Method and apparatus for sidelink communication

Abstract

Methods, apparatus, and procedures are provided for sidelink communications (e.g., using ultra low power (ULP) components). For example, a wireless transmit / receive unit (WTRU) is configured to determine information of a first transmission and a second transmission based on a ULP capability associated with a target destination, and transmit the first transmission including first sidelink control information (SCI) associated with the first transmission, and the first SCI indicates a resource for the second transmission and a ULP signal to be transmitted on the first transmission. The first transmission includes the ULP signal indicating the target destination, the resource for the second transmission, and at least a first subset of a second SCI associated with the second transmission. The WTRU is further configured to transmit the second transmission comprising at least a second subset of the second SCI and sidelink payload data.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 349,431, filed in the United States Patent and Trademark Office on June 6, 2022, the entire contents of which are incorporated herein by reference as if fully set forth herein for all applicable purposes. Background Art

[0003] In some current implementations of sidelink (SL) communications, two procedures are related to SL devices monitoring resources on any configured resource pool (RP). One procedure is for channel sensing to monitor future resource availability and is used for SL devices that are configured to (potentially) send data. The other procedure is for SL data reception, where devices are configured with a receive resource pool on which they can receive data. In both procedures, the devices may be required to perform continuous or frequent monitoring and blind decoding of at least the PSCCH on their configured resource pools, as well as decoding the second stage SCI in the PSSCH of the receive resource pool, which is energy consuming.

[0004] The current implementation of SL communication has no wake-up signal design for the side link, let alone some wake-up signal based on ULP. It is possible to close the connection between a pair of users and make the device idle / inactive on its Uu link, and possibly use some wake-up signal, but this will mean very long latency because the device needs to wake up the main radio part for Uu connection and then re-establish the connection with the user in the side link to be able to resume communication. Therefore, enhanced or new procedures for side link (SL) transmission and reception may be needed. Summary of the invention

[0005] Embodiments disclosed herein generally relate to wireless and / or wired communication networks.One or more embodiments disclosed herein relate to methods, apparatus, and procedures for sidelink communications in wireless communications (eg, using an ultra-low power (ULP) receiver).

[0006] For example, one or more embodiments disclosed herein relate to enhanced procedures that may include implementing the following: low-power monitoring of a sidelink channel using a ULP air interface, designing and selecting new sidelink formats and content to embed a ULP wake-up signal and ensure coexistence with legacy receivers and non-ULP receivers, sidelink transmission of data and control via a ULP air interface, sidelink reception of data and control via a ULP receiver, and / or sending and receiving another transmitted second stage SCI content via a ULP air interface.

[0007] In one embodiment, a method for wireless communication implemented by a wireless transmit / receive unit (WTRU) is provided. The method includes: determining information of a first transmission and a second transmission based on ultra-low power (ULP) capabilities associated with one or more target destinations; sending the first transmission based on the information, the first transmission including: 1) first sidelink control information (SCI) associated with the first transmission, the first SCI indicating a resource set for the second transmission and a ULP signal to be sent on the first transmission; and 2) the ULP signal, the ULP signal indicating the one or more target destinations, the resource set for the second transmission, and at least a first subset of a second SCI associated with the second transmission; and sending the second transmission, the second transmission including at least a second subset of the second SCI and sidelink payload data.

[0008] In one embodiment, a method for wireless communication implemented by a WTRU includes: determining information of a first transmission and a second transmission based on ULP capabilities associated with one or more target destinations; sending the first transmission based on the information, the first transmission including: 1) a first SCI associated with the first transmission, the first SCI indicating a resource set used for the second transmission and a ULP signal to be sent on the first transmission; and 2) the ULP signal, the ULP signal indicating the one or more target destinations, the resource set used for the second transmission, and the second SCI associated with the second transmission; and sending the second transmission, the second transmission including sidelink payload data.

[0009] In another embodiment, a method for wireless communication implemented by a WTRU includes: determining information of a first transmission and a second transmission based on ULP capabilities associated with one or more target destinations; determining that the one or more target destinations cannot receive a subset of the SCI; sending the first transmission based on the information, the first transmission including a ULP signal, the ULP signal indicating the one or more target destinations and a resource set for the second transmission; and sending the second transmission, the second transmission including the SCI and sidelink payload data.

[0010] In one embodiment, a WTRU includes circuitry, the WTRU including a transmitter, a receiver, a processor, and a memory, the WTRU being configured to determine information of a first transmission and a second transmission based on an ultra-low power (ULP) capability associated with one or more target destinations; to send the first transmission based on the information, the first transmission including: 1) first sidelink control information (SCI) associated with the first transmission, the first SCI indicating a resource set for the second transmission and a ULP signal to be sent on the first transmission; and 2) the ULP signal, the ULP signal indicating the one or more target destinations, the resource set for the second transmission, and at least a first subset of a second SCI associated with the second transmission; and to send the second transmission, the second transmission including at least a second subset of the second SCI and sidelink payload data. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A more detailed understanding can be obtained from the following detailed description, which is given by way of example in conjunction with its drawings. As with the detailed description, the figures in such drawings are examples. Therefore, the drawings (figures) and detailed description should not be considered limiting, and other equally effective examples are possible and expected. In addition, similar reference numerals ("ref.") in the figures indicate similar elements, and among them:

[0012] Figure 1A is a system diagram illustrating an example communication system;

[0013] Figure 1B is an example that can be Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an illustrated communication system;

[0014] Figure 1C is an example that can be Figure 1A A system diagram of an example Radio Access Network (RAN) and an example Core Network (CN) used within the illustrated communication system;

[0015] Figure 1D is an example that can be Figure 1A A system diagram of another example RAN and another example CN used within the illustrated communication system;

[0016] FIG2 is two block diagrams illustrating (a) an on-off keying (OOK) receiver based on mixer-first energy detection (ED) and (b) a frequency shift keying (FSK) receiver based on mixer-first ED;

[0017] Figure 3 is a block diagram illustrating an example of a ULP receiver with a fully passive RF front end;

[0018] Figure 4 is a diagram illustrating an example of ULP embedded reservation and retransmission according to one or more embodiments;

[0019] Figure 5 is a signal flow diagram illustrating an example procedure performed by a WTRU having a ULP receiver receiving a ULP embedded signal and a retransmission in accordance with one or more embodiments;

[0020] Figure 6 is a signal flow diagram illustrating an example of a non-ULP WTRU receiving ULP embedded SL signaling when a ULP WTRU and a non-ULP WTRU coexist according to one or more embodiments;

[0021] Figure 7 is a signal flow diagram illustrating an example of a ULP embedded procedure with feedback of a transmitted ULP signal according to one or more embodiments;

[0022] 8 is a block diagram illustrating examples of the following consecutive SL ULP embedded transmissions according to one or more embodiments: (a) a single subchannel transmission, (b) multiple subchannel transmissions with full resource allocations, and (c) multiple subchannel transmissions with consecutive resource allocations;

[0023] 9 is a block diagram illustrating examples of the following SL ULP embedded transmissions with a demodulation reference signal (DMRS) according to one or more embodiments: (a) a single subchannel transmission with contiguous ULP resource allocations, (b) multiple subchannel transmissions with contiguous ULP resource allocations, (c) a single subchannel transmission with discontinuous resource allocations, and (d) multiple subchannel transmissions with discontinuous resource allocations;

[0024] FIG10 is a block diagram illustrating an example of a ULP embedded SL frame structure with a reduced PSSCH according to one or more embodiments;

[0025] Fig.11 is a diagram illustrating an example of a sequential SL ULP embedded transmission and reservation mechanism according to one or more embodiments;

[0026] Fig.12 is a diagram illustrating an example of a continuous SL ULP embedded transmission mechanism according to one or more embodiments;

[0027] Fig.13 is a diagram illustrating an example of a ULP embedded SL slot structure with ULP signaling including small data transmission according to one or more embodiments;

[0028] Fig.14is a flow chart illustrating an example of a receive procedure for a ULP SL small data transmission and selecting an interface for monitoring according to one or more embodiments;

[0029] FIG15 is a diagram illustrating an example of a slot format for an initial transmission (with ULP signaling) and one or more subsequent transmissions (with SL payloads) according to one or more embodiments;

[0030] Fig.16 is a signal flow diagram illustrating an example of a reception procedure of ULP signaling embedded with partial second stage sidelink control information (SCI) according to one or more embodiments;

[0031] FIG17 includes three diagrams according to one or more embodiments: (a) illustrating an example first frame structure of an initial transmission including ULP signaling carrying all information of a second stage SCI for one or more subsequent transmissions, (b) illustrating an example second frame structure of subsequent transmissions with SL payloads, and (c) illustrating a signal flow diagram of an example SL transmission, wherein the initial SL transmission includes ULP embedded signaling carrying all information of a second stage SCI for subsequent transmissions;

[0032] FIG. 18 includes two frame structures illustrating examples of partial second stage SCI in initially transmitted ULP signaling and in a short PSSCH according to one or more embodiments;

[0033] FIG. 19 includes two frame structures illustrating an example of all second stage SCI in initially transmitted ULP signaling and in a short PSSCH according to one or more embodiments;

[0034] Fig. 20 is a signal flow diagram illustrating an example of a non-ULP WTRU receiving a second stage SCI in a reduced PSSCH transmission in accordance with one or more embodiments;

[0035] Fig.21 is a flow chart illustrating an example decision process for selecting a SL ULP Phase II SCI format according to one or more embodiments;

[0036] Fig. 22 is a flow chart illustrating an example procedure implemented by a WTRU with ULP feedback for SL transmission in accordance with one or more embodiments;

[0037] Fig.23 is a flow chart illustrating an example procedure implemented by a WTRU with ULP feedback for SL reception in accordance with one or more embodiments;

[0038] Fig.24is a flow chart illustrating an example procedure implemented by a WTRU transmitting a second stage SCI for a subsequent transmission in an initial transmission in accordance with one or more embodiments;

[0039] Fig.25 is a flow chart illustrating an example procedure implemented by a WTRU that receives a subsequently transmitted second stage SCI in an initial transmission in accordance with one or more embodiments;

[0040] Fig.26 is a flow chart illustrating an example procedure implemented by a WTRU having a non-ULP receiver for SL reception in accordance with one or more embodiments;

[0041] Fig. 27 is a flow chart illustrating an example procedure implemented by a WTRU for sending a SL ULP small data transmission according to one or more embodiments;

[0042] Fig.28 is a flow chart illustrating an example procedure implemented by a WTRU for receiving a SL ULP small data transmission in accordance with one or more embodiments; and

[0043] Fig.29 is a flow chart illustrating an example of a SL scheduling and transmission procedure with SL ULP signaling according to one or more embodiments. DETAILED DESCRIPTION

[0044] In the following specific embodiments, many specific details are set forth to provide a thorough understanding of the embodiments and / or examples disclosed herein. However, it should be understood that such embodiments and examples can be practiced without some or all of the specific details set forth herein. In other cases, well-known methods, procedures, components and circuits are not described in detail to avoid blurring the following description. In addition, the embodiments and examples not specifically described herein can be practiced in place of the embodiments and other examples explicitly, implicitly and / or inherently described, disclosed or otherwise provided (collectively referred to as "provided") herein, or practiced in combination with these embodiments and examples. Although various embodiments are described and / or claimed herein, wherein devices, systems, equipment, etc. and / or any of their elements perform operations, processes, algorithms, functions, etc. and / or any part thereof, it should be understood that any embodiments described herein and / or protected by the claims assume that any device, system, equipment, etc. and / or any of its elements are configured to perform any operations, processes, algorithms, functions, etc. and / or any part thereof.

[0045] Example communications systems, networks, and devices

[0046] The methods, procedures, devices, and systems provided herein are well suited for communications involving both wired and wireless networks. Figures 1A to 1D An overview of various types of wireless devices and infrastructure is provided, wherein various elements of the network can utilize the methods, apparatuses, and systems provided herein, perform the methods, apparatuses, and systems provided herein, be arranged according to the methods, apparatuses, and systems provided herein, and / or be adapted and / or configured for the methods, apparatuses, and systems provided herein.

[0047] Figure 1A is a system diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail (ZT) unique word (UW) discrete Fourier transform (DFT) spread OFDM (ZT UW DTS-sOFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0048] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104 / 113, a core network (CN) 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110 and other networks 112, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to send and / or receive wireless signals and may include (or may be) a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0049] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to, for example, facilitate access to one or more communication networks (such as the CN 106 / 115, the Internet 110, and / or the network 112). By way of example, the base stations 114a, 114b may be any of a base transceiver station (BTS), a Node B (NB), an evolved Node B (eNB), a Home Node B (HNB), a Home evolved Node B (HeNB), a gNode B (gNB), a NR Node B (NR NB), a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0050] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each or any sector of the cell. For example, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0051] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0052] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 116. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0053] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA) that may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0054] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0055] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, for example using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0056] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as IEEE 802.11 (i.e., Wireless Fidelity (Wi-Fi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0057] Figure 1AThe base station 114b in may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish any of a microcell, a picocell, or a femtocell. As Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0058] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions, such as user authentication. Although not described in detail in the text, the CN 106 / 115 may be configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions, such as user authentication. Figure 1A Although not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs any of GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or Wi-Fi radio technologies.

[0059] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 114 or a different RAT.

[0060] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0061] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other elements / peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0062] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together, such as in an electronic package or chip.

[0063] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from the base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In one embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV or visible light signal. In one embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0064] Although the transmit / receive element 122 Figure 1B 102 as a single element, but the WTRU 102 may include any number of transmit / receive elements 122. For example, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0065] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0066] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, or the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0067] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0068] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0069] The processor 118 may also be coupled to other components / peripherals 138, which may include one or more software modules / units and / or hardware modules / units that provide additional features, functionality, and / or wired or wireless connectivity. For example, the components / peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (e.g., for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. Components / peripherals 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0070] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both uplink (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via hardware (e.g., a choke) or via signal processing performed by a processor (e.g., a separate processor (not shown) or via the processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both uplink (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0071] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with one embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0072] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0073] Each of the evolved Node Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to manage radio resource management decisions, handover decisions, user scheduling in uplink (UL) and / or downlink (DL), etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0074] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0075] The MME 162 may be connected to each of the evolved Node-Bs 160a, 160b, and 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0076] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-evolved Node-B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0077] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0078] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0079] Although the WTRU Figures 1A to 1D Although described as wireless terminals, it is contemplated that in certain representative embodiments, such terminals may (eg, temporarily or permanently) use a wired communications interface with a communications network.

