Sidelink relay communication scheme in wireless communications

Abstract

A wireless communication method is provided. The method comprises receiving, by a user plane (CU-UP) of a central unit of the network node from a control plane (CU-CP) of the central unit: i) User Equipment (UE) information identifying a corresponding UE as a remote UE for U2N (UE-to-network) relay communication, or ii) a path switching indication identifying a corresponding UE as a remote UE for U2N (UE-to-network) relay communication, the path switching instruction is switched from a first path of a network node to a second path under the network node or a second path under a different network node; and performing a subsequent operation based on the UE information or the path switching indication.

Description

Technical Field

[0001] This document relates to systems, devices, and technologies used for wireless communication. Background Technology

[0002] Wireless communication technologies are driving the world toward an increasingly interconnected and networked society. The rapid growth and technological advancements in wireless communication have led to greater demands for capacity and connectivity. Other factors, such as energy consumption, equipment cost, spectrum efficiency, and latency, are also important for meeting the needs of various communication scenarios. Compared to existing wireless networks, next-generation systems and wireless communication technologies need to support an increasing number of users and devices, as well as an increasingly mobile society. Summary of the Invention

[0003] Various methods and apparatuses are provided for configuring channel state information reference signals for tracking in wireless communications.

[0004] In one example aspect, a wireless communication method is disclosed. The method includes: receiving, from the control plane (CU-CP) of the central unit of a network node, either: i) user equipment (UE) information identifying the corresponding UE as a remote UE for U2N (UE-to-network) relay communication, or ii) a path switching indication instructing a switch from a first path of the network node to a second path under the network node or a second path under a different network node; and performing subsequent operations based on the UE information or the path switching indication.

[0005] In another example, a wireless communication method is disclosed. The method includes: a CU-CP of a network node sending to a CU-UP of the same network node: i) User Equipment (UE) information identifying the corresponding UE as a remote UE for U2N (UE-to-network) relay communication, or ii) a path switching indication instructing a switch from a first path of the network node to a second path under the network node or a second path under a different network node; wherein the UE information or the path switching indication allows the CU-UP to perform subsequent operations.

[0006] In another example, a wireless communication method is disclosed. The method includes: a relay UE entering a connection state connected to a network node for relaying data for a remote UE, wherein the relay UE is a target relay UE selected during path handover.

[0007] In another example, a wireless communication method is disclosed. The method includes: a remote UE receiving configuration information from a network node, including at least one of a preamble resource, a preamble index, or a PRACH resource, the configuration information being permitted for use by a relay UE to enter a connection state with the network node.

[0008] In another example, a wireless communication method is disclosed. The method includes: a network node receiving from a source network node a list of candidate relay UEs, including the connection state of each candidate relay UE; and the network node selecting a relay UE from the candidate relay UEs for path switching.

[0009] In yet another example aspect, a wireless communication device including a processor is disclosed. The processor is configured to implement the methods described herein.

[0010] In another example, the various techniques described herein can be embodied in processor-executable code and stored on a computer-readable program medium.

[0011] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description, drawings, and claims. Attached Figure Description

[0012] Figure 1 Two example scenarios for sidelink relay communication are shown.

[0013] Figure 2 The gNB architecture is shown with CU (centralized unit) - DU (distributed unit) splitting and CU-CP (centralized unit control plane) and CU-UP (centralized unit user plane) separation.

[0014] Figure 3 An example illustrating download (DL) packet loss for a U2N relay scenario is shown, based on the traditional downlink data delivery status (DDDS) and packet dropping mechanisms.

[0015] Figure 4 An example flowchart illustrating the delay in switching from a direct to an indirect path between gNBs to an idle / inactive target relay UE is shown.

[0016] Figure 5 An example wireless communication network based on some implementations of the disclosed technology is shown.

[0017] Figure 6 This is a block diagram illustrating examples of wireless communication devices based on some implementations of the disclosed technology.

[0018] Figures 7 to 11 This is an example flowchart of a wireless communication method based on some implementations of the disclosed technology. Detailed Implementation

[0019] The disclosed technology provides implementation methods and examples for configuring channel state information reference signals for tracking in wireless communication.

