Segmented bearer scheduling in multi-path operations via SL relays

Abstract

The WTRU may receive configuration information associated with uplink transmissions on the split bearer. The split bearer may be associated with a first path and a second path. The configuration information may include a radio quality threshold associated with channel conditions on the first path and / or the second path. The WTRU may determine a (e.g., dynamic) transmit distribution percentage associated with UL transmissions on the first path and / or the second path based at least on the configuration information, channel conditions associated with the first path, and / or channel conditions associated with the second path. The WTRU may transmit uplink data associated with the split bearer based on the determined transmit distribution percentage. The WTRU may transmit an indication to a network associated with the split bearer. The WTRU may update a partition buffer threshold based on channel conditions (e.g., CBR, RSRP, etc.) of the first path and / or the second path.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 334,987 filed on April 26, 2022 and U.S. Provisional Patent Application No. 63 / 359,355 filed on July 8, 2022, which are incorporated herein by reference in their entirety. Background Art

[0003] A wireless transmit receive unit (WTRU) may be configured to communicate with one or more WTRU-to-network relays including sidelink (SL) relays. Relaying via a ProSe WTRU-to-network relay may include extending network coverage to an out-of-coverage WTRU by using a PC5 link (e.g., device-to-device (D2D)) between the out-of-coverage WTRU and the WTRU-to-network relay. For example, the ProSe WTRU-to-network relay may provide a layer 3 (L3) forwarding function that may relay one or more (e.g., any) types of IP traffic between a remote WTRU and a network. In each example, one-to-one and / or one-to-many sidelink communications may be used between the remote WTRU and the ProSe WTRU-to-network relay. For the remote WTRU and / or relay WTRU, (e.g., only) one carrier (e.g., a public safety ProSe carrier) operation may be supported (e.g., a direct link (Uu) and a PC5 link may be established for the relay / remote WTRU over the same carrier). In various examples, the remote WTRU may be authorized by one or more upper layers and / or may be within the coverage of a public safety ProSe carrier and / or outside the coverage of one or more (e.g., any) supported carriers (including a public safety ProSe carrier for WTRU to network relay discovery, (re)selection and / or communication). In various examples, the ProSe WTRU to network relay may (e.g., always) be within the coverage of the EUTRAN. Summary of the invention

[0004] A WTRU may receive configuration information associated with uplink (UL) transmissions on a split bearer. The split bearer may be associated with a first path and a second path. The WTRU may determine a transmission distribution percentage associated with UL transmissions on the first path and the second path based at least on the configuration information, a channel condition associated with the first path, and a channel condition associated with the second path. The WTRU may update the transmission distribution percentage associated with UL transmissions on the split bearer based on the channel condition associated with the first path and the channel condition associated with the second path. The configuration information may include an indication of a split buffer threshold associated with the split bearer, wherein the transmission distribution is further based on a buffer level of the WTRU. The configuration information may include a radio quality threshold (e.g., condition) associated with the channel condition on each of the first path and the second path. The radio quality threshold (e.g., condition) may include a reference signal received power (RSRP) threshold. The radio quality threshold may include a channel busy rate (CBR) threshold. The channel condition associated with the first path may include a current CBR associated with the first path. The channel condition associated with the second path may include a current radio quality associated with the second path.The WTRU may transmit uplink data associated with the split bearer based on the determined transmit distribution percentage.

[0005] The WTRU may update a split buffer threshold associated with a split buffer threshold associated with the split bearer based on a channel condition associated with the first path and a channel condition associated with the second path. The WTRU may update the transmission distribution percentage associated with UL transmissions on the split bearer based on a channel condition associated with the first path and a channel condition associated with the second path. The WTRU may transmit an indication to a network node. The WTRU may transmit an indication of the updated split buffer threshold to the network. The WTRU may transmit an indication of the updated transmission distribution percentage to the network. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] A more detailed understanding may be obtained from the following description given by way of example in conjunction with the accompanying drawings, in which like reference numerals indicate like elements, and in which:

[0007] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented;

[0008] Figure 1B is an example of an embodiment in which Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within the illustrated communication system;

[0009] Figure 1Cis an example of an embodiment in which Figure 1A a system diagram of an example Radio Access Network (RAN) and an example Core Network (CN) used within the illustrated communication system;

[0010] Figure 1D is an example of an embodiment in which Figure 1A a system diagram of another example RAN and another example CN used within the illustrated communication system; and

[0011] Figure 2A An example user plane protocol stack for a Layer 2 (L2) WTRU to network relay is illustrated.

[0012] Figure 2B An example control plane protocol stack for an L2 WTRU to network relay is illustrated.

[0013] Figure 3 An example protocol view of split bearer associated with dual connectivity is illustrated.

[0014] Figure 4 An overview of an example split bearer protocol in multipath operation is illustrated.

[0015] Figure 5 An example network associated with split bearer is illustrated.

[0016] Figure 6 Another example network associated with split bearer is illustrated.

[0017] Figure 7 An example flow diagram associated with split bearer configuration is illustrated. DETAILED DESCRIPTION

[0018] Figure 1A 1 is a 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 unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0019] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, 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 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.

[0020] 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 that is configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. While 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.

[0021] 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 (the base station may be referred to as a cell (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. 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 an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0022] 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).

[0023] 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 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0024] In an 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), which 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).

[0025] In an 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).

[0026] In an 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 the dual connectivity (DC) principle. Thus, the air interface used 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).

[0027] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), 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.

[0028] Figure 1AThe base station 114b in the 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 local areas such as commercial venues, homes, vehicles, campuses, industrial facilities, sky corridors (e.g., for use by drones), roads, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another 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 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.

[0029] 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 GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0030] The CN 106 / 115 may also serve 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 / 113 or a different RAT.

[0031] 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.

[0032] 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 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.

[0033] 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 in an electronic package or chip.

[0034] 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 an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, IR, UV or visible light signals. In another embodiment, the send / receive element 122 may be configured to send and / or receive both RF signals and optical signals. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0035] Although the transmit / receive element 122 Figure 1B 1 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, 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.

[0036] 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.

[0037] 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, and the like. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0038] 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.

[0039] 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.

[0040] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), 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. Peripheral device 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.

[0041] 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 UL (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 139 for reducing and / or substantially eliminating self-interference via signal processing performed via hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0042] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0043] 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 / or receive wireless signals from the WTRU 102a.

[0044] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0045] 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 (or 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.

[0046] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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 communication interface with a communication network.

[0051] In a representative embodiment, the other network 112 may be a WLAN.

[0052] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a 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 leading to the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and leading 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 target STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic may be transmitted between the source STA and the target STA (e.g., directly between them) using a direct link setup (DLS). 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. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0053] 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.

[0054] 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.

[0055] 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 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 sending STA. At the receiver of the receiving STA, the above-mentioned operation for 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0056] 802.11af and 802.11ah support operating modes below 1GHz. 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 instrument type control / machine type communications, 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).

[0057] 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 frequency band may be considered busy even if most of the frequency bands remain idle and may be available.

[0058] 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.

[0059] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 in accordance with an 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.

[0060] 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 gNBs 180a, 180b, 180c. 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 an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0061] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with parameter sets 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., containing different numbers of OFDM symbols and / or varying absolute time lengths over time).

[0062] 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 WTRU 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the evolved Node-B 160a, 160b, 160c. For example, the WTRU 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more evolved Node-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the evolved Node-B 160a, 160b, 160c may act as a mobility anchor for the WTRU 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRU 102a, 102b, 102c.

[0063] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle 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.

[0064] 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 possible data networks (DNs) 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.

[0065] 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, support of network slicing (e.g., handling of different 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 based on the type of services utilized 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 mobile broadband (eMBB) access, and / or services for machine type communication (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 WiFi.

[0066] 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 traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0067] 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, 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.

[0068] 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.

[0069] Given that Figures 1A to 1D as well as Figures 1A to 1D , one or more or all of the functions described herein for one or more of the following may be performed by one or more simulation 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-182ab, UPF 184a-184b, SMF 183a-183b, DN 185a-185b and / or any other device described herein. The simulation device may be one or more devices configured to mimic one or more or all of the functions described herein. For example, the simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0070] 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.

[0071] 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 laboratory 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 may include one or more antennas) can be used by the simulation device to send and / or receive data.

