Multi-path communication for user equipment in centralized unit and distributed unit splitting architectures

Abstract

Systems, methods, apparatus, or computer-readable media for multipath communication are presented. A centralized unit (CU) may send multipath configuration information to a distributed unit (DU). The CU may receive multipath configuration response information from the DU.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, including but not limited to systems and methods for multipath transmission and reception for user equipment (UE) in a centralized unit (CU) and distributed unit (DU) split architecture. Background Art

[0002] The third generation partnership project (3GPP), a standardization organization, is currently developing a new radio interface called 5G New Radio (5G NR), as well as the next generation packet core network (NG-CN or NGC). 5G NR will have three main components: 5G access network (5G-AN), 5G core network (5GC) and user equipment (UE). To facilitate the realization of different data services and requirements, the elements of 5GC (also known as network functions) have been simplified, some of which are software-based so that they can be adapted as needed. Summary of the invention

[0003] The example embodiments disclosed herein are intended to solve problems related to one or more of the problems raised in the prior art, as well as to provide additional features that will become clear by reference to the following detailed description when taken in conjunction with the accompanying drawings. According to various embodiments, example systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are presented by way of example, not limitation, and it will be clear to those of ordinary skill in the art who read this disclosure that various modifications may be made to the disclosed embodiments while remaining within the scope of this disclosure.

[0004] At least one aspect relates to a system, method, apparatus, or computer-readable medium for multipath communication. A centralized unit (CU) may send multipath configuration information to a distributed unit (DU). The CU may receive multipath configuration response information from the DU. In some embodiments, the multipath configuration information may include path indication information identifying at least one of a direct path or an indirect path.

[0005] In some embodiments, the multipath configuration information includes mapping information, which may identify: an association between an F1-U tunnel for a data radio bearer (DRB) of a remote wireless communication device and a Uu radio link control (RLC) channel for a relay wireless communication device; or an association between an F1-U tunnel for a data radio bearer (DRB) of an anchor wireless communication device and a Uu radio link control (RLC) channel for an aggregated wireless communication device.

[0006] In some embodiments, the multipath configuration information includes mapping information, which may identify: an association between a signaling radio bearer (SRB) for a remote wireless communication device and a Uu radio link control (RLC) channel for a relay wireless communication device; or an association between a signaling radio bearer (SRB) for an anchor wireless communication device and a Uu radio link control (RLC) channel for an aggregated wireless communication device.

[0007] In some embodiments, the multipath configuration information may include at least one of the following: an identifier of a radio bearer (RB), uplink (UL) user plane (UP) tunnel (TNL) information, an identifier for a relay wireless communication device, an identifier for an aggregated wireless communication device, an identifier for a Uu radio link control (RLC) channel, an identifier for a path, an indication of a direct path or an indirect path, an indication of a primary path or a secondary path, an indication of data splitting or data duplication, or a path activation indication.

[0008] In some embodiments, the identifier of the RB may be at least one of an identifier of a DRB or an SRB. In some embodiments, the multipath configuration information with mapping information may be used by the DU to avoid establishing an RLC channel of a relay wireless communication device or an anchor wireless communication device for a DRB. In some embodiments, the multipath configuration information with an indirect path indication may be used by the DU to avoid establishing an RLC channel of a relay wireless communication device or an anchor wireless communication device for a DRB or an SRB.

[0009] In some embodiments, the multipath configuration information may be used by the DU to configure a first RLC channel of the relay wireless communication device or the anchor wireless communication device for a direct path of a DRB or SRB. In some embodiments, the multipath configuration information may include a path activation indication that identifies a path as active or inactive. In some embodiments, the indication of data splitting may include at least one of a data splitting threshold or a data splitting ratio.

[0010] In some embodiments, the multipath configuration information with data splitting may indicate distribution of multiple data packets over a first RLC channel corresponding to a direct path and a second RLC channel corresponding to an indirect path. In some embodiments, the multipath configuration information may identify a DRB for multiple F1 user plane tunnels between a CU and a DU.

[0011] In some embodiments, the multipath configuration information may include uplink (UL) user plane (UP) tunnel (TNL) information for at least one of a direct path or an indirect path. In some embodiments, the multipath configuration information may include two or more UL UP TNL information for splitting DRBs.

[0012] In some embodiments, the multipath configuration response information may indicate at least one of acceptance or failure of a path. In some embodiments, the multipath configuration response information may include an identifier for the path, or an indication of a direct path or an indirect path, or an indication of a primary path or a secondary path that is accepted or rejected. In some embodiments, the multipath configuration response information may identify one of a reason for failure of a path, or non-acceptance of data packet delivery, or an identifier for a non-accepted path.

[0013] In some embodiments, the multipath configuration response information may indicate a failure of a multipath SRB or DRB establishment, or a failure of a multipath SRB or DRB modification. In some embodiments, the multipath configuration response information may include downlink (DL) user plane (UP) tunnel (TNL) information for the accepted path. In some embodiments, the multipath configuration information may include at least one of the following: a multipath establishment request, a multipath modification request, or a multipath release request. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Various example embodiments of the present solution are described in detail below with reference to the following drawings or figures. The drawings are provided for illustrative purposes only and depict only example embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be considered as limiting the breadth, scope or applicability of the present solution. It should be noted that for clarity and ease of description, these drawings are not necessarily drawn to scale.

[0015] Figure 1 illustrates an example cellular communication network in which the techniques disclosed herein may be implemented according to embodiments of the present disclosure;

[0016] Figure 2 illustrates a block diagram of example base station and user equipment apparatus according to some embodiments of the present disclosure;

[0017] Figure 3 illustrates a block diagram of a user equipment (UE) to network relay in accordance with an illustrative embodiment;

[0018] Figure 4 illustrates a block diagram of user equipment (UE) aggregation in accordance with an illustrative embodiment;

[0019] Figure 5A illustrates a block diagram of a multipath configuration within a distributed unit (DU) according to an illustrative embodiment;

[0020] Figure 5B illustrates a block diagram of a multipath configuration between distributed units (DUs) according to an illustrative embodiment;

[0021] Figure 6illustrates a communication diagram of a multipath configuration for different radio bearers (RBs) and multiple distributed units (DUs) in accordance with an illustrative embodiment;

[0022] Figure 7 illustrates a communication diagram for a multipath configuration for split bearers and multiple distributed units (DUs) in accordance with an illustrative embodiment;

[0023] Figure 8 illustrates a communication diagram of a multipath configuration for different radio bearers (RBs) and a single distributed unit (DU) in accordance with an illustrative embodiment;

[0024] Fig. 9 illustrates a communication diagram for a multipath configuration for split bearers under the same centralized unit (CU) and distributed unit (DU) according to an illustrative embodiment;

[0025] Fig.10 illustrates a communication diagram of a multipath configuration for split bearers under the same centralized unit (CU) and distributed unit (DU) for data splitting according to an illustrative embodiment;

[0026] Fig.11 A communication diagram illustrating a multipath signaling radio bearer (SRB) configuration under the same centralized unit (CU) and distributed unit (DU) for data splitting or replication according to an illustrative embodiment; and

[0027] Fig.12 A flow chart of a method for multipath communication is illustrated in accordance with an illustrative embodiment. DETAILED DESCRIPTION

[0028] Various example embodiments of the present solution are described below with reference to the accompanying drawings so that a person of ordinary skill in the art can make and use the present solution. As is clear to a person of ordinary skill in the art, after reading the present disclosure, various changes or modifications may be made to the examples described herein without departing from the scope of the present solution. Therefore, the present solution is not limited to the example embodiments and applications described and illustrated herein. In addition, the specific order or hierarchy of steps in the methods disclosed herein are merely example methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes may be rearranged while remaining within the scope of the present solution. Therefore, a person of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or actions in an example order, and unless otherwise expressly stated, the present solution is not limited to the specific order or hierarchy presented.

[0029] 1. Mobile communication technology and environment

[0030] Figure 1An example wireless communication network and / or system 100 is illustrated in which the techniques disclosed herein may be implemented in accordance with an embodiment of the present disclosure. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as "network 100." Such an example network 100 includes a base station 102 (hereinafter referred to as "BS 102"; also referred to as a wireless communication node) and a user equipment device 104 (hereinafter referred to as "UE 104"; also referred to as a wireless communication device) that may communicate with each other via a communication link 110 (e.g., a wireless communication channel), and a cluster of cells 126, 130, 132, 134, 136, 138, and 140 covering a geographic area 101. Figure 1 1, BS 102 and UE 104 are contained within respective geographic boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating within its allocated bandwidth to provide adequate radio coverage to its intended users.