[0020] For U2N relay communication, to achieve a better user experience / system performance, lossless downlink delivery should be considered during CU-DU splitting and CU-CP / CU-UP architecture separation. Furthermore, lossless downlink delivery should be considered during i2d / i2i path switching.

[0021] Generally, path handover is triggered by a deterioration in the quality of the source path link. If the path handover process takes too long, the service of the remote UE may be interrupted, i.e., when the source link is broken, the new link / target link has not yet been established. To achieve better service continuity performance, mechanisms to reduce latency for path handover to RRC_IDLE / RRC_INACTIVE target relay UEs can be considered.

[0022] With the development of wireless multimedia services, the demand for high data rates and better user experiences has increased, leading to more stringent requirements on the system capacity and coverage of cellular networks. Various application scenarios, such as short-range data sharing and local advertising, have also increased the demand for neighborhood services. Traditional base station-centric cellular networks have shown limitations in providing high data rates for neighborhood services.

[0023] Sidelink is an adaptation of base station-centric communication technologies that allows direct communication between two devices without going through a base station. This means that cars, robots, and even consumer electronics can create their own self-organizing networks without using a radio access network as an intermediary. Sidelink communication technology is well-suited for meeting the high data rate requirements of proximity services and further reduces the burden on cellular networks, lowers battery power consumption of user devices, and improves the robustness of network infrastructure. Sidelink services can also be interchangeably referred to as device-to-device (D2D) discovery and / or communication, proximity services (ProSe), one-way communication, or sidelink discovery and / or communication. The interface between two UEs can be called a PC5 interface.

[0024] To support a wider range of applications and services, sidelink-based relay communication can extend coverage and improve power consumption in scenarios such as indoor relay communication, smart agriculture, smart factories, and public safety. Figure 1 Two example scenarios for sidelink relay communication are shown.

[0025] (1) User Equipment (UE) to Network Relay Scenario

[0026] like Figure 1 As shown in the left circle, UE 111 is in an area with poor signal quality or no coverage and cannot communicate with the network. Sidelink communication allows UE1 to communicate with the network via UE2, thereby expanding coverage and increasing network capacity. In this scenario, UE2 can be referred to as a UE-to-network relay device, and UE 111 can be referred to as a remote UE.

[0027] (2) UE to UE relay scenario

[0028] In certain situations (such as during disasters or emergencies), cellular networks may malfunction. To extend the coverage of sidelink communication, multi-hop relay using one or more UE devices can be employed. For example... Figure 1 As shown in the circle on the right, UE3 communicates with UE4 through UE5. Here, UE5 can be referred to as a UE-to-UE relay device, and UE3 and UE4 can be referred to as remote UEs.

[0029] For U2N relay communication, to achieve a better user experience / system performance, lossless downlink delivery should be considered during CU-DU splitting and CU-CP / CU-UP architecture separation. Furthermore, lossless downlink delivery should be considered during i2d / i2i path switching.

[0030] Generally, path handover is triggered by a deterioration in the quality of the source path link. If the path handover process takes too long, the service of the remote UE may be interrupted, i.e., when the source link is broken, the new link / target link has not yet been established. To achieve better service continuity performance, mechanisms to reduce latency for path handover to RRC_IDLE / RRC_INACTIVE target relay UEs can be considered.

[0031] Example 1: Lossless DL Delivery for U2N Relays in GNB Split Architecture

[0032] Figure 2The diagram illustrates a gNB architecture with CU-DU splitting and CU-CP / CU-UP separation. Under the current mechanism, the DU can send the highest sequence number of the PDCP (Packet Data Convergence Protocol) PD successfully delivered to the UE in the DDDS (Downlink Data Delivery Status) based on the Uu RLC feedback from the UE. Upon receiving the DDDS, the CU-UP is allowed to remove the buffered PDCP PDU carried by the RLC AM based on the DDDS (feedback of the successfully delivered NR PDCP PDU). This means that the gNB can discard packets in the PDCP buffer based on the Uu RLC feedback from the UE. For traditional Uu, there is no critical issue because there is only one hop on the Uu, and the RLC feedback reflects the UE's reception status. However, for U2N relay / indirect path scenarios (where a remote UE connects to the network via a relay UE), a problem may arise because the relay UE's RLC feedback on the Uu does not reflect the remote UE's reception status.

