sendee-based interfaces (e.g., Nudr, N5g-eir, and Nudsf) not shown in FIG. 1C can also be used. [0041] NR-V2X architectures may support high-reliability low latency sidelink communications with a variety of traffic patterns, including periodic and aperiodic communications with random packet arrival time and size.

Techniques disclosed herein can be used for supporting high reliability in distributed communication systems with dynamic topologies, including sidelink NR V2X communication systems.

[0042] FIG. 2 illustrates a block diagram of a communication device in accordance with some embodiments. The communication device 200 may be a UE such as a specialized computer, a personal or laptop computer (PC), a tablet PC, or a smart phone, dedicated network equipment such as an eNB, a server running software to configure the server to operate as a network device, a virtual device, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that, machine. For example, the communication device 200 may be implemented as one or more of the devices shown in FIGS. 1A-1C. Note that communications described herein may be encoded before transmission by the transmitting entity (e.g., UE, gNB) for reception by the receiving entity (e.g., gNB, UE) and decoded after reception by the receiving entity.

[0043] Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules and components 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. In an example, the software may reside on a machine readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

[0044] Accordingly, the term “module" (and “component" ) 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 software, the general -purpose hardware processor may be configured as respective different modules at different times. 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.

[0045] The communication device 200 may include a hardware processor (or equivalently processing circuitry) 202 (e.g., a central processing unit (CPU), a GPU, a hardware processor core, or any combination thereof), a main memory 204 and a static memory 206, some or all of which may communicate with each other via an interlink (e.g., bus) 208. The main memory 204 may contain any or all of removable storage and non-removable storage, volatile memory or non-volatile memory. The communication device 200 may further include a display unit 210 such as a video display, an alphanumeric input device 212 (e.g., a keyboard), and a user interface (UI) navigation device 214 (e.g., a mouse). In an example, the display unit 210, input device 212 and UI navigation device 214 may be a touch screen display. The communication device 200 may additionally include a storage device (e.g., drive unit) 216, a signal generation device 218 (e.g., a speaker), a network interface device 220, and one or more sensors, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The communication device 200 may further include an output controller, 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.).

[0046] The storage device 216 may include a non-transitory machine readable medium 222 (hereinafter simply referred to as machine readable medium) on which is stored one or more sets of data structures or instructions 224 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 224 may also reside, completely or at least partially, within the main memory 204, within static memory 206, and/or within the hardware processor 202 during execution thereof by the communication device 200. While the machine readable medium 222 is illustrated as a single medium, the term "machinereadablemedium" may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 224.

[0047] The term "machinereadablemedium" may include any medium that is capable of storing, encoding, or carryring instructions for execution by the communication device 200 and that cause the communication device 200 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 machine readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of machine 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; Radio access Memory (RAM); and CD-ROM and DVD-ROM disks. [0048] The instructions 224 may further be transmitted or received over a communications network using a transmission medium 226 via the network interface device 220 utilizing any one of a number of wireless local area network (WLAN) transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks. Communications over the networks may include one or more different protocols, such as Institute of Electrical and Electronics Engineers (IEEE) 802. 11 family of standards known as Wi-Fi, IEEE 802. 16 family of standards known as WiMax, IEEE 802.15.4 family of standards, a Long Term Evolution (LTE) family of standards, a Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, a next generation (NG)/5^th generation (5G) standards among others. In an example, the network interface device 220 may include one or more physical jacks (e.g., Ethernet, coaxial, or phonejacks) or one or more antennas to connect to the transmission medium 226.

[0049] Note that the term "circuitry" as used herein refers to, is part of, or includes hardware components such as an electronic circuit, a logic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group), an Application Specific Integrated Circuit (ASIC), a field-programmable device (FPD) (e.g., a field-programmable gate array (FPGA), a programmable logic device (PED), a complex PLD (CPLD), a high-capacity PLD (HCPLD), a structured ASIC, or a programmable SoC), digital signal processors (DSPs), etc., that are configured to provide the described functionality. In some embodiments, the circuitry/ may execute one or more software or firmware programs to provide at least some of the described functionality. The term “circuitry" may also refer to a combination of one or more hardware elements (or a combination of circuits used in an electrical or electronic system) with the program code used to carry out the functionality of that program code. In these embodiments, the combination of hardware elements and program code may be referred to as a particular type of circuitry.

[0050] The term "processor circuitry" or “processor" as used herein thus refers to, is part of, or includes circuitry capable of sequentially and automatically carrying out a sequence of arithmetic or logical operations, or recording, storing, and/or transferring digital data. The term “processor circuitry" or “processor" may refer to one or more application processors, one or more baseband processors, a physical central processing unit (CPU), a single- or multi-core processor, and/or any other device capable of executing or otherwise operating computer-executable instructions, such as program code, software modules, and/or functional processes.