[0080] In a representative embodiment, the other network 112 may be a WLAN.

[0081] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STA) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and directed to the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and directed to a destination outside the BSS may be transmitted to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit traffic to the AP, and the AP may deliver traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Direct link establishment (DLS) may be utilized to transmit point-to-point traffic between the source STA and the destination STA (e.g., directly between them). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (eg, all STAs in the STA) may communicate directly with each other. This IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0082] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP may send beacons on a fixed channel (such as a primary channel). The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0083] High throughput (HT) STAs may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0084] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For the 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and data can be sent by the transmitter STA. At the receiver of the receiver STA, the above-mentioned operation for the 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC) layer, entity, etc.

[0085] 802.11af and 802.11ah support operating modes below 1 GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter type control / machine type communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0086] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only a 1MHz operating mode) is sending to the AP, the entire available band may be considered busy even if most of the band remains idle and may be available.

[0087] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0088] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 according to one embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0089] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to send signals to and / or receive signals from the WTRUs 102a, 102b, 102c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0090] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with a set of parameters that may be scalable. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (e.g., including varying numbers of OFDM symbols and / or varying absolute time lengths).

[0091] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-B 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0092] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to manage radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b, routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0093] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and at least one data network (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0094] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, supporting network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRU 102a, 102b, 102c, for example, based on the type of services used by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, and / or services for MTC access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as Wi-Fi.

[0095] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure the traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0096] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, for example, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0097] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and the N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0098] Given that Figures 1A to 1D as well as Figures 1A to 1D , one or more or all of the functions described herein with reference to any of the following may be performed by one or more simulation elements / devices (not shown): WTRU 102a-102d, base station 114a-114b, evolved Node B 160a-160c, MME 162, SGW 164, PGW 166, gNB 180a-180c, AMF 182a-182b, UPF 184a-184b, SMF 183a-183b, DN 185a-185b and / or any other element / device described herein. A simulation device may be one or more devices configured to mimic one or more or all of the functions described herein. For example, a simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0099] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0100] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which can include one or more antennas) can be used by the simulation device to send and / or receive data.

[0101] introduction

[0102] Ultra-Low Power (ULP) Receiver

[0103] In existing wireless technologies such as cellular and WLAN, the RF front end is typically a mix of passive and active components. For example, passive components include the Rx antenna, Tx / Rx path switches, and filters. These components require little power (if any power) to function. On the other hand, active components require power to function. For example, oscillators tuned to the carrier frequency, low noise amplifiers, and A / D converters in the Rx path are active components.

[0104] In recent years, advances in RF component design have made it possible to use new RF circuits that can process received RF waveforms collected by a receiving device in ultra-low power (ULP) mode through the antenna front end with minimal use or no active power source. For example, such devices may only consider passive RF components and harvest energy from the received RF waveform to run the necessary circuits to process the signal. Another increasingly popular approach is to use a mixer-first architecture, eliminate the need for an RF low noise amplifier (LNA), and focus on the development of passive RF components. Passive (or almost passive) ULP receivers use RF components such as cascade capacitors, zero-bias Schottky diodes, or MEMS to implement the functions required for voltage multipliers or rectifiers, charge pumps, and signal detectors. It is worth considering that those ULP receivers can still operate in the far field of the antenna and can support a reasonable link budget.

[0105] The ULP receiver can perform basic signal detection, such as correlation for known signature waveforms and / or reception of low data rate signals. For example, the ULP receiver can also enter an energy harvesting mode by accumulating energy from the RF waveform entering the receiver front end through the Rx antenna. Link budgets characterized by small or medium area cellular base stations are supported. For example, the ULP receiver can be used as a wake-up radio component to trigger device internal wake-up and signal interruption after detecting wake-up signaling, which then prompts the main modem receiver to start up using active RF components.

[0106] When using a ULP receiver, the reduction in device power consumption is significant. A typical cellular 3G, 4G or 5G modem transceiver can easily require up to several hundred mW of power to demodulate and process received signals during active reception (such as in RRC_CONNECTED mode). Power consumption is proportional to the number of active RF front-end chains on the device, the channel bandwidth used for reception, and the received data rate. When the device is in RRC_IDLE mode where no data is received or sent, cellular radio energy saving protocols such as IDRX ensure that the receiver only needs to be powered on at most a few times per second. Typically, for the purpose of cell (re)selection procedures and reception of paging channels, the device then performs tasks such as measuring the received signal strength of the serving cell and / or neighboring cells. In addition, the device also performs AFC and channel estimation to support coherent demodulation. The power consumption of the device when in RRC_IDLE is approximately a few mW. In 3GPP NR Release 15, such as in eMTC and / or NB-IoT devices, the sequence detection circuit for handling in-band wake-up signals in RRC_IDLE mode can also be implemented in the form of a dedicated wake-up receiver. This allows the A / D converter and important parts of the digital baseband processor to be turned off. However, several active components in the RF front end, such as low noise amplifiers and oscillators, are still used, with the LNA power consumption typically in the milliwatt range. On the other hand, the ULP receiver can reduce the power consumption of the device in RRC_IDLE to about or below 1mW by removing the RF LNA and making the power consumption dominated only by the local oscillator.

[0107] Two types of modulation schemes, On-Off Keying (OOK) and Frequency Shift Keying (FSK), are most commonly used in ULP receivers, of which OOK is the most attractive due to its simplicity when designing ULP radio components. For example, a simplified block diagram of OOK and FSK radio components based on mixer-first energy detection (ED) is shown in Figure 2. Figure 3 A simplified block diagram of a ULP receiver with a fully passive RF front end is shown in FIG.

[0108] Idle mode operation in 3GPP

[0109] In one example, while in RRC_IDLE mode, a WTRU implementing any or a combination of 2G, 3G, 4G and / or 5G RATs performs PLMN selection, cell selection / reselection, and location registration procedures. Depending on capabilities, some devices may also support manual CSG selection or MBMS frequency prioritization in RRC_IDLE mode. 5G devices may support RNA updates and operations in RRC_INACTIVE state.

[0110] In one example, when the WTRU is turned on, the WTRU may select a PLMN. For the selected PLMN, the associated RAT may be set. Through cell selection, the WTRU may search for a suitable cell of the selected PLMN, select the cell to provide available services, and monitor its control channels. The WTRU may register its presence through a NAS registration procedure in the tracking area of ​​the selected cell.

[0111] While in RRC_IDLE, the WTRU may perform received signal strength measurements on the serving cell and / or neighboring cells. If the WTRU finds a more suitable cell according to the cell reselection criteria, the WTRU reselects to that cell and camps on that cell. If the new cell does not belong to at least one tracking area to which the WTRU is registered, a location registration is performed. The WTRU may also search for a higher priority PLMN at regular time intervals and search for a suitable cell if its NAS has already selected another PLMN.

[0112] If the WTRU loses coverage of the registered PLMN, a new PLMN is automatically selected, or an indication of the available PLMNs is given to the user so that a manual selection can be performed. Various control means exist for the network to prioritize cell (re)selection on certain RATs, to control the rate at which low, medium or high mobility WTRUs perform cell reselection, and to prohibit selected tracking areas from being reselected by the WTRU.

[0113] When the WTRU is in the RRC_IDLE state or camped on a cell in the RRC_INACTIVE state, the WTRU may receive system information from the PLMN and may establish an RRC connection or resume a suspended RRC connection. The WTRU may receive ETWS or CMAS notifications. In addition, if the network needs to transmit control messages or pass data to the registered WTRU, in most cases the network knows the set of tracking areas in which the WTRU resides. A paging message may then be transmitted for the WTRU on the control channels of all cells in the corresponding set of areas. The WTRU may then receive the paging message and may respond.

[0114] Sidelink (SL) communication

[0115] In some specific implementations of NR sidelink, two procedures are related to sidelink (SL) devices monitoring resources on any configured resource pool (RP). One procedure is about channel sensing to monitor future resource availability and is used for SL devices that are configured to (potentially) send data. The other procedure is about SL data reception, where devices are configured with RX resource pools on which they can receive data.

[0116] In the data reception procedure, the SL device is required to monitor the channel and blindly decode the RX RP resources to find any potential physical sidelink shared channel (PSCCH), including the first-stage sidelink control information (SCI). When a valid first-stage SCI is found, the device should decode the second-stage SCI within the associated PSSCH in the same time slot, so the device should record and store potential PSSCH symbols and decode them if the first-stage SCI is found. At least the decoding of the second-stage SCI is mandatory in the RX resource pool because the entire destination ID of the transmission is in the second-stage SCI, and therefore the receiving side link device only knows whether it is the destination of the transmission after decoding the second-stage SCI.

[0117] In the channel sensing / resource allocation procedure, SL devices are configured with a pool of TX resources where they can be scheduled to transmit. Mainly for mode 2 scheduling, these devices should monitor and blindly decode the PSCCH for the first stage SCI and the resource reservations included therein, and perform energy measurements on the PSSCH. NR Release 17 introduces some restrictions on sensing for power efficiency, but still relies on some partial sensing or information loss (due to missed transmissions). Partial sensing in the NR sidelink is similar to partial sensing in LTE, where devices are required to monitor only selected periodicities, and monitoring of non-periodic reservations is added.

[0118] In both procedures, the device may be required to perform continuous or frequent monitoring and blind decoding of at least the PSCCH on its configured resource pool, and decode the second stage SCI in the PSSCH of the RX resource pool, which is energy consuming.

[0119] Currently, there is no wake-up signal designed for the sidelink, let alone some wake-up signal based on ULP. It is possible to close the connection between a pair of users and have the devices become idle / inactive on their Uu links, and perhaps use some wake-up signal, but this will mean very long latency because the devices need to wake up the main radio part to make the Uu connection, and then re-establish the connection with the users in the sidelink to be able to resume communication.

[0120] Therefore, enhanced procedures for sidelink (SL) transmission and reception may be required. For example: reducing the energy consumption of monitoring and receiving the first phase SCI and the second phase SCI for SL devices configured to receive transmissions, while avoiding severe latency and disconnection and reconnection procedures for SL devices with infrequent data reception; ensuring coexistence between the proposed solution and legacy devices or devices without ULP capabilities, so that other devices can still perform good data reception and / or monitoring of their channel sensing; and / or reducing the overhead of the second phase SCI transmission.

[0121] Representative procedures for sidelink signal reception

[0122] Various embodiments disclosed herein relate to sidelink data reception. Methods and procedures are provided in which a device (e.g., a WTRU) having a ULP receiver can shut down its main radio's monitoring of its conventional SL radio receiver to save energy while using the ULP receiver to monitor a channel for potential reserved transmissions.

[0123] In some examples, the ULP receiver is located in a SL device that is configured for SL reception rather than channel sensing for resource selection.

[0124] In various embodiments, a device (eg, a WTRU) is configured to perform in-band sidelink ULP transmission, where the ULP signal may be transmitted on a SL resource pool shared with devices (eg, a WTRU) that may not be equipped with a ULP receiver.

[0125] Note that this also applies to scenarios where resource sets are configured to be monitored only by ULP receivers, so that ULP signals are multiplexed separately from regular SL transmissions in the time and / or frequency domain. These resource separations can be configured using, for example, different resource pools, different BWPs, or even different frequency bands.

[0126] In some examples, the NR SL framework and frame structure may be reused to ensure backward compatibility and interoperability with other devices and to be able to operate within a regular SL channel (bandwidth part (BWP) and / or resource pool (RP)).

[0127] When, for example, the WTRU's main receiver is in sleep mode and the ULP receiver is used for channel monitoring, the sidelink user sending to the WTRU device should first send a signal suitable for the ULP receiver (e.g., a ULP signal) so that the WTRU wakes up the main receiver to receive the actual data payload.

[0128] To reduce the energy consumption of the SL device, the transmission of either the first phase SCI or the second phase SCI of the conventional SL device required for reception can be offloaded to the ULP air interface (e.g., using a ULP receiver). The ULP receiver has very low power consumption, but the data rate it can support is limited, and can be used to act as a wake-up receiver for the SL.

[0129] To ensure the coexistence of ULP signaling and reservation of the retransmission mechanism with other SL devices, the ULP signal is embedded in the conventional SL slot format, preserving the PSCCH (and possible DMRS) so that other users can perform channel sensing or correct blind decoding.

[0130] Retaining the NR SL frame structure allows resources to be reserved for retransmissions, which can be used to schedule actual data transmissions using the primary radio receiver, and other users performing channel sensing can take the reservation into account in their resource selection procedures to avoid (e.g., reduce) transmission conflicts.

[0131] Some extensions of current implementations or procedures aim to increase the interoperability of embedded ULP signaling and optimize the use of resources to reduce signaling overhead.

[0132] To reduce the signaling overhead of the second stage SCI (in subsequent transmissions), in one example, the ULP signaling (e.g., in an initial transmission) may carry some of the second stage SCI content in anticipation of subsequent transmissions. The content depends on the data rate and signaling capabilities supported by the ULP, and a new sub-format for the second stage SCI may be defined. After part of the second stage SCI has been sent using the ULP signal, subsequent transmissions may only send the remaining part to reduce overhead in retransmissions. The WTRU with the ULP receiver may then combine the configuration / information received from the two interfaces and use it to decode the data.

[0133] To ensure coexistence with other users, and in particular to allow for mixed groups (e.g., multicast) sent to ULP and non-ULP destinations, a device (e.g., WTRU) or the network may copy a portion of the second stage SCI sent on the ULP into a sub-format of the second stage SCI sent on the initial transmission. Both the ULP device and the non-ULP device may then receive the entire contents of the second stage SCI over both transmissions to decode the payload.

[0134] In various embodiments, a "non-ULP legacy device" is a device that is capable of performing 3GPP NR sidelink transmission and reception per the specification, but is unaware of changes or specification aspects of ULP signals (e.g., a device that implements the specification up to a version prior to the introduction of ULP signals for SL). The device is also unable to receive / transmit ULP signals.