[0031] For example, BS 102 may operate with the allocated channel transmission bandwidth to provide sufficient coverage to UE 104. BS 102 and UE 104 may communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 may be further divided into subframes 120 / 127, which may include data symbols 122 / 128. In the present disclosure, BS 102 and UE 104 are described herein as non-limiting examples of "communication nodes", which may generally practice the methods disclosed herein. According to various embodiments of the present solution, such communication nodes may be capable of wireless and / or wired communication.

[0032] Figure 2 A block diagram of an example wireless communication system 200 for sending and receiving wireless communication signals (e.g., OFDM / OFDMA signals) according to some embodiments of the present solution is illustrated. The system 200 may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In an illustrative embodiment, the system 200 may be used in applications such as Figure 1 The data symbols are communicated (eg, sent and received) in a wireless communication environment such as the wireless communication environment 100 of FIG. 1 , as described above.

[0033] System 200 generally includes a base station 202 (hereinafter referred to as "BS 202") and a user equipment device 204 (hereinafter referred to as "UE 204"). BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled to and interconnected with each other via a data communication bus 220 as needed. UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled to and interconnected with each other via a data communication bus 240 as needed. BS 202 communicates with UE 204 via a communication channel 250, which can be any wireless channel or other medium suitable for data transmission as described herein.

[0034] As will be appreciated by those skilled in the art, the system 200 may also include Figure 2 Any number of other modules outside the modules shown. It will be appreciated by those skilled in the art that the various illustrative blocks, modules, circuits, and processing logic described in conjunction with the embodiments disclosed herein can be implemented in hardware, computer-readable software, firmware, or any actual combination thereof. In order to clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps are generally described according to their functions. Whether such functions are implemented as hardware, firmware, or software may depend on specific applications and design constraints imposed on the entire system. People familiar with the concepts described herein can implement such functions in a suitable manner for each specific application, but such implementation decisions should not be interpreted as limiting the scope of the present disclosure.

[0035] According to some embodiments, the UE transceiver 230 may be referred to herein as an "uplink" transceiver 230, which includes a radio frequency (RF) transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in a time duplex manner. Similarly, according to some embodiments, the BS transceiver 210 may be referred to herein as a "downlink" transceiver 210, which includes an RF transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 212. The downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in a time duplex manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that the uplink receiver circuitry is coupled to the uplink antenna 232 for reception of transmissions over the wireless transmission link 250 while the downlink transmitter is coupled to the downlink antenna 212. Conversely, the operation of the two transceivers 210 and 230 may be coordinated in time such that the downlink receiver is coupled to the downlink antenna 212 for reception of transmissions over the wireless transmission link 250 while the uplink transmitter is coupled to the uplink antenna 232. In some embodiments, there is tight time synchronization with minimal guard times between changes in duplex direction.

[0036] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250, and to cooperate with an appropriately configured RF antenna arrangement 212 / 232 capable of supporting a specific wireless communication protocol and modulation scheme. In some illustrative embodiments, the UE transceiver 230 and the base station transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it should be understood that the present disclosure is not necessarily limited to application to specific standards and related protocols. Instead, the UE transceiver 230 and the base station transceiver 210 can be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0037] According to various embodiments, for example, BS 202 may be an evolved Node B (eNB), a gNB, a serving eNB, a target eNB, a femtocell or a microcell. In some embodiments, UE 204 may be embodied in various types of user equipment, such as a mobile phone, a smart phone, a personal digital assistant (PDA), a tablet, a laptop computer, a wearable computing device, etc. Processor modules 214 and 236 may be implemented or implemented with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof designed to perform the functions described herein. In this manner, the processor may be implemented as a microprocessor, a controller, a microcontroller, a state machine, etc. The processor may also be implemented as a combination of computing devices, for example, a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a digital signal processor core, or any other such configuration.

[0038] In addition, the steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be directly embodied in hardware, in firmware, in software modules executed by the processor modules 214 and 236, respectively, or in any practical combination thereof. The memory modules 216 and 234 may be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. In this regard, the memory modules 216 and 234 may be coupled to the processor modules 210 and 230, respectively, so that the processor modules 210 and 230 may read information from and write information to the memory modules 216 and 234, respectively. The memory modules 216 and 234 may also be integrated into their respective processor modules 210 and 230. In some embodiments, the memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during the execution of instructions to be executed by the processor modules 210 and 230, respectively. Memory modules 216 and 234 may also each include non-volatile memory for storing instructions to be executed by processor modules 210 and 230, respectively.

[0039] The network communication module 218 generally represents the hardware, software, firmware, processing logic and / or other components of the base station 202, which are used to enable two-way communication between the base station transceiver 210 and other network components and communication nodes configured to communicate with the base station 202. For example, the network communication module 218 can be configured to support Internet or WiMAX services. In a typical deployment, without limitation, the network communication module 218 provides an 802.3 Ethernet interface so that the base station transceiver 210 can communicate with a conventional Ethernet-based computer network. In this way, the network communication module 218 may include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). The terms "configured for", "configured to" and variations thereof as used herein with respect to a specified operation or function refer to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted and / or arranged to perform a specified operation or function.

[0040] The open systems interconnection (OSI) model (referred to herein as the "open systems interconnection model") is a concept and logical layout that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) that are open to interconnect and communicate with other systems. The model is divided into seven subcomponents or layers, each of which represents a conceptual set of services provided to the layers above and below it. The OSI model also defines a logical network and effectively describes computer packet transmission by using different layer protocols. The OSI model may also be referred to as a seven-layer OSI model or a seven-layer model. In some embodiments, the first layer may be a physical layer. In some embodiments, the second layer may be a media access control (MAC) layer. In some embodiments, the third layer may be a radio link control (RLC) layer. In some embodiments, the fourth layer may be a packet data convergence protocol (PDCP) layer. In some embodiments, the fifth layer may be a radio resource control (RRC) layer. In some embodiments, the sixth layer may be a non-access stratum (NAS) layer or an Internet protocol (IP) layer, and the seventh layer is another layer.

[0041] 2. Multipath communication for user equipment (UE) in a centralized unit (CU) and distributed unit (DU) split architecture

[0042] This paper proposes a system and method for multipath transmission and reception of UE in a CU / DU split architecture, focusing on data splitting, data replication on multipaths, and path switching between direct and indirect paths.

[0043] With the development of wireless multimedia services, the demand for high data rate services may increase significantly. In this case, the system capacity and coverage requirements of conventional cellular networks may become higher. On the other hand, due to application scenarios such as public safety, social networks, short-range data sharing, and local content placement, the demand for proximity services that allow users to confirm nearby users or objects or communicate with nearby users or objects may also increase.

[0044] However, cellular networks may have limitations in supporting high data rate services and proximity services. Therefore, device-to-device (D2D) communication technology may be proposed to meet such needs. By adopting D2D technology, the burden on cellular networks can be reduced, the power consumption of user equipment can be reduced, the data rate can be increased, and the robustness of the network infrastructure can be improved. Therefore, the needs of high data rate services and proximity services can be met. D2D technology can also be called proximity service (ProSe) or sidelink communication, and the interface between devices can be a PC5 interface.

[0045] In order to support applications and services with a wider range, sidelink-based relay communication can be used to extend coverage and reduce network power consumption. For example, sidelink-based relay communication can be applied to indoor relay communication, smart agriculture, smart factories, and public safety services. Figure 3 , depicts a block diagram of a user equipment (UE) to network relay. As shown, a scenario of sidelink-based relay communication may involve a user equipment (UE) in an area with weak coverage or no coverage (e.g., Figure 3 In this case, UE1 may be allowed to communicate with the network via a nearby UE2 covered by the network (e.g., Figure 3 The UE2 may communicate with the base station (BS) shown in the figure. Therefore, the coverage of the network can be extended and the capacity of the network is enlarged. In this case, UE2 may be referred to as a UE-to-network relay, and UE1 may be referred to as a remote UE. On the other hand, if the remote UE is within the coverage, multipath relaying may be supported. Within the coverage, the remote UE may be connected to the network via both a direct path (e.g., data sent directly between the remote UE and the network) and an indirect path (e.g., data forwarded via a relay UE). This is likely to improve reliability and robustness as well as throughput.