[0051] Any of the radio links described herein may operate according to any one or more of the following radio communication technologies and/or standards including but not limited to: a Global System for Mobile Communications (GSM) radio communication technology, a General Packet Radio Service (GPRS) radio communication technology, an Enhanced Data Rates for GSM Evolution (EDGE) radio communication technology, and/or a Third Generation Partnership Project (3GPP) radio communication technology, for example Universal Mobile Telecommunications System (UMTS), Freedom of Multimedia Access (FOMA), 3GPP Long Term Evolution (LTE), 3GPP Long Term Evolution Advanced (LTE Advanced), Code division multiple access 2000 (CDMA2000), Cellular Digital Packet Data (CDPD), Mobitex, Third Generation (3G), Circuit Switched Data (CSD), High-Speed Circuit-Switched Data (HSCSD), Universal Mobile Telecommunications System (Third Generation) (UMTS (3G)), Wideband Code Division Multiple Access (Universal Mobile Telecommunications System) (W-CDMA (UMTS)), High Speed Packet Access (HSPA), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+), Universal Mobile Telecommunications System-Time-Division Duplex (UMTS-TDD), Time Division-Code Division Multiple Access (TD-CDMA), Time Division- Synchronous Code Division Multiple Access (TD-CDMA), 3rd Generation Partnership Project Release 8 (Pre-4th Generation) (3 GPP Rel. 8 (Pre-4G)), 3GPP Rel. 9 (3rd Generation Partnership Project Release 9), 3GPP Rel. 10 (3rd Generation Partnership Project Release 10) , 3GPP Rel. 11 (3rd Generation Partnership Project Release 11), 3GPP Rel. 12 (3rd Generation Partnership Project Release 12), 3GPP Rel. 13 (3rd Generation Partnership Project Release 13), 3GPP Rel. 14 (3rd Generation Partnership Project Release 14), 3GPP Rel. 15 (3rd Generation Partnership Project Release 15), 3GPP Rel. 16 (3rd

Generation Partnership Project Release 16), 3 GPP Rel. 17 (3rd Generation Partnership Project Release 17) and subsequent Releases (such as Rel. 18, Rel.

19, etc.), 3GPP 5G, 5G, 5G New Radio (5G NR), 3GPP 5G New Radio, 3GPP LTE Extra, LTE-Advanced Pro, LTE Licensed-Assisted Access (LAA), MuLTEfire, UMTS Terrestrial Radio Access (UTRA), Evolved UMTS Terrestrial Radio Access (E-UTRA), Long Term Evolution Advanced (4th Generation) (LTE Advanced (4G)), cdmaOne (2G), Code division multiple access 2000 (Third generation) (CDMA2000 (3G)), Evolution-Data Optimized or Evolution-Data Only (EV-DO), Advanced Mobile Phone System (1 st Generation) (AMPS (1G)), Total Access Communication System, 'Extended Total Access Communication System (TACS/ETACS), Digital AMPS (2nd Generation) (D-AMPS (2G)). Push-to-talk (PTT), Mobile Telephone System (MTS), Improved Mobile Telephone System (IMTS), Advanced Mobile Telephone System (AMTS), OLT (Norwegian for Offentlig Landmobil Telefoni, Public Land Mobile Telephony), MTD (Swedish abbreviation for

Mobiltelefonisystem D, or Mobile telephony system D), Public Automated Land Mobile (Autotel/PALM), ARP (Finnish for Autoradiopuhelin, "car radio phone"), NMT (Nordic Mobile Telephony), High capacity version of NTT (Nippon Telegraph and Telephone) (Hicap), Cellular Digital Packet Data (CDPD), Mobitex, DataTAC, Integrated Digital Enhanced Network (iDEN), Personal Digital Cellular (PDC), Circuit Switched Data (CSD), Personal Handyphone System (PHS), Wideband Integrated Digital Enhanced Network (WIDEN), iBurst, Unlicensed Mobile Access (UMA), also referred to as also referred to as 3 GPP Generic Access Network, or GAN standard), Zigbee, Bluetooth(r), Wireless Gigabit Alliance (WiGig) standard, mmWave standards in general (wireless systems operating at 10-300 GHz and above such as WiGig, IEEE 802. Had, IEEE 802, 1 lay, etc.), technologies operating above 300 GHz and THz bands, (3GPP/LTE based or IEEE 802.11p or IEEE 802.11bd and other) Vehicle-to-Vehicle (V2V) and Vehicle-to-X (V2X) and Vehicle-to- Infrastructure (V2I) and Infrastructure-to-Vehicle (I2V) communication technologies, 3GPP cellular V2X, DSRC (Dedicated Short Range Communications) communication systems such as Intelligent-Transport-Systems and others (typically operating in 5850 MHz to 5925 MHz or above (typically up to 5935 MHz following change proposals in CEPT Report 71)), the European ITS-G5 system (i.e. the European flavor of IEEE 802.11p based DSRC, including ITS-G5A (i.e., Operation of ITS-G5 in European ITS frequency bands dedicated to ITS for safety re-lated applications in the frequency range 5,875 GHz to 5,905 GHz), ITS-G5B (i.e., Operation in European ITS frequency bands dedicated to ITS non- safety applications in the frequency range 5,855 GHz to 5,875 GHz), ITS-G5C (i.e., Operation of ITS applications in the frequency range 5,470 GHz to 5,725 GHz)), DSRC in Japan in the 700MHz band (including 715 MHz to 725 MHz), IEEE 802.11bd based systems, etc.