[0072] A WTRU may be configured to communicate with one or more WTRUs for network relaying, the network relay comprising a sidelink (SL) relay. Relaying via a ProSe WTRU to network relay may include extending network coverage to an out-of-coverage WTRU by using an interface (e.g., PC5 device-to-device (D2D)) between the out-of-coverage WTRU and the WTRU to network relay. For example, the ProSe WTRU to network relay may provide a layer 3 (L3) forwarding function that may relay one or more (e.g., any) types of Internet Protocol (IP) traffic between a remote WTRU and a network. In each example, one-to-one and / or one-to-many sidelink communications may be used between the remote WTRU and the ProSe WTRU to network relay. For one or more remote WTRUs and / or relay WTRUs (e.g., both), separate carrier (e.g., public safety ProSe carrier) operations may be supported (e.g., direct link (Uu) and PC5 may be the same carrier for the relay / remote WTRU). In various examples, the remote WTRU may be authorized by one or more upper layers and / or may be within the coverage of a public safety ProSe carrier and / or outside the coverage of one or more (e.g., any) supported carriers (including a public safety ProSe carrier for WTRU to network relay discovery, (re)selection and / or communication). In various examples, the ProSe WTRU to network relay may (e.g., always) be within the coverage of the EUTRAN.

[0073] The sidelink may be used to support one or more vehicle-to-everything (V2X) related road safety services. In various examples, the sidelink may support broadcast, multicast, and / or one or more unicast communications in scenarios outside of coverage and / or scenarios within network coverage. The sidelink-based relay functionality may be used to improve sidelink coverage extension, network coverage extension, and / or power efficiency. For a wider range of one or more applications and / or services, the sidelink-based relay functionality may improve sidelink coverage extension, network coverage extension, and / or power efficiency.

[0074] In each example, one or more (e.g., two) areas of coverage extension for improving sidelink-based communications may include WTRU-to-network coverage extension and / or WTRU-to-WTRU coverage extension. For example, in WTRU-to-network coverage extension, one or more WTRUs may utilize Uu coverage reachability to reach a server in a packet data network (PDN) and / or a corresponding WTRU located outside a neighboring area. Certain WTRU-to-network relays may be limited to EUTRA-based technologies. For example, in WTRU-to-WTRU coverage extension, nearby reachability may be limited to a single-hop side link via EUTRA-based and / or NR-based sidelink technologies. When Uu coverage is not present, the single-hop side link may not be used. In each example, the sidelink connectivity may support one or more enhanced QoS requirements.

[0075] Single-hop sidelink relay may have been introduced with one or more (e.g., several) objectives. For example, one objective may include one or more study mechanisms with minimal regulatory impact to support one or more service architecture (SA) requirements for sidelink-based WTRU-to-network and / or WTRU-to-WTRU relay, focusing on one or more of the following aspects for layer 3 relay and / or layer 2 relay [RAN2] (e.g., as applicable). One or more of the following aspects for layer 3 relay and layer 2 relay may include: relay selection and / or reselection criteria and / or procedures; relay / remote WTRU authorization; QoS for relay functionality; service continuity; security of relay connections; and / or impact on user plane protocol stacks and / or control plane procedures (e.g., connection management of relay connections). For example, another objective may include one or more study mechanisms to support one or more upper layer operations of the discovery model / procedures for sidelink relay without additional (e.g., new) physical layer channels / signals [RAN2].

[0076] Figure 2A An example protocol stack 200 associated with an L2 U2N relay architecture on a user plane (UP) is illustrated. Figure 2BAn example protocol stack 250 associated with an L2 U2N relay architecture on a control plane (CP) is illustrated. In various examples, a sidelink relay adaptation protocol (SRAP) sublayer may be placed at a PC5 interface and / or a Uu interface for a CP (e.g., Figure 2B exemplified) and / or UP (e.g., Figure 2A The SRAP sublayer may be located above the radio link control (RLC) sublayer of the L2 U2N remote WTRU 210 (illustrated). The Uu Service Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP), and / or Radio Resource Control (RRC) may terminate between the L2 U2N remote WTRU 210 and the gNB 230. The sSRAP, RLC, Medium Access Control (MAC) layer, and / or Physical (PHY) layer may terminate in one or more hops (e.g., each hop) (e.g., the link between the L2 U2N remote WTRU 210 and the L2 U2N relay WTRU 220 and / or the link between the L2 U2N relay WTRU 220 and the gNB 230). For the L2 U2N relay, the SRAP sublayer on the PC5 hop may be used for bearer mapping purposes. In order to relay messages for the L2 U2N remote WTRU on the Broadcast Control Channel (BCCH) and / or the Paging Control Channel (PCCH), the SRAP sublayer may not be present on the PC5 hop. For messages to L2U2N remote WTRUs on a specific signaling radio bearer (eg, SRB0), the SRAP sublayer may not be present on the PC5 hop, but the SRAP sublayer may be present on the Uu hop for DL ​​and / or UL.

[0077] For the uplink of L2 U2N relay, the Uu SRAP sublayer may support UL bearer mapping between one or more ingress PC5 relay RLC channels and / or one or more egress Uu relay RLC channels for relaying via the L2 U2N relay WTRU Uu interface. For uplink relay traffic, one or more different end-to-end RBs (e.g., signaling radio bearers (SRBs) and / or data radio bearers (DRBs)) of the same remote WTRU 210 and / or different remote WTRUs may be multiplexed on the same Uu relay RLC channel. The Uu SRAP sublayer may support L2U2N remote WTRU identification (ID) for UL traffic. Identification information of the L2 U2N remote WTRU Uu radio bearer and / or the local remote WTRU ID may be included in the Uu SRAP header at the UL. Identification information of the L2U2N remote WTRU Uu radio bearer and / or the local remote WTRU ID may be included in the Uu SRAP header at the UL so that the gNB 230 can associate one or more received packets for a (e.g., specific) PDCP entity associated with the correct Uu radio bearer of the remote WTRU. The PC5 SRAP sublayer at the L2 U2N remote WTRU 210 may support UL bearer mapping between one or more remote WTRU Uu radio bearers and one or more egress PC5 relay RLC channels.

[0078] For the downlink of L2 U2N relay, the Uu SRAP sublayer may support DL bearer mapping at the gNB to map the end-to-end radio bearers (e.g., SRBs and DRBs) of the remote WTRU into the Uu relay RLC channels through the relay WTRU Uu interface. The Uu SRAP sublayer may support DL bearer mapping and / or data multiplexing between one or more (e.g., multiple) end-to-end radio bearers (e.g., SRBs and / or DRBs) of the L2 U2N remote WTRU and / or one or more different L2U2N remote WTRUs and / or a Uu relay RLC channel through the relay WTRU Uu interface. The Uu SRAP sublayer may support remote WTRU identification for DL ​​traffic. Identification information of the remote WTRU Uu radio bearers and / or the local remote WTRU ID may be included in the Uu SRAP header by the gNB at the DL. Identification information of the remote WTRU Uu radio bearer and / or the local remote WTRU ID may be included by the gNB at the DL in the Uu SRAP header so that the relay WTRU may map one or more packets received from the remote WTRU Uu radio bearer to an associated PC5 relay RLC channel (e.g., of the relay WTRU). The PC5 SRAP sublayer at the relay WTRU may support DL bearer mapping between one or more ingress Uu relay RLC channels and one or more egress PC5 relay RLC channels. The PC5 SRAP sublayer at the remote WTRU may associate one or more received packets for (e.g., a specific) PDCP entity associated with the correct Uu radio bearer of the remote WTRU based on (e.g., the identification information included in the Uu SRAP header).

[0079] The local remote WTRU ID may be included in the PC5 SRAP header and / or the Uu SRAP header. The L2 U2N relay WTRU may be configured with the local remote WTRU ID by the gNB. The L2 U2N relay WTRU may be configured with (e.g., receives configuration information) the local remote WTRU ID by the gNB for use in the SRAP header. The remote WTRU may obtain the local remote ID from the gNB via one or more Uu RRC messages including RRCSetup, RRCReconfiguration, RRCResume and / or RRCReestablishment. The Uu DRB and / or Uu SRB may be mapped to one or more different PC5 relay RLC channels and / or Uu relay RLC channels in a PC5 hop and / or Uu hop. The gNB may be responsible for avoiding conflicts in the use of the local remote WTRU ID. The gNB may update the local remote WTRU ID by transmitting the updated local remote ID to the relay WTRU via an RRCReconfiguration message. The serving gNB may perform the local remote WTRU ID update independently of the PC5 unicast link L2 ID update procedure.

[0080] The WTRU may be configured to perform multipath operations with SL relays. For example, the WTRU may be configured to perform operations for multipath with relays, where a remote WTRU is connected to the network via one or more direct and / or indirect paths, which may improve reliability, robustness, and / or throughput.

