Method and communication device

Abstract

The method comprises determining that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit, and transmitting, via the direct communication link, an indication that the indirect communication link is no longer capable of supporting communication of the data unit and a status report of transmission or reception of the data unit for recovering any data unit that has been lost; or determining that the link quality of the direct communication link is no longer capable of supporting communication of the data unit, and transmitting, via the indirect communication link, an indication that the direct communication link is no longer capable of supporting communication of the data unit and a status report of transmission or reception of the data unit for recovering any data unit that has been lost.

Description

Technical Field

[0001] The present disclosure relates to methods and communication devices (user equipment or wireless transceiver units) configured to transmit or receive using multipath communication, the multipath communication comprising a direct communication link with an infrastructure device and an indirect communication link with a relay device via a sidelink communication link. The present disclosure claims the Paris Convention priority of European patent application EP22184827.8 filed on July 13, 2022, the contents of which are incorporated herein by reference in their entirety. Background Art

[0002] The "background" description provided herein is for the purpose of generally presenting the context of the present disclosure. To the extent described in this background section, the work of the presently named inventors and aspects of the description that may not otherwise be considered prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art against the present invention.

[0003] Wireless communication networks now support communication with a wider range of communication devices and user equipment for a variety of applications and data traffic profiles and types. For example, devices now supporting communication include reduced complexity devices, machine type communication (MTC) devices, high-resolution video displays, virtual reality headsets, etc. Some of these different types of devices may be deployed in large numbers, such as low-complexity devices used to support the "Internet of Things", and may generally be associated with the transmission of relatively small amounts of data with relatively high delay tolerance. Other types of devices (e.g., devices supporting high-definition video streaming) may be associated with the transmission of relatively large amounts of data with relatively low delay tolerance.

[0004] In order to provide coverage for an increasing number of devices (e.g., IoT), 5G radio access technology (RAT), also known as a new radio (NR) system, includes aspects and features designed to support connections over a wide range of environments. For example, in order to improve the coverage of communication devices (user equipment, etc.), technology can be used to utilize self-organizing relay devices formed by other communication devices. The wireless access interface of the relay device is called a sidelink. For the example of 3GPP, the sidelink interface is called a PC5 interface, and the direct communication interface with the infrastructure equipment of the wireless communication network is called a Uu interface. Using both direct communication links and indirect communication links at the same time can bring technical challenges. Summary of the invention

[0005] The present disclosure may help solve or alleviate at least some of the above-mentioned problems.

[0006] An embodiment of the present technology may provide a method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising: establishing multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device; and transmitting a data unit to the radio network infrastructure device using the multipath communication, or receiving a data unit from the radio network infrastructure device using the multipath communication. The direct communication link with the infrastructure device may be a Uu interface, and the sidelink communication link with the relay may use a PC5 interface. The method includes: determining that the link quality of the indirect communication link is no longer able to support the communication of data units, and transmitting via the direct communication link an indication that the indirect communication link is no longer able to support the communication of data units and a status report of the transmission or reception of data units, for recovering any data units that have been lost; or determining that the link quality of the direct communication link is no longer able to support the communication of data units, and transmitting via the indirect communication link an indication that the direct communication link is no longer able to support the communication of data units and a status report of the transmission or reception of data units, for recovering any data units that have been lost.

[0007] Example embodiments may provide effective recovery of multipath communications between a communication device and infrastructure equipment by: detecting when one of a direct communication link to an infrastructure device (gNB) via a Uu interface or an indirect communication link using a relay via a sidelink or PC5 interface no longer supports communication of data units; transmitting an indication via another that a failure did not occur in the direct communication link or the indirect communication link; and transmitting an indication of a data unit that has been successfully transmitted or the last data unit to be transmitted, so that the network can identify those data units that were lost due to a failure in the direct communication link or the indirect communication link. In one example, the data unit is a Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU).

[0008] Other aspects of the example embodiments also relate to techniques for recovering data units when one or more of the indirect and direct communication links of a multipath communication fails, wherein as part of the re-establishment process, a cell ID of a cell formed by infrastructure equipment providing the direct communication link and an ID of a relay are transmitted.

[0009] Various aspects and features of the present disclosure are defined in the accompanying claims and include communication equipment (UE) and infrastructure equipment and methods of operation thereof.

[0010] It should be understood that both the foregoing general description and the following detailed description are illustrative rather than restrictive of the present technology. The described embodiments and further advantages will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A more complete understanding of the present disclosure and its many attendant advantages will be readily obtained as the present disclosure and its many attendant advantages will become better understood by referring to the following detailed description when considered in conjunction with the accompanying drawings in which like reference numerals designate like or corresponding parts throughout the several views, and in which:

[0012] Figure 1 Schematically represents some aspects of a 5G / new radio access technology (RAT) wireless communication system that may be configured to operate in accordance with embodiments of the present disclosure;

[0013] Figure 2 is a schematic block diagram of an example scenario, wherein a remote communication device is configured to transmit or receive data as PDCP packet data units using a direct communication path link with an infrastructure device of a wireless communication network and an indirect communication path via a relay communication device, according to an example embodiment of the present disclosure;

[0014] Figure 3A It is shown Figure 2 An example of the arrangement shown, wherein one of the communication links between the relay communication device and the infrastructure device forming part of the indirect communication link has failed or is deemed not to support communication of the PDU;

[0015] Figure 3B It is shown Figure 2 An example of the arrangement shown, wherein an indirect communication link between a remote communication device and a relay communication device via a sidelink has failed or is deemed not to support communication of a PDU; and

[0016] Figure 3C It is shown Figure 2 An example of an arrangement in which a direct communication link between a remote communication device and an infrastructure device has failed or is deemed not to support communication of a PDU.

[0017] Figure 4 It is shown Figure 2 , showing a more detailed implementation of a telecommunication device, a relay communication device and a radio network infrastructure device;

[0018] Figure 5is a message flow diagram illustrating an example implementation in which a direct communication path between a remote communication device and an infrastructure device has failed or is deemed not to support communication of a PDU;

[0019] Figure 6 is a message flow diagram illustrating an example implementation of the present technology, wherein an indirect communication path between a remote UE and an infrastructure device via a relay communication device is no longer able to support PDU communication via a sidelink; and

[0020] Figure 7 is a message flow diagram illustrating an example implementation in which both a direct communication link and an indirect communication link between a remote UE and an infrastructure device have failed or are deemed not to support communication of PDUs. DETAILED DESCRIPTION

[0021] New Radio Access Technology (5G)

[0022] Figure 1 An exemplary configuration of a wireless communication network using some of the terminology proposed and used for NR and 5G is shown in FIG. Figure 1 In the figure, a plurality of transmission and reception points (TRPs) 10 are connected to distributed control units (DUs) 41, 42 via connection interfaces represented by lines 16. Each of the TRPs 10 is arranged to transmit and receive signals via a wireless access interface within a radio frequency bandwidth available to the wireless communication network. Therefore, within a range for performing radio communications via the wireless access interface, each of the TRPs 10 forms a cell of the wireless communication network represented by a circle 12. In this way, a wireless communication device 14 within the radio communication range provided by the cell 12 can transmit and receive signals to and from the TRP 10 via the wireless access interface. Each of the distributed units 41, 42 is connected to a central unit (CU) 40 (which may be referred to as a control node) via an interface 46. The central unit 40 is then connected to a core network 20, which may contain all other functions required for transmitting data for communicating with wireless communication devices, and the core network 20 may be connected to other networks 30.

[0023] Familiar as Figure 1The skilled person in the illustrated wireless communication network according to the 5G standard will appreciate that the CU 40, DU 42 and TRP 10 are collectively referred to as functions typically performed by a network base station or, in 5G terminology, a gNodeB (gNB). In terms of the broad top-level functions, the term network infrastructure equipment / access node may be used to encompass these elements of the wireless telecommunications system and more traditional base station type elements. Depending on the application at hand, the responsibility for scheduling transmissions scheduled over the radio interface between the respective DU units and the communication equipment may lie with the control node / centralized unit and / or the distributed unit / TRP.

[0024] exist Figure 1 In the figure, a communication device 14 is represented within the coverage area of ​​the first communication cell 12. The communication device 14 can therefore exchange signaling with the first CU 40 in the first communication cell 12 via a distributed unit / TRP 10 associated with the first communication cell 12. The communication device 14 can be referred to as a mobile terminal, terminal or user equipment (UE), including a chipset and having functionality corresponding to a UE device known for wireless communication network operation.

[0025] As described above, example embodiments may provide arrangements for improving reliability and communication quality, for example, where a remote UE transmits or receives data directly with a wireless communication network, that is, to a wireless infrastructure device (e.g., a gNodeB, Figure 1 The example embodiments relate to a multipath scenario in which the remote UE uses a communication path directly with the wireless communication network and a communication path indirectly with the wireless communication network via a relay UE.

[0026] It has been considered that service continuity of a single-hop layer to UE to network relay can be enhanced by switching between direct communication and indirect communication. For example, the following scenarios are envisaged:

[0027] A. Inter-gNB indirect to direct path switching, i.e. switching from UE 1<->relay UE A<->gNB X to UE 1<->gNBY;

[0028] B. Direct to indirect path switching between gNBs, i.e. switching from UE 1<->gNB X to UE 1<->relay UE A<->gNBY;

[0029] C. Indirect to indirect path switching within gNB, i.e. switching from UE 1<->relay UE A<->gNB X to UE 1<->relay UE B<->gNB X;

[0030] D. Indirect to indirect path switching between gNBs, that is, switching from UE 1<->relay UE A<->gNB X to UE 1<->relay UE B<->gNB Y.

[0031] It is also believed that there should be multipath communication, in which Layer 2 and Layer 3 communications are provided via direct and indirect paths to enhance reliability and throughput in different scenarios. That is, in a multipath scenario, the remote UE is connected to the gNB via direct and indirect links, whereby the indirect link is connected to the wireless communication network via a relay UE. According to multipath communication, the UE activates the Uu and PC5 links simultaneously, and the user traffic can be split / merged in the PDCP layer (Uu PDCP) of the gNB and UE. The benefit of this approach is that the Uu PDCP security between the gNB and the UE can be used even if the traffic is relayed via the UE to the network. Therefore, user data for downlink communication is encrypted in the PDCP entity in the gNB-CU, and then the traffic can be switched between the Uu link and another link via the relay UE. Both the remote UE and the relay UE links are Uu links and will be sent over the radio link control RLC channel. That is, the data is split between direct and indirect communication. Figure 2 An example of multipath communication is shown.