[0046] This multipath relay approach can also be used for UE aggregation, where a UE is connected to the network via a direct path and via another UE using non-standardized UE-UE interconnection. Figure 4 A block diagram of user equipment (UE) aggregation is illustrated. As shown, UE aggregation may involve a user equipment (UE) (e.g., Figure 4 UE1 shown), which aggregates other UEs (e.g., Figure 4 UE2 and UE3 shown) for their uplink (UL) transmission or downlink reception from the network. Here, the interconnection between UE1 and UE2, or between UE1 and UE3, can be based on a side link, WiFi, Bluetooth, or a wired connection. In addition, the interconnection between UEs can be an ideal connection. In the case where normal UEs are limited by the UL UE transmission power and cannot achieve the desired bit rate, especially at the cell edge, UE aggregation can be intended to provide applications that require high UL bit rates on 5G terminals. In addition, UE aggregation can also improve the reliability and stability of services and reduce delays.

[0047] As 5G mobile wireless technology develops, one technique that may be used may include a split network architecture in which the radio access network (RAN) functionality is split between a central unit (CU) and multiple distributed units (DUs). For example, the RAN functionality may be split between the packet data convergence protocol (PDCP) layer and the radio link control (RLC) layer of the 5G protocol stack. In this stack, the DU may handle all processes, including the RLC layer functionality, and the CU may handle the PDCP layer and higher layer functionality before the core network. This decomposition of RAN functionality may provide many advantages to mobile network operators. For example, by isolating the stack from the PDCP layer and above, the CU may be able to act as a cloud-based aggregation point between multiple heterogeneous technologies in the configured network, and may therefore be able to serve multiple heterogeneous DUs.

[0048] To support multipath UE-to-network relay and UE aggregation, the impact on the CU / DU split architecture can be used to focus on multipath support for multipath configuration and path switching (e.g., a direct path via the UE and an indirect path via the UE to the network relay or aggregated UE). Under UE multipath transmission, the UL transmission (Tx) capability of the UE may be limited, and one UE may be associated with many UEs for UE aggregation, or connected to many relay UEs for UE-to-network relay. In order to support higher requirements for UL services, including data rate, latency, and reliability, multipath transmission can be used. The UE can be connected to the network and perform data service transmission or reception with the network via a direct path and via one or more indirect paths (e.g., data services forwarded by another UE). UE-UE interconnection can be based on a side link connection or use a non-standardized connection.

[0049] Figure 5A A block diagram of a multipath configuration within a distributed unit (DU) is illustrated, and Figure 5BA block diagram of a multipath configuration between distribution units (DUs) is illustrated. For UEs connected to the same gNB using one direct path and one indirect path, the direct path and the indirect path may be via the same DU or different DUs. UE1 may be a remote UE or a service originating UE or an anchor UE, and UE2 may be a relay UE or an aggregation UE. UE1 and UE2 may be interconnected via PC5 or an internal interface. UE1 and UE2 may be connected by the same DU (e.g., Figure 5A ) or different DUs (e.g. Figure 5B To support multipath scenarios under CU-DU split architecture, the following issues can be examined and potential solutions are discussed below.

[0050] A. Distributed Unit (DU) Solution

[0051] In one scenario, UE1 and UE2 may be served by different DUs. This article discusses the multipath transmission configuration of UE1 between the CU and the DU.

[0052] I. Multipath Configuration for Different Radio Bearers (RB) and Multiple Distributed Units (DU)

[0053] UE1 and UE2 are served by different DUs for multipath delivery of UE1 traffic. UE1's Quality of Service (QoS) flow can be mapped to two bearers, namely, data radio bearers DRB1 and DRB2. DRB1 can be delivered via a direct path, while DRB2 can be delivered via an indirect path (forwarded by UE2). DRB1 and DRB2 can share the same Service Data Adaptation Protocol (SDAP) entity, while separate PDCP entities can be established for DRB1 and DRB2.

[0054] Reference now Figure 6 , depicting a communication diagram of a multipath configuration of different radio bearers (RBs) and multiple distributed units (DUs). The CU may request DU1 to establish DRB1 and send a direct path indication via a UE context modification request. In addition, uplink (UL) user plane (UP) tunnel (TNL) information may be included in the UE context modification request. After receiving the DRB1 establishment request, if the UL UP TNL information element (IE) is included in the UE context modification request message for DRB1, the gNB-DU may include a downlink (DL) user plane (UP) tunnel (TNL) information IE in the UE context modification response message, and may establish one radio link control (RLC) entity for DRB1 using the direct path indication.

[0055] Regarding DRB2, relevant data packets can be delivered via the relay of UE2, so it is necessary to establish a Uu RLC channel between DU2 and UE2. As shown in the figure, the CU can request DU2 to establish a Uu RLC channel via UE2-specific F1AP signaling. The CU can request DU2 to establish DRB2 via UE1-specific F1AP signaling. The CU also sends an indirect path indication, UL UP TNL information, or mapping information between the F1-U tunnel of DRB2 and the Uu RLC channel of the relay UE2 to DU2. The mapping information may include any combination of the following fields: data radio bearer identifier (DRB ID), relay UE ID or aggregated UEID, Uu RLC channel ID.

[0056] After receiving the DRB2 setup request, if the UL UP TNL information IE is included in the UE context setup request message for DRB2, the gNB-DU may include the DL UP TNL information IE in the UE context setup response message. However, since the DRB indicates an indirect path, or a mapping between the F1-U tunnel of DRB2 and the Uu RLC channel is configured, DU2 may not establish an additional RLC channel with UE1 for DRB2. DU2 may send a response message with the established DRB2 ID and a logical channel identifier (LCID) to the CU.

[0057] After the configuration based on F1AP, the CU may send an RRC reconfiguration message including the configuration or path indication of DRB1 and DRB2 to UE1. In addition, the CU may send an RRC reconfiguration message including the configuration of the Uu RLC channel or the mapping information between the Uu RLC channel and the DRB of UE1 to UE2.

[0058] Afterwards, when DU2 receives a data packet from CU via the F1-U tunnel corresponding to DRB2, DU2 may map the packet to the Uu RLC channel with UE2 and deliver the data packet to UE2. After receiving the data packet, UE2 may forward the packet to UE1 via an internal connection or via a PC5 RLC channel.

[0059] II. Multipath Configuration for Split Bearer and Multiple Distributed Units (DUs)

[0060] Reference now Figure 7, depicts a communication diagram for a split bearer and a multipath configuration for multiple distributed units (DUs). Some QoS flows of UE1 may be mapped to DRB3, and DRB3 may be configured as a split bearer that will be delivered via both a direct path and an indirect path. In this case, the CU may request DU1 and DU2 to establish DRB3, respectively. Two F1-U tunnels corresponding to DU1 and DU2 may be established for DRB3. For DL ​​packets, the PDCP entity at the CU may be responsible for data splitting and deliver the split packets to the corresponding F1-U tunnels. In this way, DU1 and DU2 may receive packets to be delivered to UE1 via a direct path and an indirect path, respectively.

[0061] Taking DU2 as an example, the CU may request DU2 to establish DRB3 via UE1-specific F1AP signaling. The CU may also send an indirect path indication, UL UP TNL information, or mapping information between the F1-U tunnel of DRB3 and the Uu RLC channel of UE2 to DU2. The mapping information may include any combination of the following fields: DRBID, relay UE ID or aggregated UE ID, Uu RLC channel ID. After receiving the DRB3 establishment request, if the UE context establishment request message for DRB3 includes the UL UP TNL information IE, the gNB-DU may include the DL UP TNL information IE in the UE context establishment response message. Since the DRB indicates that the indirect path or the mapping between the F1-U tunnel of DRB3 and the Uu RLC channel is configured, DU2 may not establish an additional RLC channel with UE1 for DRB3. DU2 may send a response message with the established DRB3 ID and LCID to the CU.

[0062] After the configuration based on F1AP, the CU may send an RRC reconfiguration message including the configuration of DRB3, data splitting rules, or indirect path mapping information to UE1. In addition, the CU may send an RRC reconfiguration message including the configuration of the Uu RLC channel, or the mapping information between the Uu RLC channel of UE2 and the DRB of UE1 to UE2.