[0081] Multipath relaying may be used for WTRU aggregation, where a WTRU is connected to a network via a direct path and another WTRU using a non-standardized WTRU-WTRU interconnect. WTRU aggregation may be intended to provide one or more applications including a high UL bit rate on a terminal. For example, when a WTRU is (e.g., too) limited by the UL WTRU transmit power and cannot achieve the desired (e.g., required) bit rate (e.g., at the cell edge), WTRU aggregation may be intended to provide one or more applications including a high UL bit rate on a terminal. Additionally or alternatively, WTRU aggregation may improve the reliability and / or stability of a service. WTRU aggregation may reduce latency for one or more services. For example, if the channel condition of a terminal is deteriorating, another terminal may be used to compensate for the unstable traffic performance caused by the changing channel conditions.

[0082] Another purpose of multipath operation may include studying the benefits of multipath support and / or potential solutions to enhance reliability and / or throughput (e.g., by switching between one or more(s) paths and / or utilizing one or more(s) paths simultaneously). For example, one or more multipath operations may be used to enhance the reliability and / or throughput of a WTRU that is connected to the same gNB via a direct path and / or an indirect path via 1) a Layer 2 WTRU to network relay and / or 2) via another WTRU (e.g., where WTRU-WTRU interconnection may be desirable). The solution used for 1) Layer 2 WTRU to network relay may be reused for the solution used for 2) another WTRU, but does not exclude the possibility of removing portions of one or more solutions that are not necessary for operation 2) (e.g., using a WTRU connected to the gNB via an indirect path via another WTRU). The WTRU to network relay in 1) Layer 2 WTRU to network relay may reuse one or more previous solutions as a baseline. Support for Layer 3 WTRU to network relay in multipath scenarios may not include RAN impact. Support for Layer 3 WTRU to network relay in multipath scenarios may include work and / or one or more solutions affected by the SA2 process.

[0083] The WTRU may be configured to perform one or more sidelink measurements and / or scheduling. In SL operation, the WTRU may configure an associated peer WTRU to perform sidelink measurements and / or report a corresponding PC5-RRC connection. In one or more cases, in SL operation, the WTRU may, for example, via an RRCReconfigurationSidelink message, configure an associated peer WTRU to perform sidelink measurements and / or report a corresponding PC5-RRC connection according to a sidelink measurement configuration for unicast.

[0084] The WTRU may derive one or more sidelink measurement results, for example, by measuring one or more (e.g., multiple) demodulation reference signals (DMRS) (e.g., a DMRS associated with each PC5-RRC connection), for example, as configured by a peer WTRU. For one or more (e.g., all) sidelink measurement results, the WTRU may, for example, apply L3 filtering before using the one or more measurement results to evaluate reporting criteria and / or measurement reports. Sidelink reference signal received power (RSRP) may be configured as a triggering amount and / or a reporting amount.

[0085] The following measurements may be associated with the sidelink: Event S1 and / or Event S2. Event S1 may be triggered when a metric associated with the serving cell becomes stronger (e.g., better) than a threshold. Event S2 may be triggered when a metric associated with the serving cell becomes weaker (e.g., worse) than a threshold. The WTRU may receive one or more measurements (e.g., one or more reports) based on S1 and / or S2, for example, to adjust the power level when sending data.

[0086] The sidelink transmission may include one or more (e.g., two) modes (e.g., Mode 1 and / or Mode 2) for resource allocation. Mode 1 may, for example, include the gNB scheduling one or more sidelink resources. Mode 2 may, for example, include the WTRU selecting (e.g., autonomously selecting) one or more sidelink resources from a set of configured and / or preconfigured sidelink resource pools, for example, based on a channel sensing mechanism. For a WTRU in coverage, the WTRU may be configured to operate in Mode 1 and / or Mode 2. For a WTRU out of coverage, the WTRU may be configured to operate (e.g., only) in Mode 2.

[0087] The channel condition may include congestion. The channel condition associated with the first path may include congestion associated with the first path. The channel condition associated with the second path may include congestion associated with the second path. Congestion control may be implemented in certain SL transmissions (e.g., for a WTRU configured in Mode 2) to prevent the transmitting WTRU from occupying a large amount (e.g., excessive) of resources in one or more sidelink transmissions (e.g., to enhance QoS). One or more (e.g., two) metrics (e.g., conditions) may be used to prevent the transmitting WTRU from occupying a large amount (e.g., excessive) of resources in one or more sidelink transmissions, for example, including a channel busy rate (CBR) and / or a channel occupancy rate (CR). CBR may refer to the portion of a subchannel whose received signal strength indicator (RSSI) exceeds a preconfigured value for a certain duration. Considering a particular time slot n, CR may be defined as (X+Y)M, where X is the number of subchannels in [na,n-1] that have been occupied by the transmitting WTRU, Y is the number of subchannels in [n,n+b] that have been granted, and M is the total number of subchannels in [na,n+b]. For congestion control, CR is defined as 限制 An upper limit on the CR indicated may be imposed on the transmitting WTRU, where CR 限制 is a function of the CBR and / or the priority of one or more sidelink transmissions. The amount of resources occupied by the transmitting WTRU cannot exceed the CR 限制 The channel condition associated with the (eg, first) path may include a current CBR associated with the (eg, first) path. The channel condition associated with the second path may include a current CBR associated with the second path.

[0088] The gNB may use the CBR reports to determine the resource pool to allocate to the sidelink communication. For example, if one or more WTRUs participating in the sidelink communication are reporting a high CBR, the gNB may increase the resource pool. For example, if the reported CBR is low, the gNB may decrease the resource pool.

[0089] In addition to one or more peer WTRUs participating in sidelink operations where one or more peer WTRUs (e.g., each other) may be configured to perform one or more measurements (e.g., periodically and / or determine one or more measurement results via S1 / S2 events), the gNB may configure one or more CBR measurements for a remote WTRU, for example, for operations within coverage (e.g., the remote WTRU may be within the coverage of the gNB). One or more CBR measurements may be performed periodically and / or on a triggering event (e.g., S1 / S2 event). One or more (e.g., two) measurement events may be configured for CBR measurement reporting. For example, measurement event C1 and / or measurement event C2 may be configured to trigger a CBR measurement report. Event C1 may be triggered if the CBR of the sidelink communication becomes stronger (e.g., better) than a threshold (e.g., an absolute threshold). Event C2 may be triggered if the CBR of the sidelink communication becomes weaker (e.g., worse) than a threshold (e.g., an absolute threshold).

[0090] The WTRU may be configured (e.g., in dual connectivity (DC)) to include one or more split bearers. The WTRU may receive configuration information associated with uplink (UL) transmissions on a split bearer, where the split bearer may be associated with a first path (e.g., Uu and / or SL) and / or a second path (e.g., Uu and / or SL). The configuration information may include a radio quality threshold associated with a channel condition on the first path and / or the second path. In DC, the WTRU may be served by two nodes, where the two nodes (e.g., each node) may include a set of one or more cells (e.g., referred to as a master cell group (MCG) and / or a secondary cell group (SCG)). The bearer may be associated with (e.g., only with) an MCG and / or an SCG and / or the bearer may be configured as a split bearer.

[0091] Figure 3 An example protocol view 300 for split bearer associated with dual connectivity is illustrated. Figure 3 As illustrated, the WTRU 302 may be associated with a PDCP entity. The peer PDCP entity on the network side may terminate at one of the gNBs (e.g., a primary gNB or a secondary gNB). Figure 3 As illustrated, the PDCP entity may terminate at the gNB 306. In the DL, the CN may provide a PDCP to the gNB (e.g., Figure 3The network may, for example, transmit the data directly to the WTRU 302 via a link between a gNB (e.g., gNB1 304) and the WTRU 302, and / or the network may forward the PDCP PDU to gNB2 304 (e.g., via an Xn interface). The gNB (e.g., gNB2 306) may transmit the data to the WTRU 302 via a link between the gNB and the WTRU 302.

[0092] In the UL, the WTRU may be configured with a primary path and a secondary path. The WTRU may also be configured with a threshold value associated with the primary path and the secondary path (e.g., UL split buffer threshold). If the UL buffer size of the primary path is less than the configured threshold value (e.g., UL split buffer threshold), the PDCP may push the data to the RLC associated with the primary path. If the buffer size becomes greater than the threshold value (e.g., UL split buffer threshold), the WTRU may (e.g., based on the specific implementation of the WTRU) push the data to the primary path or the secondary path.

[0093] As described herein, when the UL buffer size for split bearers is greater than the split buffer threshold, the WTRU may push data to the primary path or the secondary path. For example, based on the specific implementation of the WTRU, the WTRU may push data to the primary path or the secondary path because the scheduling of one or more (e.g., two) links may be done independently by each gNB.