[0032] like Figure 2 As shown, the remote UE 200 transmits and receives data via a wireless communication network, in which the gNB 100 forms part of the radio network infrastructure equipment of the wireless communication network and is connected to the core network 400. Figure 2As shown, the remote UE 200 uses PDCP protocol layers 201a, 201b to communicate data with the gNB 100 via a data link. The PDCP layers 201a, 201b form part of a protocol stack 202, which is represented as a table on the remote UE 200 and the gNB 100 as two protocol stacks 102a, 102b for a direct communication link 102a and an indirect communication link 102b. The remote UE 200 is able to communicate data with the gNB 100 at the PDCP layers 201a, 201b via a direct communication link 250 with the gNB 100 and an indirect communication link 350, 450 via a relay UE 300. The communication link 350 with the relay UE 300 is formed by a PC5 interface. The protocol stack 202 is within the remote UE 200 and thus includes a radio link control layer SL-RLC, a media access layer SL-MAC, and a physical layer SL-PHY for a side link, via which data from the PDCP is transmitted to the relay UE via the side link 350, and is transmitted from the relay UE 300 to the gNB 100 via a second direct communication link 450. As shown in the protocol stack 202 within the remote UE 200, the PDCP data is transmitted via the direct communication link 250 formed by the Uu interface, and also uses the radio link control layer RLC, the media access layer MAC, and the physical layer PHY and the corresponding layers within the protocol stack 102a at the gNB 100. Therefore, according to Figure 2 The arrangement shown, according to the currently proposed technology, uses the protocol stacks 202, 102a, 102b to transmit PDCP data transmitted to or received from the gNB 100 as a protocol data unit (PDU). That is, according to Figure 2In the arrangement shown, the relay UE 300 maps the remote UE traffic received from the gNB to the sidelink 350. The remote UE 200 will have PDCP PDUs received from the Uu interface and the SL interface. The PDCP entity in the UE will combine the traffic at the PDCP layer 201a. In addition, there will be SL-SDAP and SL-PDCP entities between the relay UE and the remote UE, which are not shown here for simplicity. Similarly, for the uplink direction, the remote UE PDCP entity will split the traffic and transmit it as PDCP PDUs via the direct communication path 250 and the indirect communication paths 350, 450, and then receive these PDUs at the gNB via the direct communication path or via the relay UE 300. Traffic splitting is one example, and redundant traffic is another example. The traffic split on the downlink can be a network decision. For uplink traffic splitting, the network will configure the UE with rules for splitting the data, for example, a split ratio of 50:50 or 60:40 based on traffic volume and / or radio conditions. However, embodiments of the present technology are used to solve the problem of multipath communication of PDCP data being subject to radio link failure, the PDCP data being repeated on the indirect communication path 350, 450, or switching between the indirect communication path 350, 450 and the direct communication path 250. This will be explained in the following paragraphs.

[0033] Radio link failure

[0034] If the remote UE is providing a service supported by multipath communication links, there is a technical problem in addressing the situation where one or both of the direct (Uu) and indirect (PC5) communication links of the multipath communication fail. In a multipath communication scenario, if both links Uu and SL fail, the UE can declare a Radio Link Failure (RLF). If one of the links fails, it should be possible to report RLF from the other surviving link. In principle, this is the same as the RLF reporting behavior when dual connectivity is configured. Figure 3A , Figure 3B and Figure 3C Some possible situations are shown in Figure 2 The components shown in FIG. 1 have the same reference numerals. Figure 3A As shown, the remote UE 200 is being served by a multipath communication including a direct communication link 250 and an indirect communication path via a relay UE using communication links 350, 450, which corresponds to Figure 2 As shown in the arrangement Figure 3A As shown, the black cross 460 indicates that the Uu communication link between the relay UE 300 and the gNB 100 has failed, and Figure 3B In FIG. 1 , a black cross 360 indicates that a sidelink communication link 350 between a remote UE 200 and a relay 300 has failed. Figure 3C , as indicated by the black cross 260, the direct communication link 250 between the remote UE 200 and the gNB 100 has failed. Radio link failure (RLF) in scenarios where the UE can switch between a direct communication path and an indirect communication path is considered in TS 38.300, which considers RLF on the sidelink and operations during failure of the direct communication path on the Uu interface. The present disclosure, together with the disclosure in TS 38.331, provides for the initiation of a radio beam failure or physical layer failure and radio resource control action re-establishment procedure on an indirect communication link via a PC5 interface and a direct communication link via a Uu interface. Operations during handover are also considered, wherein a configured sidelink authorization handover may be provided to the UE. The scenarios in the present disclosure specify processing based on the assumption that the UE can perform sidelink communication in RRC connected mode and any failure on the sidelink may be reported using the Uu link. This procedure may be used when the Uu is configured with multipath communication. However, technical problems still exist in handling radio link failures (RLFs) typically used for multipath communications, and more specifically, handling RLFs on direct communication links with radio network infrastructure equipment via a Uu interface by using a relay node via a PC5 interface for management and reporting using an indirect communication path with the infrastructure equipment. In other embodiments, the technical problem relates to handling sidelink (SL) RLFs, i.e., failures on SLs via a PC5 interface on an indirect communication path to a radio network infrastructure equipment via a relay device. In some example embodiments, a UE may have more than one SL to more than one relay device for communicating on an indirect communication path to a radio network infrastructure equipment, and RLF may occur on one of those SLs to one of those relay devices. In response, the UE may transmit a message via a direct communication link of the multipath communication link via the Uu interface, the message identifying the SL communication link that suffered the RLF with the relay device, and the message may also include an indication of which SL survived, although this may be implicit because the remaining links have survived.

[0035] In other example embodiments, the UE may establish a multipath communication link, wherein a direct communication path is established using multiple carriers, i.e., a Uu interface with carrier aggregation or dual connectivity, such that if communication on one carrier fails, communication may continue and the RLF may be reported on the surviving carrier or via the surviving SL.

[0036] Embodiments of the present technology may provide a method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising: establishing multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device; transmitting a data unit to the radio network infrastructure device using the multipath communication, or receiving a data unit from the radio network infrastructure device using the multipath communication. The method comprises: determining that the link quality of the direct communication link is no longer able to support the communication of the data unit, and transmitting an indication that the direct communication link is no longer able to support the communication of the data unit and a status report of the transmission or reception of the data unit via the indirect communication link, for recovering any data unit that has been lost.

[0037] According to another example embodiment, after establishing the multipath communication link, the communication device is configured to operate in the following manner: determining that the link quality of the indirect communication link can no longer support the communication of the data unit by transmitting the data unit to the radio network infrastructure device via the sidelink communication link, or receiving the data unit from the radio network infrastructure device; and transmitting via the direct communication link an indication that the indirect communication link can no longer support the communication of the data unit, and an indication of releasing the indirect communication path and a status report of the transmission or reception of the data unit, for recovering any data unit that has been lost. The indication can be transmitted, for example, as a Uu message.

[0038] Embodiments provide techniques to address the following examples:

[0039] 1. When RLF occurs on both the direct communication link and the indirect communication link, and the UE attempts to perform RRC re-establishment, the re-establishment may take a long time. To this end, the UE is able to discover the sidelink relay UE before the re-establishment process is successful. If the sidelink discovery is successful and the PC5 interface can be established, the RLF can be reported via the SL involving the new relay or the old relay.

[0040] 2. When RLF occurs on the SL / PC-5 interface, the PC-5 RRC connection is released and reported to the gNB via Uu message using SL Information, with a procedure for managing data loss, including, for example, a new PDCP Status Report or the last successfully received PDCP Sequence Number SN included in the SL Information Uu message.

[0041] Figure 4 Provided Figure 1 and Figure 2 A more detailed schematic diagram of the components shown. Figure 4 As a simplified representation, it corresponds to Figure 1 The TRP 120 of the TRP 10 in the figure includes a transmitter 126, a receiver 124 and a controller or control processor 122, which can be operated to control the transmitter 126 and the receiver 124 to transmit and receive radio signals to one or more UEs within a cell provided by the TRP 120 (not shown in Figure 3 for clarity).

[0042] like Figure 4 As shown, the TRP 120 is connected to the DU 140 via a physical interface 130, which may be, for example, a fiber optic cable. Thus, the physical interface 130 provides a communication link for data and signaling services from the TRP 210 via the DU 140 and the CU 160 to the core network 400. The interface 150 between the DU 140 and the CU 160 is referred to as an F1 interface, which may be a physical or logical interface. The F1 interface 150 between the DU 140 and the CU 160 may be operated in accordance with the specifications 3GPP TS 38.470 and 3GPP TS 38.473, and may be formed by an optical fiber or other wired or wireless high-bandwidth connection. The connection between the TRP 120 and the core network 400 may generally be referred to as a backhaul, which includes the physical interface 130 from the TRP 120 to the DU 140 and the F1 interface 150 from the DU 140 to the CU 160.

[0043] like Figure 2 As shown, the TRP 120 may be configured to transmit downlink radio signals and receive uplink radio signals from the remote UE 200 via a direct wireless communication link 250 to the remote UE 200. In one example, the direct wireless communication link 250 may be a Uu interface. The remote UE 200 is shown to include a transmitter 226, a receiver 224, and a controller 222, which is configured to control the transmitter 226 and the receiver 224 to transmit uplink signals to the TRP 120 and receive downlink signals from the TRP 120 via the wireless communication link 250 formed between the remote UE 200 and the TRP 120. When the remote UE 200 communicates with the TRP 120 / gNB 100 via the direct wireless communication link 250 between the remote UE 200 and the TRP 120 / gNB 100, it can be said that the remote UE 200 communicates with the TRP 120 / gNB 100 via a "direct path". A direct wireless communication link for a communication device (e.g., UE) is interpreted as a wireless communication link to an infrastructure device of a wireless communication network (e.g., gNB) without the need for an intermediate wireless communication link (e.g., a sidelink wireless communication link).

[0044] like Figure 4 As shown, the TRP 120 may be configured to transmit downlink radio signals and receive uplink radio signals from the relay UE 300 via a direct wireless communication link 450. In one example, the direct wireless communication link 450 may be a Uu interface. The relay UE 300 is shown to include a transmitter 326, a receiver 324, and a controller 322, which is configured to control the transmitter 326 and the receiver 324 to transmit uplink signals to the TRP 120 and receive downlink signals from the TRP 120 via the direct wireless communication link 450 formed between the relay UE 300 and the TRP 120.