[0033] Figure 3 An example of DL packet loss in a U2N relay scenario is shown, based on traditional DDDS and packet drop mechanisms. Assume packets 1, 2, 3, 4, and 5 are sent to the remote UE via the gNB DU and the relay UE (steps 1a, 1b, and 1c). In the U2N relay / indirect path scenario, the DU sends the PDCP PDU delivery status / DDDS of the remote UE's downlink data to the CU-UP based on the relay UE's Uu RLC feedback. Figure 3 In steps 2a and 2b of the relay UE, regardless of whether the packet is transmitted to the remote UE via the PC5 interface, the CU-UP is therefore allowed to discard packets (step 3), such as packets 1, 2, 3, and 4. However, the relay UE's RLC acknowledgment does not mean that the remote UE has successfully received DL data packets on the PC5 interface (steps 4 and 5). Instead, in step 4, the remote UE sends PC5 RLC acks for packets 1, 2, and 3, but no ack for packet 4. If the CU-UP discards the remote UE's packets from the PDCP buffer based on the relay UE's Uu RLC feedback, the packets acknowledged by the relay UE but not received by the remote UE (e.g., packet 4) will be discarded from the PDCP buffer and therefore cannot be retransmitted, resulting in packet loss at the remote UE (step 6).

[0034] To ensure lossless delivery of DL packets in U2N relay scenarios, the following solutions can be considered:

[0035] 1) The DU sends the DDDS of the remote UE's DL data to the CU-UP in the conventional manner (based on Uu RLC feedback from the relay UE). If the CU-UP can identify the UE as a U2N remote UE, the CU-UP does not remove buffered packets from the PDCP buffer based on the DDDS. Instead, the CU-UP can remove buffered packets from the PDCP buffer based on the PDCP drop timer or the PDCP status report from the remote UE. Therefore, the CU-UP can remove packets that are successfully acknowledged in the PDCP status report (instead of the DDDS). The PDCP drop timer is implemented and / or maintained by the gNB / CU-UP implementation according to relevant specifications. The duration of the timer is configured by the upper layer. The PDCP status report carries the first missing packet ("First Missing COUNT." This field indicates the COUNT value of the first missing PDCP SDU within the reordering window, i.e., RX_DELIV), and a bitmap indicates which packets are missing and which packets were correctly received.

[0036] In some implementations, to enable the CU-UP to identify the UE as a U2N remote UE, the CU-CP can send UE type information (U2N remote UE, U2N relay UE, etc.) to the CU-UP. In some implementations, the CU-CP can forward / send authorization information to the CU-UP (e.g., a U2N remote UE authorization indicating that the UE is authorized to act as an L2 U2N remote UE). The CU-CP can identify the U2N remote UE based on the UE type information in the SidelinkUEInformation reported by the UE, or based on authorization information from the AMF via the NG interface, or based on authorization information from the neighboring gNB via the Xn interface. By identifying the U2N remote UE, the CU-UP does not remove buffered packets from the PDCP buffer even when the DU sends DDDS based on the Uu RLC feedback of the relay UE.

[0037] 2) The DU can identify the U2N remote UE based on UE type information (the UE type in the SUI carried in the CU-DU RRC information IE in the F1AP message), authorization information, or indirect path configuration information (PC5 relay RLC channel / bearer mapping between end-to-end radio bearers and PC5 relay RLC channels). The DU obtains the UE type information from the CU-CP, which is carried in the CU-DU RRC information IE in the F1AP message. Then, the DU learns that the relay UE's RLC feedback does not necessarily mean that the remote UE is also receiving data. When the DU receives the relay UE's RLC feedback, it can delay sending the remote UE's DDDS to the CU-UP.