[0135] In various embodiments, a "non-ULP non-legacy device" is a device that implements the 3GPP NR sidelink specification and is capable of SL transmission and reception. The device does not have a ULP receiver (or at least the ULP receiver is not active at the time considered), but the device implements and follows the specification on how to handle signaling reception related to ULP coexistence. It may or may not be able to send ULP signals.

[0136] In various embodiments, a "ULP capable device" is a device that includes a ULP receiver in addition to a main radio transceiver and is compatible with the 3GPP NR specifications for handling ULP signal reception.

[0137] Representative procedures for in-band ULP signaling in sidelink transmission

[0138] Representative procedures for embedding reservations for ULP signaling and transmission (retransmission)

[0139] Utilize the transmission (retransmission) and reservation scheme for ULP

[0140] In one embodiment, to adapt the wake-up / ULP signal to the existing NR sidelink framework, the enhanced method / procedure may include embedding the ULP signal into the resources of the PSSCH, and / or utilizing a retransmission reservation scheme to allow the transmission of SL data to be performed in two steps. First, the initial SL transmission carries the ULP embedded signaling to wake up the WTRU with the ULP receiver, and carries the regular PSCCH with the first stage SCI to reserve resources for retransmissions and allow coexistence with other devices performing channel sensing or reception. Second, the subsequent transmission reserved by the initial transmission carries the actual transmission payload of the destination that has been awakened.

[0141] The RP can be configured to allow one or two resource blocks to be reserved for retransmissions in the future. The reservation is declared in the first phase SCI (i.e., in the PSCCH) in the initial transmission. Note that in NR SL, the resources reserved for retransmissions can be selected in any of the next 32 logical slots of the resource pool and can be selected anywhere in the frequency domain of the resource pool. The reserved resources are determined by the time and frequency resource assignment indication in the first phase SCI.

[0142] like Figure 3 As illustrated, an initial transmission with a frequency width of 4 subchannels is performed in the SL resource pool, which includes a ULP indication (described below). The initial transmission uses the first stage SCI indication in the PSCCH to provide resource reservation for future transmissions (retransmissions). The reservation mechanism is the same as that in NR SL to ensure coexistence with nearby users. The retransmission is a regular sidelink transmission that the destination can receive using the main SL radio receiver of the device.

[0143] The combination of conventional SL and ULP signals in transmission allows the present invention to ensure coexistence between ULP devices and non-ULP devices (legacy or non-legacy) when sharing a common BWP / RP.

[0144] When monitoring the ULP signal, a ULP-receiver device cannot read the PSCCH and therefore cannot determine the scheduled reservation for retransmission. However, the scheduling information (time and frequency resource assignments) may be carried in the ULP signaling jointly with the destination of the wake-up signal (see next section).

[0145] Alternatively, it is possible to schedule without sending retransmission information, but the ULP WTRU has to reactivate the monitoring of the regular SL channel within the (pre)configured maximum time delay and resume blind decoding on all time slots of its resource pool, which consumes more energy than knowing when the user should wake up for the next transmission.

[0146] like Figure 5 As illustrated, a WTRU device with a ULP-receiver may be configured to monitor the ULP signal and perform in-band monitoring when the conventional radio receiver is off or in deep sleep (i.e., not monitoring the sidelink channel). Upon receiving a ULP signal intended for the WTRU, the WTRU decodes the ULP signal and determines whether the WTRU is the intended recipient of the signal and the scheduled reserved transmission. If the WTRU is the destination, the ULP receiver will notify and wake up the primary sidelink receiver, and the WTRU device prepares itself to receive the transmit payload on the retransmission resources. In subsequent transmissions (retransmissions), the transmission uses the conventional sidelink format, with both the PSCCH and the PSSCH including two SCIs and the data payload to be decoded. If configured to do so, the WTRU may perform HARQ feedback to the transmitter.

[0147] like Figure 6 As illustrated, non-ULP users and / or legacy devices configured to monitor SL on the same or overlapping resource pools will decode the first phase SCI in the PSCCH as they normally do and obtain the scheduling information for the reserved resources so that the device can take this information into account in the resource selection procedure. Upon decoding an indication of ULP embedded signaling, the absence of a second phase SCI, or an unknown second phase SCI, the non-ULP WTRU may ignore and discard the contents of the remaining resources sent. Retransmissions are typical NR SL transmissions and may therefore be processed normally by these devices. However, these devices will not be compatible with reading ULP signals that are not intended for them and may discard the received signal, but may still perform measurements on the "PSSCH" or DMRS symbols if required by other procedures (such as channel sensing).

[0148] ULP reception failure detection and handling

[0149] exist Figure 5 In the simplified scheme illustrated, the ULP receiver, upon detecting a ULP wake-up signal for itself, will trigger the main radio receiver chain to monitor the channel and receive subsequent transmissions. However, in the event that the ULP signal cannot be properly received (and if no action is taken), the main radio components will not wake up in time to receive the transmission.

[0150] In one embodiment, failure detection at the TX client is managed via HARQ feedback of (re)transmissions. Figure 5 As illustrated, the RX WTRU performs HARQ feedback after receiving the payload transmission if the configuration of the SL transmission requires it.HARQ feedback is enabled / disabled using a bit flag in the second stage SCI and is therefore transmission specific.

[0151] In unicast transmissions and some multicast transmissions, HARQ uses ACK / NACK feedback (no feedback reception is discontinuous transmission (DTX)). On the TX side, after sending the payload, one of the following is received from the receiver:

[0152] - ACK indicates that both the ULP wake-up call and the SL payload transmission have been successful, and the next transmission (if any) can continue as usual;

[0153] -NACK indicates that the ULP signal, PSCCH and second-stage SCI were received successfully, but the payload was not received successfully. In this case, a normal SL retransmission can be performed, and the normal HARQ process and retransmission management can be resumed; and / or

[0154] - In case neither ACK nor NACK is received (DTX), the TX user knows that at least the second stage SCI was not received, but does not know whether the ULP signal was received, and therefore does not know whether the main SL radio component is activated.

[0155] In one example, to mitigate this situation, when the ULP signal is correctly detected but the second stage SCI is not detected afterwards, the RX transmits a status update to the TX via the MAC layer (e.g., sidelink MAC CE), PHY layer signaling (e.g., for ULP dynamic activation (deactivation)), or RRC reconnection / reconfiguration. In this way, the TX user knows that the RX has woken up its main radio part, and the TX user can then retransmit using regular SL transmission. If the TX user does not receive an indication within a configured time period, it should assume that the RX user did not receive the ULP signaling, and should retry sending the ULP signaling, wait for the main SL monitoring that works periodically, or notify the network of the ULP failure.

[0156] In a multicast transmission using NACK-only HARQ feedback (absence of feedback is interpreted as ACK), the receipt of a NACK will mean that the ULP was successfully detected, the PSCCH and second stage SCI were also successfully decoded, but the payload was not successful. In this case, a regular SL retransmission can be performed, resuming the regular HARQ process and retransmission management. The absence of a reply from the ULP user is ambiguous and may mean that the ULP and SL were successful, the ULP was successful but the SL transmission was not successful when it was too far away from the TX (because there is a distance limit for replying HARQ feedback in a NACK-only SL multicast), or the ULP was unsuccessful and the primary SL was not awakened. If the RX user receives the ULP signal, but the user has no NACK to send within the configured time period, it can use PHY layer or MAC layer signaling to transmit an indication of its status (i.e., the primary SL radio component is activated) to the TX user. This will confirm the successful reception of the ULP signaling to the TX user, and the following transmissions can be performed regularly.

[0157] In one embodiment, if Figure 7 As illustrated, it is proposed that a WTRU with a ULP receiver transmits a feedback transmission to confirm the reception of a ULP signal. Upon receiving a ULP signal for the ULP receiver, the WTRU wakes up the main SL radio and reports the reception using the physical sidelink feedback channel (PSFCH) associated with the ULP embedded transmission. The feedback may be a preconfigured method or enabled by an indication in the ULP signaling.

[0158] -ACK implies correct reception of the expected ULP signal;

[0159] -NACK implies that the ULP signal was not correctly (or not completely) detected / decoded, but the UE determined that it was the destination of the ULP signaling. One possible scenario is if the ULP signaling contains a destination ID and other content (e.g., scheduling information) transmitted as two consecutive signals, and only the destination ID was received correctly; another scenario is if the ULP signal itself implicitly helps determine the destination (e.g., if the schedule of the ULP signaling is mapped to a specific ID), but the content was not decoded; and / or

[0160] -DTX implies that no ULP signaling was received.

[0161] Upon receiving ACK, TX may continue with transmission (retransmission) to the primary SL radio receiver. Upon receiving NACK, TX may continue with transmission (retransmission) to the primary SL radio receiver, but shall assume that only the ULP destination ID is correctly received. In case of DTX, TX user shall proceed with fallback mechanism, e.g., shall restart ULP wake-up signal or wait for periodic monitoring of primary SL receiver or report failure to gNB.

[0162] As an alternative, the RX WTRU may transmit a command / control message to the TX WTRU indicating that regular SL monitoring may be resumed which may include additional configuration (e.g., similar to SL RRC reconfiguration) rather than reporting using the PSFCH. This allows for more information but requires regular SL transmission, i.e., with resource selection, transmission preparation, etc., which adds significant latency to the process.

[0163] As described above, it is possible for a WTRU with a ULP receiver to be configured to perform "periodic" monitoring of the SL channel using its primary radio receiver. This may be enabled for recovery in case of ULP failure (e.g., a scenario where the ULP signal is out of range). The periodic operation of the primary radio receiver is configured as part of the (pre-)configuration of the RP layer or the SL RRC configuration, which may be configured, for example, as periodic monitoring in time (e.g., every 100 ms) or periodic in multiple logical time slots from the RP (e.g., one time slot every 32 time slots). This monitoring of the SL channel is a fallback mechanism that may be used by a TX user that attempts to perform a ULP wake-up signal in the event that no ACK / NACK feedback is received.

[0164] As an alternative / supplementary fallback mechanism, a TX user that does not receive any feedback or status update from the ULP device within a configured time may report a failure to the network, and the network may proceed to wake up the ULP device through dedicated ULP or Uu signaling (e.g., paging).

[0165] ULP Embedding and Resource Mapping

[0166] In the initial transmission of the ULP embedded transmission scheme, the sidelink transmitter transmits a new sidelink format based on the frame structure and time slot format of Release 16 / 17.

[0167] The proposed format retains the NR SL PSCCH, which still includes the first stage SCI. AGC and guard symbols are also retained to protect the signal and help the receiver adapt between adjacent transmissions from different users. However, the resources used for PSSCH in conventional SL transmissions as indicated in the first stage SCI (frequency assignment) are replaced and allocated to ULP signal transmission.

[0168] It should be noted that the resources allocated for ULP signaling are not necessarily all used for ULP signal transmission itself, and may also include potential guard time in the time domain and / or guard band in the frequency domain, depending on the design and requirements of the ULP signal itself. For example, if the designed ULP signal occupies a limited or fixed bandwidth, but the SL frequency resources are larger than the bandwidth, then the "empty" frequency resources adjacent to the ULP signal can be used as the guard band in the ULP resource allocation.

[0169] The NR SL design is done so that a transmission can span any number of subchannels in a resource pool (which is a configured multiple of the resource blocks for a given resource pool). In addition, for blind decoding purposes, the size of the PSCCH is one subchannel over 2 or 3 fixed symbols (also configured per resource pool). Therefore, if a transmission is scheduled on multiple subchannels, the frequency resources that are adjacent in the frequency domain to the PSCCH on the same symbol are usually used for the PSSCH (or DMRS).

[0170] There are several variations on how to map the physical resources for ULP signals.The configuration of which options and formats of ULP can be used is (pre-)configured, for example, as part of the SL RRC connection / reconfiguration procedure or RRC connection / reconfiguration procedure or via SIB indications.

[0171] In one embodiment, the resources allocated to ULP signaling represent all resources of the SL time slots scheduled in the PSCCH, except for the PSCCH itself and symbols used for AGC and protection. This means that DMRS symbols are not sent. It should be noted that the DMRS associated with the PSSCH is not required to decode the PSCCH, because the DMRS associated with the PSCCH already exists in the PSCCH resources. It should be noted that in this case, the measurement of RSRP for channel sensing should not be based on PSSCH-RSRP, and the resource pool should be configured to enable the user to perform PSCCH-RSRP. Alternatively, non-ULP but non-legacy devices may be able to perform signal strength measurements using ULP signals, and the configuration mapping between the ULP-RSRP measurements and the corresponding conventional PSSCH-RSRP can also be used to reduce the potential difference in signaling power sent for conventional PSSCH and ULP signals.

[0172] This embodiment maximizes the resource usage of the ULP signal while having contiguous resource blocks in the time domain.Three alternatives are illustrated in FIG8 .

[0173] In the case of single subchannel transmission ( FIG. 8( a )), the resources allocated for ULP signaling are resource blocks that are consistent in frequency and time domains, which may be beneficial to ULP signal design and can simplify ULP signal transmission and detection.

[0174] For the case of scheduling transmission on multiple subchannels (Figure 8(b) and Figure 8(c)), some resources are adjacent to the PSCCH in the frequency domain on the same time symbol. If the ULP signal design supports transmission on such resource blocks, as illustrated in Figure 8(b), the ULP embedded structure is configured to allow these resources to be allocated for the ULP signal. Otherwise, the resources used for the ULP can be restricted to the "square" time-frequency resource blocks on the symbols after the PSCCH, as illustrated in Figure 8(c).

[0175] Note that the AGC symbols not required for detecting / decoding the ULP may be limited to the subchannels of the PSCCH in the frequency domain, so that other users can only expect received power on the PSCCH.

[0176] In another embodiment (see the example in Figure 9), the resources allocated to ULP signaling correspond to the resources of the SL time slot scheduled in the PSCCH, except for the PSCCH itself, symbols for AGC and protection, and DMRS. Sidelink transmissions of other users are used for measurement (e.g., during sensing), and the RP can be configured to use PSSCH-RSRP as a metric to determine whether the resource is available (e.g., whether it can be reused). Therefore, it may be useful for other users to retain identifiable signals (e.g., DMRS) for measurement. When DMRS symbols are not sent adjacent to the first or last symbol transmitted in the time slot, they will create discontinuity with the ULP resources.