[0052] Aspects described herein can be used in the context of any spectrum management scheme including dedicated licensed spectrum, unlicensed spectrum, license exempt spectrum, (licensed) shared spectrum (such as LSA = Licensed Shared Access in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz and further frequencies and SAS = Spectrum Access System / CBRS = Citizen Broadband Radio System in 3.55-3.7 GHz and further frequencies). Applicable spectrum bands include IMT (International Mobile Telecommunications) spectrum as well as other types of spectrum/bands, such as bands with national allocation (including 450 - 470 MHz, 902-928 MHz (note: allocated for example in US (FCC Part 15)), 863-868.6 MHz (note: allocated for example in European Union (ETSI EN 300 220)), 915.9-929.7 MHz (note: allocated for example in Japan), 917-923.5 MHz (note: allocated for example in South Korea), 755-779 MHz and 779-787 MHz (note: allocated for example in China), 790 - 960 MHz, 1710 - 2025 MHz, 2110 - 2200 MHz, 2300 - 2400 MHz, 2.4-2.4835 GHz (note: it is an ISM band with global availability and it is used by Wi-Fi technology family (11b/g/n/ax) and also by Bluetooth), 2500 - 2690 MHz, 698-790 MHz, 610 - 790 MHz, 3400 - 3600 MHz, 3400 - 3800 MHz, 3800 - 4200 MHz, 3.55-

3.7 GHz (note: allocated for example in the US for Citizen Broadband Radio Service), 5.15-5.25 GHz and 5.25-5.35 GHz and 5.47-5.725 GHz and 5.725-5.85 GHz bands (note: allocated for example in the US (FCC part 15), consists four U-NII bands in total 500 MHz spectrum), 5.725-5.875 GHz (note: allocated for example in EU (ETSI EN 301 893)), 5.47-5.65 GHz (note: allocated for example in South Korea, 5925-7125 MHz and 5925-6425MHz band (note: under consideration in US and EU, respectively. Next generation Wi-Fi system is expected to include the 6 GHz spectrum as operating band but it is noted that, as of December 2017, Wi-Fi system is not yet allowed in this band. Regulation is expected to be finished in 2019-2020 time frame), IMT-advanced spectrum, IMT-2020 spectrum (expected to include 3600-3800 MHz, 3800 - 4200 MHz, 3.5 GHz bands, 700 MHz bands, bands within the 24.25-86 GHz range, etc.), spectrum made available under FCC's "Spectrum Frontier" 5G initiative (including 27.5 - 28.35 GHz, 29.1 - 29.25 GHz, 31 - 31.3 GHz, 37 - 38.6 GHz, 38.6 - 40 GHz, 42 - 42.5 GHz, 57 - 64 GHz, 71 - 76 GHz, 81 - 86 GHz and 92 - 94 GHz, etc), the ITS (Intelligent Transport Systems) band of 5.9 GHz (typically 5.85-5.925 GHz) and 63-64 GHz, bands currently allocated to WiGig such as WiGig Band 1 (57.24-59.40 GHz), WiGig Band 2 (59.40-61 .56 GHz) and WiGig Band 3 (61.56-63.72 GHz) and WiGig Band 4 (63.72-65.88 GHz), 57- 64/66 GHz (note: this band has near-global designation for Multi-Gigabit Wireless Systems (MGWS)/WiGig . In US (FCC part. 15) allocates total 14 GHz spectrum, while EU (ETSI EN 302 567 and ETSI EN 301 217-2 for fixed P2P) allocates total 9 GHz spectrum), the 70.2 GHz - 71 GHz band, any band between 65.88 GHz and 71 GHz, bands currently allocated to automotive radar applications such as 76-81 GHz, and future bands including 94-300 GHz and above. Furthermore, the scheme can be used on a secondary basis on bands such as the TV White Space bands (typically below 790 MHz) where in particular the 400 MHz and 700 MHz bands are promising candidates. Besides cellular applications, specific applications for vertical markets may be addressed such as PMSE (Program Making and Special Events), medical, health, surgery, automotive, low-latency, drones, etc. applications.

[0053] Aspects described herein can also implement a hierarchical application of the scheme is possible, e.g. by introducing a hierarchical prioritization of usage for different types of users (e.g., low/medium/high priority, etc.), based on a prioritized access to the spectrum e.g. with highest priority to tier-1 users, followed by tier-2, then tier-3, etc. users, etc.

[0054] 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.

[0055] Some of the features in this document are defined for the network side, such as APs, eNBs, NR or gNBs - note that this term is typically used in the context of 3GPP fifth generation (5G) communication systems, etc. Still, a UE may take this role as well and act as an AP, eNB, or gNB; that is some or all features defined for network equipment may be implemented by a UE.

[0056] NR sidelink enhancements for Rel. 17 target reduction of device power consumption and support of UE power saving mechanisms. The initial NR sidelink design (that was completed in the Rel. 16) provided support for mission critical low latency NR V2X sidelink communication for devices that are not constrained by a battery level, which include vehicle UEs or Road Side Units (RSUs). Reduced power consumption can be achieved by downgrading capabilities or requirements on the device in various ways. One way of reducing the power is reducing the number of slots and/or the bandwidth to be monitored by the receiver. For Rel. 16 NR SL, it is assumed that the receiver is always on and monitoring all system resources defined in the system configuration. This means a substantial amount of processing is used at the receiver at all times. [0057] Some advanced V2X use cases, for example, VRU protection, may involve the use of handheld devices such as wearables and smartphones. Such devices are much more constrained in terms of power consumption compared to vehicles and roadside units.