[0094] Figure 4 An example 400 associated with an overview of a split bearer protocol in multipath operation is illustrated. In multipath operation, a direct link (e.g., Uu1) between a remote WTRU 402 and a gNB 404 and / or a backhaul link between a relay WTRU 406 and a gNB 404 may be served by the same gNB 404 and / or the same cell of the same gNB 404. If mode 1 is selected to schedule the SL between the remote WTRU 402 and the relay WTRU 406, the gNB 404 may schedule one or more (e.g., all) links (e.g., Uu1, Uu2, SL). If the gNB 404 uses mode 2 and / or pre-configures a resource pool that the remote WTRU 402 may autonomously use for the SL, the gNB 404 may determine the resource pool configuration. Thus, the gNB 404 may control the scheduling on the SL (e.g., although the real-time nature of the scheduling may not be as real-time as in the case of mode 1). After the UL split buffer threshold has been exceeded, the WTRU's determination of path selection for UL traffic for one or more split bearers may be suboptimal (e.g., in a multipath relay case where the same gNB 404 is responsible for scheduling both links).

[0095] Although the techniques are described in conjunction with split buffering in a scenario where a remote WTRU is multipath connected to the same gNB via a direct link (e.g., a Uu link) and a SL relay, the techniques described herein may also or alternatively be used in other scenarios, including, for example, in conjunction with a multi-hop scenario (e.g., where a relay WTRU is further connected to a parent relay WTRU (which is connected to a gNB)).

[0096] Figure 5 An example network 500 is depicted. Figure 5 As illustrated, the network 500 may include a remote WTRU 502, a relay WTRU 504, and a gNB 506. The gNB 506 may be connected to the remote WTRU 502 via a Uu1 connection 508. As described herein, the WTRU 502 may be directly connected to the gNB 506 (e.g., the network) via the Uu1 connection 508 (e.g., which may be referred to herein as a direct connection). The gNB 506 may be connected to the relay WTRU 504 via a Uu2 connection 512. The remote WTRU 502 may be connected to the relay WTRU 504 via a SL connection 510. As described herein, the WTRU 502 may be indirectly connected to the gNB 506 (e.g., the network) via the SL connection 510 (e.g., which may be referred to herein as an indirect connection).

[0097] As described herein, a split bearer may be configured with a primary path (e.g., Uu1 connection 508 or SL connection 510) and / or a secondary path (e.g., Uu1 connection 508 or SL connection 510). A UL split buffer threshold may be configured, for example, where the split buffer threshold may be set to a value from 0 or infinity. For example, setting the UL split buffer threshold to 0 may indicate that there is no primary path (e.g., SL or Uu link may be used). For example, setting the UL split buffer threshold to infinity may indicate that (e.g., only) the primary path is used (e.g., regardless of the size of the UL buffer).

[0098] Apparatus, methods, and systems for split buffer scheduling in multipath operation are discussed herein. In one or more examples, a remote wireless transmit / receive unit (WTRU) may be configured with split bearers and / or one or more associated split buffer thresholds that depend on channel occupancy rate (CR) / channel busy rate (CBR) and / or direct link (Uu) / side link (SL) radio quality, and / or the remote wireless transmit / receive unit may determine and / or use split buffer thresholds corresponding to configured Uu / SL related thresholds and / or current Uu / SL conditions.

[0099] In various examples, the remote WTRU may be configured with split bearers and / or associated split buffer thresholds and / or one or more split distribution percentages between Uu and SL, which may depend on CR / CBR and / or Uu / SL radio quality. The WTRU may determine a distribution percentage value corresponding to the configured Uu / SL related thresholds and / or current Uu / SL conditions to distribute UL data between the primary path and / or the secondary path according to the determined distribution percentage.

[0100] In various examples, a remote WTRU may be configured with a split bearer and / or one or more associated split buffer threshold configurations that depend on channel occupancy rate (CR) / channel busy rate (CBR) and / or direct link (Uu) / side link (SL) radio quality. The WTRU may determine and / or use a split buffer threshold that corresponds to a configured Uu / SL related threshold, and / or current Uu / SL conditions, and / or an associated split distribution percentage between Uu and SL that may depend on CR / CBR and / or Uu / SL radio quality. The WTRU may determine a distribution percentage value corresponding to the configured Uu / SL related threshold and / or current Uu / SL threshold conditions to distribute UL data between the primary path and the secondary path according to the determined distribution percentage. In various examples, the split distribution percentage between Uu and SL may depend on the SL scheduling mode (e.g., mode 1 and / or mode 2). In various examples, the WTRU may be configured to apply one or more different split bearer processing behaviors depending on the SL scheduling mode (e.g., Mode 1 and / or Mode 2) (e.g., to determine a split buffer threshold and / or a split bearer distribution factor based on one or more Uu / SL radio thresholds / conditions and / or SL CBR).

[0101] In each example, the remote WTRU may be configured to indicate a preferred split bearer handling behavior (e.g., a preferred primary path, a preferred split buffer threshold, a preferred split distribution percentage, a preferred split bearer distribution factor, etc.) based on one or more radio thresholds / conditions (e.g., Uu reference signal received power (RSRP) / reference signal received quality (RSRQ), SL RSRP / RSRQ / SINR, SL CBR / CR) and / or one or more current UL buffer levels at the WTRU (e.g., total UL buffer, total buffer on SL, total buffer on Uu, buffer level for a given bearer and / or one or more bearer sets, etc.).

[0102] A WTRU may receive configuration information associated with uplink (UL) transmissions on a split bearer. The split bearer may be associated with a first path and a second path. The WTRU may determine a transmission distribution percentage associated with UL transmissions on the first path and the second path based on at least the configuration information, a channel condition associated with the first path, and a channel condition associated with the second path. The WTRU may update the transmission distribution percentage associated with UL transmissions on the split bearer based on the channel condition associated with the first path and the channel condition associated with the second path. The configuration information may include an indication of a split buffer threshold associated with the split bearer, wherein the transmission distribution is further based on a buffer level of the WTRU. The configuration information may include a radio quality threshold (e.g., condition) associated with the channel condition on each of the first path and the second path. The radio quality threshold (e.g., condition) may include a reference signal received power (RSRP) threshold. The radio quality threshold may include a channel busy rate (CBR) threshold. The channel condition associated with the first path may include a current CBR associated with the first path. The channel condition associated with the second path may include a current radio quality associated with the second path. The WTRU may transmit uplink data associated with the split bearer based on the determined transmit distribution percentage.

[0103] The WTRU may update a split buffer threshold associated with a split bearer based on a channel condition associated with a first path and a channel condition associated with a second path. The WTRU may update a transmit distribution percentage associated with UL transmissions on the split bearer based on a channel condition associated with the first path and a channel condition associated with the second path. The WTRU may transmit an indication to a network node. The WTRU may transmit an indication of the updated split buffer threshold to the network. The WTRU may transmit an indication of the updated transmit distribution percentage to the network.

[0104] The split buffer threshold and / or the (e.g., dynamic) transmit distribution percentage may be based on one or more channel conditions on the first path and / or the second path. For example, the channel conditions may include radio conditions, as described herein. For example, the channel conditions may include congestion, as described herein.

[0105] The split buffer threshold may depend on the CBR and / or CR and / or be modified based on the CBR and / or CR (e.g., by the remote WTRU). In various examples, the remote WTRU (e.g., the remote WTRU 502) may be configured to modify the UL split buffer threshold associated with the split bearer based on the SL CBR and / or CR (e.g., and / or any other suitable measurement results associated with the radio conditions on the SL). For example, the WTRU may be configured with one or more (e.g., multiple) split buffer thresholds, wherein one or more (e.g., each) split buffer threshold corresponds to a range of (e.g., specific) CBR / CR values. For example, the WTRU may be configured with a first split buffer threshold (threshold 1) (used when the CBR is below a first CBR threshold cbr1), a second split buffer threshold (threshold 2) (used when the CBR value is between cbr1 and a second CBR threshold cbr2) and / or a third split buffer threshold (threshold 3) (used when the CBR is greater than cbr2). The WTRU may also or alternatively be configured with a baseline split buffer threshold and / or a scaling factor that depends on the CBR. For example, the WTRU may be configured to use a baseline threshold for a CBR below cbr1. Additionally or alternatively, the WTRU may be configured to increase and / or decrease the threshold by a percentage difference between the current CBR and cbr1 using a baseline threshold and / or a scaling factor. The WTRU may be configured with a baseline buffer threshold and / or a change value that depends on the CBR may be applied. For example, the WTRU may use a baseline threshold for one or more CBRs below cbr1, and / or may apply an increase or decrease by a certain amount and / or percentage for one or more (e.g., each time) a certain amount or percentage increase in CBR.