[0045] like Figure 4 As shown, the controller 322 of the relay UE 300 may be configured to control the transmitter 326 to transmit a downlink signal to the remote UE 200 via the sidelink wireless communication link 350, and to control the receiver 324 to receive an uplink signal from the remote UE 200 via the sidelink wireless communication link 350. Similarly, the controller of the remote UE 200 may be configured to control the receiver 224 to receive a downlink signal from the relay UE 300, and to control the transmitter 226 to transmit an uplink signal to the relay UE 300. The sidelink wireless communication link 350 between the relay UE 300 and the remote UE 200 is a sidelink wireless communication link, such as a PC-5 interface. Therefore, the relay UE 300 may be configured to relay signals between the remote UE 200 and the TRP 120. When the remote UE 200 communicates with the TRP 120 / gNB 100 via the relay UE 300 (i.e., via the sidelink wireless communication link 350 between the remote UE 200 and the relay UE 300 and the direct wireless communication link 450 between the relay UE 300 and the TRP 120 / gNB 100), the remote UE 200 may be said to be communicating with the gNB 100 via an “indirect path”. Figure 4 Not shown, but the indirect path may also include one or more other relay UEs.

[0046] exist Figure 4 In the example shown, since the relay UE 300 relays signals between the remote UE 200 and the infrastructure equipment of the wireless communication network, i.e., the gNB 100, the relay UE 300 may be referred to as a "UE to Network (U2N)" relay. As will be appreciated by those skilled in the art, one or more other relay UEs may relay signals between the remote UE 200 and the relay UE 300 along an indirect path to the gNB 100, thereby acting as a "UE to UE (U2U)" relay.

[0047] The transmitters 126, 226, 326 and the receivers 124, 224, 324 (as well as other transmitters, receivers and transceivers described in the examples and embodiments of the present disclosure) may include radio frequency filters and amplifiers and signal processing components and devices to transmit and receive radio signals according to, for example, the 5G / NR standard. The controllers 122, 222, 322 (as well as other controllers described in the examples and embodiments of the present disclosure) may be, for example, microprocessors, CPUs or dedicated chipsets, etc., which are configured to execute instructions stored on a computer-readable medium (e.g., non-volatile memory). The processing steps described herein may be performed by, for example, a microprocessor in combination with a random access memory, operating according to instructions stored on a computer-readable medium. For ease of representation, the transmitter, receiver and controller are schematically shown as separate elements in FIG. 3. However, it should be understood that the functions of these elements may be provided in a variety of different ways, for example, using one or more appropriately programmed programmable computers, or one or more appropriately configured dedicated integrated circuits / circuitry systems / chips / chipsets.

[0048] like Figure 4 As shown, TRP 120, DU 140 and CU 160 may collectively form gNB 100, which is an example of infrastructure equipment of a wireless communication network. Therefore, references to remote UE 200 or relay UE 300 communicating with TRP 120 may alternatively be considered as references to remote UE 200 or relay UE 300 communicating with gNB 100. Furthermore, it should be understood that remote UE 200 and relay UE 300 are examples of communication equipment. It should be understood that infrastructure equipment / TRP / base station / gNB and UE / communication equipment will typically include various other elements associated with their operating functions.

[0049] Thus, as described above, the remote UE 200 may communicate with the gNB 100 via a direct path (i.e., via a direct wireless communication link 250 between the remote UE 200 and the gNB 100) or via an indirect path (i.e., via a sidelink wireless communication link 350 between the remote UE 200 and the relay UE 300 and a direct wireless communication link 450 between the relay UE 300 and the gNB 100). Conventionally, the remote UE 200 is configured to communicate via a direct path or an indirect path at any one time, but not both at the same time. For example, the remote UE 200 may be configured to communicate via a direct path when the remote UE 200 is in a cell provided by the gNB 100. Alternatively, the remote UE 200 may be configured to communicate via an indirect path when the remote UE 200 is outside a cell provided by the TRP 120, but the relay UE 300 is within a cell provided by the TRP 120. The relay UE 300 may thus provide coverage for the remote UE 200.

[0050] Uu link failure and reporting to gNB via relay UE

[0051] According to an example implementation, once the UE detects that the Uu link has failed or the Uu link quality is below a threshold, the UE notifies the relay UE that the Uu link can no longer support communication via the direct communication link. Figure 5 As shown. Figure 5 As shown in the first stage in FIG, the remote UE 200 is supported by multipath communication using a direct communication link with the gNB 100 via the Uu interface and an indirect communication path via the remote UE 300 using a sidelink (SL) PC5 interface with the relay UE 300, and the relay UE has established a communication link with the gNB 100 via the Uu interface. As shown, during the initial stage 500, the remote UE receives downlink data in the form of PDUs from the gNB 100 and transmits uplink data in the form of PDUs to the gNB 100 via the direct link (via the Uu interface) and via the relay UE 300 (using the PC5 interface) using multipath communication. However, at a certain point 502, the link quality of the Uu interface with the gNB 100 is below a predetermined threshold, so the Uu interface is no longer available over the direct communication link with the gNB 100.

[0052] The network may configure a threshold to determine that the communication link with the gNB 100 via the Uu interface is below a level that will support PDCP PDU communication, the network may reuse the existing event A2 in the established handover process. The wireless communication network may configure multiple thresholds for event A2, i.e., one threshold when splitting the service, and a lower threshold if the same service is sent via direct and indirect communication paths (Uu and SL) or based on the network or UE implementation. Therefore, according to an example embodiment, once the remote UE 200 has determined that the direct communication link with the gNB 100 via the Uu interface has failed or is below a predetermined threshold, the remote UE 200 sends an indication that the direct communication path is no longer able to support the communication of PDUs to / from the gNB 100 via the indirect communication path (i.e., via the relay UE 504a, 504b). According to an example embodiment, the wireless communication network may then, based on the indication, direct the remote UE 200 to establish and transmit the service (PDU) via another communication link. Another communication link may be established with another gNB as part of the handover, or via another relay UE (sidelink), or a single link may be maintained for a period of time. Additionally, the remote UE 200 may report the status of successfully received or transmitted PDCP PDUs in order to identify those PDUs that were not successfully transmitted or received. Reporting PDCP PDUs is better because the PDCP in the gNB-CU can coordinate data loss and we already have a framework to perform PDCP status reporting (done at RLF and handover, whereby the UE reports the lost PDCP SN, and is already known and implemented in 38.300 / 38.323 and configured by RRC38.331). However, it can also be done on the RLC layer.

[0053] Therefore, according to an example embodiment, once the remote UE 200 detects that the Uu link has failed or the Uu link quality is below a threshold, the remote UE 200 may notify the relay UE that the direct communication link via the Uu interface is no longer available to support data communications. The event that the Uu link quality is below a threshold may be event A2. When the Uu link fails, an indication of the failure is transmitted to the gNB 100 via a sidelink (PC5), which is an indirect communication link and the relay UE 300. According to an example embodiment, the remote UE 200 then reports the status of the successfully received or transmitted PDCP PDUs so that the corresponding entity within the gNB 100 can identify any PDUs that were not successfully transmitted or received.

[0054] SL link failure is reported to gNB

[0055] Figure 6 The corresponding Figure 5Another example embodiment of the example embodiment of, for example, wherein the indirect communication link to the relay UE 300 fails or the link quality is below a predetermined threshold established for acceptable efficient communication integrity. Figure 6 The example shown is like Figure 5 In the example of , during the initial phase 500, the remote UE 200 receives downlink data in the form of PDUs from the gNB 100 and transmits uplink data in the form of PDUs to the gNB 100 via a direct link (via the Uu interface) and via an indirect communication link via the relay UE 300 (using the PC5 interface) using multipath communication. However, at point 602, the link quality of the PC5 interface with the relay UE 300 is below a predetermined threshold or is deemed to have failed, so that the communication path via the relay UE 300 is no longer available on the indirect communication link with the gNB 100. In this example, there is already a process for the remote UE 200 to report a sidelink radio link failure (SL-RLF) to the wireless communication network via the direct communication link (i.e., via the Uu interface to the gNB 100). After the sidelink failure is detected or the link quality is below a predetermined threshold, a report 604 of the sidelink failure is shown. Currently, the existing event X2 (traditionally used to trigger handover) can be used to send a message that the SL link quality has fallen below a predetermined threshold or has failed, where the serving L2 U2N relay UE has become worse than an absolute threshold. The remote UE 200 then reports the PDCP status to the gNB 100 via the direct communication link Uu interface, as shown by arrow 606.

[0056] According to this example embodiment, the remote UE reports event X2, which triggers a PDCP status reporting procedure in a corresponding manner in which the remote UE reports a PDCP status report when a direct communication link via the Uu interface has failed. According to some example embodiments, event X2 for triggering a failure or identifying that the link quality is insufficient to support efficient communication may be determined by comparing the link quality with different thresholds, wherein multipath communication is used for redundancy or segmentation between a direct communication path and an indirect communication path.

[0057] In some example embodiments, the form and process of the PDCP status report triggered after an X2 event may be configured by the wireless communication network.

[0058] according to Figure 6In another example embodiment shown, the UE may have more than one SL to more than one relay UE 300 for communicating on an indirect communication path to a radio network infrastructure device. For example, in step 602, RLF occurring on one or more of those SLs to one or more of those relay devices may cause the UE to transmit a Uu message in response in step 604 via a direct communication link of a multipath communication link via a Uu interface, the Uu message identifying the SL communication link that suffered the RLF of the relay device, and also including an indication of which SL survived, although this may be implicit. For example, if there are only two SLs to two relay devices, and one SL suffers RLF, it means that the other SL has survived. However, in general, it will be understood that there may be N SLs that are indirect or have L relay devices, and M of those SLs suffer RLF, then NM SLs have survived. By indicating to the wireless communication network the M links that have suffered RLF, the NM surviving links may be implicit, or the NM surviving links may be explicitly indicated in the Uu message.

[0059] According to another example embodiment, after establishing the multipath communication link, the UE is configured to operate in the following manner: determining that the link quality of the indirect communication link can no longer support the communication of the data unit by transmitting the data unit to the radio network infrastructure equipment via the sidelink communication link, or receiving the data unit from the radio network infrastructure equipment; and transmitting, via the direct communication link, an indication that the indirect communication link can no longer support the communication of the data unit, and an indication of releasing the indirect communication path and a status report of the transmission or reception of the data unit, for recovering any data unit that has been lost. The indication can be transmitted, for example, as a Uu message.