[0177] In the case where the ULP signal does not support discontinuity, the ULP signaling resource allocation spans the resources between the remaining SL signals / channels as illustrated in Figures 9(a) and 9(b) for the single subchannel and multiple subchannel cases, respectively. In the case where the ULP signal supports non-continuous transmission, the resources allocated to the ULP signaling may span all resources that are "released" due to the absence of the PSSCH. This is illustrated in Figure 9(c) for single subchannel transmission and Figure 9(d) for multiple subchannel transmission.

[0178] Note also that similar options can be derived in the case where PSFCH is needed in a timeslot and therefore the last symbols (guard, AGC, PSFCH and guard symbols) are not allocated for ULP signaling. Depending on the ULP signal design and the available data rates, it may be easier to avoid such timeslots to maximize the utilization of ULP resources.

[0179] Alternative SL structure with PSCCH and PSSCH for ULP embedded transmission

[0180] An alternative format for sidelink transmission with ULP embedded signaling is that the initial transmission includes ULP signaling, PSCCH with first-stage SCI, and PSSCH. In this scenario, the size of the PSSCH is reduced not to carry payload, but to carry second-stage SCI. To ensure backward compatibility, the PSSCH carrying the second-stage SCI should be placed first before the ULP resources, for example, where the second-stage SCI is located in a conventional SL transmission.

[0181] In this way, a non-ULP user monitoring the channel can also decode the information of the second stage SCI and, for example, know the destination and source of the transmission, which may help to know whether the non-ULP user is part of the destination, such as as a group destination. The source and destination information can also be used to improve resource selection (e.g., avoid selecting resources with duplex conflicts for the destination or source of the transmission) or in the case of cooperation / coordination between users.

[0182] As illustrated in FIG. 10 , several formats may be defined, which may be used depending on the scheduling. Since PSSCH is to be decoded, it is necessary to reserve some PSSCH-DMRS symbols. In NR Releases 16 and 17, at least 2 symbols are used for DMRS (e.g., Section 8.4.1.1.2 of 3GPP TS 38.211), as illustrated by the examples of 2 DMRS symbols in FIG. 10( b ), FIG. 10( c ), FIG. 10( e ), and FIG. 10( f ). In these cases, implementations and options without PSSCH may also be applied. For example, FIG. 10( b ) illustrates an example of a single subchannel transmission with PSSCH and non-contiguous ULP resources; FIG. 10( c ) illustrates an example of a single subchannel transmission with continuous blocks of PSSCH and ULP resources; FIG. 10( e ) illustrates an example of multiple subchannel transmission with PSSCH and non-contiguous ULP resources; FIG. 10( f ) illustrates an example of multiple subchannel transmission with PSSCH and continuous ULP resources. Note that in the cases illustrated in FIG. 10( e ) and FIG. 10 ( f ), the PSSCH resources are not limited to being adjacent to the PSCCH resources, which depends on the size, slot format and transmission format of the PSSCH.

[0183] It is proposed that since PSSCH is restricted to the second stage SCI here, only one DMRS symbol can be used to decode PSSCH, thereby reserving more resources for ULP signaling, which are used for single subchannel transmission and multiple subchannel transmission, respectively, as illustrated in Figures 10(a) and 10(d). This new DMRS pattern needs to be added to the sl-PSSCH-DMRS-TimePatternList configuration including the DMRS pattern list. Alternatively, the traditional time pattern list can be retained for better backward compatibility, but when the transmission does not carry a payload, only the first DMRS symbol is actually used.

[0184] ULP monitoring and time slot grouping for periodic operation for ULP embedded transmission

[0185] To further reduce the processing requirements and energy consumption of ULP devices, it is proposed that the opportunities for ULP embedded transmissions can be grouped into specific time and / or frequency resources in a resource pool, so that the opportunities for sending the new ULP SL format on the same resources used for legacy devices and / or non-ULP devices can be limited. This can take the form of configuring the resource pool used to work on a periodic basis. This is a balance between latency and energy saving, and can be configured for RP or ULP users to take into account application needs.

[0186] The resource pool can be configured to regroup ULP receiver devices on specific time slots of the SL BWP. In the case where the resources used for ULP signaling are not dedicated to ULP signals (i.e., these resources can be used for ULP or regular SL transmissions), the processing burden depends on the grouping of resources. If regrouping is on the same time slot, the regrouped ULP devices will receive more ULP signals and may attempt to decode and process these signals until it is determined that these devices are not the destination (i.e., a false alarm situation), but it will ensure that non-ULP devices do not bear the burden of receiving unnecessary transmissions on other time slots. If the ULP devices are configured so that their ULP signaling does not use the same time slot, it will avoid false alarm problems and optimize the battery life of the ULP devices, while increasing the opportunity for non-ULP devices to decode unnecessary transmissions.

[0187] In case the resources used for ULP signaling are configured to be monitored only by the ULP receiver, non-ULP users can skip decoding of these resources and also reduce processing and energy consumption.

[0188] There are three ways to configure resource pools for ULP embedded SL and SL:

[0189] First, separate resource pools and switching. Resource pools are separated by configuration and configured independently. Control (e.g., SCI or DCI) enables switching between RPs to be activated once. RPs for ULP embedded SL transmission can be quite sparse to perform monitoring that works periodically. When ULP monitoring is activated (deactivated), switching can also be considered to be done implicitly.

[0190] Second, the ULP is a subset of the regular RX RP. The resource pool used for ULP monitoring is a subset of the active SL RPs used by the user when switching to ULP monitoring. The subset can be configured for each RP (e.g., by SL RRC) or globally as a scheme for any RP. In this way, no specific dynamic signaling is required to activate (deactivate) the ULP monitoring RP.

[0191] Third, separate resource pools, but each interface is "active". The resource pools are separated by configuration and configured independently. Compared to NR SL (up to Release 17) which only allows a single RP to be active for a user at a time, it is proposed that both RPs are active, i.e. one RP per interface. However, the TX device will select the RP to transmit to based on the ULP monitoring status of the RX device.

[0192] ULP signal indication and first stage SCI format

[0193] The first stage SCI carries important information for scheduling reservations and how to interpret the second stage SCI. The sidelink users in the RP perform blind decoding of the underlying PSCCH of the first stage SCI. Upon successful decoding of the first stage SCI, the user can attempt to decode the corresponding PSSCH (second stage SCI and data payload) based on the information of the first stage SCI (such as transmission size, MCS, DMRS mode, second stage format). Therefore, the first stage SCI is modified by adopting a new format to embed the ULP signal so that users monitoring the channel understand the ongoing transmission.

[0194] Upon receiving the first stage SCI indicating that the PSSCH content is actually a ULP signal, users that are not targeted by the transmission may ignore the PSSCH. Note that these users may still perform measurements if desired.

[0195] For the indication of the ULP content itself, several options / implementations are possible:

[0196] Use reserved values ​​in the Phase 1 SCI. Non-legacy users will understand the use of a one-bit indication as a ULP signal indication, while legacy users will consider it a reserved field (and therefore ignore it). To enable this option, a new Phase 1 SCI needs to be defined that adds the ULP indication to the regular Phase 1 SCI (SCI format 1-A). Either through a new format with a specific name, such as SCI format 1-B or equivalent; or by modifying the existing Phase 1 SCI to place the indication in the reserved bit and activate it through resource pool configuration. Legacy users will discard the unknown bit and the size of the reserved bit is configured on the resource pool.

[0197] The second stage SCI format indication is used in the first stage SCI, which is an explicit indication of the second stage SCI format. This indication is currently a 2-bit field with one option reserved. The reserved option can be reassigned to the ULP signal indication (or alternatively indicates that there is no second stage SCI). For example, the original table from 38.212-8.3.1.1-1 (v17) can be modified as follows:

[0198] The value of the second stage SCI format field Phase II SCI format 00 SCI Format 2-A 01 SCI Format 2-B 10 SCI Format 2-C 11 ULP signaling (or absence of Phase 2 SCI)

[0199] This indication will be interpreted by non-ULP non-legacy users as an indication of a ULP signal (or at least a signal not intended for these users), while legacy devices will interpret this as not supporting the format of the second stage SCI and will therefore not attempt to decode the PSSCH.

[0200] An additional MCS table indicator field is used, which indicates the MCS table to be used (e.g., Table 8.1.3.1-1 and Table 8.1.3.1-2 in 3GPP TS 38.214). Note that section 8.3 of standard 38.214 mentions: "If SCI format 1-A indicates an MCS table that the UE does not support, the UE need not decode the corresponding SCI formats 2-A and 2-B nor the PSSCH associated with SCI format 1-A." The table for MCS table mapping can be used to refer to the new "MCS table", i.e., the modulation of the ULP signal. Alternatively, a reserved value can be used to indicate that the PSSCH is a ULP transmission. Therefore, non-ULP neighboring users may not attempt to decode the content.

[0201] It is also possible not to include any indication of the PSSCH content in the first stage SCI, and when other users attempt to decode the second stage SCI, these users will fail and discard the transmission. However, this solution will result in unnecessary decoding.

[0202] Representative procedures for ULP signal content

[0203] When a ULP-receiver device is configured to monitor ULP signals and not monitor the SL resource pool associated with a conventional radio receiver, the ULP-receiver device cannot read non-ULP signals, including PSCCH and PSSCH (if any). The ULP signal content should carry some information required for the ULP device to understand whether it needs to wake up and how to proceed with future transmissions.

[0204] The information elements that need to be determined by the user receiving the ULP signal may include: information about the identity of the destination (ie, "should the device be awakened"); the scheduling of retransmissions (ie, "when should the device be up and ready"); and / or information about the identity of the sender.

[0205] It is worth noting that these are very few of all the information carried by the first and second phase SCI. The reason for not carrying all the information is that, except for the scheduling of the retransmission, these information relate to the same timeslot SL transmission and are therefore not necessary for the ULP device, which only reads the ULP signal. All the necessary information for the actual payload will be repeated in the first and second phase SCI of the retransmission.

[0206] To overcome the capacity limitations and limited number of sequences that a ULP receiver can support, it is possible to compress the acquisition of the ULP payload. The network can send sequences that will act as a signature to identify which content is delivered.

[0207] The WTRU must know the mapping between signatures and their corresponding content and this mapping is initially received by the main radio component using the conventional Uu or SL interface, for example using SIB configuration, RRC signaling or UE-to-UE configuration as part of discovery or SL RRC connection.

[0208] All contents of the ULP signal are configurable according to the capabilities of the user. Note that in the case of a sidelink, both the transmitting user and the ULP receiver user should be compatible (as Tx or Rx) to be able to perform the transmission. For example, the ULP format to be used is agreed upon during SL RRC configuration.

[0209] The configuration may contain a list of possible content that may be used by the ULP-capable device.The signature for each content may be associated with the content (eg, hashing the content) or may simply be based on an index of a row in the list.

[0210] The signature may be network specific, specific to a set of cells within a particular area, a user group, a given resource pool, or a given user. The signature and sequence may be received by the ULP receiver at any time using a low power correlator or receiver without having a predefined schedule or timing associated with each configuration or signature. Alternatively, the signature may be received by the ULP receiver according to a predefined schedule sequence. The signature may also be transmitted after a reference signal (e.g., LP-PSS and / or LP-SSS) so that the receiver can identify the source of the signature. The timing between the reference signal and the signature may be part of a scheduled / configured sequence.

[0211] ULP destination indication

[0212] The ULP signal should contain an indication of the ULP destination ID. This can be a single user ID (either as the ULP ID or as a regular user ID), an ID for a user group (or a shortened single user ID that actually corresponds to a user group with a similar shortened ID), or a simple single signal that acts as a broadcast for all ULP devices. Broadcast or group-based IDs require fewer bits of information to be effective, which makes ULP signal reception more robust and / or requires less processing, but will wake up several unintended users, causing unnecessary energy consumption by these users.

[0213] The destination ID to be used and the associated format in the ULP signal are (pre-)configured as part of the user's RRC connection, the RRC connection of the SL pair, or may be configured as part of the ULP-specific SIB / RRC.

[0214] Upon receiving a ULP signal with a destination ID matching the device, the ULP receiver should also determine the remaining information (if any) in the ULP signal and prepare to wake up the main radio receiver for subsequent SL transmission.

[0215] Reservation Mode / Configuration

[0216] In NR SL Release 16 to 17, the reservation of retransmissions can be performed up to 32 logical slots ahead in time using the time resource assignment field of the first phase SCI (coded as 5 or 9 bits). The frequency resource assignment is also coded as a few bits to allow flexible frequency scheduling (the exact number of bits depends on the number of subchannels in the RP and the maximum number of retransmissions).

[0217] The resource reservation assignments sent (retransmitted) in the first stage SCI are not decoded by the targeted ULP device. However, due to the limited data rate and total number of bits available via the ULP signal (either as a signature or explicit data), it is useful to signal the overhead of reservations as much as possible. The indication of the scheduled retransmission resources may include all retransmission resources reserved by the transmitter. Alternatively, the indication may contain only the first next reserved resources and the WTRU. In this way, the size of the indication is smaller and the overhead is reduced, and the ULP receiver device should determine the subsequent reservation (if any) by decoding the retransmitted PSCCH using its primary radio receiver.

[0218] One element of resource reservation is the size sent in the frequency domain. If this information can be detected by the receiver through the size of the ULP signal, it can be inferred without the need to be additional, dynamically signaled information. As an alternative, the ULP signal may be limited to a specific size due to hardware or user capabilities. In this case, the ULP signal size in the frequency domain is also known (configured based on capabilities) and can therefore be omitted from the ULP signaling.

[0219] In one embodiment, the time mode (and frequency mode if needed) may be signaled using a list of time / frequency patterns (pre)configured between users, e.g., via RRC configuration or sidelink SIB or ULP SIB. This list maps to a list of signatures supported by the ULP receiver. The transmitter may transmit one such signature in the ULP signal so that the receiver can determine the time-frequency pattern for retransmissions.