[0106] The WTRU may switch the primary path for a split bearer based on the CBR. For example, if the SL CBR is below a given CBR threshold (e.g., cbr1), the WTRU may be configured to switch the primary path to SL. For example, if the SL CBR is above a given threshold (e.g., cbr2), the WTRU may be configured to switch the primary path to Uu.

[0107] The split buffer threshold may depend on the radio conditions (e.g., current radio conditions) of the SL and / or Uu. The remote WTRU may be configured to modify the UL split buffer threshold used for the split bearer based on the radio conditions (e.g., radio quality and / or thresholds) associated with the SL and / or Uu (e.g., RSRP, reference signal received power (RSRQ), signal-to-noise ratio (SINR), etc.). For example, the radio quality threshold may include an RSRP threshold. For example, the radio quality threshold may include a CBR threshold. For example, the WTRU may be configured with one or more (e.g., multiple) split buffer thresholds, wherein one or more (e.g., each) split buffer threshold corresponds to a (e.g., specific) range of one or more SL radio conditions (e.g., if the SL radio quality is lower than sl_thresh1, threshold 1 may be used as the split buffer threshold, if the SL radio quality is between sl_thresh1 and sl_thresh2, threshold 2 may be used as the split buffer threshold, and / or if the SL radio quality is higher than sl_thresh2, threshold 3 may be used as the split buffer threshold, etc.). The WTRU may be configured with a baseline buffer threshold and / or may be configured to apply a varying value depending on the SL radio conditions. For example, the WTRU may be configured with a baseline threshold that is used as a split buffer threshold in the event that the SL radio quality is below sl_quality1. The WTRU may, for example, increase and / or decrease the baseline threshold based on a percentage difference between the current SL radio quality and a given radio quality sl_quality1, etc. The WTRU may also or alternatively be configured with multiple split buffer thresholds, each of which corresponds to a range of one or more Uu radio conditions (e.g., threshold 1 for Uu radio quality below uu_thresh1, threshold 2 for Uu radio quality between uu_thresh1 and uu_thresh2, threshold 3 for Uu radio quality above uu_thresh2, etc.). Additionally or alternatively, the WTRU may be configured with a baseline buffer threshold and / or may be configured to apply a varying value depending on one or more Uu radio conditions (e.g., using a baseline threshold for Uu radio quality below uu_quality1, increasing and / or decreasing the threshold by a percentage difference between the current Uu radio quality and uu_quality1, etc.). The channel condition associated with the (e.g., second) path may include the current radio quality associated with the (e.g., second) path.

[0108] The WTRU may use the split buffer threshold in one or more combinations, for example, as described herein. One or more of the following may apply. For example, based on a comparison of SL and Uu radio conditions with thresholds, the WTRU may use the split buffer threshold in one or more combinations. For example, based on a separate comparison of SL with a threshold and Uu with another threshold, the WTRU may use the split buffer threshold in one or more combinations. For example, based on a comparison of CBR with a threshold, SL with a second threshold, and / or Uu with a third threshold, the WTRU may use the split buffer threshold in one or more combinations. For example, the WTRU may be configured with one or more (e.g., multiple) split buffer thresholds, each of which corresponds to a comparison of SL and / or Uu radio conditions (e.g., corresponding to threshold 1 when the radio quality of SL is better than the radio condition of Uu by a certain threshold, corresponding to threshold 2 when the radio quality of SL is worse than the radio condition of Uu by a certain threshold, etc.).

[0109] The WTRU may be configured to calculate a change value of the scaling factor and / or application based on one or more threshold comparisons as described herein (e.g., to take into account one or more CBR and / or SL / Uu radio conditions). The WTRU may limit the change value of the scaling factor and / or application to a configured maximum threshold and / or minimum threshold. For example, if the calculated buffer threshold is above the maximum threshold, the WTRU may be configured to use the maximum threshold. For example, if the calculated buffer threshold is below the minimum threshold, the WTRU may be configured to use the minimum threshold.

[0110] The WTRU (e.g., a remote WTRU) may be configured to switch the primary path of the split bearer based on the radio conditions of the SL and / or the radio conditions of the Uu (e.g., the current radio conditions of the SL and / or the current radio conditions of the Uu). For example, if the SL radio quality is above a certain threshold, the WTRU may be configured to switch the primary path of the split bearer to the SL. For example, if the Uu radio quality is above a certain threshold, the WTRU may be configured to switch the primary path of the split bearer to the Uu. For example, if the Uu radio quality is above a certain threshold and / or the SL radio quality is below another threshold, the WTRU may be configured to switch the primary path of the split bearer to the Uu.

[0111] The WTRU may be configured to perform fractional distribution between paths associated with a split bearer. The (e.g., remote) WTRU may be configured to distribute UL data between Uu and SL, for example, based on a dynamic transmit distribution percentage (e.g., 20% on Uu and 80% on SL). For example, the (e.g., remote) WTRU may transmit uplink data associated with the split bearer based on the determined transmit distribution percentage. The WTRU may update the transmit distribution percentage associated with UL transmission on the split bearer based on the channel condition associated with the first path and / or the channel condition associated with the second path. The (e.g., remote) WTRU may be configured to set the dynamic transmit distribution percentage based on one or more (e.g., several) factors (e.g., conditions), such as, but not limited to, CBR, SL radio quality, Uu radio quality, and / or congestion. The WTRU may determine the transmit distribution percentage associated with UL transmission on the split bearer based on, for example, configuration information, channel conditions associated with the first path (e.g., current channel conditions), and / or channel conditions associated with the second path. For example, the WTRU may be configured with multiple distribution percentage values, where each distribution percentage value corresponds to a (e.g., specific) range of CBR (e.g., if the CBR is below cbr1, send 1% of UL data on the SL, if the CBR is between cbr1 and cbr2, send 2% of UL data on the SL, if the CBR is between cbr2 and cbr3, send 3% of UL data on the SL, and / or if the CBR is above cbr3, do not send UL data on the SL, etc.). The WTRU may be configured with a baseline distribution percentage value and / or a scaling factor that depends on the CBR. For example, the WTRU may be configured with a baseline distribution percentage and reduce and / or increase the baseline distribution percentage threshold based on the percentage difference between the current CBR and cbr1. For example, the WTRU may be configured with multiple distribution percentage values, where each distribution percentage value corresponds to a (e.g., a specific) range of SL radio qualities (e.g., if the SL radio quality is lower than sl_quality1, no UL data is sent on the SL, if the SL radio quality is between sl_quality1 and sl_quality2, 1 percentage of UL data is sent on the SL, and / or if the SL radio quality is between sl_quality2 and sl_quality3, 2 percentage of UL data is sent on the SL, etc.).The WTRU may also or alternatively be configured with multiple distribution percentage values, where each distribution percentage value corresponds to a (e.g., specific) range of Uu radio quality (e.g., if the Uu radio quality is lower than uu_quality1, then no incoming UL data is sent on Uu, if the Uu radio quality is between uu_quality1 and uu_quality2, then percentage 1 of UL data is sent on Uu, if the Uu radio quality is between uu_quality2 and uu_quality3, then percentage 2 of UL data is sent on Uu, etc.).

[0112] The WTRU may distribute percentages in one or more (e.g., any) combinations described herein. For example, the WTRU may distribute percentages based on a comparison between the SL radio condition and the Uu radio condition and a threshold. For example, the WTRU may distribute percentages based on a separate comparison of the SL radio condition and a threshold and the Uu radio condition and another threshold. For example, the WTRU may distribute percentages based on a comparison of the CBR and a threshold, the SL and a second threshold, and / or the Uu and a third threshold. In each example, the WTRU may be configured with multiple distribution percentage values, each of which corresponds to a condition associated with the radio quality of the SL and / or the radio quality of the Uu. For example, when the SL radio quality is above a certain threshold of the Uu radio condition, the WTRU may be configured with percentage 1. For example, when the SL radio quality is below a certain threshold of the Uu radio condition, the WTRU may be configured with percentage 2.

[0113] The send distribution percentage may be (e.g., further) limited based on a split buffer threshold associated with the split bearer. For example, when the buffer size is below the split buffer threshold, the WTRU may (e.g., only) use the primary path. Once the buffer size is greater than the split buffer threshold, the WTRU may, for example, start distributing data according to the configured and / or determined percentage distribution (e.g., until the WTRU's buffer level / size drops below the buffer split threshold again).

[0114] The send distribution percentage may be (e.g., further) limited by a configured distribution duration and / or split buffer threshold. For example, the send distribution percentage may be based on the WTRU's buffer level. For example, when the buffer size is below a first split buffer threshold, the WTRU may be configured to (e.g., only) use the primary path. Once the buffer size is exceeded (e.g., greater than the first split buffer threshold), the WTRU may, for example, distribute data according to the configured and / or determined percentage distribution (e.g., until the buffer level / size drops below / less than the threshold and / or a configured duration has been exceeded since distribution to the secondary buffer began and / or whichever occurs first).