[0060] Link failure and recovery via another relay UE

[0061] Example embodiments may also provide improvements when both communication links of a multipath communication fail. Figure 7 An example implementation is shown that illustrates a process for restoring communications when both a direct communication link and an indirect communication link fail. Figure 7 shown, and corresponds to Figure 5 and Figure 6In other embodiments, during the initial phase 500, the remote UE 200 receives downlink data in the form of PDUs from the gNB 100, and transmits uplink data in the form of PDUs to the gNB 100 via a direct communication link (via the Uu interface) and via an indirect communication link of the relay UE 300 (using a sidelink (PC5) interface) using multipath communication. However, at point 700, the link quality of the PC5 interface with the gNB 100 is below a predetermined threshold and is deemed to be unable to support communication of the PDUs or has failed, and the link quality of the communication via the direct communication link on the Uu interface is also deemed to be unable to support communication of the PDUs or has failed, so that the communication path via the remote UE 300 and directly via the gNB 100 is no longer available. In this example, before performing the RRC re-establishment process, the remote UE 200 may discover another relay UE 702 in a discovery process 704 to re-establish a communication link with the gNB 100 or another gNB, or to indicate a handover to another gNB. Once the remote UE 200 discovers the new relay UE 702, the remote UE 200 establishes a new sidelink connection 707 with the other remote UE 702. Then, the remote UE 200 transmits a report 708 indicating radio link failure of the Uu interface and the sidelink interface. The cell ID of the cell formed by the gNB 100 in which the Uu interface has experienced a radio link failure and an identifier (relay UE ID) of the relay UE 300 for identifying the sidelink relay UE 300 that has also experienced a radio link failure are included in the information transmitted to the other relay UE 702. This information may be included in message 1, message 3, or message 5 as part of the random access procedure, and the message 1, message 3, or message 5 is transmitted to the other remote UE 702 before security activation or later after activating PDCP security on the sidelink. That is, UuPDCP security and SL PDCP security will be established. SL security is point-to-point, and PDCP security is meaningful because the information goes into the gNB.

[0062] Therefore, according to an example embodiment, the cell ID of the cell formed by the gNB serving the remote UE 200 suffering from the radio link failure and the identifier of the relay UE for identifying the sidelink of the relay UE, which also suffers from the radio link failure, are included in the message sent by the remote UE to the new relay UE. After receiving the cell ID and the identifier of the relay UE for providing multipath communication, the wireless communication network can therefore identify the UE context and thus reestablish the connection more quickly.

[0063] According to other example embodiments, a sidelink communication link forming part of a multipath communication may use configured authorized resources, for example, a sidelink configured authorization type 1 (SL CG type 1 resource). When a radio link failure occurs on a direct communication link (Uu interface) and triggers reestablishment, the configured authorized resources of the sidelink remain valid for the sidelink relay even if the remote UE loses connection with the master cell group (MCG) or cell. In this way, for sidelink communications, when the MCG radio link fails, there is no need to stop using the type 1 resources, and there is no need to perform RRC reestablishment, because the remote UE can continue to use the sidelink configured authorization type 1 resources via the sidelink relay. According to this example embodiment, the configured authorized resources of the sidelink relay of the indirect communication link are maintained even if there is a radio link failure on the direct communication link via the Uu interface.

[0064] According to other example embodiments, when multipath communication supports the remote UE, the remote UE may be configured to prioritize uplink data transmission via a sidelink or uplink (direct communication link) to the gNB. This is because in some examples, for example, in the time domain, the remote UE cannot perform simultaneous transmission via the uplink Uu interface and the sidelink PC5 interface. According to this example embodiment, data transmission via the uplink or sidelink is performed based on a priority and threshold configured or preconfigured by the wireless communication network (i.e., the radio access network). When the UE cannot perform V2X sidelink transmission and uplink transmission simultaneously in the time domain, prioritization between the two transmissions is performed based on priority. According to this example embodiment, in multipath communication, the remote UE notifies the gNB of the priority selected between unicast transmission on the Uu interface and the sidelink on PC5. Therefore, the remote UE notifies the gNB of the priority selected between unicast on the Uu interface and PC5 using the selected link, so that the network can disable or deactivate the multipath configuration.

[0065] The UE establishes multiple direct and / or indirect communication links

[0066] In other example embodiments, the UE may establish a multipath communication link, wherein a direct communication path is established using multiple carriers, i.e., a Uu interface with carrier aggregation or dual connectivity, such that if communication on one carrier fails, communication may continue and the RLF may be reported on the surviving carrier or via the surviving SL.

[0067] According to other example embodiments, a UE may establish multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a plurality of direct communication links with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, each indirect communication link comprising an SL communication link with a relay device, and the plurality of relay communication devices providing direct communication links with the radio network infrastructure device. The UE may be configured to transmit a data unit to the radio network infrastructure device using the multipath communication, or to receive a data unit from the radio network infrastructure device using the multipath communication. The UE is then configured to determine, by transmitting a data unit to the radio network infrastructure device, or by receiving a data unit from the radio network infrastructure device, that a link quality of one or more of the plurality of indirect communication links is no longer capable of supporting communication of the data unit, or by transmitting a data unit to the radio network infrastructure device, or by receiving a data unit from the radio network infrastructure device, that a link quality of one or more of the plurality of direct communication links is no longer capable of supporting communication of the data unit. The UE is also configured to identify at least one surviving communication link among the plurality of indirect communication links or among the plurality of direct communication links, and to transmit, via the at least one surviving communication link, an indication that one or more of the plurality of direct communication links or one or more of the plurality of indirect communication links can no longer support communication of the data unit. If the at least one surviving communication link is an indirect communication link, the UE is configured to transmit an indication of a cell identifier of a cell formed by the radio network infrastructure device and an identifier of a relay communication device forming the indirect communication link, which indication can be used by the wireless communication network to recover any data units that have been lost. If the at least one surviving communication link is a direct communication link, an indication of a cell identifier of a cell formed by the radio network infrastructure device forming the direct communication link is transmitted, which indication can be used by the wireless communication network to recover any data units that have been lost.

[0068] The following numbered paragraphs provide further example aspects and features of the present technology:

[0069] Paragraph 1. A method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising:

[0070] establishing a multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device,

[0071] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication, wherein the method comprises:

[0072] determining that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure equipment, or receiving the data unit from the radio network infrastructure equipment via the sidelink communication link, and

[0073] An indication is transmitted via the direct communication link that the indirect communication link can no longer support communication of data units, and an indication of releasing the indirect communication path and a status report of the transmission or reception of data units for use in recovering any data units that have been lost.

[0074] Paragraph 2. A method according to paragraph 1, wherein, if it is determined that the link quality of the indirect communication link is no longer able to support the communication of data units, the status report transmitted to the radio network infrastructure equipment via the direct communication link includes an indication of data units that have been transmitted via the indirect communication link before it is determined that the indirect communication link is no longer able to support the communication of data units or data units that have been received from the indirect communication link before it is determined that the indirect communication link is no longer able to support the communication of data units.

[0075] Paragraph 3. A method according to paragraph 1, wherein, if it is determined that the link quality of the indirect communication link is no longer able to support the communication of data units, the status report includes an indication of data units that have not been transmitted via the indirect communication link due to the determination that the indirect communication link is no longer able to support the communication of data units or the last data unit that has been received from the indirect communication link before it is determined that the indirect communication link is no longer able to support the communication of data units.

[0076] Paragraph 4. A method according to paragraphs 1, 2 or 3, wherein an indication that the indirect communication link is no longer able to support the communication of a data unit and an indication of releasing the indirect communication path and a status report of the transmission or reception of the data unit are transmitted to the radio network infrastructure equipment using a Uu message.

[0077] Paragraph 5. A method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising:

[0078] establishing a multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, the indirect communication links comprising a plurality of sidelink communication links with the plurality of relay communication devices, each of the plurality of relay communication devices providing an additional direct communication link with the radio network infrastructure device,

[0079] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication, wherein the method comprises:

[0080] determining that a link quality of at least one indirect communication link with at least one relay device of the plurality of relay devices is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure device or receiving the data unit from the radio network infrastructure device via the at least one sidelink communication link, respectively, and

[0081] An indication of one or more indirect communication links among a plurality of indirect communication links that are no longer able to support communication of the released data unit is transmitted via a direct communication link, together with a status report of transmission or reception of the data unit, the status report being used to recover any data units that have been lost.

[0082] Paragraph 6. A method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising:

[0083] establishing a multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device,

[0084] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication, wherein the method comprises:

[0085] determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that the link quality of the direct communication link is no longer capable of supporting the communication of the data unit, and

[0086] An indication that the direct communication link can no longer support communication of the data unit is transmitted via the indirect communication link.

[0087] Paragraph 7. A method according to paragraph 6, comprising status reporting of transmission or reception of data units for use in recovering any data units that have been lost.

[0088] Paragraph 8. A method according to paragraph 6, wherein, if it is determined that the link quality of the direct communication link is no longer able to support the communication of data units, the status report includes an indication of data units that have been transmitted via the direct communication link before it is determined that the direct communication link is no longer able to support the communication of data units, or data units that have been received from the direct communication link before it is determined that the direct communication link is no longer able to support the communication of data units.

[0089] Paragraph 9. A method according to paragraph 6, wherein, if it is determined that the link quality of the direct communication link is no longer able to support the communication of data units, the status report includes an indication of data units that were not transmitted via the direct communication link due to the determination that the direct communication link is no longer able to support the communication of data units or the last data unit that has been received from the direct communication link before it is determined that the direct communication link is no longer able to support the communication of data units.

[0090] Paragraph 10. A method according to any one of paragraphs 1 to 9, wherein the data unit is a Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU), and transmission and reception of the PDU are controlled by a PDCP layer connection to the PDCP layer in the radio network infrastructure equipment.

[0091] Paragraph 11. A method according to any one of paragraphs 1 to 10, comprising monitoring the link quality of one or both of the indirect communication link and the direct communication link, or receiving an indication of the link quality of one or both of the indirect communication link and the direct communication link from a radio network infrastructure device, and determining that the link quality of the indirect communication link is no longer able to support the communication of data units comprises determining that the link quality has fallen below a first predetermined threshold, and determining that the link quality of the direct communication link is no longer able to support the communication of data units comprises determining that the link quality has fallen below a second predetermined threshold.

[0092] Paragraph 12. The method of Paragraph 11, wherein the first predetermined threshold is the same as the second predetermined threshold.