[0038] 3) In traditional L2 U2N relay, RLC on PC5 (between the remote UE and the relay UE) and RLC on Uu (between the relay UE and the gNB) are hop-by-hop. This means that RLC feedback on PC5 and RLC feedback on Uu are independent of each other. For example, when a packet is successfully received from the gNB, the relay UE can send an RLC acknowledgment to the gNB without considering whether the packet was successfully delivered to the remote UE. Then, to ensure lossless DL delivery, the relay UE can delay sending Uu RLC feedback to the DU. For example, when the relay UE receives PC5 RLC feedback about a packet from the remote UE, the relay UE delays sending Uu RLC feedback. Then, traditional mechanisms can be applied. For example, the DU sends the remote UE's DDDS to the CU-UP based on the relay UE's RLC feedback, and the CU-UP is allowed to remove DL packets from the PDCP buffer based on the DDDS.

[0039] Example 2: Lossless DL Delivery During Path Switching

[0040] This embodiment addresses lossless delivery of deep learning (DL) during indirect-to-indirect or indirect-to-direct path handovers within the same gNB or from a source gNB to a target gNB. During inter-gNB i2d / i2i path handovers, to ensure lossless DL delivery during the handover process, the source gNB can proactively forward all data in its PDCP buffer to the target gNB. However, as discussed earlier, if packets not yet received by the remote UE are removed from the source gNB's PDCP buffer, those packets will still be lost. To avoid losing such packets, packets not yet received by the remote UE do not need to be removed from the source gNB's PDCP buffer during path handover. Generally, the solution in Embodiment 1 can be reused. Furthermore, the following solutions can be considered.

[0041] In some implementations, when the CU-CP of the source gNB decides to initiate an inter-gNB i2d / i2i path handover, or when the CU-CP of the source gNB receives a handover request confirmation (path handover command) message from the target gNB, the CU-CP sends a path handover indication to the CU-UP. The path handover indication may also include at least one of i2d path handover, i2i path handover, and source indirect path. In a direct path, the UE is directly connected to the cell / gNB. In an indirect path, the remote UE is connected to the NW via a U2N relay UE. i2i path handover refers to an indirect-to-indirect path handover. In an i2i path handover, the remote UE switches from relay UE1 to relay UE2 to connect to the NW. In an i2d path handover, the remote UE first connects to the NW via a relay UE, but subsequently switches to a direct path (directly connected to the NW). In a d2i path handover, the remote UE is first directly connected to the NW, and then switches to an indirect path (connected to the NW via a relay UE). Upon receiving this instruction, the source gNB's CU-UP stops removing DL packets from the PDCP buffer. Therefore, even if the DDDS instruction is successfully delivered, the source gNB's CU-UP stops removing buffered DL packets from the PDCP buffer. Furthermore, even if the PDCP discard timer expires, the source gNB's CU-UP does not remove buffered DL packets from the PDCP buffer.

[0042] Example 3: Latency reduction for path handover to RRC idle / inactive relay UE-U2N

[0043] For i2i / d2i path handover, a gNB can select an L2 U2N relay UE in any RRC state (e.g., RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED) as the target L2 U2N relay UE. If an RRC_IDLE / RRC_INACTIVE target relay UE is selected, the path handover process (especially for inter-gNB cases) has a long delay due to the following steps, such as... Figure 4 As shown, taking direct-to-indirect path switching between gNBs as an example:

[0044] 1) The switching on the Xn interface between gNBs and the processing latency within the gNB;

[0045] 2) PC5-S and PC5-RRC signaling are used to establish a PC5 unicast link / PC5-RRC connection between the remote UE and the selected target relay UE;

[0046] 3) Steps used to trigger the IDLE / INACTIVE target relay UE to enter RRC_CONNECTED;

[0047] 4) After entering RRC_CONNECTED, signaling exchanges are conducted between the target relay UE and its serving gNB to prepare the relay UE for relay traffic for the remote UE.

[0048] Generally, path handover is triggered by a deterioration in the quality of the source path link. If the path handover process takes too long, the service of the remote UE may be interrupted, i.e., when the source link is broken, the new link / target link has not yet been established. To achieve better service continuity performance, mechanisms to reduce latency for path handover to RRC_IDLE / RRC_INACTIVE target relay UEs can be considered.