[0115] The send distribution percentage may be (e.g., further) limited by a second split buffer threshold. The second split buffer threshold may, for example, be less than (e.g., less than) another (e.g., legacy) split buffer threshold. The WTRU may use the second split buffer threshold to determine when to stop using the secondary path. For example, when the buffer size is less than the first split buffer threshold, the WTRU may be configured to (e.g., only) use the primary path. Once the buffer size is exceeded (e.g., greater than the first split buffer threshold), the WTRU may, for example, distribute data according to the configured and / or determined percentage distribution (e.g., until the buffer size drops below / less than the second split buffer threshold). For example, if the buffer size is less than the second split buffer threshold, the WTRU may only use the primary path to distribute the data, which may allow the WTRU to prevent (e.g., frequent) switching between using the secondary path and using the primary path.

[0116] Additionally or alternatively, the use of a second segmentation buffer threshold may be combined with the use of a distribution duration as discussed herein. For example, the WTRU may be configured to use the secondary path until the configured duration expires and / or the buffer size has dropped below / less than the second threshold.

[0117] The WTRU may be configured to apply a distribution factor. The WTRU may determine (e.g., calculate) a distribution factor based on one or more (e.g., any) distribution examples discussed herein (e.g., taking into account one or more CBRs and / or SL / Uu radio conditions). The WTRU may limit the applied distribution factor to a configured maximum threshold percentage value and / or a minimum threshold percentage value. For example, the WTRU may be configured to route a minimum of 20% of the segmented buffered data and / or a maximum of 50% of the segmented buffered data via the SL. For example, if the WTRU calculates a distribution factor below 20%, the WTRU may set the distribution factor to 20%. For example, if the WTRU calculates a distribution factor above 50%, the WTRU may set the distribution factor to 50%.

[0118] The WTRU may be configured to take into account the maximum amount of data allowed on each path, as described herein. In various examples, one or more split bearers may be configured to allow a maximum amount of data to be sent on a given link. For example, a first portion of UL data may be transmitted on SL and / or Uu, where the first portion may not exceed a first maximum value for UL data. For example, a second portion of data may be transmitted on SL and / or Uu, where the second portion may not exceed a second maximum value for UL data.

[0119] For a given split bearer, the remote WTRU may send up to a maximum amount of data (eg, x MB) on one path (eg, the primary path) and / or the remote WTRU may be configured to send the remaining data via other paths.

[0120] The maximum data limit may be (e.g., only) specific to a given duration (e.g., data rate limit). For example, the remote WTRU may be configured to send UL transmissions up to x Mbps on the primary path and / or the remote WTRU may be configured to start using the secondary path when the data rate on the primary path exceeds x Mbps.

[0121] The remote WTRU may be configured to perform a combination of the techniques described herein to send data (e.g., uplink data) on a split bearer. For example, the remote WTRU may be configured to send a certain amount of data on a path based on a comparison between the radio conditions of the SL and / or the radio conditions of the Uu and a threshold. In another example, the remote WTRU may be configured to send a certain amount of data on a path based on a separate comparison of the radio conditions of the SL with a threshold and the radio conditions of the Uu with another threshold. In another example, the remote WTRU may be configured to send a certain amount of data on a path based on a comparison of the CBR with a threshold, a comparison of the radio quality of the SL (e.g., RSRP and RSRQ, etc.) with a second threshold, and a comparison of the radio quality of the Uu with a third threshold. In one or more cases, the remote WTRU may be configured with multiple values ​​of the maximum data or data rate allowed for each path, where each value corresponds to a condition of the radio quality of the SL and a condition of the radio quality of the Uu.

[0122] The WTRU may be configured to take into account UL data traffic. In some scenarios, path selection for sending UL data on a split bearer may (e.g., only) take into account the buffer level of a particular bearer. In some scenarios, the WTRU may be configured to take into account all UL data traffic (e.g., as opposed to only the UL data associated with the split bearer).

[0123] The remote WTRU may be configured with a different (e.g., new) split buffer threshold (e.g., total_buffer_split_thresold) associated with the buffer level of more than one bearer. For example, the remote WTRU may be configured with a split buffer threshold associated with the buffer level of all bearers. In another example, the remote WTRU may be configured with a split buffer threshold associated with bearers of a certain QoS type. In another example, the remote WTRU may be configured with a split buffer threshold associated with a subset of predefined bearers, such as but not limited to predefined bearers based on a list of bearer IDs.

[0124] In certain scenarios, the remote WTRU may be configured to specify a separate total_split_buffer_threshold (e.g., threshold_uu and threshold_sl) for each link. For example, a first buffer threshold (e.g., threshold uu) may be associated with a first path. For example, a second buffer threshold (e.g., threshold_sl) may be associated with a second path. For the case where the total UL buffer size on Uu is greater than a specified threshold for the Uu link, the remote WTRU may be configured to send the UL data on the SL. When the total UL buffer size on Uu is greater than a specified threshold for the Uu link, the remote WTRU may be configured to push the UL data to the SL, even if the bearer to which the specific data belongs is configured to use Uu as the primary path and the split buffer threshold for the bearer has not been exceeded. For the case where the total UL buffer size on SL is greater than a specified threshold for the SL link, the remote WTRU may be configured to send the UL data on Uu. In one or more cases where the total UL buffer size on the SL is greater than a specified threshold for the SL link, the remote WTRU may be configured to push the UL data to the Uu if the bearer to which the data belongs is configured to use the SL as the primary path and the split buffer threshold for the bearer has not been exceeded.

[0125] The WTRU may combine the threshold configuration described herein with a threshold configuration that takes into account the total buffer size. The WTRU may update the buffer threshold associated with the split bearer based on the channel conditions associated with the first path and / or the channel conditions associated with the second path. For example, the WTRU may update threshold_uu and / or threshold_sl based on one or more of the following: CBR / CR, radio quality of Uu, radio quality of SL, congestion on SL, congestion on Uu, and / or a comparison between the radio quality of Uu and the radio quality of SL. The WTRU may also or alternatively configure different distribution percentages between Uu and SL. For example, the WTRU may configure different distribution percentages between Uu and SL based on the size of the UL buffer to be processed on Uu and / or SL. In addition or alternatively, the WTRU may configure different distribution percentages between Uu and SL based on one or both of threshold_uu and threshold_sl.

[0126] In certain scenarios, the remote WTRU may be configured to reserve a certain amount of UL buffer space for SL communications (e.g., only for SL communications). For example, the remote WTRU may be configured to reserve a certain amount of UL buffer space for direct SL communications between the remote WTRU and the relay WTRU that are not directed to the gNB.

[0127] The remote WTRU may be configured to take into account the serving cell of both Uu and SL. For example, if the SL (eg, relay WTRU) is being served by the same cell as the Uu link, the remote WTRU may perform any of the techniques discussed herein.

[0128] Based on whether the SL is being served by a cell different from the cell serving the Uu link, the remote WTRU may be configured to apply different configurations for each link associated with the split bearer. For example, the remote WTRU may be configured with one or more (e.g., two) configuration sets associated with the split bearer. If the Uu link and the SL are served by the same cell, a first configuration may be used, and if the Uu link and the SL are served by different cells, another configuration may be used. In addition or alternatively, the remote WTRU may be configured with a configuration used when the Uu link and the SL are served by the same cell, and if the Uu link and the SL are served by different cells (e.g., applying a change value or scaling factor), information associated with converting the buffer threshold or distribution factor included in the configuration may be provided to the remote WTRU.

[0129] As described herein, the remote WTRU may be configured to apply different configurations depending on whether the SL is being served by a gNB different from the gNB serving the Uu link (e.g., the WTRU is configured in DC operation and / or the WTRU is configured to identify the gNB ID based on a cell identity, etc.). For example, the remote WTRU may be configured with one or more (e.g., two) configuration sets. If the Uu link and the SL are served by the same gNB, a first configuration may be used. If the Uu link and the SL are served by different gNBs, another configuration may be used. In addition or alternatively, the remote WTRU may be configured with a configuration used when the Uu link and the SL are served by the same gNB, and if the Uu link and the SL are served by different cells (e.g., applying a change value or scaling factor), information associated with converting the buffer threshold or distribution factor included in the configuration may be provided to the remote WTRU.

[0130] As described herein, a given split bearer configuration may apply to one or more (e.g., all) bearers. For example, each split bearer may be associated with a corresponding split buffer configuration. The split buffer configuration may include: a set of split buffer thresholds corresponding to a particular range of CBR / CR values, a baseline threshold and a scaling factor and / or a variation value, and information associated with applying the scaling factor / variation value.