[0220] In one example, especially in case of low data rate requirements, a single (pre-)configured pattern is used for ULP based transmission, which avoids the use of additional signaling.

[0221] In all cases, the reserved time and frequency pattern is explicitly provided in the first stage SCI (ie, the converted ULP configuration / signaling information) so that other users reading the PSCCH can understand the same reservation pattern.

[0222] Retransmission Scheduling Notes

[0223] The device performing resource selection, for example at the gNB (mode 1) or the transmitting user (mode 2) or another scheduling device in case of assisted scheduling, should prepare the resources required for the transmission (both initial transmission and retransmission) taking into account the required size of the embedded ULP signal and the size of the actual regular PSSCH transmission.

[0224] This is done so that the same amount of resources is used in all (re)transmissions, which is a requirement of the specification for the SL reservation indication. For example, if the ULP signal resource requirement is higher than the PSSCH payload, the scheduler should modify the transmission format of the payload to fit the available resources (e.g., by reducing the MCS or adding some padding).

[0225] In case the ULP signal has a (pre) configured size or a fixed size (e.g. as required by the ULP radio capabilities), the configuration of the ULP transmission (at the connection layer between SL users or at the resource pool configuration layer) includes the corresponding ULP signal size requirement. Enabling such requirements limits scheduling flexibility but alleviates hardware and processing requirements at the ULP receiver end. One specific case is that if the ULP signal cannot be multiplexed with other channels / signals in the frequency domain, the ULP signal may need to occupy the entire bandwidth portion or the entire resource pool. Another specific case is if the ULP signaling design requires that the ULP signal (and possibly some guard bands) have a fixed size, and the transport block size and MCS will have to be adapted so that the transmitted packets fit into a SL transmission of the same size as the ULP embedded transmission.

[0226] An alternative approach is to separate the SL ULP signaling from the actual SL data transmission. In this way, the SL ULP embedded transmission can be performed using a resource size that is appropriate for the ULP signal (for its design and ULP content); and the SL payload can be sent using an independent transmission, where the initial transmission and retransmissions follow the normal SL format and procedures. This approach optimizes the use of resources, but does not make the ULP receiver WTRU aware of the scheduling information of the payload and must wake up the main radio components to perform blind decoding, which is energy consuming.

[0227] Representative procedures for sequential ULP embedded transmission

[0228] Thus far in this disclosure, an embedded retransmission scheme has been described where the initial transmission includes ULP signaling and subsequent transmissions include the actual payload. In this subsection, the principle is extended so that multiple transmissions may include embedded ULP signaling prior to subsequent SL payload transmissions. In this case, all transmissions with ULP signaling may be performed using the described SL embedded ULP transmission slot / format.

[0229] The purpose of this extension is to enable the ULP channel to carry more information. Each ULP transmission has a low data rate. In the case where the content to be transmitted over the ULP air interface is greater than the capacity in a single transmission, multiple ULP transmissions can double the total number of bits received at the expense of delay and increased overhead and resource usage in the SL resource pool.

[0230] This scheme increases the latency of receiving the actual data payload in exchange for having better flexibility and control of ULP signaling. Note however that in the sidelink, the resource reservation window is limited by the latency budget and therefore the resources selected for each (re)transmission in time should fall within the acceptable latency of the payload, assuming the processing time and latency are also within the acceptable packet delay budget.

[0231] exist Fig.12 In FIG. 5 , an illustrative example is given in which a first ULP embedded transmission of width 4 subchannels is sent, and resources are reserved for two subsequent transmissions. The first retransmission is also a ULP embedded SL transmission, and the subsequent transmissions are payload transmissions.

[0232] An example of multiple ULP transmissions could be that the initial transmission carries information about the reference table to use, and the second transmission carries information about the index of a row in that table. This could be helpful, for example, in the context of resource allocation for SL retransmissions, where the number of scheduling possibilities for time and frequency patterns is very large and full flexibility would require a large number of bits.

[0233] The schedule of successive ULP embedded transmissions can be preconfigured using a known time-frequency pattern. The pattern of time-frequency resources is defined within a potential resource reservation window and an available resource pool.

[0234] Note that if the reservation follows a predefined pattern, the scheduler should perform an altered resource selection procedure, where multiple resources of the pattern are jointly selected to ensure that all resources of the pattern are available.

[0235] In one of the special cases above, and in order to avoid additional latency due to multiple ULP transmissions before the actual SL payload, the transmitter can schedule ULP embedded transmissions in consecutive time slots so that the ULP payload can be decoded as quickly as possible without waiting for subsequent transmissions, such as Fig.12 exemplified.

[0236] In case multiple modes are possible (or if the possible modes are not predefined), it is also possible to add an indication of the next ULP signal schedule as part of the ULP signal, as a signature or as explicit data.

[0237] Upon receiving multiple ULP signals, the RX WTRU combines the ULP contents to determine associated information. For example, if the first ULP sends a signature involving a resource pattern table and the second ULP sends a table index, the WTRU uses the signaled index in the signaled table to determine the SL resource pattern to use.

[0238] Representative procedures for sending SL small data based on ULP

[0239] Another possible use of ULP embedded transmission is to use the ULP signal to perform the transmission of the actual payload data. In some cases, the data to be transmitted is very small and only a few bits are required. Using the ULP signal (even at a limited data rate) to transmit small packets may be an interesting alternative to avoid the overhead of multiple transmissions, potential reconnection / resynchronization, or energy consumption due to the use of the main radio receiver.

[0240] This may use a similar ULP embedded SL timeslot structure as previously presented, where the ULP signaling would include small data transmissions such as Fig.13 exemplified.

[0241] The content of the ULP signal can be (pre)configured to match the application needs of a small data payload. This can be done using explicit data transmission or tabulated data that can be decoded by the ULP receiver, i.e., a certain data table is preconfigured and only the index corresponding to the expected data payload is transmitted, which is transmitted as explicit data or a signature.

[0242] After the initial transmission including the SDT, the transmitter may prepare for further transmissions using either the conventional interface or the ULP interface. In this case, further indications in the ULP signaling may be performed, for example, using a configured signature to indicate the interface of the future transmission and / or scheduling information about the transmission. In this case, the initial transmission may include a reservation for future transmissions in its first stage SCI.

[0243] If the initial transmission is a single transmission with no future transmissions planned, then there is no need to reserve resources for the retransmission data payload using the primary radio receiver.

[0244] From the receiver's perspective, Fig.14 As illustrated, when monitoring the ULP signal and receiving the ULP SL SDT signal, the WTRU determines which interface should be active after the SDT based on the indication (or absence of indication) in the ULP signal. For example, if no indication is included, the WTRU may resume ULP monitoring. If there is an indication to wake up or scheduled transmission on a regular SL channel, the WTRU should switch to regular SL monitoring.

[0245] This SL ULP small data transmission can also be used in conjunction with the multiple ULP embedded transmission scheme presented previously to increase the size of the total payload carried by the ULP signal.

[0246] Representative procedures for using ULP signals to carry Phase II SCI content

[0247] In various embodiments, the use of ULP signals embedded in the SL slot structure allows the ULP transmission to convey some information. In one embodiment, one or more information bits may be used to carry a portion of the second stage SCI of a subsequent transmission.

[0248] If the initially transmitted ULP signal carries some information of the subsequently transmitted second stage SCI, the subsequent transmission does not need to transmit this information again. If there are enough bits available in the ULP signal and all the contents of the second stage SCI can be sent in the ULP signal, the subsequent transmission of the second stage SCI can be completely omitted.

[0249] The reduction or absence of the second stage SCI in the subsequently transmitted PSSCH allows the PSSCH to be fully utilized for payload and maximizes the capacity of the SL channel.

[0250] The entire second stage SCI (SCI 2-A, version 16) contains 35 bits of raw information, and after CRC, channel decoding and rate matching, the total number of coded bits required to send the second stage SCI depends on the transmission format (e.g., MCS) of the PSSCH. The second stage SCI is mapped to the first resource in the frequency and time domains that can be obtained from the PSSCH.

[0251] Depending on the device capabilities, configurations and circumstances (such as scheduling and resource availability), it is possible to summarize different scenarios to share the second stage SCI content between the ULP embedded transmission and the subsequent SL transmission.

[0252] There are three scenarios here: A) The ULP signal carries part of the second-stage SCI information of the subsequent transmission in the initial transmission without PSSCH; B) The ULP signal carries all the second-stage SCI information of the subsequent transmission in the initial transmission without PSSCH; C) The ULP signal does not carry the second-stage SCI information of the subsequent transmission in the initial transmission without PSSCH.

[0253] Additionally, for the purpose of coexistence, two additional situations can be derived: A) the ULP signal carries partial information of the second stage SCI sent subsequently and is repeated as part of the PSSCH sent initially; B) the ULP signal carries all information of the second stage SCI sent subsequently and is repeated as part of the PSSCH sent initially.

[0254] A.-ULP signal carries part of the second stage SCI information to be sent later

[0255] In scenario A, it is proposed to use ULP signaling to carry some contents of the second stage SCI to be sent subsequently.

[0256] First, ULP signaling comes from a given sending user, for some ULP users. Depending on the configuration, a certain level of information about the source and destination IDs, which is usually carried by the second stage SCI, can be inferred.

[0257] Second, ULP signaling may be configured to carry further content of the second stage SCI, such as the broadcast type or a request for CSI feedback, which may be helpful to know in advance so that devices can prepare for reception accordingly.

[0258] A new "partial" second stage SCI format may then be defined. A subformat of this second stage SCI includes data carried by ULP signaling. The content of this subformat is configured between users or for a given resource pool, for example using RRC configuration. What content may be included in a subformat depends on the channel configuration and device capabilities, for example, the data rates supported by the ULP.

[0259] The format of the initial transmission and subsequent SL transmissions can be illustrated in Figure 15, where the second stage SCI is partially sent within the ULP signaling and partially sent in the PSSCH of the subsequent transmission. It should be noted that even though only one example of the format is given here, it can also be applied equally to all formats given in this disclosure. It should be noted that the division of resources in the PSSCH between part of the second stage SCI and the payload is not fixed and depends on the SCI content, PSSCH size and / or transmission format.

[0260] like Fig.16 As illustrated, when receiving the ULP signaling, the receiver determines the content of the portion of the second stage SCI based on the configuration.

[0261] The remaining contents of the subsequently transmitted second stage SCI shall be grouped in a supplementary sub-format, which shall be transmitted in the subsequently transmitted PSSCH.

[0262] Once the two supplemental subformats are received (one with ULP signaling and one with regular SL channels), the WTRU may combine the contents to determine the full second stage SCI and proceed to resume reception and decoding of the payload if necessary.

[0263] In some examples, in the context of ULP signaling, minimizing the amount of data to be sent using the ULP is critical because capacity is very limited. To avoid transmitting some content of the second stage SCI in the ULP, some content may be preconfigured as part of a table that regroups the most commonly expected values.

[0264] For example, when a device is configured to monitor the ULP instead of directly monitoring the SL channel, it is expected that the device is not actively receiving data (e.g., similar to RRC IDLE / INACTIVE mode, although this concept is not used for NR SL in existing releases). Therefore, it can be expected that values ​​such as NDI, RV, and HARQ ID are reset to one or a few possible values, and thus the 7 bits are combined into a few combinations (e.g., few bits).

[0265] In one example, the following subformat content may be used:

[0266] -HARQ process number - 4 bits.

[0267] - New data indicator - 1 bit.

[0268] - Redundancy version - 2 bits.

[0269] - Source ID - 8 bits.

[0270] - Destination ID - 16 bits.

[0271] Then, the source and destination IDs may be carried by the ULP design to identify the transmission, and the HARQ, NDI and RV may be compressed into, for example, a 2-bit table.

[0272] When using a compressed table for ULP transmission, and in case the desired configuration is not in the table, the transmitter shall fall back to explicit transmission either through the ULP channel (if possible) or by sending a regular second stage SCI in the PSSCH of a subsequent transmission.

[0273] In one embodiment, the presence and / or format of the partial second stage SCI may be indicated as a ULP signature / preamble so that the ULP device expects to receive a ULP signal containing the partial second stage SCI.

[0274] In another embodiment, the possible sub-formats are not statically configured, the ULP receiver can expect different formats, and the ULP signaling (using a codebook or explicit data) indicates the format used. This allows a more dynamic approach to adapt to the capacity of the ULP signal each time it is sent.

[0275] In the above implementation of "ULP signal indication and first stage SCI format", several options are proposed, including using the second stage SCI format indication in the first stage SCI (instead of PSSCH) to indicate the presence of ULP signal, which may also mean that there is no second stage SCI in PSSCH.

[0276] In the initial transmission (transmission with ULP embedded signal), this indication may clearly indicate that the second stage SCI is not in the PSSCH.

[0277] In subsequent transmissions, the first stage SCI shall indicate the presence of a subformat of the second stage SCI (the supplementary subformat sent on the PSSCH), however, if the 4th raw data indicated by the second stage format is used, it shall be understood by the device as a partial second stage SCI format. This dual meaning (absence and partial SCI format) can be determined by the ULP-receiver device, since it is aware of the scheduling of the subsequent transmission and is preparing to receive the resource.

[0278] Other users receiving the indication may attempt to decode the PSSCH to receive the partial second stage SCI, and if they cannot decode it (eg, because it is not present), these users may simply ignore and discard the data.

[0279] In case the content of the sub-format is not statically configured, a WTRU receiving a partial second stage SCI indication shall decode the second stage SCI sub-format in a subsequently transmitted PSSCH based on the information already received in the ULP signaling.

[0280] B.-ULP signal carries all the information of the second stage SCI to be sent later

[0281] In scenario B, the ULP signaling may carry all the contents of the second stage SCI. This scenario may be viewed as an extension or special case of scenario A, where the sub-format is the entire second stage SCI.

[0282] The main difference from scenario A is that the subsequent transmission does not need to transmit any second stage SCI in the PSSCH, and the configuration (second stage SCI) used to decode the payload of the subsequent transmission comes from the previous ULP embedded transmission, as illustrated in Figure 17.

[0283] Thus, the indication of the second stage SCI is simplified because the transmitter can indicate the absence of the second stage SCI in the first stage SCI in both the initial transmission and subsequent transmissions.