[0049] (1) In the traditional approach, after establishing a PC5 unicast link with the target relay UE, the remote UE sends an RRCReconfigurationComplete message via the relay UE, which triggers the relay UE to enter the RRC connection state. The timing for triggering the relay UE to enter the RRC connection can be advanced. For example, the relay UE is triggered to enter the RRC connection (initiating the RACH procedure with the target cell) when it receives a PC5 link establishment request message from the remote UE, or when it decides to accept the request, or when it transmits a PC5 link establishment response message to the remote UE. The PC5 link establishment request message may include a path handover indication.

[0050] (2) Page the selected target relay UE to enter the RRC connection as soon as possible. In some implementations, if the selected target relay UE is in RRC_INACTIVE, the gNB (which selected the target relay UE) can initiate RAN paging for the target relay UE to trigger the relay UE to enter the RRC connection. The paging message includes the relay UE ID. The relay UE ID can be at least one of L2 ID and I-RNTI. If the selected target relay UE is in RRC_IDLE, the gNB can send a request message to the core network / AMF to request the core network to initiate CN paging for the relay UE. The request message can include at least one of paging indication, the relay UE's L2 ID, and the relay UE's 5G-S-TMSI. In the case of intra-gNB, the remote UE can report the RRC status of each candidate relay UE to the gNB, so that the gNB is explicitly aware of the RRC status of the selected target relay UE. In the case of inter-gNB, the source gNB sends a list of candidate relay UEs to the target gNB, and the target gNB ultimately selects the target relay UE. When sending a list of candidate relay UEs to the target gNB, the RRC status of each candidate relay UE can also be included in the XnAP message.

[0051] (3) When the gNB selects an RRC idle / inactive target relay UE, the gNB includes at least one of the preamble resources, preamble index, or PRACH resources used by the relay UE to perform contention-free / contention-free random access in the RRC reconfiguration to the remote UE. The remote UE then sends this information (preamble resources / preamble index / PRACH resources used by the relay UE to perform contention-free / contention-free random access in the RRC reconfiguration) to the relay UE via a container in a PC5-S message or via a PC5-RRC message. Upon receiving this information, the relay UE uses the indicated resources to perform random access with the gNB. The relay UE sends an RRC connection request message along with a relay indication or path switching indication. For example, when sending an RRC connection request message to the gNB, the relay UE includes a relay indication or path switching indication. Therefore, the gNB can determine that it is a relay UE or target relay UE for path switching of the remote UE and prioritizes the relay UE's RRC connection. Relay indications or path switching indications may also include the remote UE ID (L2 ID, C-RNTI, or local ID).

[0052] Figure 5 An example of a wireless communication system (such as a Long Term Evolution (LTE), 5G, or NR cellular network) is illustrated, comprising a BS 720 and one or more user equipments (UEs) 711, 712, and 713. In some embodiments, uplink transmissions (731, 732, 733) may include uplink control information (UCI), higher-layer signaling (e.g., UE assistance information or UE capabilities), or uplink information. In some embodiments, downlink transmissions (741, 742, 743) may include DCI, higher-layer signaling, or downlink information. The UE may be, for example, a smartphone, tablet, mobile computer, machine-to-machine (M2M) device, terminal, mobile device, Internet of Things (IoT) device, etc.

[0053] Figure 6This is a block diagram representation of a portion of an apparatus according to some embodiments of the disclosed technology. Apparatus 810 (such as a network device, base station, or wireless device (or UE)) may include processor electronics 820, such as a microprocessor implementing one or more technologies presented in this document. Apparatus 810 may include transceiver electronics 830 for transmitting and / or receiving wireless signals via one or more communication interfaces, such as antenna 840. Apparatus 810 may include other communication interfaces for transmitting and receiving data. Apparatus 810 may include one or more memories (not explicitly shown) configured to store information such as data and / or instructions. In some embodiments, processor electronics 820 may include at least a portion of transceiver electronics 830. In some embodiments, at least some of the disclosed technologies, modules, or functions are implemented using apparatus 810.

[0054] Some preferred embodiments may include the following solutions.