[0058] Bandwidth/slot reduction [0059] One of the most promising approaches for UE power saving is a design option that reduces the number of frequency and time resources monitored by the receiver without actual data reception/transrnission. In the NR sidelink design, the frequency and time resources monitored by the receiver includes the number of monitored sub-channels and slots. [0060] FIG. 3 illustrates sidelink sub-channels in different slots in accordance with some embodiments. The example in FIG. 3 illustrates a scenario in which, out of N = 8 consecutive slots, the receiver is switched on only in M = 4 slots. In addition, in these M = 4 slots, only S = 3 out of F = 4 sub-channels are processed. This indicates that this monitoring pattern of used and unused sub-channels would continue with a periodicity of 8 slots.

[0061] There are multiple ways a device may select the subset of subchannel s/slots for monitoring. The list below provides some of the examples for selection of UE monitored sub channel s/slots:

[0062] A subset of the available resources for monitoring in the resource pool is assigned by higher layers. This may be via a traditional cellular network, other devices communicating via V2X or a higher capable V2X device without battery constraints, like an RSU that assigns monitored sidelink resources to UEs. Alternatively , the subset of the available resources for monitoring in the resource pool may be assigned according to the specific features of the V2X service, for example, dependent on whether the UE is or is not a member or a leader of a cluster.

[0063] This selection may be based on a device specific configuration. The configuration can be updated via other communication interface. It is also possible that the selection is dependent on the geographic location of the device or is randomly selected out of a per resource pool configured subset. The UE can be configured with multiple settings of configurations of N, M, S, F parameters that can serve different purposes: e.g. 1) for partial sensing immediately prior to actual transmission (i.e. when packet arrives to internal buffer, i.e. outgoing traffic) or 2) for monitoring of a sidelink signal, a wakeup signal, or a go to sleep signal originating from the Uu or PC5 interfaces (i.e. when incoming traffic arrives).

[0064] Based on CBR measurements, a UE can periodically perform full sensing of the V2X radio environment in order to determine activity on resources. Based on metric of the most likely used sub-channels and/or slots, the UE can afterwards select a subset of all available resources to monitor in a power saving state. One metric may be the CBR. This “breathing" of the used resources can be implemented via a state machine. [0065] FIG. 4 illustrates state transitions for determining receive resources in accordance with some embodiments. In particular, the state model shown in FIG. 4 show's three different states and state transitions for determining receive resources. In FIG. 4, a different percentage of the overall resource can be utilized. Depending on how busy these resources are, the devices are going to transition among power saving state with a different amount of resources for processing. Based on the partial or initial full sensing, the device can start operation in one of these states.

[0066] For uni-cast/group-cast connection setup, the participating devices could agree to use only a subset of the available time frequency resource for communication (resources distributed over time and serving as entry' points for establishing connection or transmission of some of the control messages). This can also be combined with selection of the subset of available resources as above. In an example use case, multiple platoons or clusters want to communicate, an RSU assigns different sub-resources to the different platoons or clusters. If inter platoon or cluster communication is not used, the devices may limit monitoring of resources to only the resource assigned for their own platoon or cluster.

[0067] Geo-based partitioning/assignment of sidelink resources may be used. In this case, a subset of resources within the sidelink resource pool is assigned based on UE coordinates or zone ID.

[0068] The UE may also exchange messages regarding monitored bandwidth, then collectively decide on a set of reduced resources for monitoring. In order to not miss important information, it can be agreed to have predefined resources that are to be monitored by all devices. Information about reducing or increasing the number of (other) resources for monitoring can be contained in the predefined resources. This can also be managed by a device with higher capabilities - a sidelink resource coordinator.

[0069] Sleep states [0070] When a predetermined set of slots exist in which the reception of any channel is not undertaken, as shown in the slots without any monitored sub- channels in FIG. 3, it is possible to put the UE into a deep-sleep or microsleep state. Whether the deep-sleep or microsleep state is used depends on the time duration during which no reception is to be undertaken. One reason to distinguish these two states (deep-sleep or microsleep) is that the cost (in terms of energy) to put the receiver into microsleep as well as the corresponding wakeup is different than for a deep-sleep state. Of course, the remaining power usage during the deep-sleep and microsleep state is also different. FIG. 5 illustrates state transitions for sleep states in accordance with some embodiments. [0071] Implications on other sidelink operations

[0072] As in sidelink resource allocation mode 2, the sensing procedure has a direct connection to the transmit resource selection. Thus, for mode 2, the devices may only be able to transmit in the resources associated with monitored resources, i.e. a part of their receive resources and thus consistent with the sensing operation. If a device selected to transmit actually transmits in resource that, is no longer monitored, for example due to the monitoring bandwidth changing, the device also transmits in the resource that are part of the current monitoring bandwidth. The device shifts the allocation before shifting the amount of monitored resources. If a process similar to that shown in FIG. 4 is used, the new transmit resource as well as the monitoring resource are jointly allocated during the periodic full sensing.

[0073] Another interaction with the different power saving techniques may include use of a device that does not perform sensing to transmit data. If another device recognizes that transmission of another device in the same window allocated resource would collide with one of the devices own transmission, the device may refrain from transmitting to avoid potential interference.