[0093] Paragraph 13. A method according to paragraph 11, wherein monitoring the link quality of the indirect communication link includes monitoring the link quality of the sidelink communication link with the relay communication device, or receiving an indication of the link quality of the sidelink communication link with the relay communication device from a radio network infrastructure device, and determining that the link quality of the indirect communication link is no longer able to support the communication of data units includes determining that the link quality of the sidelink communication link with the relay communication device has fallen below a second predetermined threshold.

[0094] Paragraph 14. A method according to paragraph 11, wherein determining that the link quality of the indirect communication link is no longer able to support the communication of the data unit includes detecting that the indirect communication link has suffered a radio link failure, and determining that the link quality of the direct communication link is no longer able to support the communication of the data unit includes detecting that the direct communication link has suffered a radio link failure.

[0095] Paragraph 15. A method according to any one of paragraphs 1 to 14, wherein the multipath communication includes transmitting data units by exchanging data units between a direct communication link and an indirect communication link, or copying data units on both the direct communication link and the indirect communication link and transmitting the data units, or receiving data units that have been transmitted by a radio network infrastructure device that switches between a direct communication link and an indirect communication link, or that are copied and transmitted on both the direct communication link and the indirect communication link.

[0096] Paragraph 16. A method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising:

[0097] establishing a multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a first relay communication device, the indirect communication link comprising a sidelink communication link with the first relay communication device, the first relay communication device providing a second communication link with the radio network infrastructure device,

[0098] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication,

[0099] determining that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, and

[0100] determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of the direct communication link is no longer capable of supporting communication of the data unit,

[0101] discovering another communication device capable of acting as a relay communication device,

[0102] establishing a new sidelink communication link with the discovered relay communication device, the discovered relay communication device providing a third direct communication link with the radio network infrastructure device or with another radio network infrastructure device,

[0103] transmitting, via the new sidelink communication link, an indication that the direct communication link and the indirect communication link can no longer support communication of the data unit, and

[0104] A cell identifier of a cell formed by the radio network infrastructure equipment and an indication of an identifier of the first relay communication device is transmitted, which indication can be used by the wireless communication network to recover any data units that have been lost.

[0105] Paragraph 17. A method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising:

[0106] establishing multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a plurality of direct communication links with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, each indirect communication link comprising a sidelink communication link with the communication device, the plurality of relay communication devices providing direct communication links with the radio network infrastructure device,

[0107] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication,

[0108] determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more of the plurality of indirect communication links is no longer capable of supporting communication of the data unit, or

[0109] determining, by transmitting the data unit to the radio network infrastructure device, or by receiving the data unit from the radio network infrastructure device, that a link quality of one or more of the plurality of direct communication links is no longer capable of supporting communication of the data unit,

[0110] identifying at least one surviving communication link among the plurality of indirect communication links or among the plurality of direct communication links, and

[0111] transmitting, via at least one surviving communication link, an indication that one or more of the plurality of direct communication links or one or more of the plurality of indirect communication links can no longer support communication of the data unit, and

[0112] if at least one of the surviving communications links is an indirect communications link, transmitting an indication of a cell identifier of a cell formed by the radio network infrastructure equipment and an identifier of a relay communications device forming the indirect communications link, which indication can be used by the wireless communications network to recover any data units that have been lost, or

[0113] If at least one of the surviving communications links is a direct communications link, an indication of a cell identifier of a cell formed by the radio network infrastructure equipment forming the direct communications link is transmitted, which indication can be used by the wireless communications network to recover any data units that have been lost.

[0114] Paragraph 18. The method according to paragraph 17 includes transmitting a status report via a new sidelink communication link, the status report indicating the status of transmission or reception of data units, for recovering any data units lost because the direct communication link and the indirect communication link are no longer able to support communication of data units.

[0115] Paragraph 19. A method according to paragraph 18, wherein, if it is determined that the link quality of the indirect communication link and the direct communication link can no longer support the communication of data units, the status report includes an indication of data units that have been transmitted via the indirect communication link and the direct communication link before it is determined that the communication of data units can no longer be supported, or data units that have been received from the indirect communication link and the direct communication link before it is determined that the communication of data units can no longer be supported.

[0116] Paragraph 20. A method according to paragraph 18, wherein, if it is determined that the link quality of the indirect communication link and the direct communication link can no longer support the communication of the data unit, the status report includes an indication of the data unit that has not been transmitted due to the determination that the indirect communication link and the direct communication link can no longer support the communication of the data unit or the last data unit that has been received from the indirect communication link and the direct communication link before it is determined that the communication of the data unit can no longer be supported.

[0117] Paragraph 21. A method according to paragraphs 18, 19 or 20, wherein the data unit is a Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU), and transmission and reception of the PDU are controlled by a PDCP layer connection to the PDCP layer in the radio network infrastructure equipment.

[0118] Paragraph 22. A method according to any one of paragraphs 17 to 21, comprising monitoring the link quality of an indirect communication link and a direct communication link, or receiving indications of the link quality of an indirect communication link and a direct communication link from a radio network infrastructure device, and determining that the link quality of the indirect communication link is no longer able to support the communication of data units comprises determining that the link quality has fallen below a first predetermined threshold, and determining that the link quality of the direct communication link is no longer able to support the communication of data units comprises determining that the link quality has fallen below a second predetermined threshold.

[0119] Paragraph 23. The method of Paragraph 22, wherein the first predetermined threshold is the same as the second predetermined threshold.

[0120] Paragraph 24. A method according to any one of paragraphs 16 to 23, wherein the multipath communication includes transmitting data units by splitting the data units between a direct communication link and an indirect communication link, or copying the data units on both the direct communication link and the indirect communication link and transmitting the data units, or receiving data units that have been transmitted by a radio network infrastructure device that switches between the direct communication link and the indirect communication link, or copied and transmitted on both the direct communication link and the indirect communication link.

[0121] Paragraph 25. A method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising:

[0122] establishing multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a plurality of direct communication links with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, each indirect communication link comprising a sidelink communication link with the communication device, the plurality of relay communication devices providing direct communication links with the radio network infrastructure device,

[0123] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication,

[0124] determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more of the plurality of indirect communication links is no longer capable of supporting communication of the data unit, or

[0125] determining, by transmitting the data unit to the radio network infrastructure device, or by receiving the data unit from the radio network infrastructure device, that a link quality of one or more of the plurality of direct communication links is no longer capable of supporting communication of the data unit,

[0126] identifying at least one surviving communication link among the plurality of indirect communication links or among the plurality of direct communication links, and

[0127] transmitting, via at least one surviving communication link, an indication that one or more of the plurality of direct communication links or one or more of the plurality of indirect communication links can no longer support communication of the data unit, and

[0128] if at least one of the surviving communications links is an indirect communications link, transmitting an indication of a cell identifier of a cell formed by the radio network infrastructure equipment and an identifier of a relay communications device forming the indirect communications link, which indication can be used by the wireless communications network to recover any data units that have been lost, or

[0129] If at least one of the surviving communications links is a direct communications link, an indication of a cell identifier of a cell formed by the radio network infrastructure equipment forming the direct communications link is transmitted, which indication can be used by the wireless communications network to recover any data units that have been lost.

[0130] Paragraph 26. The method according to Paragraph 25 includes transmitting a status report via the surviving communication link, the status report indicating the status of transmission or reception of the data unit, for recovering any data units lost because the direct communication link and the indirect communication link are no longer able to support the communication of the data units.

[0131] Paragraph 27. A method according to paragraph 25 or 26, wherein the data unit is a Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU), and transmission and reception of the PDU is controlled by a PDCP layer connection to the PDCP layer in the radio network infrastructure equipment.

[0132] Paragraph 28. A method according to any one of paragraphs 25 to 27, comprising monitoring the link quality of an indirect communication link and a direct communication link, or receiving indications of the link quality of an indirect communication link and a direct communication link from a radio network infrastructure device, and determining that the link quality of one or more of a plurality of indirect communication links is no longer capable of supporting the communication of a data unit comprises determining that the link quality has fallen below a first predetermined threshold, and determining that the link quality of one or more of a plurality of direct communication links is no longer capable of supporting the communication of a data unit comprises determining that the link quality has fallen below a second predetermined threshold.

[0133] Paragraph 29. The method of Paragraph 28, wherein the first predetermined threshold is the same as the second predetermined threshold.

[0134] Paragraph 30. A method according to any one of paragraphs 25 to 29, wherein the multipath communication includes transmitting data units by splitting the data units between multiple direct communication links and multiple indirect communication links, or copying the data units on multiple direct communication links and multiple indirect communication links and transmitting the data units, or receiving data units that have been transmitted by a radio network infrastructure device that switches between multiple direct communication links and multiple indirect communication links, or that are copied and transmitted on both direct communication links and indirect communication links.

[0135] Paragraph 31. A method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising:

[0136] establishing a multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device,

[0137] Transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication, wherein a sidelink communication link with a relay communication device is formed by a configured authorized resource of a sidelink radio interface, and the method comprises:

[0138] determining that a link quality of the direct communication link is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure device, or receiving the data unit from the radio network infrastructure device,

[0139] performing a re-establishment procedure to re-establish a direct communication link with the radio network infrastructure equipment,

[0140] According to the multipath communication, data units are transmitted to the radio network infrastructure device using the re-established direct communication link, or data units are received from the radio network infrastructure device using the re-established direct communication link, and data units are transmitted to the radio network infrastructure device using the configured authorized resources that have been established for the sidelink communication link, or data units are received from the radio network infrastructure device using the configured authorized resources that have been established for the sidelink communication link.

[0141] Paragraph 32. A method for transmitting data to or receiving data from a wireless communication network performed by a communication device, the method comprising:

[0142] establishing a multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device,

[0143] Transmitting a data unit to a radio network infrastructure device, or receiving a data unit from a radio network infrastructure device, using multipath communication, wherein transmitting a data unit to a radio network infrastructure device using multipath communication comprises:

[0144] determining that data units for an uplink cannot be transmitted to the radio network infrastructure equipment simultaneously using an indirect communication link and a direct communication link,

[0145] prioritizing transmission of uplink data units by selecting an indirect communication link or a direct communication link via a sidelink communication link, and

[0146] The data unit is transmitted to the radio network infrastructure equipment using the selected sidelink communication link or the selected direct communication link.