[0055] Clause 1. A method for wireless communication (e.g., such as...) Figure 7 The method 1000 shown includes: receiving 1010 from the control plane (CU-CP) of the central unit of the network node: i) user equipment (UE) information, which identifies the corresponding UE as a remote UE for U2N (UE to network) relay communication, or ii) a path switching indication, which instructs the user plane (CU-UP) of the central unit of the network node to switch from a first path of the network node to a second path under the network node or a second path under a different network node; and performing 1020 subsequent operations based on the UE information or the path switching indication.

[0056] Clause 2. A method for wireless communication (e.g., such as...) Figure 8 The method shown (1100) includes: sending from the CU-CP of the network node to the CU-UP of the network node: i) User Equipment (UE) information, which identifies the corresponding UE as a remote UE for U2N (UE to network) relay communication, or ii) a path switching indication, which instructs the CU-UP to switch from a first path of the network node to a second path under the network node or a second path under a different network node; wherein the UE information or the path switching indication allows the CU-UP to perform subsequent operations.

[0057] Clause 3. The method according to Solution 1 or 2, wherein the UE information includes UE type information indicating that the corresponding UE is a remote UE.

[0058] Clause 4. The method according to Solution 1 or 2, wherein the UE information includes authorization information indicating that the corresponding UE is authorized to act as a remote UE.

[0059] Clause 5. The method according to Solution 1 or 2, wherein the path switching indication further includes at least one of: i2d path switching, i2i path switching, or source indirect path.

[0060] Clause 6. The method according to Solution 1, wherein performing subsequent operations includes: in response to UE information or path switching indication, the CU-UP of the network node causes the data of the radio bearer not to be removed from the buffer according to the indication in the downlink data delivery status (DDDS) for successful data delivery.

[0061] Clause 7. The method according to Solution 1, wherein performing subsequent operations includes: in response to UE information or path switching indication, the CU-UP of the network node stopping the removal of radio bearer data from the buffer.

[0062] Clause 8. The method according to Solution 7, wherein stopping the removal of data from the buffer causes the CU-UP of the network node to stop removing data from the buffer in response to an indication in the downlink data delivery status (DDDS) for successful data delivery or in response to the expiration of a discard timer.

[0063] Clause 9. The method according to Solution 2 further includes: determining, by the CU-CP of the network node, to initiate a path switch, wherein the path switch indication is sent in response to the determination.

[0064] Clause 10. The method according to Solution 2 further includes: receiving a message in response to a path switching request from a different network node by the CU-CP of the network node, wherein the path switching indication is sent in response to the receipt.

[0065] Clause 11. A method for wireless communication (e.g., such as...) Figure 9 The method 1200 shown includes: a relay UE entering a connection state connected to a network node for relaying data for a remote UE, wherein the relay UE is a target relay UE selected during path switching.

[0066] Clause 12. The method according to Solution 11 further includes: receiving a link establishment request message including a path switching indication from a remote UE, wherein the relay UE enters a connected state in response to receiving the link establishment request message.

[0067] Clause 13. The method according to Solution 11 further includes: receiving a link establishment request message including a path switching indication from a remote UE; and determining to accept the link establishment request message, wherein the relay UE enters a connected state in response to the determination.

[0068] Clause 14. The method according to Solution 11 further includes: receiving a link establishment request message including a path switching indication from a remote UE; and sending a link establishment response message to the remote UE, wherein the relay UE enters a connected state in response to sending the link establishment response message.

[0069] Clause 15. The method according to Solution 11 further includes: receiving a paging message from a network node for a paging relay UE, wherein the relay UE enters a connected state in response to receiving the paging message.

[0070] Clause 16. The method according to Solution 15 further includes: receiving from the source network node a list of candidate relay UEs including the connection status of each candidate relay UE; selecting from the candidate relay UEs a relay UE for path switching; and transmitting a paging message for the relay UE by the network node.

[0071] Clause 17. The method according to Solution 11 further includes: receiving at least one of a preamble resource, a preamble index, or a PRACH resource from a remote UE, wherein the relay UE is configured to use the received resource to perform random access with a network node.

[0072] Clause 18. The method according to Solution 11 further includes: the relay UE sending the relay indication or path switching indication to the network node by including the relay indication or path switching indication in the RRC connection request message to the network node.