[0074] Anchor resources [0075] Anchor resources (e.g., an anchor subchannel) may be defined for independent resource monitoring selections. These sidelink resources may be a minimal mandatory resource to be monitored by the devices engaged in sidelink communication. In these anchor sidelink resources, all critical information as well as possible bandwidth changes, may be sent. Different anchor resources can be assigned to provide different, functionality (e.g. device discovery, connection unicast/groupcast establishment, sidelink paging, other control signaling, etc.).

[0076] Adaptation of used Tx/Rx antennas and other phy layer parameters [0077] To save UE power it. is possible for devices participating in unicast or groupcast to be limited to transmissions that use a subset of the allowed physical layer parameters allowed by the resource pool. In one example, the number of transmit or receive antennas used may be limited, e.g., during platooning. For example, if the UEs are vehicles, as the distance between the vehicles, as well as the channel, remains roughly constant, communicating with a vehicle in front may use front-facing antennas; use of any rear facing antennas may be avoided in this case. In the same fashion, it. is also possible to limit one or more of the number of multiple input, multiple output (MIMO) layers, the Modulation and Coding Scheme (MCS) used, or the allowed demodulation reference signal (DMRS) patterns. In summary, for power saving purpose, the UE can reduce the number of RF and baseband (BB) chains used for sidelink transmission and reception, as well as restricting the number of MIMO layers, MCS, and TX power ranges. [0078] Power saving states and transitions

[0079] In contrast to LTE, the NR sidelink in addition to broadcast communication supports groupcast/multicast and unicast communication.

Groupcast and unicast offer additional dimension of context establishment in the sidelink group that, can help to organize communication in a much more power efficient manner. In a communication session, at least one UE can be assumed to be the controller/scheduler/coordinator UE.

[0080] In one example, at least two power consumption-related states for sidelink communication (PC5 interface power saving state) are introduced. State A: regular power consumption state, i.e. no power saving technique is applied, and the UE performs all normal functions/procedures. In some embodiments, an activity timer TA may be running during the active state, and the regular power consumption state may be kept until the tinier expires (assuming that the timer serves as a trigger condition for the UE to switch to another state, such as the power saving state). Other events device events, like low battery or higher layer information, may also trigger this state transition.

[0081] State B: power saving state, i.e. a state when at least one of power saving features are enabled and activated at the UE. In some embodiments, a sleep timer T_s may be running during the sleep state, and the power saving state may be kept until the time is expired (assuming that the timer serves as a trigger condition so that the UE switches to another state, such as the regular power consumption state). Higher layer information may also trigger this state transition. The power saving techniques may include one or a combination of. reduced number or rate of PSCCH blind decoding in a slot; reduced number/rate of slots for PSCCH blind decoding; reduced maximum PSSCH processing bandwidth; or reduced number of tran smi t/receive antennas used for sidelink processing.

[0082] In relation to the above example, the power saving state may further have several grades that are characterized by the level of power consumption and/or a set of power saving features enabled. In relation to the embodiment, the power consumption state may be defined one or more of: per- UE, per-connection/link associated with a UE, per-resource pool, or even per- CC. For the per-UE state, the power saving or regular state is applied for all services/links in a LIE. For the per-link state, the power saving or regular state is applied on a given link, and there may be multiple links maintained by a UE which are characterized by different power consumption states.

[0083] FIG. 6 illustrates sidelink power saving states and transitions in accordance with some embodiments. A UE may transition from one state to another state based on a trigger, as illustrated in FIG. 6. The trigger may be one of the following: State A to State B transition (regular state to power saving state): an activity tinier expires; a keep active (KA) signal is not detected; a go- to-sleep (GTS) signal is detected; higher layer information is received; or the device state changes (such as low battery’). For a State B to State A transition (power saving state to regular state): a sleep timer expires; a wake-up signal (WUS) is detected; a keep sleeping (KS) signal is not detected; or higher layer information is received.

[0084] Whenever the state is changed or a trigger instructing to keep the state (A->A or B->B) is received, the timer of the state (activity timer or sleep timer) is reset. [0085] Power saving state transition triggering signals

[0086] One power saving technique involving physical layer procedures may involve a power saving state transition triggering signal (PSTT). As outlined above, the PSTT may trigger transition between power saving states.

Depending on the states for transition, i.e. A->B, B->A, A->A, B->B, the notion of the special signal may change. For example, if a signal is designed to switch the regular state to the power saving state, then the signal can be called a “go to sleep" (GTS) signal. If a signal is designed to switch the power saving state to the regular activity state, the signal can be called a “wake-up" signal (WUS). If a signal is designed to keep an active state or the sleep state, the signal can be called a “keep active" (KA) or “keep sleeping" (KS) signal. Regardless of the state transition of a PSTT, there are common design aspects of this signal such for example common physical structure that can be used.

[0087] Physical layer structure of a PSTT [0088] The physical layer structure of a PSTT is expected to offer relatively low complexity of implementation and monitoring/transmission. Furthermore, the PSTT physical layer structure should also offer backward and forward compatibility at least in terms of channel access, i.e. a transmission carrying PSTT should not impact performance of legacy UEs. [0089] A PSTT signal can be either sent by a gNB on a DL or by a UE on a SL. A PSTT signal sent/monitored on the DL may be indicated as a PSTT- D and a PSTT signal sent/monitored on a SL may be indicated as a PSTT-S.