[0063] When DU2 receives a DL packet from the F1-U tunnel corresponding to DRB3, DU2 can detect that the packet from the F1-U tunnel will be mapped to the Uu RLC channel with UE2 (relay UE or aggregation UE). Then, DU2 can add an adaptation layer header and deliver the packet to the Uu RLC channel with UE2 and send it to UE2. When UE2 receives a data packet from the Uu RLC channel, UE 2 can check the adaptation layer header and then forward the packet to UE1 via the PC5 interface or internal connection.

[0064] For UL packets, the PDCP entity at UE1 can perform data splitting based on the splitting rules configured by the CU, and deliver packets to Uu via its own RLC channel (direct path), or to UE2 via the PC5 interface or internal connection (indirect path). When UE2 receives a data packet from UE1, UE2 can detect the corresponding source UE and RB ID, then map the packet to the UuRLC channel, and deliver the packet to DU2. DU2 can identify the source UE ID and radio bearer (RB) ID in the adaptation layer header, and detect that it is a packet for DRB3 of UE1. Then, DU2 can forward the packet to CU via the F1-U tunnel corresponding to DRB3 of UE1. Data packets sent via an indirect path may include an adaptation layer header (ie, including UEID and RB ID). This can be encapsulated by UE1 or UE2. For an indirect path between UE1 and UE2 via an internal connection or PC5 connection, UE2 can be configured with a mapping between UE1's DRB ID and UE2's Uu RLC channel ID. DU2 can also forward packets to CU via the F1-U tunnel. The PDCP entity of DRB3 located at the CU can perform PDCP PDU decryption, decompression and reordering.

[0065] III. Multipath Configuration for Packet Data Convergence Protocol (PDCP) Replication

[0066] Some QoS flows of UE1 may be mapped to DRB4. DRB4 may be configured for PDCP duplication, and packets may be delivered via both a direct path and an indirect path. In this case, the CU may request DU1 and DU2 to establish DRB4 respectively. Two F1-U tunnels corresponding to DU1 and DU2 may be established for DRB4. For DL ​​packets, the PDCP entity at the CU may be responsible for data duplication and deliver the duplicated packets to the corresponding F1-U tunnel. In this way, DU1 and DU2 may receive packets to be delivered to UE1 via a direct path and an indirect path respectively.

[0067] Taking DU2 as an example, the CU may request DU2 to establish DRB4 via UE1-specific F1AP signaling. The CU may also send a primary path or secondary path indication, configured multipath replication, multipath replication activation, UL UP TNL information, or mapping information between the F1-U tunnel of DRB4 and the Uu RLC channel of UE2 to DU2. Among them, multipath replication activation may be configured as active or inactive. The mapping information may include any combination of the following fields: DRBID, relay UE ID or aggregated UE ID, Uu RLC channel ID. After receiving the DRB4 establishment request, if the UL UP TNL information IE is included in the UE context establishment request message of DRB4, the gNB-DU may include the DL UP TNL information IE in the UE context establishment response message. Since the mapping between the F1-U tunnel of DRB4 and the Uu RLC channel is configured, DU2 may not establish an additional RLC channel with UE1 for DRB4. DU2 may send a response message with the established DRB4 ID and LCID to the CU.

[0068] After the configuration based on F1AP, the CU may send an RRC reconfiguration message including the configuration of DRB4, data replication indication, or indirect path mapping information to UE1. In addition, the CU may send an RRC reconfiguration message including the configuration of the Uu RLC channel, or the mapping information between the Uu RLC channel and the DRB of UE1 to UE2. If DU2 receives multipath replication activation as inactive, the replicated packets received from the corresponding F1-U tunnel may be discarded.

[0069] When DU2 receives a DL packet from the F1-U tunnel corresponding to DRB4, DU2 can detect that the packet from the F1-U tunnel will be mapped to the Uu RLC channel with UE2 (relay UE or aggregated UE). Then, DU2 can add an adaptation layer header and deliver the packet to the Uu RLC channel with UE2 and send it to UE2. When UE2 receives a data packet from the Uu RLC channel, DU2 can check the adaptation layer header and then forward the packet to UE1 via the PC5 interface or internal connection.

[0070] For UL, UE1 can duplicate the data packets of DRB4 and deliver the packets to DU1 and UE2 respectively. When UE2 receives the data packet from UE1, DU2 can detect the corresponding source UE and RB ID, then map the packet to the Uu RLC channel, and deliver the packet to DU2. DU2 can also forward the packet to the CU via the F1-U tunnel. The PDCP entity of DRB4 at the CU can perform PDCP PDU decryption, decompression, reordering, and duplicate packet discard.

[0071] For UL packets, the PDCP entity at UE1 may perform data replication and deliver the packet to Uu via its own RLC channel (e.g., via a direct path), or to UE2 via a PC5 interface or internal connection (e.g., via an indirect path). When UE2 receives a data packet from UE1, UE2 may detect the corresponding source UE and RB ID. UE2 may then map the packet to the Uu RLC channel and deliver the packet to DU2. DU2 identifies the source UE ID and RB ID in the adaptation layer header and detects that the packet is a packet of DRB4 of UE1. DU2 may then forward the packet to the CU via the F1-U tunnel corresponding to DRB4 of UE1. The data packet sent via the indirect path may include an adaptation layer header (e.g., including UE ID and RB ID). This may be encapsulated by UE1 or UE2. DU2 may also forward the packet to the CU via the F1-U tunnel. UE2 may be configured by the gNB with a mapping between the UE1 DRBID and the Uu RLC channel of UE2. The PDCP entity of DRB4 located at the CU can perform PDCP PDU decryption, decompression and reordering. B. Scenario within the distributed unit (DU)

[0072] UE1 and UE2 may be served by the same DU, and the multipath delivery of UE1 traffic discussed herein is the multipath transmission configuration of the UE between the CU and the DU.

[0073] I. Multipath Configuration for Different Radio Bearers (RB) in the Same Distributed Unit (DU)

[0074] UE1 and UE2 are served by the same DU. For multipath delivery of UE1 services, the following scenarios can be considered. UE1's QoS flow can be mapped to two bearers, DRB1 and DRB2. DRB1 can be delivered via a direct path, while DRB2 can be delivered via an indirect path (forwarded by UE2). DRB1 and DRB2 can share the same SDAP entity, while separate PDCP entities are established for DRB1 and DRB2.

[0075] Reference now Figure 8 , depicting a communication diagram of a multipath configuration of different radio bearers (RBs) and a single distributed unit (DU). As shown, the CU may request DU1 to establish DRB1 via a UE context modification request. In addition, UL UP TNL information may be included in the UE context modification request. After receiving the DRB1 establishment request, if the UE context modification request message for DRB1 includes the UL UP TNL information IE, DU1 may include the DL UP TNL information IE in the UE context modification response message and establish an RLC entity for DRB1.

[0076] Regarding DRB2, relevant data packets can be delivered via the relay of UE2, so it is necessary to establish a Uu RLC channel between DU1 and UE2. The CU can request DU1 to establish a Uu RLC channel via UE2-specific F1AP signaling. The CU can request DU1 to establish DRB2 via UE1-specific F1AP signaling. The CU can also send UL UP TNL information and mapping information between the F1-U tunnel of DRB2 and the Uu RLC channel of UE2 to DU1. The mapping information may include any combination of the following fields: DRB ID, relay UE ID or aggregated UE ID, Uu RLC channel ID. After receiving the DRB2 establishment request, if the UL UP TNL information IE is included in the UE context establishment request message of DRB2, DU1 may include the DL UP TNL information IE in the UE context establishment response message. Since the mapping between the F1-U tunnel of DRB2 and the Uu RLC channel is configured, DU1 may not establish an additional RLC channel with UE1 for DRB2. Instead, the Uu RLC channel of UE2 may be used for the delivery of data packets of DRB2.DU2 may send a response message with the established DRB2 ID and LCID to CU.

[0077] After the configuration based on F1AP, the CU may send an RRC reconfiguration message including the configuration or path indication of DRB1 and DRB2 to UE1. In addition, the CU may send an RRC reconfiguration message including the configuration of the Uu RLC channel or the mapping information between the Uu RLC channel and the DRB of UE1 to UE2.