[0131] As described herein, the split bearer configuration may be configured for each split bearer. The split bearer configuration as described herein may also be applied to a split bearer set (e.g., all split bearers with Uu as the primary path and / or all split bearers with SL as the primary path). Additionally or alternatively, the split bearer configuration techniques described herein may be applied to a split bearer set, including, for example, bearers within a bearer list, bearers with certain bearer IDs, and / or bearers with a certain QoS type, etc.

[0132] A split bearer may share a portion of another split bearer configuration (e.g., a configuration common to all split bearers), and additionally or alternatively include other portions that are bearer specific (e.g., for each bearer and / or for a subset of bearers, etc.). For example, each split bearer may have a baseline split buffer threshold, and all bearers or a subset of bearers (e.g., specified in a bearer ID list and / or associated with certain QoS types) may share a scaling factor or variation value to apply when the CBR is greater than a certain value.

[0133] The remote WTRU may transmit an indication to the network regarding (e.g., any) modified behavior (e.g., modification of the split bearer threshold by the WTRU). For example, the remote WTRU may be configured to transmit an indication to the network based on the modification. For example, if the behavior regarding the split bearer operation is updated (e.g., using any of the techniques described herein), the remote WTRU may be configured to transmit an indication to the network. For example, the remote WTRU may be configured to update the split bearer buffer threshold based on changes to one or more of the following: CBR and / or CR, radio quality of SL (e.g., RSRP, RSRQ, etc.) and / or radio quality of Uu (e.g., RSRP, RSRQ, etc.). The WTRU may transmit an indication of the updated split buffer threshold to the network. Additionally or alternatively, the remote WTRU may be configured to switch the primary path of the split bearer based on changes to one or more of the following: CBR / CR, radio quality of SL (e.g., RSRP, RSRQ, etc.) and / or radio link quality of Uu (e.g., RSRP, RSRQ, etc.). The remote WTRU may be configured to update the distribution percentage between the primary link and the secondary link based on changes to one or more of: CBR / CR, radio quality of SL (e.g., RSRP, RSRQ, etc.), and / or radio link quality of Uu (e.g., RSRP, RSRQ, etc.). The WTRU may transmit an indication of the updated transmission distribution percentage to the network.

[0134] The remote WTRU may be configured to provide an indication of the modification of the split buffer configuration to the network via a dedicated message (e.g., RRC and / or MAC CE, etc.). For example, the WTRU may be configured to include the indication in other messages (e.g., a measurement report transmitted to the gNB, a SL buffer status report (BSR), and / or a Uu BSR, etc.).

[0135] The remote WTRU may be configured to take into account the scheduling mode for the SL connection. For example, the remote WTRU may be configured to apply any of the techniques described herein (e.g., those related to split buffer thresholds or split bearer distribution factors depending on SL radio quality or SL congestion), regardless of the scheduling mode used on the SL (e.g., Mode 1 or Mode 2).

[0136] Additionally or alternatively, when the scheduling mode used on the SL is Mode 1, the remote WTRU may be configured to apply the techniques described herein (e.g., those relating to split buffer thresholds and / or split bearer distribution factors that depend on the radio quality of the SL or congestion of the SL). For example, when Mode 2 is used for scheduling on the SL, the remote WTRU may be configured to apply other (e.g., legacy) split buffer processing. For example, the SL scheduling mode may initially be set to Mode 1, and the WTRU may perform split bearer processing configuration according to the techniques described herein. If the SL scheduling mode is changed to Mode 2 (e.g., based on instructions / configuration received from the network), the WTRU may save the current split bearer processing configuration and revert from the (e.g., legacy) split bearer processing to another split bearer processing. If the SL scheduling mode is changed back to Mode 1, the WTRU may restore the saved split bearer processing configuration and operate accordingly.

[0137] When the scheduling mode used on the SL is Mode 2, the remote WTRU may be configured to apply the techniques described herein (e.g., those relating to split buffer thresholds or split bearer distribution factors that depend on SL radio quality or SL congestion). The remote WTRU may also or alternatively be configured to apply other split buffer processing techniques when scheduling is performed using Mode 1 on the SL. For example, the SL scheduling mode may initially be set to Mode 2, and the WTRU may be configured with a split bearer processing configuration according to the techniques discussed herein. If the SL scheduling mode is changed to Mode 1 (e.g., based on instructions / configuration received from the network), the WTRU may save the current split bearer processing configuration and revert to another form of (e.g., legacy) split bearer processing. If the SL scheduling mode is changed back to Mode 2, the WTRU may restore the saved split bearer processing configuration and operate accordingly.

[0138] The split bearer configuration technique may also be applied to one or more bearers when SL scheduling is in mode 1. For example, the split bearer technique described herein may also or alternatively be applied to one or more bearers configured in mode 2. The split bearer technique described herein may be applied to one or more bearers regardless of the scheduling mode (e.g., for both mode 1 and mode 2).

[0139] The remote WTRU may be configured with one or more (e.g., two) split bearer configuration sets. For example, a first split bearer configuration set may be used when the SL scheduling is mode 1, and another split bearer configuration set may be used when the SL scheduling is mode 2. The two configurations may be independent of each other. In some scenarios, the WTRU may receive a split bearer configuration associated with a first mode (e.g., mode 1 or mode 2), and may derive a configuration for another mode by applying a certain change configuration / change value on top of the received configuration associated with the first mode (e.g., when a mode 1 configuration is received, the other mode is mode 2, or when a mode 2 configuration is received, the other mode is mode 1).

[0140] For example, if the SL scheduling mode is Mode 2, the remote WTRU may be configured to consider the total number of resources pre-configured for the SL when deciding whether to send split bearer data on Uu or on SL. For example, the WTRU may be provided with a configuration to calculate the split buffer threshold based on the radio quality of the Uu, the radio quality of the SL and / or the CBR / CR of the SL, as discussed herein. Such a configuration may be associated with a given value or a given range of values ​​for the number of SL resources pre-configured for Mode 2. For example, if the network reconfigures the SL resources for Mode 2, the WTRU may calculate the split buffer threshold based on the received configuration. The WTRU may enlarge or reduce the value based on whether the number of SL resources now configured for Mode 2 is lower or higher than the SL resource value (e.g., or a range of values) associated with the split buffer configuration. For example, if the SL resources now configured correspond to x% of the SL resources associated with the received split bearer configuration (e.g., where x<100%), the WTRU may enlarge the split buffer threshold for split bearers whose primary path is Uu, and the WTRU may reduce the split buffer threshold for split bearers whose primary path is SL (e.g., to compensate for the lower amount of resources currently available on the SL compared to the resource level associated with the split bearer processing configuration). Similarly, if the SL resources now configured correspond to y% of the SL resources associated with the configuration (e.g., where y>100%), the WTRU may reduce the split buffer threshold for split bearers whose primary path is Uu, and the WTRU may enlarge the split buffer threshold for split bearers whose primary path is SL (e.g., to utilize the higher amount of resources currently available on the SL compared to the resource level associated with the split bearer processing configuration).

[0141] The WTRU may provide an indication to the network regarding the WTRU's preferred split bearer configuration. For example, the remote WTRU may be configured to transmit an indication to the network indicating the WTRU's preferred handling of split bearers. For example, the WTRU may indicate to the network that the WTRU prefers that the primary path for a given bearer (e.g., and / or a set of split bearers) be switched to Uu (e.g., if it was previously SL) or SL (e.g., if it was previously Uu). In another example, the WTRU may indicate to the network a preferred split buffer threshold level for a given split bearer (e.g., or a set of split bearers). In another example, the WTRU may indicate to the network a preferred split bearer distribution factor / percentage for the primary path and secondary path for a given split bearer (e.g., or a set of split bearers). In another example, the WTRU may indicate to the network that the WTRU prefers to modify the bearer type of a given non-split bearer or a set of non-split bearers to a split bearer. In one or more cases, the WTRU may indicate to the network that the WTRU prefers to modify the bearer type of a given non-split bearer or a set of non-split bearers to a split bearer (e.g., and including the preferred primary path and split buffer threshold or distribution factor in the indication). In another example, the WTRU may indicate to the network that the WTRU prefers to modify the bearer type of a given split bearer or a set of split bearers to a non-split bearer. In one or more cases, the WTRU may indicate to the network that the bearer type of a given split bearer or a set of split bearers is modified to a non-split bearer and include a preferred bearer association (e.g., associated with Uu or SL).

[0142] The WTRU may provide a trigger to the network for an indication of preferred split bearer handling.