[0090] In one example, a PSTT-S signal is conveyed by a new 1^st stage SCI format 1-B/C/etc. carried on the PSCCH. There may be no associated 2^nd stage SCI and PSSCH if there is no data to cany, i.e. the PSCCH carrying PSTT-

S may be transmitted in standalone manner comprising only the PSCCH.

[0091] In another example, a PSTT-S signal is conveyed by a new 2^nd stage SCI format 2-C/D/E etc. carried on the PSSCH. In this case, the 1^st stage SCI format 1-X (‘X’ means any suitable 1^st stage format) can indicate the new 2^na stage SCI format as part of the “2^nd stage format" field" or as part of the reserved bits field or as a combination thereof. Alternatively, new configurable fields may be introduced into existing 2^nd stage SCI formats 2-A and/or 2-B.

Configurable here means that the presence of the field is known in advance from RRC (pre-)configuration. [0092] In another example, a PSTT-S signal is multiplexed with a data medium access control (MAC) packet data unit (PDU) by attaching a M AC Control Element (CE) carrying the PSTT-S. For example, a last transmission of a packet may include a GTS signal as a MAC CE to trigger a UE to turn to a power saving state since no further MAC PDUs are to be transmitted before the active timer expiration.

[0093] In another example, a PSTT-S signal is a dedicated sequence multiplexed on DMRS, channel state information reference signal (CSI-RS), or physical sidelink feedback channel (PSFCH) different from the Rel. 16 versions of these signals. [0094] In another example, a PSTT-S signal is a physical channel different from the PSCCH, PSSCH, and PSFCH.

[0095] When a PSTT-D is transmitted and monitored on the DL, in one example, the PSTT-D can be carried by a new DCI format 2_Y or 3_Y ( 'Y' means any notation other than resulting in existing formats).

[0096] Transmission and monitoring procedure of a PSTT (Power Saving Transition Triggering)

[0097] Transmission and monitoring of a PSTT signal is confined to a subset of resources used for regular data transmission/exchange in order to reduce the active time for monitoring. There are different ways of providing a subset of resources for PSTT transmission and monitoring.

[0098] In one example, a separate TX and RX resource pool may be (pre-)configured for PSTT-S transmission and monitoring respectively. In practice, the resource pool configuration message may include a new flag which allows or prohibits transmission/monitoring of a PSTT-S signal in this resource pool. The separate resource pool may be expected to have a sparse configuration in time and/or frequency. This resource pool may either be provided by RRC (pre-)configuration or may be provided by PC5 RRC signaling established between UEs. [0099] In another example, a sub-resource pool configuration for TX and

RX resource pools may be introduced for PSTT-S transmission and monitoring respectively. The sub-resource pool configuration may include a subset of sub- channels in a slot and a subset of slots in a resource pool. The frequency domain subset may be (pre-)configured as one or a combination of the following: a single sub-channel with a configured or predefined index within the resource pool. For example, the lowest or the highest sub-channel may be dedicated for this purpose; a bitmap over sub-channels of the resource pool, where '1' means the sub-channel is activated and W means the sub-channel is not activated for PSTT-S transmission/monitoring; or a starting sub-channel and a number of consecutive sub-channels in the resource pool activated for PSTT-S transmission/monitoring. The time domain subset may be (pre-)configured as follows: a logical slot periodicity P_PSTT within a resource pool can be applied to indicate periodic occurrence of slots with possibility PSTT-S transmission; a logical slot periodicity P_PSTT and a number of consecutive slots N_PSTT within a resource pool can be applied to indicate periodic occurrence of N_PSTT slots with possibility PSTT-S transmission; or a bitmap with a periodicity over resources of the pool .

[00100] Related to this example, the sub-resource pool may either be provided by a RRC (pre-)configuration or may be provided by PC5 RRC signaling defined and established between UEs. In case of conveying PSTT-D on downlink, in one example, procedures for monitoring the PDCCH for a given DCI format may be reused. In addition, procedures for monitoring a Uu wake- up signal (DCI format 2 6) may be combined with monitoring the PSTT-D. [00101] The PSTT-S/D signal can be monitored/transmitted in different manners dependent on the source and/or destination of the signal. For a destination-aware PSTT transmission, the PSTT transmitter knows in advance the target UE that should trigger transition into the other state. For example, a UE can send a destination-aware PSTT-S to a UE by setting a destination L1/L2 ID of the UE(s) that are to wake up or go to sleep. For a source-aware PSTT transmission, the transmitter of PSTT may not know in advance who should transition into the other state. In this case, a UE can send a source-aware PSTT- S and set its own Source L1/L2 ID. The UEs interested in monitoring this source ID can then trigger a state transition (wake up or go to sleep). Moreover, a combination of source- and destination-aware approaches may be used. The source- and destination-aware PSTT transmissions can be combined, and both DST and SRC IDs set accordingly. In the context of this embodiment, a PSTT may be broadcast, groupcast, or unicast. The 2^nd stage SCI format can convey the cast-type of the PSTT-S. [00102] PSTT payload/message

[00103] The payload of the PSTT message can be defined such that the same message can convey different functionalities by switching bit-fields states. In one example, a PSTT-S for a WUS/KS conveys 1 -bit information, where one state of the bit is interpreted as a transition to the active/regular state A and another state of the bit is interpreted as keeping the power saving state B. In another example, a PSTT-S for a GTS/KA conveys 1 -bit information, where one state of the bit is interpreted as transition from the power saving state B to the active state A and another state of the bit is interpreted as keeping the active state A. In another example, a PSTT-S for a WUS/KS conveys Z-bits of information, where each of the Z bits indicates activation or de-activation of a certain power saving technique from a set of Z power saving features.