[0073] Clause 19. A method for wireless communication (e.g., such as...) Figure 10 The method 1300 shown includes: receiving configuration information from a network node by a remote UE, including at least one of a preamble resource, a preamble index, or a PRACH resource, the configuration information being permitted for use by a relay UE to enter a connection state with the network node.

[0074] Clause 20. The method according to Solution 19 further includes: sending configuration information from a remote UE to a relay UE.

[0075] Clause 21. A method for wireless communication (e.g., such as...) Figure 11 The method 1400 shown includes: receiving 1410 a list of candidate relay UEs, including the connection status of each candidate relay UE, from a source network node by a network node; and selecting 1420 a relay UE for path switching from the candidate relay UEs by the network node.

[0076] Clause 22. The method according to Solution 21 further includes: transmitting a paging message of the paging relay UE by a network node.

[0077] Clause 23. A wireless communication device, comprising a processor configured to implement the method according to any one of the solutions described above.

[0078] Clause 24. A computer storage medium having code stored thereon, which, when executed by a processor, causes the processor to perform the method according to any one of the above solutions.

[0079] The disclosed and other embodiments, modules, and functional operations described in this document can be implemented in digital electronic circuits, or in computer software, firmware, or hardware (including the structures disclosed in this document and their structural equivalents), or in one or more combinations thereof. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more computer program instruction modules encoded on a computer-readable medium for execution by or control of the operation of a data processing apparatus. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of materials that implements machine-readable propagation signals, or one or more combinations thereof. The term "data processing apparatus" covers all means, devices, and machines for processing data, including, by way of example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, the apparatus may include code that creates an execution environment for the computer program in discussion, such as code constituting processor firmware, a protocol stack, a database management system, an operating system, or one or more combinations thereof. A propagation signal is an artificially generated signal, such as a machine-generated electrical, optical, or electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device.

[0080] Computer programs (also known as programs, software, software applications, scripts, or code) can be written in any programming language, including compiled or interpreted languages; and can be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suitable for a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored as part of a file containing other programs or data (e.g., one or more scripts stored in a markup language document), as a single file dedicated to the program in discussion, or as multiple coordinating files (e.g., a file storing one or more modules, subroutines, or portions of code). A computer program can be deployed to execute on a single computer, or on multiple computers located at one site or distributed across multiple sites and interconnected via a communication network.

[0081] The processes and logic flows described in this document can be executed by one or more programmable processors that execute one or more computer programs to perform functions by manipulating input data and generating outputs. The processes and logic flows can also be executed by special-purpose logic circuitry (such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits)), and devices can also be implemented as such special-purpose logic circuitry.

[0082] Processors suitable for executing computer programs include, by way of example, both general-purpose microprocessors and special-purpose microprocessors, as well as any one or more processors in any kind of digital computer. Typically, a processor receives instructions and data from read-only memory or random access memory, or both. The fundamental elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include, or be operatively coupled to, one or more mass storage devices for storing data, to receive data from, or to transfer data, or both, such as magnetic disks, magneto-optical disks, or optical disks. However, a computer does not necessarily have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, by way of example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM discs. Processors and memory may be supplemented by or incorporated into special-purpose logic circuitry.

[0083] While this document contains numerous specific details, these should not be construed as limiting the scope of the claimed invention or the scope that may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as operating in certain combinations, or even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and the claimed combination may involve sub-combinations or variations thereof. Similarly, although operations are depicted in a specific order in the drawings, this should not be construed as requiring the performance of such operations in the specific order shown or in sequential order, or requiring the performance of all shown operations to achieve the desired result.

[0084] Only a few examples and implementations are disclosed. Variations, modifications, and enhancements can be made to the described examples, implementations, and other implementations based on the disclosed content.

Claims

1. A method for wireless communication, comprising: The user plane (CU-UP) of the central unit of the network node receives from the control plane (CU-CP) of the central unit: i) user equipment (UE) information, which identifies the corresponding UE as a remote UE for U2N (UE to network) relay communication, or ii) path switching indication, which indicates a switch from a first path of the network node to a second path under the network node or a second path under a different network node. as well as Subsequent operations will be performed based on the UE information or the path switching indication.