[0143] The WTRU may send an indication to the network regarding the WTRU's preferred split bearer configuration based on the radio conditions on the Uu and / or SL. For example, the remote WTRU may be configured to request that the primary path of the split bearer be changed to the SL when the CBR of the SL is below a certain threshold. In another example, the remote WTRU may be configured to request that the primary path of the split bearer be changed to the SL when the RSRP / RSRQ of the SL is above a certain threshold. In another example, the remote WTRU may be configured to request that the primary path of the split bearer be changed to the SL when the RSRP / RSRQ of the Uu is below a certain threshold. In yet another example, the remote WTRU may be configured to request that the primary path of the split bearer be changed to the SL when a combination of one or more of the following occurs: the CBR of the SL is below a certain threshold, the RSRP / RSRQ of the SL is above a certain threshold, and / or the RSRP / RSRQ of the Uu is below a certain threshold.

[0144] The remote WTRU may be configured to request a change of the primary path of the split bearer to Uu for reasons similar to the reasons discussed herein for requesting a change of the primary path of the split bearer to SL (e.g., requesting a change when one or more of the following occurs: the CBR of SL is below a certain threshold, the RSRP / RSRQ of SL is above a certain threshold, and / or the RSRP / RSRQ of Uu is below a certain threshold).

[0145] Based on the buffer level at the WTRU, the WTRU may be triggered to send an indication to the network regarding the preferred split bearer configuration of the WTRU. For example, the WTRU may send an indication regarding the preferred split buffer configuration of the WTRU based on one or more of the following: the total UL buffer level at the WTRU is above / below a certain threshold; the total UL buffer level waiting for transmission on Uu at the WTRU is above / below a certain threshold; the total UL buffer level waiting for transmission on SL at the WTRU is above / below a certain threshold; the total UL buffer level at the WTRU belonging to a certain LCID (e.g., or LCG) or a set of LCIDs (e.g., or LCG) is above / below a certain threshold, etc.

[0146] The WTRU's preferred split bearer configuration indication may apply to multiple (eg, all) split bearers.

[0147] The WTRU's preferred split bearer configuration indication may apply to one bearer or a subset of bearers (eg, those bearers for which the WTRU included the bearer ID in the preference indication).

[0148] The WTRU's preferred split bearer configuration indication may be provided to the network via a dedicated message (eg, via RRC WTRU assistance information, MAC CE, etc.).

[0149] The WTRU's preferred split bearer configuration indication may be provided in other messages. For example, the WTRU may include the indication in a measurement report. In another example, the WTRU may include the indication in a SL or Uu BSR transmitted to the gNB.

[0150] Figure 6 and Figure 7 Examples associated with the techniques discussed herein are illustrated. Figure 6 and Figure 7As shown, the WTRU may be configured with a split bearer. For example, the WTRU may be configured with a split bearer where Uu is the primary path and SL is the secondary path. In addition or alternatively, the WTRU may be configured with a split bearer where Uu is the secondary path and SL is the primary path. The WTRU may additionally be configured with one or more of a split buffer threshold, a default percentage distribution between the primary path and the secondary path, and a mapping between the percentage distribution and the SL / Uu conditions and the WTRU conditions. As described herein, the SL / Uu conditions may, for example, include CBR / CR thresholds and SL / Uu radio quality thresholds, etc. As described herein, the WTRU conditions may, for example, include a total UL buffer.

[0151] Figure 7 An example flow chart 700 associated with a split bearer configuration is illustrated. At 702, the WTRU may be configured with a split bearer where Uu is the primary path and SL is the secondary path (e.g., or Uu as the secondary path and SL as the primary path). Additionally or alternatively, the WTRU may be configured with one or more of: a split buffer threshold; a default percentage distribution (e.g., for UL data) between the primary and secondary paths (e.g., primary percentage and secondary percentage); and / or a mapping between the percentage distribution and one or more SL and / or Uu thresholds / conditions (e.g., CBR and / or CR thresholds, SL and / or Uu radio quality thresholds) and one or more WTRU thresholds / conditions (e.g., total UL buffer, etc.).

[0152] At 704, the WTRU may determine whether the UL buffer is greater than the split buffer threshold. If the WTRU determines that the UL buffer is not greater than the split buffer threshold (e.g., at 704: No), the WTRU may push (e.g., send) the UL data to the RLC associated with the primary path (e.g., at 706). If the WTRU determines that there is no UL grant available, the WTRU may transmit a Uu BSR to the gNB (e.g., at 710). If the WTRU determines that the UL buffer is greater than the split buffer threshold (e.g., at 704: Yes), the WTRU may determine a distribution percentage for pending UL data between Uu and SL (e.g., at 708). The WTRU may determine the distribution percentage for pending UL data between Uu and SL based on one or more of: a default percentage distribution; one or more current WTRU and / or network thresholds / conditions (e.g., CBR / CR and SL / Uu radio quality, etc.); and / or one or more associated thresholds. At 712, the WTRU may distribute the traffic on Uu and / or SL according to the determined distribution percentage. At 714, the WTRU may transmit an indication to the network (e.g., to indicate that the split buffer threshold has been exceeded, the percentage has been updated, etc.). At 716, if the WTRU determines that there is no UL grant available on Uu, the WTRU may transmit a Uu BSR to the gNB. At 718, if the WTRU determines that there is no UL grant available on SL, the WTRU may transmit a SL BSR to the gNB.

[0153] Although features and elements are described 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. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in 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 software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A wireless transmit receive unit (WTRU), the wireless transmit receive unit (WTRU) comprising: Memory; and A processor, the processor being configured to: receiving configuration information associated with uplink (UL) transmissions on a split bearer, wherein the split bearer is associated with a first path and a second path; determining a transmission distribution percentage associated with UL transmissions on the first path and the second path based at least on the configuration information, a channel condition associated with the first path, and a channel condition associated with the second path; as well as Based on the determined transmission distribution percentage, uplink data associated with the split bearer is transmitted.

2. The WTRU of claim 1 , wherein the configuration information comprises a radio quality threshold associated with a channel condition on each of the first path and the second path.

3. The WTRU of claim 2, wherein the radio quality threshold comprises a reference signal received power (RSRP) threshold.

4. The WTRU of claim 2, wherein the radio quality threshold comprises a channel busy rate (CBR) threshold.

5. The WTRU of claim 1 , wherein the configuration information includes an indication of a split buffer threshold associated with the split bearer, and wherein the transmit distribution percentage is further based on a buffer level of the WTRU.

6. The WTRU of claim 5, wherein the processor is further configured to update the split buffer threshold associated with the split bearer based on a channel condition associated with the first path and a channel condition associated with the second path.

7. The WTRU of claim 6, wherein the channel condition associated with the first path comprises a current CBR associated with the first path.

8. The WTRU of claim 6, wherein the channel condition associated with the second path comprises a current radio quality associated with the second path.

9. The WTRU of claim 5, wherein the processor is further configured to transmit an indication of the updated segmentation buffer threshold to a network.

10. The WTRU of claim 1 , wherein the processor is further configured to update the transmission distribution percentage associated with UL transmissions on the split bearer based on a channel condition associated with the first path and a channel condition associated with the second path.

11. The WTRU of claim 7, wherein the processor is further configured to transmit an indication of the updated transmit distribution percentage to a network.

12. A method performed by a wireless transmit receive unit (WTRU), the method comprising: receiving configuration information associated with uplink (UL) transmissions on a split bearer, wherein the split bearer is associated with a first path and a second path; determining a transmission distribution percentage associated with UL transmissions on the first path and the second path based at least on the configuration information, a channel condition associated with the first path, and a channel condition associated with the second path; as well as Based on the determined transmission distribution percentage, uplink data associated with the split bearer is transmitted.

13. The method of claim 12, wherein the configuration information includes a radio quality threshold associated with a channel condition on each of the first path and the second path.

14. The method of claim 12, wherein the configuration information includes an indication of a split buffer threshold associated with the split bearer, and wherein the transmit distribution percentage is further based on a buffer level of the WTRU.

15. The method of claim 14, further comprising updating the split buffer threshold associated with the split bearer based on a channel condition associated with the first path and a channel condition associated with the second path.

16. The method of claim 15, wherein the channel condition associated with the first path comprises a current CBR associated with the first path.

17. The method of claim 15, wherein the channel condition associated with the second path comprises a current radio quality associated with the second path.

18. The method of claim 14, further comprising transmitting an indication of the updated segmentation buffer threshold to a network.

19. The method of claim 12, further comprising updating the transmission distribution percentage associated with UL transmissions on the split bearer based on a channel condition associated with the first path and a channel condition associated with the second path.

20. The method of claim 16, further comprising transmitting an indication of the updated transmit distribution percentage to a network.

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