[0284] In order to be able to carry all the contents of the second stage SCI, the use of a preset compression table (i.e., codebook) is configured as part of the SL ULP signaling configuration between two users or for a given resource pool. Only a few bits are needed to cover the most likely use cases and can be used to represent the entire second stage SCI. Similar to the previous section, if the desired configuration of the second stage SCI is not configured in the preset table, the transmitter can fall back to the classic transmission of the second stage SCI.

[0285] C.-ULP signal does not carry the information of the second stage SCI sent later .

[0286] In scenario C, the ULP signal does not include information about the content of the subsequently sent second stage SCI, except possibly some information from the destination ID and source ID for wake-up purposes.

[0287] This scenario is a case where the ULP signal is used as a simple wake-up command, thereby improving the reliability of the ULP signaling or increasing the coverage and / or reducing the complexity and energy consumption of the receiving device.

[0288] However, it is worth noting that since the ULP signal is configured between the sending user and the target ULP user or user group, the ULP signal already carries information about the destination ID. If the ULP signal is designed to be source-specific, the ULP signal may also carry information about the source ID. It should be noted that in the case of a broadcast ULP signal, there is no information about the destination ID.

[0289] Therefore, a specific sub-format of the second phase SCI can be defined, which includes the source ID and destination ID, and in which the number of bits of the source ID and destination ID carried by the ULP signal is reduced. If the source ID or destination ID included in the traditional second phase SCI can be completely inferred by the ULP signal, these fields can be completely omitted, saving up to 24 bits of information. If the source ID and destination ID are not known at all (for example, if the ULP is a "simple" broadcast), then this sub-format is empty, and the supplementary sub-format is the entire conventional second phase SCI. In this way, scenario C can also be regarded as a special case of scenario A, where the sub-format does not include anything (or only includes the source ID / destination ID).

[0290] Coexistence and support for sending to mixed groups of ULP receivers and non-ULP receivers

[0291] In the SL slot structure proposed so far, if the ULP embedded signaling includes part or all of the second stage SCI, users without ULP capabilities cannot receive this information and are therefore unaware of the partial configuration of the subsequent transmission. While this is not a problem for unicast transmissions where the ULP WTRU is the destination of the transmission, this becomes a potential problem for multicast.

[0292] In multicast, a user group is the destination for transmission. If the group contains a mix of ULP users and non-ULP users, the non-ULP users will not be able to receive information transmitted using ULP signaling.

[0293] In order to enable multicast between ULP users and non-ULP users, and thus better coexist with other users, it is also proposed that, in addition to the ULP signaling with partial or full second-stage SCI content, the initial transmission also carries a PSSCH containing partial or full second-stage SCI content. The content of the (partial) second-stage SCI in the initial transmission must be matched between the PSSCH signaling and the ULP signaling so that non-ULP users and ULP users collect complete information. These are scenario D (with partial information) and scenario E (with full information), and are illustrated in Figures 18 and 19, respectively. Note that the scenario in which no second-stage SCI information is carried as part of the ULP signal and therefore no PSSCH is required in the first transmission (or at least the entire second-stage SCI must be performed anyway in subsequent transmissions) is equivalent to scenario A.

[0294] The indication in the first stage SCI has to be indicated to enable non-ULP users to determine that (part of) the second stage SCI in the initially transmitted PSSCH is actually for the retransmitted payload.

[0295] When determining that there is ULP signaling in the first stage SCI, an implicit indication may be made if the user assumes that one or several formats of the second stage SCI are sent in the short PSSCH. This may be done by (pre)configuration. If a single (sub)format of the second stage SCI is configured, decoding is straightforward, whereas if several (sub)formats are possible (e.g. no second stage SCI and one or more sub-formats are present), the user has to try and blindly decode the correct format.

[0296] Where it is possible to indicate ULP signalling and format in the first stage SCI, explicit indications may also be performed. These indications may be performed using the "reserved" indication of the first stage SCI to add, for example, an indication of the ULP signalling, and the remaining raw data of the second stage SCI table indication may be used to indicate the sub-format.

[0297] When it is determined that ULP signaling is present, the user will assume that the second stage SCI content (if any) is relevant to the subsequent transmission.

[0298] By adding the PSSCH to the initial transmission, other users of the resource pool can now decode information about that transmission, rather than simply discarding the entire transmission.

[0299] like Fig. 20As illustrated, a non-ULP user may first receive an initial transmission including a PSCCH and a PSSCH (with a second-stage SCI), determine that there is a (partial) second-stage SCI that applies to a subsequent transmission, decode part or all of the second-stage SCI from the PSSCH, and discard the remaining resources (ULP); then, when a subsequent transmission is sent with the remaining content (if any) of the second-stage SCI, the non-ULP user may combine the two parts of the second-stage SCI (if partial) and, if necessary (i.e., if the user is the destination), ultimately be able to decode the payload.

[0300] In an alternative, even if the ULP signaling carries only part of the second stage SCI, the PSSCH of the initial transmission may also transmit the regular full second stage SCI of the subsequent transmission to reduce the number of formats designed in the specification. Non-ULP users can decode the second stage SCI in the initial transmission, store it, and also decode the partial second stage SCI in the subsequent transmission (if any) before decoding the payload.

[0301] Selection Procedure

[0302] In this subsection, a selection procedure is described that can be used to determine the type and format of partial phase 2 SCI transmissions in the ULP and SL. Fig.21 A generalized flow chart is illustrated. Note that the following description is intended to cover the case of transmission to several users (ie multicast), but with some simplifications this also applies to the case of transmission to a single destination.

[0303] When a transmitting SL device is capable and configured to transmit a ULP signal, assuming that several (sub)formats of the second stage SCI are available, the device has to decide which format is appropriate for the transmission.

[0304] When preparing to transmit, the transmitting device should first check whether the receiver or receiver group includes a device configured to monitor the ULP signal, that is, whether some destinations are not using conventional SL radio components to monitor the channel. If all intended destinations monitor the channel in a conventional manner, the transmitter should only use conventional SL transmission.

[0305] Otherwise, ie if at least one receiver is configured to monitor for ULP signals, the transmitter shall use ULP signals. Now it needs to be decided which (sub)format to use.

[0306] The transmitter should check if there are some devices in the destination that are not monitoring the ULP signal. This is to know if the initial transmission needs to repeat what was sent using the ULP signal, like regular SL transmission using the sub-format of the second stage SCI in the PSSCH.

[0307] If all destinations are monitoring the ULP signal, the transmitter can use the ULP embedded structure without repeating the information in the PSSCH of the initial transmission. The last check is to verify whether the configured ULP signaling can support the transmission of the expected second-stage SCI content. For example, if the configured preset sub-format list does not include all possible combinations, it is possible that the expected second-stage SCI is not part of the preset list. In this case, fallback to scenario C must be performed. If the second-stage SCI for transmission is suitable for configuration, the transmitter can use the ULP signal to carry some content of the second-stage SCI, which corresponds to scenario A or scenario B.

[0308] If some destinations do not monitor the ULP signal (i.e. the case of a mixed group of ULP and non-ULP devices), the information transmitted on the ULP and PSSCH should match. In this case, once again, verification is performed to ensure that the non-ULP monitoring devices are legacy devices, in which case these devices will not understand the newly proposed sub-format. In this case, the transmission should include all second stage SCI content as part of the subsequent transmission, so this is scenario C.

[0309] If the destination group is a mix of ULP monitoring devices and non-ULP monitoring devices, but all are capable of decoding and processing the new subformat, the subformat may be included in the initially transmitted ULP and PSSCH. The transmitter shall check whether the selected second stage SCI is suitable for the configuration used to transmit SCI content on the ULP signal. If this is appropriate, this corresponds to scenario D or scenario E. Otherwise, the transmitter falls back to scenario C.

[0310] Representative procedures for in-band SL transmission embedded in ULP signal

[0311] Exemplary embodiments are provided below from the perspective of two different types of devices: a sender device and a ULP-receiver device.

[0312] Sidelink TX user supports transmission to ULP SL users. In one example, a first WTRU communicating with one or more second WTRUs is configured to perform any of the following operations: exchange SL and ULP transmission capabilities and configurations with the second WTRU; determine a first format for a first transmission and a second format for a subsequent transmission based on the ULP capabilities of the one or more second WTRUs; determine a first first stage SCI indicating reserved resources for subsequent transmissions and indicating a first format, wherein the first format includes a ULP signal, such as a ULP signature / preamble; transmit a first transmission including a first first stage SCI and a ULP signal for one or more second WTRUs; determine a second first stage SCI indicating reserved resources for subsequent transmissions and indicating a second format, wherein the second format includes a second stage SCI and a payload; and / or transmit a subsequent transmission of a second format according to the reserved resources indicated in the first transmission, the subsequent transmission including a second first stage SCI, a second stage SCI, and a data payload.

[0313] Capabilities including supported signatures / preambles and groupings and supported SCI formats on resource pools may be exchanged as part of a discovery procedure or UE-to-UE connection / establishment (e.g., SL RRC configuration). ULP signaling may also include information about reserved resources for one or more subsequent transmissions. The format and content of the ULP signal is based on the supported (pre) configurations and signatures, resource selection (supported BW) and destination user capabilities (e.g., supported data rates) and whether any of the destinations is currently monitoring the ULP channel. The initial transmission (ULP embedded transmission) is repeated in one or more reserved subsequent transmissions, and the actual payload transmission (PSCCH+PSSCH) is sent in one or more further subsequent transmissions.

[0314] The ULP message is split into one or more sidelink ULP embedded transmissions, which may be consecutive or non-consecutive in time, for example, a first transmission including a ULP signature indicating an index table and a second transmission including a ULP signature indicating an index in the table. In addition to the initially reserved set of resources, subsequent transmissions may also reserve resources for further retransmissions, and the further retransmissions may be repetitions of the first transmission (i.e., PSCCH+ULP channel) or subsequent transmissions (PSCCH+PSSCH). The determination of the format and content of the transmission and the scheduling is performed by a different WTRU (e.g., by a gNB, a relay node, or an assisting UE), which sends an assignment / grant to the SL TX user including the format, content, and scheduling of the SL transmission to be performed.

[0315] In one example, the initial transmission with ULP signaling is performed by a first user, while subsequent transmissions are performed by a third user (e.g., a situation where a secondary device (e.g., a roadside unit, another WTRU, etc.) performs a ULP wake-up signal on behalf of a user having a payload to be transmitted).

[0316] In one example, after transmitting the first transmission and before transmitting the second transmission, the first WTRU receives feedback from the second WTRU confirming decoding of the ULP signal and may proceed to send the subsequent transmission. In one example, after transmitting the first transmission and before transmitting the second transmission, the first WTRU does not receive feedback from the second WTRU (or receives a NACK) and should proceed with a fallback solution, such as restarting the procedure or reporting to the network. In one example, after transmitting the subsequent transmission, without receiving the expected feedback from the second WTRU, the first WTRU shall proceed with a fallback solution, such as restarting the procedure or reporting to the network.

[0317] Fig.23 An exemplary flow chart including feedback after ULP transmission is provided and illustrated:

[0318] A WTRU with an ULP receiver acts as a sidelink receiver. A first WTRU monitoring signals from one or more second WTRUs is configured to perform any of the following operations: exchange SL and ULP transmission capabilities and configurations with the second WTRU; receive ULP signals, such as one or more ULP signatures or preambles, and detect a configured identifier (e.g., a unique identifier or a group identifier); determine the scheduled resources for subsequent SL transmissions based on the received ULP signals; and / or wake up the primary sidelink radio component, utilize the primary sidelink radio component to receive the scheduled subsequent transmissions, and decode the payload data and recover the normal sidelink data / control procedures.

[0319] In one example, ULP capabilities and SL configurations (including supported signatures / preambles and supported SCI formats on a resource pool) may be exchanged as part of a discovery procedure or UE-to-UE connection / establishment (e.g., SL RRC configuration). The determination of reserved SL transmit resources is based on a preconfigured or received ULP SL configuration, for example, using a resource mode. The determination of reserved SL transmit resources is based on the determination of reserved SL transmit resources based on a received ULP indication. The determination of reserved SL transmit resources is based on a combination of a preconfigured or received ULP SL configuration and a received ULP indication. The ULP message is received via multiple transmissions, each in a subsequent sidelink ULP embedded transmission, and the content is decoded based on these multiple ULP signal transmissions (e.g., a first transmission including a ULP signature indicating an index table and a second transmission including a signature of an index to the indication table).

[0320] In one example, upon successful decoding of the ULP signal and waking up the primary radio, the first WTRU transmits an acknowledgement feedback to the second WTRU. In one example, upon successful identification of the target identifier but failure to decode the remaining ULP signal and wake up the primary radio, if identified, the first WTRU transmits a non-acknowledgement feedback to the second WTRU. In one example, upon successful decoding of the ULP signal and the SL payload, and in the absence of a need for ACK feedback, the first WTRU transmits an acknowledgement to the second WTRU to indicate its status.

[0321] Fig.24 An exemplary flow diagram including feedback after ULP transmission is provided and illustrated.

[0322] Representative procedures for using SL ULP signals to carry Stage 2 SCI content

[0323] Exemplary implementations corresponding to Scenario A, Scenario B, Scenario C, Scenario D, and Scenario E are provided below from the perspective of three different types of devices: a sender device, a ULP-receiver device, and a non-ULP non-legacy device.

[0324] The sidelink TX user supports transmission to the ULP SL user. A first WTRU in communication with one or more second WTRUs is configured to perform any of the following operations:

[0325] • Exchange SL and ULP transmission capabilities and configurations with the second WTRU.

[0326] • Determining a first format for a first transmission and a second format for a subsequent transmission based on ULP capabilities of one or more second WTRUs.

[0327] ● Determine a first first stage SCI indicating reserved resources for subsequent transmission and indicating a first format, wherein the content of the first format includes a ULP signal (eg, ULP signature / preamble) and a first content of a second stage SCI based on a payload of the subsequent transmission.

[0328] • A transmission includes a first first stage SCI, a first content of a second stage SCI, and a first transmission of a ULP signal to one or more second WTRUs.