[0078] Afterwards, when DU1 receives a data packet from CU via the F1-U tunnel corresponding to DRB2, DU1 may map the packet to the Uu RLC channel with UE2 and deliver the data packet to UE2. After receiving the data packet, UE2 may forward the packet to UE1 via an internal connection or via a PC5 RLC channel.

[0079] II. Multipath Splitting Bearer Configuration under the Same DU and CU for Data Splitting

[0080] Some QoS flows of UE1 may be mapped to DRB3, and DRB3 is configured as a split bearer to be delivered via both direct and indirect paths. In this case, CU may request DU1 to establish DRB3. Fig. 9, depicts a communication diagram for a multipath configuration for split bearers under the same centralized unit (CU) and distributed unit (DU). Two F1-U tunnels corresponding to the direct path and the indirect path for DRB3 can be established. For DL ​​packets, the PDCP entity at the CU can be responsible for data splitting and deliver the split packets to the corresponding F1-U tunnels. In this way, DU1 can receive split packets from different F1-U tunnels and then deliver them to UE1 via the direct path and the indirect path, respectively.

[0081] Since the data packets of DRB3 will be delivered via the relay (indirect path) of UE2, a Uu RLC channel can be established between DU1 and UE2. As shown in the figure, the CU can request DU1 to establish a Uu RLC channel via UE2-specific F1AP signaling. Then, the CU can request DU1 to establish DRB3 via UE1-specific F1AP signaling. The CU can also send a set of path information to DU1, which may include at least one of the following information: path ID, direct path or indirect path indication, primary path or secondary path indication, UL UP TNL information, or mapping information between the F1-U tunnel of DRB3 and the Uu RLC channel of UE2. The mapping information may include any combination of the following fields: DRB ID or UL UP TNL information, relay UE ID or aggregate UE ID, Uu RLC channel ID.

[0082] More than one UL UP TNL information may be included. One information may be for a direct path and the other information may be for an indirect path. Alternatively, one standard UL UP TNL information may be sent by the CU to DU1, and one or more additional UL UP TNLs for data splitting may be sent by the CU to DU1. In addition, the CU may also include a primary path or secondary path indication to DU1. For example, the CU may indicate to DU1 that the indirect path (or one of the F1-U tunnels) is the primary path and the direct path (another F1-U tunnel) is the secondary path, or vice versa.

[0083] After receiving the DRB3 Setup Request, DU1 may configure an RLC entity or logical channel for the direct path of DRB3. For the indirect path, DU1 may not establish an additional RLC channel with UE1 for DRB3. Instead, the UuRLC channel with UE2 may be used for DRB3 delivery. DU1 may send a response message with the established DRB3 ID and LCID to the CU. After receiving the DRB3 Setup Request, if the UL UP TNL Information IE is included in the UE Context Setup Request message for DRB3, the gNB-DU may include the DL UP TNL Information IE in the UE Context Setup Response message.

[0084] If DU1 can accept one of the data packet delivery paths, DU1 can send a response to the CU to indicate which path is accepted. For example, DU1 can send a response to the CU to indicate that the direct path or the indirect path or both are accepted. Alternatively, DU1 can send a response to the CU to indicate that the primary path or the secondary path or both are accepted. DU1 can also send the accepted (multiple) path IDs or the rejected path IDs to the CU. In addition, the response message sent by DU1 to the CU may include one or more corresponding DL UP TNL information. Alternatively, if DU1 can accept one of the data packet delivery paths, DU1 can send a response to the CU to indicate that the DRB establishment failed. In addition, DU1 can send a path id to the CU indicating that the reason for the failure is that one of the data packet delivery paths is not accepted or is not accepted.

[0085] After the configuration based on F1AP, the CU may send an RRC reconfiguration message including the configuration of DRB3, data splitting rules, or indirect path mapping information UE1. In addition, the CU may send an RRC reconfiguration message including the configuration of the Uu RLC channel, or the mapping information between the Uu RLC channel and the DRB of UE1 to UE2. Afterwards, the data packets of DRB3 may be delivered via both the direct path and the indirect path between UE1 and DU / CU.

[0086] III. Multipath Configuration for Splitting Bearers under the Same Centralized Unit (CU) and Distributed Unit (DU) for Data Splitting

[0087] Some QoS flows of UE1 may be mapped to DRB3, and DRB3 may be configured as a split bearer to be delivered via both direct and indirect paths. In this case, CU may request DU1 to establish DRB3. Compared with the case of the above-mentioned multipath split bearer configuration, in this case, there may be an F1-U tunnel between DU1 and CU for DRB3. CU may send data splitting rules to DU1, and DU1 may be responsible for data splitting and deliver the split packets to the corresponding RLC channel.

[0088] Since the data packets of DRB3 will be delivered via the relay of UE2 (indirect path), a Uu RLC channel can be established between DU1 and UE2. Fig.10 , depicts a communication diagram of a multipath configuration for split bearers under the same centralized unit (CU) and distributed unit (DU) for data splitting. As shown in the figure, the CU can request DU1 to establish a Uu RLC channel via UE2 specific F1AP signaling.

[0089] The CU may then request DU1 to establish DRB3 via UE1-specific F1AP signaling. The CU may also send data splitting rules and a set of path information for DRB3, which may include at least one of the following information: path ID, direct path or indirect path indication, primary path or secondary path indication, or mapping information. The data splitting rules may include a threshold for data splitting or a data splitting ratio between path sets. The mapping information may include any combination of the following fields: DRBID, relay UE ID or aggregate UE ID, or Uu RLC channel ID, etc. A UL UP TNL information may be included in the DRB3 establishment request sent from the CU to DU1.

[0090] After receiving the DRB3 establishment request, DU1 may configure an additional RLC entity or logical channel with UE1 for a direct path for DRB3 or a path not associated with bearer mapping information. For an indirect path or a path associated with bearer mapping information, DU1 may not establish an additional RLC entity or logical channel with UE1 for DRB3. Instead, the Uu RLC channel with UE2 may be used for DRB3 delivery. DU1 may send a response message with the established DRB3 ID to the CU. After receiving the DRB3 establishment request, if the UL UP TNL information IE is included in the UE context establishment request message for DRB3, the gNB-DU may include the DL UP TNL information IE in the UE context establishment response message.

[0091] If DU1 can accept one of the data packet delivery paths, DU1 can send a response to the CU to indicate which path is accepted. For example, DU1 can send a response to the CU to indicate that the direct path, or the indirect path, or both are accepted. Alternatively, DU1 can send a response to the CU to indicate that the primary path, or the secondary path, or both are accepted. DU1 can also send the accepted (multiple) path IDs or the rejected path IDs to the CU. In addition, the response message sent by DU1 to the CU may include one or more corresponding DL UP TNL information. Alternatively, if DU1 can only accept one of the data packet delivery paths, DU1 can send a response to the CU to indicate that the DRB establishment failed. In addition, DU1 can send an indication to the CU that the reason for the failure is that one of the data packet delivery paths is not accepted, or the path id is not accepted.

[0092] After the configuration based on F1AP, the CU may send an RRC reconfiguration message including the configuration of DRB3, data splitting rules, or indirect path mapping information UE1. In addition, the CU may send an RRC reconfiguration message including the configuration of the Uu RLC channel, or the mapping information between the Uu RLC channel and the DRB of UE1 to UE2. Afterwards, the data packets of DRB3 may be delivered via both the direct path and the indirect path between UE1 and DU / CU.

[0093] When DU1 receives a DL packet from the F1-U tunnel corresponding to DRB3, DU1 can detect that the packet from the F1-U tunnel will be split into a direct path and an indirect path. The direct path can be configured as the primary path, and the indirect path can be configured as the secondary path, and the threshold for data splitting can be configured. In this case, when the data buffer size of DRB3 is lower than the threshold for data splitting, DU1 can send data packets to the direct path. Otherwise, DU1 can send packets to the direct path or the indirect path. Alternatively, if the data splitting ratio is configured at DU1, DU1 can distribute the data packets to the RLC channel corresponding to the direct path or the indirect path based on the data splitting ratio.