[0147] Paragraph 33. The method according to paragraph 32, comprising:

[0148] An indication is transmitted to the radio network infrastructure equipment of a selected one of an indirect communication link or a direct communication link via the sidelink communication link, and multipath communication is disabled for the uplink.

[0149] Paragraph 34. A communication device for transmitting data to or receiving data from a wireless communication network, the communication device comprising:

[0150] a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of a wireless communication network or another communication device acting as a relay communication device,

[0151] A controller circuit configured to control the transceiver circuit to establish multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device, and to transmit a data unit to the radio network infrastructure device using the multipath communication or to receive a data unit from the radio network infrastructure device using the multipath communication, wherein the controller circuit is configured to:

[0152] determining that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure equipment, or receiving the data unit from the radio network infrastructure equipment via the sidelink communication link, and

[0153] The transmitter circuit is controlled to transmit via the direct communication link an indication that the indirect communication link can no longer support communication of data units, and an indication to release the indirect communication path and a status report of transmission or reception of data units for use in recovering any data units that have been lost.

[0154] Paragraph 35. A communication device for transmitting data to or receiving data from a wireless communication network, the communication device comprising:

[0155] a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of a wireless communication network or another communication device acting as a relay communication device,

[0156] A controller circuit configured to control the transceiver circuit to establish multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, the indirect communication links comprising a plurality of sidelink communication links with a plurality of relay communication devices, each of the plurality of relay communication devices providing a further direct communication link with the radio network infrastructure device, and to transmit a data unit to the radio network infrastructure device using the multipath communication or to receive a data unit from the radio network infrastructure device using the multipath communication, wherein the controller circuit is configured to:

[0157] determining that a link quality of at least one indirect communication link with at least one relay device of the plurality of relay devices is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure device or receiving the data unit from the radio network infrastructure device via the at least one sidelink communication link, respectively, and

[0158] Transmitting, via a direct communication link, an indication of one or more indirect communication links among a plurality of indirect communication links that are determined to no longer be able to support communication of the released data unit, and a status report of transmission or reception of the data unit, wherein the status report is used to recover any data unit that has been lost.

[0159] Paragraph 36. A communication device for transmitting data to or receiving data from a wireless communication network, the communication device comprising:

[0160] a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of a wireless communication network or another communication device acting as a relay communication device,

[0161] a controller circuit configured to control the transceiver circuit,

[0162] to establish multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device,

[0163] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication, wherein the controller circuit is configured to:

[0164] determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that the link quality of the direct communication link is no longer capable of supporting the communication of the data unit, and

[0165] The transceiver circuitry is controlled to transmit via the indirect communication link an indication that the direct communication link can no longer support communication of the data unit, and a status report of the transmission or reception of the data unit for use in recovering any data units that have been lost.

[0166] Paragraph 37. A communication device for transmitting data to or receiving data from a wireless communication network, the communication device comprising:

[0167] a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of a wireless communication network or another communication device acting as a relay communication device,

[0168] a controller circuit configured to control the transceiver circuit,

[0169] to establish multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a first relay communication device, the indirect communication link comprising a sidelink communication link with the first relay communication device, the first relay communication device providing a second direct communication link with the radio network infrastructure device,

[0170] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication, wherein the controller circuit is configured to:

[0171] determining that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, and

[0172] determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of the direct communication link is no longer capable of supporting communication of the data unit,

[0173] discovering another communication device capable of acting as a relay communication device,

[0174] establishing a new sidelink communication link with the discovered relay communication device, the discovered relay communication device providing a third direct communication link with the radio network infrastructure device or with another radio network infrastructure device,

[0175] controlling the transceiver circuitry to transmit an indication via the new sidelink communication link that the direct communication link and the indirect communication link are no longer capable of supporting communication of the data unit, and

[0176] The transceiver circuitry is controlled to transmit an indication of a cell identifier of a cell formed by the radio network infrastructure equipment and an identifier of the first relay communication device, which indication can be used by the wireless communication network to recover any data units that have been lost.

[0177] Paragraph 38. A communication device for transmitting data to or receiving data from a wireless communication network, the communication device comprising:

[0178] a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of a wireless communication network or another communication device acting as a relay communication device; and a controller circuit configured to control the transceiver circuit,

[0179] to establish multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a plurality of direct communication links with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, each indirect communication link comprising a sidelink communication link with the communication device, the plurality of relay communication devices providing direct communication links with the radio network infrastructure device,

[0180] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication, wherein the controller circuit is configured to:

[0181] determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more of the plurality of indirect communication links is no longer capable of supporting communication of the data unit, or

[0182] determining, by transmitting the data unit to the radio network infrastructure device, or by receiving the data unit from the radio network infrastructure device, that a link quality of one or more of the plurality of direct communication links is no longer capable of supporting communication of the data unit,

[0183] identifying at least one surviving communication link among the plurality of indirect communication links or among the plurality of direct communication links, and

[0184] controlling the transceiver circuitry to transmit, via the at least one surviving communication link, an indication that one or more of the plurality of direct communication links or one or more of the plurality of indirect communication links can no longer support communication of the data unit, and

[0185] if at least one of the surviving communications links is an indirect communications link, controlling the transceiver circuitry to transmit an indication of a cell identifier of a cell formed by the radio network infrastructure equipment and an identifier of a relay communications device forming the indirect communications link, the indication being usable by the wireless communications network to recover any data units that have been lost, or

[0186] If at least one surviving communication link is a direct communication link, the transceiver circuitry is controlled to transmit an indication of a cell identifier of a cell formed by the radio network infrastructure equipment forming the direct communication link, which indication can be used by the wireless communication network to recover any data units that have been lost.

[0187] Paragraph 39. A communication device for transmitting data to or receiving data from a wireless communication network, the communication device comprising:

[0188] a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of a wireless communication network or another communication device acting as a relay communication device,

[0189] a controller circuit configured to control the transceiver circuit,

[0190] to establish multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device, and

[0191] transmitting a data unit to a radio network infrastructure device using multipath communication, or receiving a data unit from a radio network infrastructure device using multipath communication, wherein a sidelink communication link with the relay communication device is formed by a configured authorized resource of the sidelink wireless interface, and the controller circuit is configured to control the transceiver circuit:

[0192] determining that a link quality of the direct communication link is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure device, or receiving the data unit from the radio network infrastructure device,

[0193] performing a re-establishment procedure to re-establish a direct communication link with the radio network infrastructure equipment,

[0194] Control the transceiver circuit to transmit data units to the radio network infrastructure device using the re-established direct communication link or receive data units from the radio network infrastructure device using the re-established direct communication link based on the multipath communication, and transmit data units to the radio network infrastructure device using the configured authorized resources that have been established for the sidelink communication link or receive data units from the radio network infrastructure device using the configured authorized resources that have been established for the sidelink communication link.

[0195] Paragraph 40. A communication device for transmitting data to or receiving data from a wireless communication network, the communication device comprising:

[0196] a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of a wireless communication network or another communication device acting as a relay communication device; and a controller circuit configured to control the transceiver circuit,

[0197] to establish multipath communication with a radio network infrastructure device of a wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device,

[0198] Controlling a transceiver unit to transmit a data unit to a radio network infrastructure device using multipath communication, or to receive a data unit from the radio network infrastructure device, wherein the controller circuit is configured to control the transceiver circuit to transmit the data unit to the radio network infrastructure device using multipath communication by:

[0199] determining that data units for an uplink cannot be transmitted to the radio network infrastructure equipment simultaneously using an indirect communication link and a direct communication link,

[0200] prioritizing transmission of uplink data units by selecting an indirect communication link or a direct communication link via a sidelink communication link, and

[0201] The data unit is transmitted to the radio network infrastructure equipment using the selected sidelink communication link or the selected direct communication link.

[0202] Although the present disclosure has been described in conjunction with some embodiments, the present disclosure is not intended to be limited to the specific form set forth herein. In addition, although a feature may appear to be described in conjunction with a specific embodiment, those skilled in the art will recognize that the various features of the described embodiments may be combined in any manner suitable for implementing the technology.

[0203] References

[0204] [1] TS 38.470

[0205] [2]TS 38.423[3]TS 38.300[4]TS 38.323[5]TS 38.331.

Claims

1. A method for transmitting data to a wireless communication network or receiving data from the wireless communication network performed by a communication device, the method comprising: establishing a multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving the data unit from the radio network infrastructure equipment using the multipath communication, wherein the method comprises: determining that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure equipment or receiving the data unit from the radio network infrastructure equipment via the sidelink communication link, and An indication that the indirect communication link can no longer support communication of the data unit is transmitted via the direct communication link, as well as an indication of releasing the indirect communication path and a status report of the transmission or reception of the data unit, the status report being used to recover any data units that have been lost.

2. The method according to claim 1, wherein: If it is determined that the link quality of the indirect communication link is no longer able to support the communication of the data unit, the status report transmitted to the radio network infrastructure equipment via the direct communication link includes an indication of the data units that have been transmitted via the indirect communication link before it is determined that the indirect communication link is no longer able to support the communication of the data unit or the data units that have been received from the indirect communication link before it is determined that the indirect communication link is no longer able to support the communication of the data unit.

3. The method according to claim 1, wherein: If it is determined that the link quality of the indirect communication link is no longer able to support the communication of the data unit, the status report includes an indication of the data unit that was not transmitted via the indirect communication link due to the determination that the indirect communication link is no longer able to support the communication of the data unit or the last data unit that was received from the indirect communication link before it was determined that the indirect communication link is no longer able to support the communication of the data unit.

4. The method according to claim 1, wherein: An indication that the indirect communication link can no longer support the communication of the data unit and an indication to release the indirect communication path and the status report of the transmission or reception of the data unit are transmitted to the radio network infrastructure equipment using Uu messages.

5. A method for transmitting data to a wireless communication network or receiving data from the wireless communication network, performed by a communication device, the method comprising: establishing a multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, the indirect communication links comprising a plurality of sidelink communication links with the plurality of relay communication devices, each of the plurality of relay communication devices providing an additional direct communication link with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving a data unit from the radio network infrastructure equipment using the multipath communication, wherein the method comprises: determining that a link quality of at least one indirect communication link with at least one relay device of a plurality of relay devices is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure device or receiving the data unit from the radio network infrastructure device via at least one sidelink communication link, respectively, and Transmitting, via a direct communication link, an indication of one or more indirect communication links among the multiple indirect communication links that are no longer able to support communication of the released data unit, and a status report of transmission or reception of the data unit, the status report being used to recover any data units that have been lost.