[0329] • Determine a second first stage SCI indicating reserved resources for subsequent transmission and indicating a second format, wherein the second format includes a second content of the second stage SCI and a payload.

[0330] - Delivering a subsequent transmission in a second format based on the reserved resources and the first content of the second stage SCI indicated in the first transmission, the subsequent transmission comprising a second first stage SCI, the second content of the second stage SCI and a payload.

[0331] In one example, the first content and the second content of the second stage SCI are applied to the payload of the subsequent transmission. In one example, the format and content of the second stage SCI are based on the supported second stage SCI (pre) configuration and signature, resource selection (supported BW) and destination user capabilities (e.g., supported data rates) and whether the destination is currently monitoring the ULP channel. In one example, the second content of the second stage SCI includes the remaining content of the conventional second stage SCI format, which is not included in the first content.

[0332] In one example, the step of determining the format and content results in the use of a portion of the second stage SCI being inappropriate (e.g., due to unindexed content or the message being too long for ULP capabilities); and therefore the first content of the first transmission step is sent without including the second stage SCI in either the ULP signaling or the PSSCH; and the subsequent transmission is sent as a regular SL transmission with a complete second stage SCI. In one example, the step of determining the format results in the use of a portion of the second stage SCI being inappropriate due to the presence of a legacy destination user; and the subsequent transmission is sent as a regular SL transmission with a complete second stage SCI. In another example, the step of determining the format and content of the second stage SCI results in the first content including the complete second stage SCI; and therefore the subsequent transmission includes an indication of the absence of the second stage SCI in the PSSCH and does not carry the second stage SCI in the PSSCH; and the second stage SCI content received in the first transmission is used to decode the SL payload.

[0333] Note that the examples of the TX WTRU in the previous section also apply to this WTRU.

[0334] A WTRU with a ULP receiver and a sidelink as a receiver. A first WTRU monitoring signals from one or more second WTRUs is configured to perform any of the following operations:

[0335] • Exchange SL and ULP transmission capabilities and configurations with the second WTRU.

[0336] • Receive a ULP signal, eg, one or more ULP signatures or preambles, and detect a configured identifier (eg, a unique identifier or a group identifier).

[0337] • Determine the scheduled resources for subsequent SL transmission based on the received ULP signal, and determine the first content of the second stage SCI.

[0338] - Waking up the primary side link radio, utilizing the primary side link radio to receive the scheduled subsequent transmission, including the second content and payload of the second stage SCI.

[0339] • Decode the payload based on a combination of the first content and the second content of the second stage SCI.

[0340] In one example, the determination of the content and format of the second stage SCI of the subsequent transmission is based on either the received ULP signal and an indication in the first stage SCI of the subsequent transmission. In one example, the ULP signal does not carry the second stage SCI content, and thus the conventional radio components receive the second stage SCI content of the subsequent transmission as part of the subsequent transmission itself. In one example, the ULP signal carries the entire second stage SCI, and thus the device determines that the second stage SCI is not carried in the subsequent transmission, and the device uses the second stage SCI content carried by the ULP to decode the PSSCH payload of the subsequent transmission.

[0341] Note that the examples of the RX WTRU in the previous section also apply to this WTRU.

[0342] Fig.25 An exemplary flow diagram of a WTRU receiver with ULP is provided and illustrated.

[0343] A WTRU without a ULP receiver - acting as a receiver. A first WTRU monitoring signals from one or more second WTRUs is configured to perform any of the following operations:

[0344] ● Exchange SL capabilities and configuration with the second WTRU.

[0345] • Receive a SL transmission and determine the scheduled resources and a first format for a subsequent SL transmission based on an indication in a first stage SCI, wherein the first format indicates a ULP embedded signal.

[0346] Based on the determined first format, determine the first content of the second stage SCI and discard the ULP signal.

[0347] • Receive the scheduled subsequent transmission and determine a second format, wherein the second format indicates a second content and payload of the second stage SCI.

[0348] ●determine the second content of the second-stage SCI based on the determined second format;

[0349] ● Receive and decode the payload based on the combination of the first content and the second content of the second stage SCI.

[0350] In one example, capabilities including supported SCI formats on a resource pool may be exchanged as part of a discovery procedure or UE-to-UE connection / establishment (e.g., SL RRC configuration). In one example, upon determining that the user is not the destination for the payload, the user discarding the transmitted PSSCH content also includes clearing the received signal of the initial transmission (e.g., for HARQ soft combining). In one example, the received and indicated content and format of the second stage SCI in the initial transmission is the entire second stage format for subsequent transmissions; storing the second stage SCI; receiving subsequent transmissions and using the stored second stage SCI content to decode the payload. In one example, the received and indicated content and format of the second stage SCI for subsequent transmissions is not present in the initial transmission; receiving a subsequent transmission including the second stage SCI and decoding the payload. In one example, upon determining an unknown or unsupported format for the first or second stage SCI, the device should discard the content.

[0351] Fig.26 An exemplary flow diagram of a non-ULP receiver of a WTRU is provided and illustrated.

[0352] Representative procedures for ULP-based sidelink small data transmission

[0353] The sidelink TX user supports SDT transmission to the ULP SL user. A first WTRU in communication with one or more second WTRUs is configured to perform any of the following operations:

[0354] • Exchange SL and ULP transmission capabilities and configurations with the second WTRU.

[0355] • Determining a first format for the first transmission based on ULP capabilities of one or more second WTRUs.

[0356] • Determining a first first stage SCI indicating a first format, wherein the first format includes a ULP signal, eg, a ULP signature / preamble.

[0357] • The transmission includes a first stage 1 SCI and a first transmission of a ULP signal to one or more second WTRUs, the first transmission including SDT content.

[0358] In one example, capabilities including supported ULP signatures / preambles, SDT configurations, and supported SCI formats on a resource pool may be exchanged as part of a discovery procedure or UE-to-UE connection / establishment (e.g., SL RRC configuration). In one example, the first transmission also indicates that the second WTRU should wake up its primary radio receiver in anticipation of a subsequent transmission. In one example, the first transmission also indicates a resource reservation for a subsequent transmission.

[0359] Fig. 27 An exemplary flow diagram of a WTRU's SL ULP SDT transmitter is provided and illustrated.

[0360] WTRU with ULP receiver and sidelink - as receiver:

[0361] A first WTRU monitoring a signal from one or more second WTRUs is configured to perform any of the following operations:

[0362] • Exchange SL and ULP transmission capabilities and configurations with the second WTRU.

[0363] • Receive a ULP signal, eg, one or more ULP signatures or preambles, and detect a configured identifier (eg, a unique identifier or a group identifier).

[0364] ● Determine the small data transmission format based on the received ULP signal.

[0365] • Decode small data payloads based on configuration and received indications.

[0366] In one example, capabilities including supported signatures / preambles, SDT configurations, and supported SCI formats on a resource pool may be exchanged as part of a discovery procedure or UE-to-UE connection / establishment (e.g., SL RRC configuration). In one example, the first WTRU also determines a schedule for subsequent transmissions based on the received ULP signaling. In one example, the first WTRU also determines that an indication is received to wake up the primary radio receiver and use the primary radio receiver to further monitor the SL channel.

[0367] Fig.28 An exemplary flow diagram of a ULP SDT receiver of a WTRU is provided and illustrated.

[0368] refer to Fig.29 , an example of a SL scheduling and transmission procedure with SL ULP signaling is provided. In this example, the WTRU uses an initial SL ULP wake-up signal (WUS) to determine the scheduling of SL initial transmissions and retransmissions. Based on the capabilities of the receiver (e.g., data rate and ULP reception availability), the WTRU determines the format and content of the initial transmission (including the ULP signal) and the format and content of the retransmission. The ULP signal may indicate the targeted WTRU, the scheduled subsequent SL transmission resources, and the portion of the second stage SCI for the subsequent transmission. The first stage SCI of the initial SL transmission may indicate the presence of the same reserved resources and embedded ULP signal. The retransmission may include a first stage SCI indicating a partial second stage SCI format, a partial second stage SCI, and / or a SL payload. The WTRU may send the initial transmission and the retransmission according to the scheduled resources, wherein the retransmission includes the SL payload.

[0369] In another example, the entire contents of the second stage SCI may be transmitted in the ULP signal and removed from subsequent transmissions, such as when the ULP data rate permits. In some cases, when the destination is mixed with ULP WTRUs and non-ULP WTRUs, the same (partial or full) contents of the second stage SCI may be transmitted in the ULP signal and the PSSCH of the initial transmission.

[0370] In one embodiment, the WTRU may determine information for a first transmission and a second transmission based on ULP capabilities associated with one or more target destinations. The WTRU may send a first transmission based on the information, the first transmission comprising: 1) a first SCI associated with the first transmission, the first SCI indicating a resource set for the second transmission and a ULP signal to be sent on the first transmission; and 2) a ULP signal indicating the one or more target destinations, a resource set for the second transmission, and at least a first subset of a second SCI associated with the second transmission. The WTRU may also send a second transmission comprising at least a second subset of the second SCI and sidelink payload data.

[0371] In one embodiment, a method for wireless communication implemented by a WTRU includes: determining information of a first transmission and a second transmission based on ULP capabilities associated with one or more target destinations; sending the first transmission based on the information, the first transmission including: 1) a first SCI associated with the first transmission, the first SCI indicating a resource set used for the second transmission and a ULP signal to be sent on the first transmission; and 2) the ULP signal, the ULP signal indicating the one or more target destinations, the resource set used for the second transmission, and the second SCI associated with the second transmission; and sending the second transmission, the second transmission including sidelink payload data.

[0372] In another embodiment, a method for wireless communication implemented by a WTRU includes: determining information of a first transmission and a second transmission based on ULP capabilities associated with one or more target destinations; determining that the one or more target destinations cannot receive a subset of the SCI; sending the first transmission based on the information, the first transmission including a ULP signal, the ULP signal indicating the one or more target destinations and a resource set for the second transmission; and sending the second transmission, the second transmission including the SCI and sidelink payload data.

[0373] Although the features and elements of the present invention are described with a focus on a single TX WTRU, in the event that another device is performing scheduling for a transmitting SL user (e.g., a gNB in ​​NR SL Mode 1, a relay node, or another user scheduled for that user in a collaborative context), the implementation scheme related to the transmitting user may be changed such that the scheduling node is performing the determination and preparation steps and sending a grant or schedule to the transmitting user prior to its first transmission.

[0374] Another alternative scenario is that one side link user (e.g., side link user, road side unit, user cluster head) is performing SL ULP transmission to wake up the ULP device, while the other side link user is performing SL data transmission (i.e., a node that can wake up the ULP device on behalf of another node).

[0375] in conclusion

[0376] Although features and elements are provided above in specific combinations, it will be understood by those of ordinary skill in the art that each feature or element may be used alone or in any combination with other features and elements. The present disclosure is not limited to the specific embodiments described in this patent application, which are intended to be illustrative of various aspects. Many modifications and variations can be made without departing from the essence and scope of the present invention, as they will be apparent to those skilled in the art. Unless explicitly provided as such, any element, action or description used in the present application specification should not be understood as being essential or necessary to the present invention. According to the foregoing description, in addition to those listed herein, functionally equivalent methods and devices within the scope of the present disclosure will be apparent to those skilled in the art. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is limited only to the terms of the appended claims and the full range of equivalent forms of such entitled claims. It should be understood that the present disclosure is not limited to a specific method or system.

[0377] For simplicity, the foregoing embodiments are discussed with reference to the terminology and structure of infrared capable devices (i.e., infrared transmitters and receivers). However, the embodiments discussed are not limited to these systems, but can be applied to other systems using other forms of electromagnetic waves or non-electromagnetic waves (such as sound waves).

[0378] It should also be understood that the terms used herein are for the purpose of describing specific embodiments only and are not intended to be limiting. As used herein, the term "video" or the term "image" may mean any of a snapshot, a single image, and / or a plurality of images displayed on a temporal basis. For example, when referred to herein, the term "user equipment" and its abbreviation "UE", the term "remote" and / or the term "head-mounted display" or its abbreviation "HMD" may mean or include (i) a wireless transmit and / or receive unit (WTRU); (ii) any of a plurality of embodiments of the WTRU; (iii) a wireless and / or wired (e.g., tetherable) device configured with (in particular) some or all of the structure and functionality of the WTRU; (iii) a wireless and / or wired device configured with less than all of the structure and functionality of the WTRU; or (iv), etc. This document is relative to Figures 1A to 1D Details of an example WTRU are provided that may represent any WTRU described herein. As another example, various disclosed embodiments herein are described above and below as utilizing a head mounted display. Those skilled in the art will recognize that devices other than head mounted displays may be utilized and that some or all of the present disclosure and various disclosed embodiments may be modified accordingly without undue experimentation. Examples of such other devices may include drones or other devices configured to stream information to provide an adapted reality experience.

[0379] In addition, the methods provided herein may be implemented in a computer program, software, or firmware incorporated into a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (sent via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as built-in hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

[0380] Variations of the methods, devices, and systems provided above are possible without departing from the scope of the present invention. In view of the various embodiments that may be applied, it should be understood that the illustrated embodiments are merely examples and should not be considered to limit the scope of the following claims. For example, the embodiments provided herein include handheld devices that may include or be used with any suitable voltage source (such as a battery, etc.) that provides any suitable voltage.

[0381] In addition, in the embodiments provided above, processing platforms, computing systems, controllers and other devices including processors are indicated. These devices may include at least one central processing unit ("CPU") and memory. According to the practice of those skilled in the art of computer programming, references to the symbolic representations of actions and operations or instructions may be performed by various CPUs and memories. Such actions and operations or instructions may be referred to as being "executed", "computer executed" or "CPU executed".

[0382] Those of ordinary skill in the art will appreciate that the actions and symbolic representations of operations or instructions include manipulation of electrical signals by the CPU. The electrical system represents data bits, which may result in the ultimate transformation of electrical signals or reduction of electrical signals and the retention of data bits at memory locations in the memory system, thereby reconfiguring or otherwise changing the operation of the CPU and performing other processing of signals. The memory location that holds the data bits is a physical location that has specific electrical, magnetic, optical, or organic properties that correspond to or represent the data bits. It should be understood that the embodiments are not limited to the above-mentioned platforms or CPUs, and other platforms and CPUs may also support the provided methods.