[0094] For UL packets, the PDCP entity at UE1 can perform data splitting based on the splitting rules configured by the CU, and deliver the packet to Uu via its own RLC entity or logical channel (e.g., via a direct path), or to UE2 via a PC5 interface or internal connection (e.g., via an indirect path). When UE2 receives a data packet from UE1, UE2 can detect the corresponding source UE and RB ID. UE2 can then map the packet to the Uu RLC channel and deliver the packet to DU1. DU1 identifies the source UE ID and RB ID in the adaptation layer header, and detects that the packet is a packet of DRB3 of UE1. DU1 can then forward the packet to the CU via the F1-U tunnel corresponding to DRB3 of UE1. In addition, when DU1 receives a data packet of DRB3 from UE1, DU1 can also forward the packet to the CU via the same F1-U tunnel corresponding to DRB3 of UE1. The PDCP entity of DRB3 located at the CU can perform PDCP PDU decryption, decompression, and reordering. IV. Multipath Signaling Radio Bearer (SRB) Configuration under the Same Centralized Unit (CU) and Distributed Unit (DU) for Data Splitting or Replication

[0095] SRB2 of UE1 may be configured as a duplicate or split bearer to be delivered via both direct and indirect paths. In this case, CU may request DU1 to establish SRB2. CU may send data splitting rules or duplication indications to DU1, and DU1 may be responsible for data splitting or duplication and deliver the split or duplicated packets to the corresponding RLC channel.

[0096] Since the data packets of SRB2 will be delivered via the relay of UE2 (indirect path), a Uu RLC channel can be established between DU1 and UE2. Fig.11 , depicts a communication diagram of a multipath signaling radio bearer (SRB) configuration under the same centralized unit (CU) and distributed unit (DU) for data splitting or duplication. As shown in the figure, the CU can request DU1 to establish a Uu RLC channel via UE2-specific F1AP signaling. Then, the CU can request DU1 to establish SRB2 via UE1-specific F1AP signaling. The CU can also send a data splitting rule or duplication indication for SRB2 to DU1.

[0097] In addition, the CU may send a set of path information, which may include at least one of the following information: path ID, direct path or indirect path indication, primary path or secondary path indication, or mapping information. The data splitting rule may include a threshold for data splitting or a data splitting ratio between path sets. The mapping information may include any combination of the following fields: SRB ID, relay UE ID or aggregate UE ID, Uu RLC channel ID.

[0098] After receiving the SRB2 establishment request, DU1 may configure an RLC entity or logical channel for SRB2 if a direct path is configured or a path not associated with bearer mapping information is configured. For an indirect path or a path associated with bearer mapping information, DU1 may establish an additional RLC entity or logical channel with UE1 not for SRB2. Instead, the Uu RLC channel with UE2 may be used for DRB3 delivery. DU1 may send a response message with the established SRB ID to the CU.

[0099] If DU1 can accept one of the data packet delivery paths, DU1 can send a response to the CU to indicate which path is accepted. For example, DU1 sends a response to the CU to indicate that the direct path or the indirect path or both are accepted. Alternatively, DU1 can send a response to the CU to indicate that the primary path or the secondary path or both are accepted. DU1 can also send the accepted (multiple) path IDs or the rejected path IDs to the CU. Alternatively, if DU1 cannot accept all data packet delivery paths, DU1 can send a response to the CU to indicate that the SRB establishment failed. In addition, DU1 can send an indication to the CU that the reason for the failure is that one of the data packet delivery paths is not accepted, or the path id is not accepted.

[0100] After the configuration based on F1AP, the CU may send an RRC reconfiguration message including the configuration of SRB2, data splitting rules, or indirect path mapping information UE1. In addition, the CU may send an RRC reconfiguration message including the configuration of the Uu RLC channel, or the mapping information between the Uu RLC channel and the SRB of UE1 to UE2. Afterwards, the data packets of SRB2 may be delivered via both the direct path and the indirect path between UE1 and DU / CU.

[0101] When DU1 receives the data packets of SRB2 included in the F1AP signaling to UE1, DU1 can detect that the data packets of SRB2 will be split or copied to the direct path and the indirect path. The threshold for data splitting can be configured. Through this configuration, when the data buffer size of DRB3 is lower than the threshold for data splitting, DU1 can send the data packet to the direct path. Otherwise, DU1 can send the packet to the direct path or the indirect path. Alternatively, if the data splitting ratio is configured at DU1, DU1 can distribute the data packets of SRB2 to the RLC channel corresponding to the direct path or the indirect path based on the data splitting ratio. On the other hand, if the data packets of SRB2 are configured to be copied, DU1 can perform packet copying and then distribute the copied data packets of SRB2 to the RLC entity or logical channel corresponding to the direct path or the indirect path.

[0102] When UE1 initially accesses the network via a direct path, the SRB of UE1 via the direct path can be used for signaling delivery. After a period of time, if an indirect path is configured, both the direct path and the indirect path can be used for SRB packet delivery. The CU can send DU1 to request DU1 to modify the SRB. The CU can send a list of SRBs to be modified to DU1. The list may include at least one of the following fields: SRB ID, data splitting rule or replication indication, replication activation indication, path set to be added or modified, or release information, etc.

[0103] For the path information to be added or modified, the information may include at least one of the following information: a path ID, a direct path or indirect path indication, a primary path or secondary path indication, or mapping information. For the path information to be released, the information may include a path ID, a direct path or indirect path indication, a primary path or secondary path indication. The mapping information may include any combination of the following fields: SRB ID, relay UE ID or aggregate UE ID, Uu RLC channel ID. The replication activation indication may indicate active or inactive. Based on the SRB modification request sent from the CU, DU1 may modify the corresponding SRB configuration and then perform SRB packet delivery accordingly.

[0104] V.UE aggregation multiple F1-U tunnel configuration

[0105] For the CU / DU split scenario, multiple F1-U tunnels can be established between the CU and the DU for each aggregate transmission. For example, the DRB1 service of UE1 can be delivered via the aggregation of UE1, UE2, and UE3, and an aggregation mode similar to the Dual Active Protocol Stack (DAPS) can be used. In this case, DRBs for the same QoS flow set can be configured for UE1, UE2, and UE3. Here, a DAPS-like aggregation mode can mean that a common PDCP entity responsible for PDCP sequence number (SN) allocation or PDCP reordering and duplicate discard can be established at UE1 and the CU. On the other hand, a separate PDCP entity responsible for packet encryption and decryption, or compression and decompression of UE1 can be established at UE1, UE2, UE3, and the CU. When the DU delivers data packets from these DRBs to the CU, the DU can deliver the DRBs via different F1-U tunnels so that the CU can further deliver these data packets to different PDCP entities. In this sense, for a given service source UE, multiple DRBs and corresponding F1-U tunnels can be established between the CU and the DU for DAPS-like aggregation.

[0106] For aggregation like DAPS, different GTP-U tunnels can be established between CU and DU for each aggregation path. Alternatively, F1-U can be enhanced to include path ID or UE ID and DRB ID information for CU to identify the corresponding PDCP entity for subsequent decryption and decompression processing.

[0107] On the other hand, for aggregation based on L2 SL U2N relay, one F1-U tunnel can be used regardless of how many paths are configured for data delivery of a given DRB. However, the CU can send data splitting rules to the DU so that the DU can perform data splitting and distribute the data packets to the RLC channel or logical channel of the corresponding UE. Regarding replication, the CU can also notify the DU of the aggregation-based replication of the DRB. The CU can establish two GTP-U tunnels with the DU, which correspond to the source packet and the replicated packet delivery. In this case, the UE DRB request and response to be established may include two GTP-U tunnel configurations. One configuration can be used for the source packet and the other configuration can be used for the replicated packet. In addition, the DU can be notified of the mapping between the two GTP-U tunnels and the aggregation path, the UE ID, and the RLC channel or logical channel ID.