6. A method for transmitting data to a wireless communication network or receiving data from the wireless communication network, performed by a communication device, the method comprising: establishing a multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving a data unit from the radio network infrastructure equipment using the multipath communication, wherein the method comprises: determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of the direct communication link is no longer capable of supporting communication of the data unit, and An indication is transmitted via the indirect communication link that the direct communication link can no longer support communication of the data unit.

7. A method according to claim 6, comprising status reporting of the transmission or reception of the data units, the status reporting being used to recover any data units that have been lost.

8. The method according to claim 6, wherein: If it is determined that the link quality of the direct communication link is no longer able to support the communication of the data unit, the status report includes an indication of the data unit that has been transmitted via the direct communication link before it is determined that the direct communication link is no longer able to support the communication of the data unit, or the data unit that has been received from the direct communication link before it is determined that the direct communication link is no longer able to support the communication of the data unit.

9. The method according to claim 6, wherein: If it is determined that the link quality of the direct communication link is no longer able to support the communication of the data unit, the status report includes an indication of the data unit that was not transmitted via the direct communication link due to the determination that the direct communication link is no longer able to support the communication of the data unit or the last data unit that was received from the direct communication link before it was determined that the direct communication link is no longer able to support the communication of the data unit.

10. The method according to claim 1, wherein: The data unit is a Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU), and transmission and reception of the PDU are controlled by a PDCP layer connection with a PDCP layer in the radio network infrastructure device.

11. The method of claim 1 , comprising monitoring the link quality of one or both of the indirect communication link and the direct communication link, or receiving an indication of the link quality of one or both of the indirect communication link and the direct communication link from the radio network infrastructure equipment, and determining that the link quality of the indirect communication link is no longer able to support the communication of the data unit comprises determining that the link quality has fallen below a first predetermined threshold, and determining that the link quality of the direct communication link is no longer able to support the communication of the data unit comprises determining that the link quality has fallen below a second predetermined threshold.

12. The method according to claim 11, wherein: The first predetermined threshold is the same as the second predetermined threshold.

13. The method according to claim 11, wherein: Monitoring the link quality of the indirect communication link includes monitoring the link quality of the sidelink communication link with the relay communication device, or receiving an indication of the link quality of the sidelink communication link with the relay communication device from the radio network infrastructure device, and determining that the link quality of the indirect communication link is no longer able to support the communication of the data unit includes determining that the link quality of the sidelink communication link with the relay communication device has fallen below the second predetermined threshold.

14. The method according to claim 11, wherein: Determining that the link quality of the indirect communication link is no longer able to support communication of the data unit comprises detecting that the indirect communication link has suffered a radio link failure, and determining that the link quality of the direct communication link is no longer able to support communication of the data unit comprises detecting that the direct communication link has suffered a radio link failure.

15. The method according to claim 1, wherein: The multipath communication includes transmitting the data unit by exchanging the data unit between the direct communication link and the indirect communication link, or duplicating the data unit on both the direct communication link and the indirect communication link and transmitting the data unit, or receiving the data unit that has been transmitted by the radio network infrastructure equipment that switches between the direct communication link and the indirect communication link, or duplicated and transmitted on both the direct communication link and the indirect communication link.

16. A method for transmitting data to a wireless communication network or receiving data from the wireless communication network, performed by a communication device, the method comprising: establishing a multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a first relay communication device, the indirect communication link comprising a sidelink communication link with the first relay communication device, the first relay communication device providing a second communication link with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving a data unit from the radio network infrastructure equipment using the multipath communication, determining, by transmitting the data unit to the radio network infrastructure equipment or by receiving the data unit from the radio network infrastructure equipment, that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit, and determining, by transmitting the data unit to the radio network infrastructure equipment or by receiving the data unit from the radio network infrastructure equipment, that a link quality of the direct communication link is no longer capable of supporting communication of the data unit, discovering another communication device capable of acting as a relay communication device, establishing a new sidelink communication link with a discovered relay communication device, said discovered relay communication device providing a third direct communication link with said radio network infrastructure device or with another radio network infrastructure device, transmitting, via the new sidelink communication link, an indication that the direct communication link and the indirect communication link are no longer capable of supporting communication of the data unit, and A cell identifier of a cell formed by the radio network infrastructure equipment and an indication of an identifier of the first relay communication device is transmitted, the indication being usable by the wireless communication network to recover any data units that have been lost.

17. A method for transmitting data to a wireless communication network or receiving data from the wireless communication network, performed by a communication device, the method comprising: establishing multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a plurality of direct communication links with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, each indirect communication link comprising a sidelink communication link with a communication device, the plurality of relay communication devices providing direct communication links with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving a data unit from the radio network infrastructure equipment using the multipath communication, determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more of the plurality of indirect communication links is no longer capable of supporting communication of the data unit, or determining, by transmitting the data unit to the radio network infrastructure equipment or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more direct communication links of the plurality of direct communication links is no longer capable of supporting communication of the data unit, identifying at least one surviving communication link among the plurality of indirect communication links or among the plurality of direct communication links, and transmitting, via the at least one surviving communication link, an indication that one or more of the plurality of direct communication links or one or more of the plurality of indirect communication links can no longer support communication of the data unit, and if the at least one surviving communication link is an indirect communication link, transmitting an indication of a cell identifier of a cell formed by the radio network infrastructure equipment and an identifier of a relay communication device forming the indirect communication link, said indication being usable by the wireless communication network to recover any data units that have been lost, or If the at least one surviving communication link is a direct communication link, an indication of a cell identifier of a cell formed by the radio network infrastructure equipment forming the direct communication link is transmitted, which indication can be used by the wireless communication network to recover any data units that have been lost.

18. The method of claim 17, comprising transmitting a status report via the new sidelink communication link, the status report indicating a status of transmission or reception of the data unit, for recovering any data units lost because the direct communication link and the indirect communication link are no longer able to support communication of the data units.

19. The method according to claim 18, wherein: If it is determined that the link quality of the indirect communication link and the direct communication link is no longer able to support the communication of the data unit, the status report includes an indication of the data units that have been transmitted via the indirect communication link and the direct communication link before it is determined that the communication of the data unit is no longer able to be supported, or the data units that have been received from the indirect communication link and the direct communication link before it is determined that the communication of the data unit is no longer able to be supported.

20. The method according to claim 18, wherein: If it is determined that the link quality of the indirect communication link and the direct communication link can no longer support the communication of the data unit, the status report includes the data unit that was not transmitted due to the determination that the indirect communication link and the direct communication link can no longer support the communication of the data unit or an indication of the last data unit that has been received from the indirect communication link and the direct communication link before it is determined that the communication of the data unit can no longer be supported.

21. The method according to claim 18, wherein: The data unit is a Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU), and transmission and reception of the PDU are controlled by a PDCP layer connection with a PDCP layer in the radio network infrastructure device.

22. The method of claim 17, comprising monitoring the link quality of the indirect communication link and the direct communication link, or receiving indications of the link quality of the indirect communication link and the direct communication link from the radio network infrastructure equipment, and determining that the link quality of the indirect communication link is no longer able to support the communication of the data unit comprises determining that the link quality has fallen below a first predetermined threshold, and determining that the link quality of the direct communication link is no longer able to support the communication of the data unit comprises determining that the link quality has fallen below a second predetermined threshold.

23. The method according to claim 22, wherein: The first predetermined threshold is the same as the second predetermined threshold.

24. The method according to claim 16, wherein: The multipath communication includes transmitting the data unit by splitting the data unit between the direct communication link and the indirect communication link, or duplicating the data unit on both the direct communication link and the indirect communication link and transmitting the data unit, or receiving the data unit that has been transmitted by the radio network infrastructure equipment that switches between the direct communication link and the indirect communication link, or duplicated and transmitted on both the direct communication link and the indirect communication link.

25. A method for transmitting data to a wireless communication network or receiving data from the wireless communication network, performed by a communication device, the method comprising: establishing multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a plurality of direct communication links with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, each indirect communication link comprising a sidelink communication link with a communication device, the plurality of relay communication devices providing direct communication links with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving a data unit from the radio network infrastructure equipment using the multipath communication, determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more of the plurality of indirect communication links is no longer capable of supporting communication of the data unit, or determining, by transmitting the data unit to the radio network infrastructure equipment or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more direct communication links of the plurality of direct communication links is no longer capable of supporting communication of the data unit, identifying at least one surviving communication link among the plurality of indirect communication links or among the plurality of direct communication links, and transmitting, via the at least one surviving communication link, an indication that one or more of the plurality of direct communication links or one or more of the plurality of indirect communication links can no longer support communication of the data unit, and if the at least one surviving communication link is an indirect communication link, transmitting an indication of a cell identifier of a cell formed by the radio network infrastructure equipment and an identifier of a relay communication device forming the indirect communication link, said indication being usable by the wireless communication network to recover any data units that have been lost, or If the at least one surviving communication link is a direct communication link, an indication of a cell identifier of a cell formed by the radio network infrastructure equipment forming the direct communication link is transmitted, which indication can be used by the wireless communication network to recover any data units that have been lost.

26. The method of claim 25, comprising transmitting a status report via the surviving communication link, the status report indicating a status of transmission or reception of the data unit for recovering any data units lost because the direct communication link and the indirect communication link are no longer able to support communication of the data units.

27. The method according to claim 25, wherein: The data unit is a Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU), and transmission and reception of the PDU are controlled by a PDCP layer connection with a PDCP layer in the radio network infrastructure device.

28. The method of claim 25, comprising monitoring the link qualities of the indirect communication link and the direct communication link, or receiving indications of the link qualities of the indirect communication link and the direct communication link from the radio network infrastructure equipment, and determining that the link quality of one or more of the multiple indirect communication links is no longer able to support the communication of the data unit comprises determining that the link quality has fallen below a first predetermined threshold, and determining that the link quality of one or more of the multiple direct communication links is no longer able to support the communication of the data unit comprises determining that the link quality has fallen below a second predetermined threshold.

29. The method according to claim 28, wherein: The first predetermined threshold is the same as the second predetermined threshold.

30. The method of claim 25, wherein: The multipath communication includes transmitting the data unit by splitting the data unit between the multiple direct communication links and the multiple indirect communication links, or copying the data unit on the multiple direct communication links and the multiple indirect communication links and transmitting the data unit, or receiving the data unit that has been transmitted by the radio network infrastructure equipment that switches between the multiple direct communication links and the multiple indirect communication links or copied and transmitted on both the direct communication links and the indirect communication links.