[00104] Resource allocation for PSTT

[00105] When a PSTT-S is transmitted using a PSCCH and PSSCH, the allocation may follow the existing Mode-1 (gNB scheduled) and Mode-2 (UE selected) resource allocation and selection procedures. Since a PSTT-S has a different purpose than just schedule data, the resource allocation may be changed at least since there may be no associated SCH and therefore associated QoS parameters. [00106] In one example, a L1 priority for a PSTT-S transmission may be

(pre-)configured per resource pool. Alternatively, the L1 priority associated with the sidelink shared channel (SL-SCH) currently in the buffer may be used as the L1 priority for the PSTT-S transmission. Furthermore, the L1 priority of the PSTT-S may be a function of L1 priority of the SL-SCH. [00107] In another alternative, the L1 priority for the PSTT-S may be fixed to the higher priority (i.e. smallest priority value 0). This L1 priority may be used for Mode-2 resource allocation and may be signaled in SCI format 1-X to other UEs for sensing, resource selection, and prioritization purposes. In one example, a delay budget for a Mode-2 resource allocation procedure for the PSTT-S may be (pre-)configured per L1 priority per resource pool.

[00108] In one example, the number of retransmissions including the initial transmission may be separately (pre-)configured for the PSTT-S per L1 priority per resource pool. The PSTT-S transmission on the PSCCH+PSSCH can employ both blind transmission and feedback-based transmission. In one example, it may be (pre-)configured whether or not feedback is enabled for the PSTT-S. For Mode-1 operation, the PSTT-S transmission may be scheduled by a grant from the gNB. The DCI format 3 0 may include a separate flag to differentiate scheduling of the PSTT-S transmission.

[00109] Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments 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. The accompanying drawings that form a part hereof show, by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. [00110] The subject matter may be referred to herein, individually and/or collectively, by the term “embodiment" merely for convenience and without intending to voluntarily limit, the scope of this application to any single inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. [00111] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term" or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B,""B but not A," and "A and B," unless otherwise indicated. In this document, the terms"including" and "in which" are used as the plain-English equivalents of the respective terms"comprising" and "wherein." Also, in the following claims, the terms “including" and "comprising" are open-ended, that is, a system, UE, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms" first,""second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[00112] The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

Claims

CLAIMS What is claimed is:

1. An apparatus for a user equipment (UE), the apparatus comprising: processing circuitry configured to: determine whether to enter a power saving state from a nonpower saving state; in response to a determination to enter the power saving state: configure the UE to enter into the power saving state, and select a subset of sidelink resources in a sideiink resource pool to monitor; and after entry into the power saving state, limit sidelink transmission to the subset of sidelink resources; and a memory configured to store the subset of sidelink resources.

2. The apparatus of claim 1, wherein the subset of sidelink resources is at least one of: assigned by higher layers via a cellular network or another UE in communication via vehicle-to-everything (V2X), or dependent on a specific role of the UE in the sidelink communications.

3. The apparatus of claim 1, wherein the subset of sidelink resources is dependent on a device configuration, the device configuration containing parameters that control partial sensing of the subset of sidelink resources in response to reception, at an internal buffer, of a packet for sidelink transmission and monitoring for a sidelink wakeup signal (WUS) or go-to-sleep (GTS) signal on a Uu or PC5 interface.

4. The apparatus of claim 1, wherein the subset of sidelink resources is dependent on a geographic location of the UE that uses at least one of geographic coordinates of the UE or a zone in which the UE is disposed.

5. The apparatus of claim 1, wherein the processing circuitry' is further configured to: periodically perform full sensing to determine activity on the sidelink resources based on Channel Busy Ratio (CBR) measurements, and select the subset of sidelink resources based on the CBR measurements.

6. The apparatus of claim 5, wherein the processing circuitry is further configured to select: a first subset of sidelink resources in response to the CBR measurements being below a first threshold, and a second subset of sidelink resources in response to the CBR measurements being at least the first threshold and below a second threshold that is higher than the first threshold, the first subset of sidelink resources having fewer resources than the second subset of sidelink resources.

7. The apparatus of claim 1, wherein: the subset of sidelink resources is dependent on a type of communication used for the sidelink resources and a cluster to which the UE is assigned, the cluster is one of a plurality of clusters each containing multiple UEs configured for sidelink communications, the type of communication includes unicast and groupcast communications, and the processing circuitry is further configured to select the subset of sidelink resources dependent on whether the UE is to engage in inter-cluster sidelink communications.

8. The apparatus of claim 1, wherein: the processing circuitry is further configured to select the subset of sidelink resources dependent on a collective decision with other UEs based on a monitored bandwidth among the UE and the other UEs, and the subset of sidelink resources include an anchor set of sidelink resources to be monitored by the UE and the other UEs, the anchor set of sidelink resources containing information about adjusting a number of sidelink resources to be monitored and independent of the collective decision with other UEs.

9. The apparatus of claim 8, wherein the anchor set of sidelink resources is selected from among a plurality of anchor sets of sidelink resources that provide different functionalities, including UE discovery, connection unicast or groupcast establishment, and sidelink paging.