[0108] C. Path switching

[0109] UE1 and UE2 can be served by the same DU. CU can configure UE1 to use multipath delivery of DRB or SRB of UE1. Multipath delivery can be reconfigured based on radio conditions and traffic load requirements. The following path switching scenarios can be considered: I. Direct path to and from multipath

[0110] SRB1 of UE1 may initially be configured to use direct path delivery. After a period of time, the CU may reconfigure multipath delivery for SRB1 of UE1. For DL, the CU may split or copy the signaling of SRB1 to two or more paths. The CU may request the DU to configure the Uu RLC channel and mapping rules on the indirect path. In addition, the CU may request the DU to modify the SRB configuration of UE1, which may include the SRB ID and the modified path configuration. The modified path configuration may include path addition information. The path addition information configuration may include any combination of the following fields: path ID, direct path or indirect path, primary path or secondary path, path activation, and bearer mapping, etc. The CU may then split or copy the PDCP PDU and send the PDU via multiple direct and indirect paths. From the perspective of the service terminating UE1, UE1 may now start receiving DL PDCP PDUs from multiple paths. For UL, after the anchor UE1 receives the configuration to switch to multiple paths, UE1 may start delivering subsequent PDCP PDUs to multiple direct and indirect paths.

[0111] On the other hand, the CU can switch the DRB transmission of UE1 from multipath to using only the direct path. For DL, the CU can request the DU to modify the DRB configuration of UE1, which may include the DRB ID and the modified path configuration. The modified path configuration may include path release information. The path release information configuration may include any combination of the following fields: path ID, direct path or indirect path, primary path or secondary path, deactivation, etc. The CU or anchor UE1 can no longer deliver DL or UL PDCP PDUs to the RLC channel of the indirect path. Instead, the CU or UE1 can deliver DL or UL PDCP PDUs to the logical channel of the direct path. Since the packet has been delivered to the RLC channel of the indirect path, the packet can still be sent until the RLC channel or the logical channel is empty.

[0112] II. Direct path to and from the indirect path

[0113] For the switch from direct path to indirect path, the CU or anchor UE can no longer deliver DL or UL PDCP PDU to the RLC entity or logical channel of the direct path. Instead, the CU or UE can deliver DL or UL PDCP PDU to the RLC channel of the indirect path. To support this, the CU can request DU to modify the DRB configuration of UE1, which may include the DRB or SRB ID and the modified path configuration. The modified path configuration may include indirect path addition and direct path release configuration, which may also include any combination of the following fields: path ID, direct path or indirect path, primary path or secondary path, path activation or deactivation, etc. Since the packet has been delivered to the RLC entity or logical channel of the direct path, the packet can still be sent until the RLC entity or logical channel is empty. This can also apply to the switch from indirect path to direct path.

[0114] III. Indirect Paths for Round Trip Multipath

[0115] The gNB may send the Uu RLC channel configuration to UE2. The gNB may then switch the data packet from UE1 to UE2. Similarly, for the uplink, the gNB may send the Uu RLC channel to UE2, and then UE1 may send the UL data packet to UE2, and UE2 may forward it to the gNB.

[0116] D. Multipath Communication Process

[0117] Reference now Fig.12, depicts a flow chart of a multipath communication method 1200. The method 1200 may be implemented using or performed by any of the components described above, such as a centralized unit (CU) and one or more distributed units (DUs) of a base station 102 or 202. Under the method 1200, the CU may send multipath configuration information (1205). The DU may receive the multipath configuration information (1210). The DU may send multipath configuration response information (1215). The CU may receive the multipath configuration response information (1220).

[0118] In more detail, the CU may provide, send, or otherwise send multipath configuration information to the DU (e.g., DU1 or DU2) (1205). The multipath configuration information may include various information for adding, establishing, modifying, or releasing a path at the DU. In some embodiments, the multipath configuration information may include a multipath establishment request for establishing, adding, or setting up a path, a multipath modification request for modifying an existing path, or a multipath release request for releasing a path. The multipath configuration information may include or identify path indication information. The path indication information may identify a direct path or an indirect path to be configured.

[0119] The multipath configuration information may identify or include mapping information. In some embodiments, the mapping information may include or identify an association between an F1-U tunnel of a data radio bearer (DRB) for a remote UE (e.g., UE 104 or 204) and a Uu radio link control (RLC) channel for a relay UE (e.g., UE 104 or 204). In addition, the mapping information may include an association between a signaling radio bearer (SRB) for a remote UE and a Uu radio link control (RLC) channel for a relay UE. A remote UE (or a remote wireless communication device) may be connected to a base station via a relay UE (or a relay wireless communication device) that is directly connected to the base station.

[0120] In some embodiments, the mapping information may include or identify an association between an F1-U tunnel of a DRB for an anchor UE (e.g., UE 104 or 204) and a Uu RLC channel for an aggregated UE. In some embodiments, the mapping information may include or identify an association between a signaling radio bearer (SRB) for an anchor wireless communication device and a Uu radio link control (RLC) channel for an aggregated wireless communication device. An aggregated UE (or aggregated wireless communication device) may be connected to a base station through another UE (e.g., an anchor UE or an anchor wireless communication device), or may be connected to a base station.

[0121] In addition, the multipath configuration information may include or identify various identifiers. In some embodiments, the multipath configuration information may include an identifier for a path (e.g., an indirect path or a direct path) to be configured (e.g., added, modified, or released). In some embodiments, the multipath configuration information may include an identifier for a radio bearer (RB). The identifier may be a data radio bearer (DRB) or a signaling radio bearer (SRB) for the path to be configured.

[0122] Continuing, the multipath configuration information may include or identify an identifier for the UE. In some embodiments, the multipath configuration information may include an identifier for a relay UE. The relay UE may be directly connected to the base station and may support indirect connections for remote UEs. In some embodiments, the multipath configuration information may include an identifier for an aggregate UE. The aggregate UE may include a collection of UEs connected to each other and to the base station.

[0123] The multipath configuration information may include or identify various indicators associated with the path to be configured. In some embodiments, the multipath configuration information may include an indication of the path indication as a direct path or an indirect path. The direct path may be a direct link between the UE and the base station. In some embodiments, the multipath configuration information may include an indication of the path as a primary path or a secondary path. The primary path may correspond to a path via which packet transmission takes precedence over the secondary path. In some embodiments, the multipath configuration information may include a path activation indication. The path activation indication may identify whether the path is active or inactive to receive data packets.

[0124] In some embodiments, the multipath configuration information may include an indication of data splitting or duplication of one or more paths. Data splitting may specify the splitting of packets on a direct path and an indirect path. Data duplication may specify the duplication of packets when sent via a direct path and a direct path. In some embodiments, the indication of data splitting may identify a data splitting threshold or a data splitting ratio. The data splitting threshold may define the amount of data that initiates data splitting on a path. The data splitting ratio may define the ratio of the amount of data transmitted on a path. In some embodiments, the multipath configuration information may define, identify or indicate the distribution of data packets on a direct path (e.g., corresponding to a first RLC channel) and an indirect path (e.g., corresponding to a second RLC channel) for data splitting.

[0125] The multipath configuration information may include or identify tunnel information. In some embodiments, the multipath configuration information may identify or include uplink (UL) user plane (UP) tunnel (TNL) information. In some embodiments, UL UP TNL information may be used for a direct path or an indirect path. UL UP TNL information may be included for a specific DRB. In some embodiments, multiple groups of UL UP TNL information may be used to split DRBs. In some embodiments, the multipath configuration information may include an identifier for a Uu radio link control (RLC) channel for use. The Uu RLC channel of the UE may be mapped to the F1-U tunnel of the DRB. In some embodiments, the multipath configuration information may identify a set of F1-U tunnels of the DRB between the CU and the DU (e.g., using a DRB ID).

[0126] The DU may acquire, identify, or otherwise receive multipath configuration information from the CU (1210). Upon receipt, the DU may parse the multipath configuration information to extract or identify various information, such as mapping information. The DU may use the multipath configuration to configure a direct path or a path that is not associated with the mapping information (e.g., using a DRB or SRB). The direct path or the unrelated path may correspond to an RLC channel. In some embodiments, the DU may use the multipath configuration information to configure an RLC channel of a relay UE or an anchor UE for a direct path of a DRB or SRB.

[0127] On the other hand, the DU may use a multipath configuration to avoid establishing an additional RLC channel for an RB (such as a DRB or SRB). The additional RCL channel may be used for an indirect path. In some embodiments, the DU may use mapping information to avoid establishing an RLC channel for a relay UE or anchor UE for a DRB. In some embodiments, the DU may use an indirect path to avoid establishing an RLC channel for a relay UE or anchor UE for a DRB or SRB.