31. A method for transmitting data to a wireless communication network or receiving data from the wireless communication network, performed by a communication device, the method comprising: establishing a multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure device using the multipath communication, or receiving a data unit from the radio network infrastructure device using the multipath communication, wherein the sidelink communication link with the relay communication device is formed by a configured authorized resource of a sidelink radio interface, and the method comprises: determining, by transmitting the data unit to the radio network infrastructure equipment or receiving the data unit from the radio network infrastructure equipment, that the link quality of the direct communication link is no longer capable of supporting the communication of the data unit, performing a re-establishment procedure to re-establish said direct communication link with said radio network infrastructure equipment, According to the multipath communication, the data unit is transmitted to the radio network infrastructure device using the re-established direct communication link, or the data unit is received from the radio network infrastructure device using the re-established direct communication link, and the data unit is transmitted to the radio network infrastructure device using the configured authorized resources that have been established for the sidelink communication link, or the data unit is received from the radio network infrastructure device using the configured authorized resources that have been established for the sidelink communication link.

32. A method for transmitting data to a wireless communication network or receiving data from the wireless communication network, performed by a communication device, the method comprising: establishing a multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure device and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure equipment, or receiving a data unit from the radio network infrastructure equipment using the multipath communication, wherein transmitting the data unit to the radio network infrastructure equipment using the multipath communication comprises: determining that the data unit for uplink cannot be transmitted to the radio network infrastructure equipment simultaneously using the indirect communication link and the direct communication link, prioritizing transmission of uplink data units by selecting the indirect communication link or the direct communication link via the sidelink communication link, and The data unit is transmitted to the radio network infrastructure equipment using the selected sidelink communication link or the selected direct communication link.

33. The method according to claim 32, comprising: An indication is transmitted to a radio network infrastructure device via a selected one of the indirect communication link or the direct communication link of the sidelink communication link, and for the uplink, the multipath communication is disabled.

34. A communication device for transmitting data to a wireless communication network or receiving data from the wireless communication network, the communication device comprising: a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of the wireless communication network or another communication device acting as a relay communication device, a controller circuit configured to control the transceiver circuit to establish a multipath communication with the radio network infrastructure equipment of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure equipment and an indirect communication link via the relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure equipment, and to transmit a data unit to the radio network infrastructure equipment using the multipath communication or to receive the data unit from the radio network infrastructure equipment using the multipath communication, wherein the controller circuit is configured to: determining that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure equipment or receiving the data unit from the radio network infrastructure equipment via the sidelink communication link, and Controlling the transmitter circuit to transmit, via the direct communication link, an indication that the indirect communication link can no longer support communication of the data unit, and an indication of releasing the indirect communication path and a status report of the transmission or reception of the data unit, the status report being used to recover any data units that have been lost.

35. A communication device for transmitting data to a wireless communication network or receiving data from the wireless communication network, the communication device comprising: a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of the wireless communication network or another communication device acting as a relay communication device, a controller circuit configured to control the transceiver circuit to establish a multipath communication with the radio network infrastructure equipment of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure equipment and a plurality of indirect communication links via a plurality of relay communication devices, the indirect communication links comprising a plurality of sidelink communication links with the plurality of relay communication devices, each of the plurality of relay communication devices providing a further direct communication link with the radio network infrastructure equipment, and to transmit a data unit to the radio network infrastructure equipment using the multipath communication or to receive the data unit from the radio network infrastructure equipment using the multipath communication, wherein the controller circuit is configured to: determining that a link quality of at least one indirect communication link with at least one of the plurality of relay devices is no longer capable of supporting communication of the data unit by transmitting the data unit to the radio network infrastructure device or receiving the data unit from the radio network infrastructure device via at least one sidelink communication link, respectively, and An indication of one or more indirect communication links among a plurality of indirect communication links that are no longer able to support communication of the released data unit is transmitted via the direct communication link, as well as a status report of transmission or reception of the data unit, the status report being used to recover any data units that have been lost.

36. A communication device for transmitting data to a wireless communication network or receiving data from the wireless communication network, the communication device comprising: a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of the wireless communication network or another communication device acting as a relay communication device, a controller circuit configured to control the transceiver circuit, to establish multipath communication with the radio network infrastructure equipment of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure equipment and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure equipment, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving the data unit from the radio network infrastructure equipment using the multipath communication, wherein the controller circuit is configured to: determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of the direct communication link is no longer capable of supporting communication of the data unit, and The transceiver circuitry is controlled to transmit, via the indirect communications link, an indication that the direct communications link can no longer support communication of the data unit and a status report of transmission or reception of the data unit, the status report being used to recover any data units that have been lost.

37. A communication device for transmitting data to a wireless communication network or receiving data from the wireless communication network, the communication device comprising: a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of the wireless communication network or another communication device acting as a relay communication device, a controller circuit configured to control the transceiver circuit, to establish a multipath communication with the radio network infrastructure equipment of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure equipment and an indirect communication link via a first relay communication device, the indirect communication link comprising a sidelink communication link with the first relay communication device, the first relay communication device providing a second direct communication link with the radio network infrastructure equipment, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving the data unit from the radio network infrastructure equipment using the multipath communication, wherein the controller circuit is configured to: determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of the indirect communication link is no longer capable of supporting communication of the data unit, and determining, by transmitting the data unit to the radio network infrastructure device or by receiving the data unit from the radio network infrastructure device, that the link quality of the direct communication link can no longer support the communication of the data unit, finding another communication device that can act as a relay communication device, establishing a new sidelink communication link with a discovered relay communication device, said discovered relay communication device providing a third direct communication link with said radio network infrastructure device or with another radio network infrastructure device, controlling the transceiver circuitry to transmit, via the new sidelink communication link, an indication that the direct communication link and the indirect communication link are no longer capable of supporting communication of the data unit, and The transceiver circuitry is controlled to transmit an indication of a cell identifier of a cell formed by the radio network infrastructure equipment and an identifier of the first relay communications device, the indication being usable by the wireless communications network to recover any data units that have been lost.

38. A communication device for transmitting data to a wireless communication network or receiving data from the wireless communication network, the communication device comprising: a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of the wireless communication network or another communication device acting as a relay communication device; and a controller circuit configured to control the transceiver circuit, to establish multipath communication with a radio network infrastructure device of the wireless communication network, the multipath communication comprising a plurality of direct communication links with the radio network infrastructure device and a plurality of indirect communication links via a plurality of relay communication devices, each indirect communication link comprising a sidelink communication link with the communication device, the plurality of relay communication devices providing direct communication links with the radio network infrastructure device, transmitting a data unit to the radio network infrastructure equipment using the multipath communication, or receiving the data unit from the radio network infrastructure equipment using the multipath communication, wherein the controller circuit is configured to: determining, by transmitting the data unit to the radio network infrastructure equipment, or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more of the plurality of indirect communication links is no longer capable of supporting communication of the data unit, or determining, by transmitting the data unit to the radio network infrastructure equipment or by receiving the data unit from the radio network infrastructure equipment, that a link quality of one or more direct communication links of the plurality of direct communication links is no longer capable of supporting communication of the data unit, identifying at least one surviving communication link among the plurality of indirect communication links or among the plurality of direct communication links, and controlling the transceiver circuitry to transmit, via the at least one surviving communication link, an indication that one or more of the plurality of direct communication links or one or more of the plurality of indirect communication links can no longer support communication of the data unit, and if the at least one surviving communication link is an indirect communication link, controlling the transceiver circuitry to transmit an indication of a cell identifier of a cell formed by the radio network infrastructure equipment and an identifier of the relay communication device forming the indirect communication link, the indication being usable by the wireless communication network to recover any data units that have been lost, or If the at least one surviving communication link is a direct communication link, controlling the transceiver circuitry to transmit an indication of a cell identifier of a cell formed by the radio network infrastructure equipment forming the direct communication link, which indication can be used by the wireless communication network to recover any data units that have been lost.

39. A communication device for transmitting data to a wireless communication network or receiving data from the wireless communication network, the communication device comprising: a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of the wireless communication network or another communication device acting as a relay communication device, a controller circuit configured to control the transceiver circuit, to establish multipath communication with the radio network infrastructure equipment of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure equipment and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure equipment, and transmitting a data unit to the radio network infrastructure device using the multipath communication, or receiving the data unit from the radio network infrastructure device using the multipath communication, wherein the sidelink communication link with the relay communication device is formed by a configured authorized resource of a sidelink radio interface, and the controller circuit is configured to control the transceiver circuit: determining, by transmitting the data unit to the radio network infrastructure equipment or receiving the data unit from the radio network infrastructure equipment, that the link quality of the direct communication link is no longer capable of supporting the communication of the data unit, performing a re-establishment procedure to re-establish said direct communication link with said radio network infrastructure equipment, Controlling the transceiver circuit to transmit the data unit to the radio network infrastructure device using the re-established direct communication link or receive the data unit from the radio network infrastructure device using the re-established direct communication link based on the multipath communication, and to transmit the data unit to the radio network infrastructure device using the configured authorized resources that have been established for the sidelink communication link or receive the data unit from the radio network infrastructure device using the configured authorized resources that have been established for the sidelink communication link.

40. A communication device for transmitting data to a wireless communication network or receiving data from the wireless communication network, the communication device comprising: a transceiver circuit configured to transmit signals to and receive signals from one or more radio network infrastructure devices of the wireless communication network or another communication device acting as a relay communication device; and a controller circuit configured to control the transceiver circuit, to establish multipath communication with the radio network infrastructure equipment of the wireless communication network, the multipath communication comprising a first direct communication link with the radio network infrastructure equipment and an indirect communication link via a relay communication device, the indirect communication link comprising a sidelink communication link with the relay communication device, the relay communication device providing a second direct communication link with the radio network infrastructure equipment, controlling the transceiver circuitry to transmit data units to the radio network infrastructure equipment or to receive data units from the radio network infrastructure equipment using the multipath communication, wherein the controller circuitry is configured to control the transceiver circuitry to transmit the data units to the radio network infrastructure equipment using the multipath communication in the following manner: determining that the data unit for uplink cannot be transmitted to the radio network infrastructure equipment simultaneously using the indirect communication link and the direct communication link, prioritizing transmission of uplink data units by selecting the indirect communication link or the direct communication link via the sidelink communication link, and The data unit is transmitted to the radio network infrastructure equipment using the selected sidelink communication link or the selected direct communication link.

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