10. The apparatus of claim 1, wherein the processing circuitry is further configured to select among different sleep states dependent on timing between adjacent sidelink resources in the subset of sidelink resources.

11. The apparatus of claim 1, wherein: the subset of sidelink resources is one of a plurality of subsets of sidelink resources, each subset of sidelink resources is related to a different set of physical layer parameters to use for sidelink transmission, and the set of physical layer parameters include transmit and receive antennas or multiple input, multiple output (MIMO) layers, Modulation and Coding Scheme (MCS), and allowed demodulation reference signal (DMRS) patterns.

12. The apparatus of claim 1, wherein the processing circuitry' is further configured to: determine whether to enter the power saving state based on at least one of: expiration of an activity timer, non-detection of a keep alive signal, detection of a go-to-sleep signal, occurrence of a device state change, or reception of higher layer information, and determine whether to exit the power saving state to the non-power saving state based on at least one of: expiration of a sleep tinier, detection of a wakeup signal, non-detection of a keep sleeping signal, or reception of other higher layer information.

13. The apparatus of claim 1, wherein the processing circuitry is further configured to determine whether to change between the power saving state and the non-power saving state based on reception of a power saving state transition triggering signal (PSTT) from one of another UE on sidelink resources (PSTT-S) or a 5^th generation NodeB (gNB) on downlink resources (PSTT-D) carried by a downlink control information (DCI) format.

14. The apparatus of claim 13, wherein the PSTT-S is one of: conveyed by a 1^st stage sidelink control information (SCI) format carried on a physical sidelink control channel (PSCCH) without an associated 2^nd stage SCI and physical sidelink shared channel (PSSCH) if there is no data to carry, conveyed by a 2^nd stage SCI format that is indicated by an associated 1 ^st stage SCI in at least one of a 2^nd stage format field or reserved bits field, multiplexed with a data medium access control (MAC) packet data unit

(PDU) by attaching a MAC Control Element (CE) carrying the PSTT-S, a dedicated sequence multiplexed on a demodulation reference signal (DMRS), channel state information reference signal (CSI-RS), or physical sidelink feedback channel (PSFCH), or a physical channel different from the PSCCH, PSSCH, and PSFCH.

15. The apparatus of claim 13, wherein: the PSTT-S is carried on a dedicated resource pool provided by a radio resource control (RRC) configuration or PC5 RRC signaling between UEs, and a resource pool configuration message includes a flag that allows or prohibits transmission or monitoring of the PSTT-S signal in the dedicated resource pool.

16. The apparatus of claim 13, wherein: a sub-resource pool configuration for the PSTT-S includes a subset of subchannels in a particular slot and a subset of slots in a particular resource pool, a frequency domain subset is configured as at least one of: a single subchannel with a configured or predefined index within the particular resource pool, a bitmap over subchannels of the particular resource pool, a starting subchannel and a number of consecutive subchannels in the particular resource pool activated for PSTT-S transmission or monitoring, and a time domain subset is configured as at least one of: a first, logical slot periodicity within the particular resource pool to indicate a periodic occurrence of slots with a possible PSTT-S transmission, a second logical slot periodicity and a number of consecutive slots within the particular resource pool to indicate a periodic occurrence of slots with the possible PSTT-S transmission, or a bitmap with a periodicity over resources of the particular resource pool .

17. An apparatus for a user equipment (UE), the apparatus comprising: processing circuitry’ configured to: determine whether to change between a power saving state and a non-power saving state based on reception of a power saving state transition triggering signal from another UE on sidelink resources (PSTT-S), the PSTT-S containing one of: a sidelink wakeup signal (WUS) or keep sleeping (KS) signal when in the power saving state, go-to-sleep (GTS) signal or keep awake (KA) signal when in the non-power saving state; and in response to entry- into the power saving state, monitor a subset of sidelink resources in a sidelink resource pool; and a memory configured to store the subset of sidelink resources.

18. The apparatus of claim 17, wherein at least one of: a L1 priority for the PSTT-S is one of: configured per resource pool, an l/l priority associated with a sidelink shared channel (SL- SCH) currently in a buffer of the UE, or a function of the L1 priority of the SL-SCH, the L1 priority for the PSTT-S is used for Mode-2 resource allocation and signaled to other UEs in a sidelink control information (SCI) format, a delay budget for the Mode-2 resource allocation for the PSTT-S is configured per L1 priority per resource pool, or a number of retransmissions and an initial transmission is configured for the PSTT-S per L I priority per resource pool.

19. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of a user equipment (UE), the one or more processors to configure the UE to, when the instructions are executed: determine whether to change between a power saving state and a nonpower saving state based on reception of a power saving state transition triggering signal from another UE on sidelink resources (PSTT-S); and after entry into the power saving state based on the determination, periodically perform full sensing to determine activity on the sidelink resources based on Channel Busy Ratio (CBR) measurements and select a subset of sidelink resources in a sidelink resource pool to monitor based on the CBR measurements.

20. The medium of claim 19, wherein the one or more processors further configure the UE to, when the instructions are executed, select: a first subset of sidelink resources in response to the CBR measurements being below a first threshold, and a second subset of sidelink resources in response to the CBR measurements being at least the first threshold and below a second threshold that is higher than the first threshold, the first subset of sidelink resources having fewer resources than the second subset of sidelink resources.