[0128] The DU may provide, send, or otherwise transmit multipath configuration response information to the CU (1215). When using the multipath configuration information, the DU may generate the multipath configuration response information. The CU may obtain, identify, or otherwise receive the multipath configuration response information from the DU (1220). In some embodiments, the multipath configuration response information may identify or include the configured downlink (DL) user plane (UP) tunnel (TNL) information for the path. The path may correspond to the path accepted at the DU.

[0129] In some embodiments, the multipath configuration response information may identify or include an identifier for the path. The path may correspond to a path configured using multiple configuration information. In some embodiments, the multipath configuration response information may identify or include an indication of a direct path or an indirect path. The indirect path or the direct path may correspond to a path configured using multiple configuration information. In some embodiments, the multipath configuration response information may identify or include an indication of a primary path or a secondary path that is accepted or rejected.

[0130] In some embodiments, the multipath configuration response information may identify or indicate the acceptance or failure of the path. The indication and related information may be generated and provided by the DU. In some embodiments, the multipath configuration response information may include or identify the cause of the failure of the path. For example, the cause may include the non-acceptance of data packet delivery on the path, or an identifier for the path that was not accepted, etc. In some embodiments, the multipath configuration response information may identify or indicate the failure of multipath SRB or DRB establishment. In some embodiments, the multipath configuration response information may identify or indicate the failure of multipath SRB or DRB modification.

[0131] Although various embodiments of the present solution have been described above, it should be understood that they are presented only by way of example rather than by way of limitation. Similarly, various figures may depict example architectures or configurations, which are provided to enable those of ordinary skill in the art to understand the example features and functions of the present solution. However, these people will understand that the present solution is not limited to the example architectures or configurations shown, but can be implemented using various alternative architectures and configurations. In addition, as will be understood by those of ordinary skill in the art, one or more features of an embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-mentioned illustrative embodiments.

[0132] It should also be understood that any reference to an element using names such as "first," "second," etc., herein generally does not limit the number or order of these elements. Instead, these names can be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Therefore, reference to a first element and a second element does not mean that only two elements can be used, or that the first element must precede the second element in some way.

[0133] In addition, those skilled in the art will appreciate that information and signals may be represented using any of a variety of different methods and techniques. For example, data, instructions, commands, information, signals, bits, and symbols, etc., that may be referenced in the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0134] Those of ordinary skill in the art will further understand that any of the various illustrative logic blocks, modules, processors, devices, circuits, methods, and functions described in conjunction with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of the two), firmware, various forms of programs or design codes in conjunction with instructions (which, for convenience, may be referred to herein as "software" or "software modules"), or any combination of these technologies. In order to clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functions. Whether such functions are implemented as hardware, firmware, or software, or a combination of these technologies depends on the specific application and the design constraints imposed on the entire system. A skilled technician may implement the described functions in various ways for each specific application, but such implementation decisions will not result in a departure from the scope of the present disclosure.

[0135] In addition, it will be understood by those of ordinary skill in the art that the various illustrative logic blocks, modules, devices, components, and circuits described herein may be implemented or performed within an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, or any combination thereof. The logic blocks, modules, and circuits may also include antennas and / or transceivers to communicate with various components within a network or within a device. A general-purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other suitable configuration for performing the functions described herein.

[0136] If implemented in software, these functions can be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media include both computer storage media and communication media, including any medium that can transfer a computer program or code from one place to another. The storage medium can be any available medium that a computer can access. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to store the desired program code in the form of instructions or data structures and can be accessed by a computer.

[0137] In this document, the term "module" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the relevant functions described herein. In addition, for the purpose of discussion, various modules are described as discrete modules; however, as is clear to one of ordinary skill in the art, two or more modules can be combined to form a single module that performs the associated functions according to an embodiment of the present solution.

[0138] In addition, memory or other storage devices and communication components can be used in the embodiment of the present solution. It should be understood that, for the sake of clarity, the above description has described the embodiment of the present solution with reference to different functional units and processors. However, it is clear that any suitable functional distribution between different functional units, processing logic elements or domains can be used without departing from the present solution. For example, the functions performed by a separate processing logic element or controller can be performed by the same processing logic element or controller. Therefore, reference to a specific functional unit is only a reference to an appropriate manner for providing the described function, rather than representing a strict logical or physical structure or organization.

[0139] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the embodiments shown herein, but should be consistent with the broadest scope consistent with the novel features and principles disclosed herein, as described in the following claims.

Claims

1. A multipath communication method, comprising: The centralized unit (CU) sends multipath configuration information to the distributed unit (DU); as well as The CU receives multipath configuration response information from the DU.

2. The method according to claim 1, wherein the multipath configuration information comprises: Path indication information identifying at least one of a direct path or an indirect path.

3. The method according to claim 1, wherein the multipath configuration information includes mapping information, and the mapping information identifies: an association between an F1-U tunnel for a data radio bearer (DRB) of a remote wireless communication device and a Uu radio link control (RLC) channel for a relay wireless communication device; or Association between an F1-U tunnel for a data radio bearer (DRB) of an anchor wireless communication device and a Uu radio link control (RLC) channel for an aggregated wireless communication device.

4. The method according to claim 1, wherein the multipath configuration information includes mapping information, and the mapping information identifies: an association between a Signalling Radio Bearer (SRB) for a remote wireless communication device and a Uu Radio Link Control (RLC) channel for a relay wireless communication device; or Association between a Signaling Radio Bearer (SRB) for an anchor wireless communication device and a Uu Radio Link Control (RLC) channel for an aggregated wireless communication device.

5. The method of claim 1 , wherein the multipath configuration information comprises at least one of: an identifier of a radio bearer (RB), uplink (UL) user plane (UP) tunnel (TNL) information, an identifier for a relay wireless communication device, an identifier for an aggregated wireless communication device, an identifier for a Uu radio link control (RLC) channel, an identifier for a path, an indication of a direct path or an indirect path, an indication of a primary path or an auxiliary path, an indication of data splitting or data duplication, or a path activation indication. 6 . The method according to claim 5 , wherein the identifier of the RB can be at least one of the identifiers of a DRB or an SRB.

7. The method according to claims 3 to 5, wherein the multipath configuration information with mapping information is used by a DU to avoid establishing an RLC channel of a relay wireless communication device or an anchor wireless communication device for the DRB.

8. The method according to claims 3 to 5, wherein the multipath configuration information with indirect path indication is used by a DU to avoid establishing an RLC channel of a relay wireless communication device or an anchor wireless communication device for the DRB or SRB.

9. The method of claim 1, wherein the multipath configuration information is used by the DU to configure a first RLC channel of a relay wireless communication device or an anchor wireless communication device for a direct path of a DRB or SRB.

10. The method according to claim 1, wherein the multipath configuration information comprises: A path activation indication that identifies the path as active or inactive.

11. The method according to claim 5, wherein the indication of data splitting comprises: At least one of a data splitting threshold or a data splitting ratio.

12. The method of claim 1, wherein the multipath configuration information with data splitting indicates distribution of a plurality of data packets on a first RLC channel corresponding to a direct path and a second RLC channel corresponding to an indirect path.

13. The method according to claim 1, wherein the multipath configuration information identifies: DRBs for multiple F1 user plane tunnels between the CU and the DU.

14. The method according to claim 1, wherein the multipath configuration information comprises: Uplink (UL) user plane (UP) tunnel (TNL) information for at least one of a direct path or an indirect path.

15. The method according to claim 1, wherein the multipath configuration information comprises: Two or more UL UP TNL information for splitting DRBs.

16. The method of claim 1, wherein the multipath configuration response information indicates at least one of acceptance or failure of a path.

17. The method according to claim 16, wherein the multipath configuration response information comprises: An identifier for the path, either a direct path or an indirect path, or an indication of a primary path or a secondary path that is accepted or rejected.

18. The method of claim 16, wherein the multipath configuration response message identifies one of: a reason for the failure of the path, or non-acceptance of data packet delivery, or an identifier for the non-accepted path.

19. The method according to claim 16, wherein the multipath configuration response information indicates: a failure of multipath SRB or DRB establishment, or a failure of multipath SRB or DRB modification.

20. The method according to claim 16, wherein the multipath configuration response information comprises: Downlink (DL) user plane (UP) tunnel (TNL) information for the accepted path.

21. The method according to claim 1, wherein the multipath configuration information comprises at least one of the following: a multipath establishment request, a multipath modification request, or a multipath release request.

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