[0383] The data bits may also be maintained on computer-readable media, including magnetic disks, optical disks, and any other volatile (e.g., random access memory ("RAM")) or non-volatile (e.g., read-only memory ("ROM")) mass storage system readable by the CPU. The computer-readable media may include cooperating or interconnected computer-readable media that reside solely on the processing system or distributed across multiple interconnected processing systems that may be local or remote relative to the processing system. It should be understood that the embodiments are not limited to the above-mentioned memories, and other platforms and memories may also support the provided methods.

[0384] In an exemplary embodiment, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer-readable instructions may be executed by a processor of a mobile unit, a network element, and / or any other computing device.

[0385] There is little difference between hardware implementation and software implementation of various aspects of the system. The use of hardware or software is usually (but not always, because in some contexts, the choice between hardware and software may become important) a design choice that represents a trade-off between cost and efficiency. There may be various media (e.g., hardware, software, and / or firmware) that can implement the processes and / or systems and / or other technologies described herein, and the preferred media may vary with the context of the deployment process and / or system and / or other technologies. For example, if the implementer determines that speed and accuracy are most important, the implementer may choose a media that is primarily hardware and / or firmware. If flexibility is most important, the implementer may choose a specific implementation that is primarily software. Alternatively, the implementer may choose some combination of hardware, software, and / or firmware.

[0386] The above specific embodiments have been listed various embodiments of devices and / or processes by using block diagrams, flow charts and / or examples. Where such block diagrams, flow charts and / or examples include one or more functions and / or operations, it will be understood by those skilled in the art that each function and / or operation within such block diagrams, flow charts or examples may be implemented individually and / or collectively by a wide range of hardware, software, firmware or almost any combination thereof. In one embodiment, several parts of the subject matter described herein may be implemented via application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs) and / or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein may be equivalently implemented in integrated circuits as a whole or in part as one or more computer programs running on one or more computers (e.g., one or more programs running on one or more computer systems), one or more programs running on one or more processors (e.g., one or more programs running on one or more microprocessors), firmware or almost any combination thereof, and according to the present disclosure, designing circuits and / or writing software and / or firmware codes will be completely within the technical scope of those skilled in the art. Furthermore, those skilled in the art will appreciate that the mechanisms of the subject matter described herein can be distributed as a program product in a variety of forms, and that the illustrative embodiments of the subject matter described herein apply regardless of the specific type of signal-bearing medium used to actually perform the distribution. Examples of signal-bearing media include, but are not limited to, the following: recordable type media (such as floppy disks, hard drives, CDs, DVDs, digital tapes, computer memory, etc.); and transmission type media (such as digital and / or analog communication media (e.g., fiber optic cables, waveguides, wired communication links, wireless communication links, etc.)).

[0387] Those skilled in the art will recognize that it is common in the art to describe devices and / or processes in the manner set forth herein, and thereafter use engineering practices to integrate such described devices and / or processes into a data processing system. That is, at least a portion of the devices and / or processes described herein can be integrated into a data processing system via a reasonable amount of experimentation. Those skilled in the art will recognize that a typical data processing system generally may include one or more of the following: a system unit housing; a video display device; a memory, such as a volatile memory and a non-volatile memory; a processor, such as a microprocessor and a digital signal processor; a computing entity, such as an operating system, a driver, a graphical user interface, and an application; one or more interactive devices, such as a touch pad or a screen; and / or a control system, including a feedback loop and a control motor (e.g., a feedback for sensing position and / or velocity, a control motor for moving and / or adjusting components and / or quantities). A typical data processing system may be implemented using any suitable commercially available components, such as those typically found in data computing / communication and / or network computing / communication systems.

[0388] The subject matter described herein sometimes illustrates different components included in or connected to different other components. It should be understood that such depicted architectures are merely examples, and in fact many other architectures that achieve the same function can be implemented. In a conceptual sense, any arrangement of components that achieve the same function is effectively "associated" so that the desired function can be achieved. Therefore, any two components that are combined to achieve a specific functionality in this article can be considered to be "associated" with each other so that the desired functionality is achieved, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered to be "operably connected" or "operably coupled" to each other to achieve the desired functionality, and any two components that can be so associated can also be considered to be "operably coupled" to each other to achieve the desired functionality. Specific examples of operable coupling include, but are not limited to, components that can physically cooperate and / or physically interact and / or components that can wirelessly interact and / or wirelessly interact and / or components that can logically interact and / or components that can logically interact.

[0389] With respect to substantially any plural and / or singular terms used herein, those skilled in the art may translate from the plural to the singular and / or from the singular to the plural as appropriate, as appropriate to the context and / or application. For clarity, various singular / plural arrangements may be explicitly listed herein.

[0390] It will be understood by those skilled in the art that, in general, the terms used herein, and particularly in the appended claims (e.g., the bodies of the appended claims), are generally intended to be "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "comprising" should be interpreted as "including but not limited to," etc.). It will also be understood by those skilled in the art that if a specific number of an introduced claim recitation is intended, such intent will be explicitly recited in the claim, and in the absence of such recitation, no such intent is present. For example, where only one item is intended, the term "single" or similar language may be used. To aid understanding, the following appended claims and / or the description herein may include the use of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed as implying that any particular claim that includes such introduced claim recitation subject matter is limited to embodiments that include only one such recitation subject matter by the indefinite article "a" or "an" to introduce the claim recitation subject matter, even when the same claim includes the introductory phrases "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be interpreted as meaning "at least one" or "one or more"). The same applies to the use of definite articles to introduce claim recitation subjects. Furthermore, even if a specific number of introduced claim recitation subjects is explicitly recited, one skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitation subjects" means at least two recitation subjects or two or more recitation subjects in the absence of other modifiers). Additionally, in those instances where a convention similar to “at least one of A, B, and C, etc.” is used, generally speaking, such construction is meant to be understood by one skilled in the art (e.g., “a system having at least one of A, B, and C” would include, but is not limited to, systems having A alone, B alone, C alone, both A and B, both A and C, both B and C, and / or both A, B, and C, etc.). In those instances where a convention similar to “at least one of A, B, or C, etc.” is used, generally speaking, such construction is meant to be understood by one skilled in the art (e.g., “a system having at least one of A, B, or C” would include, but is not limited to, systems having A alone, B alone, C alone, both A and B, both A and C, both B and C, and / or both A, B, and C, etc.). It should also be understood by those skilled in the art that, in fact, any separate words and / or phrases presenting two or more alternative terms, whether in the specification, claims or drawings, should be understood to contemplate the possibility of including one of the terms, any one of the terms, or both of the terms.For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B." Additionally, as used herein, the term "any of..." followed by a listing of multiple items and / or multiple categories of items is intended to include "any of...", "any combination of...", "any multiples of...", and / or "any combination of multiples of...", of the items and / or categories of items, either alone or in combination with other items and / or other categories of items. Additionally, as used herein, the term "set" is intended to include any number of items, including zero. Additionally, as used herein, the term "quantity" is intended to include any quantity, including zero. And, as used herein, the term "plurality" is intended to be synonymous with "multiple."

[0391] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also described in terms of any individual member or subgroup of members of the Markush group.

[0392] As will be understood by those skilled in the art, for any and all purposes (such as in terms of providing a written description), all ranges disclosed herein also encompass any and all possible sub-ranges and combinations of their sub-ranges. Any listed range can be easily identified as fully describing and enabling the same range to be divided into at least equal halves, one-third, one-quarter, one-fifth, one-tenth, etc. As a non-limiting example, each range discussed herein can be easily divided into a lower third, a middle third, and an upper third, etc. As will be understood by those skilled in the art, all languages ​​such as "up to", "at least", "greater than", "less than", etc. include the cited numbers and refer to the ranges that can be subsequently divided into sub-ranges as described above. Finally, as will be understood by those skilled in the art, the range includes each individual number. Therefore, for example, a group with 1 to 3 units refers to a group with 1, 2 or 3 units. Similarly, a group with 1 to 5 units refers to a group with 1, 2, 3, 4 or 5 units, etc.

[0393] Furthermore, the claims should not be read as limited to the order or elements provided unless otherwise stated. Furthermore, the use of the term "means for..." in any claim is intended to invoke 35 U.S.C. § 112, 6 or parts-plus-function claim format, and any claim without the term "means for..." is not intended to be so.

[0394] A processor in association with software may be used to implement the use of a radio frequency transceiver in a wireless transmit receive unit (WTRU), user equipment (UE), terminal, base station, mobility management entity (MME) or evolved packet core (EPC) or any host. The WTRU may be used in conjunction with a module implemented in hardware and / or software including a software defined radio (SDR) and other components such as a camera, video camera module, videophone, speakerphone, vibration device, speaker, microphone, television transceiver, hands-free headset, keyboard, module, a frequency modulation (FM) radio unit, a near field communication (NFC) module, a liquid crystal display (LCD) display unit, an organic light emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an internet browser, and / or any wireless local area network (WLAN) or ultra-wideband (UWB) module.

[0395] Although the present invention has been described in terms of a communication system, it is contemplated that the system may be implemented in software on a microprocessor / general purpose computer (not shown). In certain embodiments, one or more of the functions of the various components may be implemented in software controlling a general purpose computer.

Claims

1. A method for wireless communication implemented by a wireless transmit / receive unit (WTRU), the method comprising: determining information for the first transmission and the second transmission based on ultra low power (ULP) capabilities associated with one or more target destinations; transmitting the first transmission based on the information, the first transmission comprising: 1) first sidelink control information (SCI) associated with the first transmission, wherein the first SCI indicates a resource set for the second transmission and a ULP signal to be transmitted on the first transmission; and 2) the ULP signal, the ULP signal indicating at least a first subset of the one or more target destinations, the resource set for the second transmission, and a second SCI associated with the second transmission; as well as The second transmission is transmitted, the second transmission comprising at least a second subset of the second SCI and sidelink payload data.

2. The method of claim 1, further comprising determining that the one or more target destinations are capable of receiving a subset of the second SCI.

3. The method of any preceding claim, wherein the one or more target destinations include at least a ULP WTRU and a non-ULP WTRU.

4. The method of any of the preceding claims, wherein the first subset of the second SCI is transmitted in the ULP signal and on a Physical Sidelink Shared Channel (PSCCH) of the first transmission.

5. The method according to any one of the preceding claims, wherein the first SCI is a first stage SCI and the second SCI is a second stage SCI.

6. A method according to any preceding claim, wherein the second transmission comprises the first SCI indicating a format of the second SCI.

7. A method for wireless communication implemented by a wireless transmit / receive unit (WTRU), the method comprising: determining information for the first transmission and the second transmission based on ultra low power (ULP) capabilities associated with one or more target destinations; transmitting the first transmission based on the information, the first transmission comprising: 1) first sidelink control information (SCI) associated with the first transmission, wherein the first SCI indicates a resource set for the second transmission and a ULP signal to be transmitted on the first transmission; and 2) the ULP signal, the ULP signal indicating the one or more target destinations, the resource set for the second transmission, and a second SCI associated with the second transmission; and The second transmission is transmitted, the second transmission comprising sidelink payload data. The method of claim 7 , wherein the ULP signal indicates the entire content of the second SCI.

9. The method according to any one of claims 7 to 8, further comprising determining that the one or more target destinations are capable of receiving a subset of the second SCI.

10. The method of any one of claims 7 to 9, wherein the one or more target destinations include at least a ULP WTRU and a non-ULP WTRU.

11. The method according to any one of claims 7 to 10, wherein the first subset of the second SCI is transmitted in the ULP signal and on a Physical Sidelink Shared Channel (PSCCH) of the first transmission.

12. The method according to any one of claims 7 to 11, wherein the first SCI is a first-stage SCI and the second SCI is a second-stage SCI.

13. The method according to any one of claims 7 to 12, wherein the second transmission comprises the first SCI indicating a format of the second SCI.

14. A method for wireless communication implemented by a wireless transmit / receive unit (WTRU), the method comprising: determining information for the first transmission and the second transmission based on ultra low power (ULP) capabilities associated with one or more target destinations; determining that the one or more target destinations are unable to receive a subset of sidelink control information (SCI); transmitting the first transmission based on the information, the first transmission comprising a ULP signal indicating the one or more target destinations and a set of resources for the second transmission; and The second transmission is transmitted, the second transmission comprising the SCI and sidelink payload data.

15. A wireless transmit / receive unit (WTRU) comprising circuitry, the WTRU comprising a transmitter, a receiver, a processor, and a memory, the WTRU being configured to: determining information for the first transmission and the second transmission based on ultra low power (ULP) capabilities associated with one or more target destinations; The first transmission is sent based on the information, the first transmission comprising: 1) first sidelink control information (SCI) associated with the first transmission, wherein the first SCI indicates a set of resources for the second transmission and a ULP signal to be sent on the first transmission; and 2) the ULP signal, the ULP signal indicating the one or more target destinations, the set of resources for the second transmission, and at least a first subset of a second SCI associated with the second transmission; as well as The second transmission is transmitted, the second transmission comprising at least a second subset of the second SCI and sidelink payload data.

16. The WTRU of claim 15, wherein the processor is further configured to determine a subset of the one or more target destinations that are capable of receiving the second SCI.

17. The WTRU of any one of claims 15 to 16, wherein the one or more target destinations include at least a ULP WTRU and a non-ULP WTRU.

18. The WTRU of any one of claims 15 to 17, wherein the first subset of the second SCI is transmitted in the ULP signal and on a physical sidelink shared channel (PSCCH) of the first transmission.

19. The WTRU of any one of claims 15 to 18, wherein the first SCI is a first stage SCI and the second SCI is a second stage SCI.

20. The WTRU of any one of claims 15 to 19, wherein the second transmission includes the first SCI indicating a format of the second SCI.

21. The WTRU of any one of claims 15 to 20, wherein the processor is further configured to determine a first format for the first transmission and a second format for the second transmission based on the ULP capabilities associated with the one or more target destinations.

22. A wireless transmit / receive unit (WTRU) comprising circuitry, the WTRU comprising a transmitter, a receiver, a processor and a memory, the WTRU being configured to implement the method according to any one of claims 1 to 14.

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