2. A method for wireless communication, comprising: The CU-CP of the network node sends to the CU-UP of the network node: i) User Equipment (UE) information, which identifies the corresponding UE as a remote UE for U2N (UE to network) relay communication, or ii) Path switching indication, which indicates a switch from the first path of the network node to the second path under the network node or the second path under a different network node. The UE information or the path switching indication allows the CU-UP to perform subsequent operations.

3. The method according to claim 1 or 2, wherein, The UE information includes UE type information indicating that the corresponding UE is the remote UE.

4. The method according to claim 1 or 2, wherein, The UE information includes authorization information indicating that the corresponding UE is authorized to act as the remote UE.

5. The method according to claim 1 or 2, wherein, The path switching indication also includes at least one of the following: i2d path switching, i2i path switching, or source indirect path.

6. The method according to claim 1, wherein, The subsequent operations include: In response to the UE information or the path switching indication, the CU-UP of the network node causes the data of the radio bearer not to be removed from the buffer according to the indication in the downlink data delivery status (DDDS) of successful data delivery.

7. The method according to claim 1, wherein, The subsequent operations include: In response to the UE information or the path switching indication, the CU-UP of the network node stops removing radio bearer data from the buffer.

8. The method according to claim 7, wherein, Stopping the removal of data from the buffer causes the CU-UP of the network node to stop removing the data from the buffer in response to an indication in the downlink data delivery status (DDDS) for successful data delivery or in response to the expiration of a discard timer.

9. The method according to claim 2, further comprising: The CU-CP of the network node determines to initiate a path switch, wherein the path switch indication is sent in response to the determination.

10. The method according to claim 2, further comprising: The CU-CP of the network node receives messages in response to path switching requests from different network nodes. The path switching indication is sent in response to the receipt.

11. A wireless communication method, comprising: The relay UE enters a connection state with the network node to relay data for remote UEs. The relay UE is the target relay UE selected during path handover.

12. The method of claim 11, further comprising: Receive a link establishment request message including a path switching indication from the remote UE. The relay UE enters the connection state in response to receiving the link establishment request message.

13. The method of claim 11, further comprising: Receive a link establishment request message including a path switching indication from the remote UE; as well as Confirm that the link establishment request message is accepted. The relay UE enters the connection state in response to the determination.

14. The method of claim 11, further comprising: Receive a link establishment request message including a path switching indication from the remote UE; as well as Send a link establishment response message to the remote UE. The relay UE enters the connection state in response to sending the link establishment response message.

15. The method of claim 11, further comprising: Receive a paging message from the network node that paging the relay UE. The relay UE enters the connection state in response to receiving the paging message.

16. The method according to claim 15, wherein, The relay UE is selected from among the candidate relay UEs included in a list of candidate relay UEs, wherein the list is received by the network node from the source network node and includes the connection status of each candidate relay UE.

17. The method of claim 11, further comprising: The remote UE receives at least one of preamble resources, preamble index, or PRACH resources. The relay UE is configured to use the received resources to perform random access with the network node.

18. The method of claim 11, further comprising: The relay UE sends the relay indication or the path switching indication to the network node by including the relay indication or path switching indication in the RRC connection request message to the network node.

19. A wireless communication method, comprising: The remote UE receives configuration information from the network node, including at least one of preamble resources, preamble index, or PRACH resources, which is permitted for use by the relay UE to enter a connection state with the network node.

20. The method of claim 19, further comprising: The configuration information is sent from the remote UE to the relay UE.

21. A wireless communication method, comprising: The network node receives a list of candidate relay UEs from the source network node, including the connection status of each candidate relay UE; as well as The network node selects a relay UE for path switching from the candidate relay UEs.

22. The method of claim 21, further comprising: The network node transmits a paging message to the relay UE.

23. A wireless communication device, comprising a processor configured to implement the method according to any one of the preceding claims.

24. A computer storage medium having code stored thereon, said code, when executed by a processor, causing the processor to perform the method according to any one of the preceding claims.

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