CN110365609B

CN110365609B - Data packet segmentation method and device

Info

Publication number: CN110365609B
Application number: CN201810316979.1A
Authority: CN
Inventors: 李铕; 袁世通; 朱元萍; 刘菁; 戴明增; 刘亚林
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-04-10
Filing date: 2018-04-10
Publication date: 2021-12-14
Anticipated expiration: 2038-04-10
Also published as: WO2019196656A1; CN110365609A

Abstract

The embodiment of the invention provides a data packet segmentation method and a related product, wherein the method comprises the following steps: if the RLC SDU contained in the second RLC PDU is not segmented, the first node obtains a segmentation serial number of the first RLC PDU, the first node is a layer2relay node, the segmentation serial number has uniqueness in a bearing where the first RLC PDU is located, and the first RLC PDU is the segment of the second RLC PDU and the second RLC PDU is the RLC PDU received by the first node; the first node transmits a first RLC PDU containing a segmentation sequence number. The relay node at L2 segments the RLC PDU and uses the unique segmentation sequence number in the bearer to provide basis for RLC PDU reassembly, so as to avoid the problem that the first node cannot complete segmentation due to lack of segmentation sequence number.

Description

Data packet segmentation method and device

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for segmenting a data packet.

Background

A Long Term Evolution (LTE) relay (relay) technology is a technology for forwarding data between a base station (evolved non-radio access network node B, eNB) and User Equipment (UE) by deploying a Relay Node (RN) in a network, and can enhance network capacity, solve backhaul connection between base stations, and solve coverage holes.

In a wireless relay networking scene facing 5G (5th generation mobile networks or 5th generation wireless systems), besides a scene supporting LTE relay, a multi-hop wireless relay and a multi-connection scene are also supported. In the networking scene of the multi-hop wireless relay, the number of relay nodes participating in data forwarding between user equipment and a base station is at least two, and the number of the relay nodes is the hop number.

In a multi-hop wireless relay networking scenario, the relay nodes may use Radio Link Control (RLC) management on a hop-by-hop basis, that is, each relay node may directly use a 5G/NR (new radio, NR) method to process data destined for a next hop or a previous hop.

In order to adapt to the link condition between the sending node and the receiving node of the data packet, the relay node may need to segment a Packet Data Convergence Protocol (PDCP) data packet at the RLC layer. For example: when the channel quality is degraded, less data can be transmitted, so that the bottom layer can carry more redundant information to improve reliability.

Disclosure of Invention

The technical problem to be solved by the embodiments of the present invention is to provide a technical solution for segmenting RLC Packet Data Units (PDUs) in layer 2(layer 2, L2).

In one aspect, an embodiment of the present invention provides a data packet segmentation method, including:

if the RLC SDU contained in the second RLC PDU is not segmented, the first node obtains a segmentation serial number of the first RLC PDU, the first node is a layer2relay node, the segmentation serial number has uniqueness in a bearing where the first RLC PDU is located, the first RLC PDU is the segmentation of the second RLC PDU, and the second RLC PDU is the RLC PDU received by the first node;

the first node transmits a first RLC PDU containing a segmentation sequence number.

In this embodiment, the first node may be a relay node of L2, which has a function of segmenting RLC PDUs. The fact that the segmentation sequence number is unique in a certain bearer means that no other RLC PDU segments use the segmentation sequence number in the bearer, and a basis is provided for RLC PDU segmentation. How to ensure the uniqueness of the segment sequence number is not described uniquely in the embodiments of the present invention. As an example of an optional implementation manner, the fragment sequence number may be a sequence number of the PDCP PDU, which is also referred to as a Sequence Number (SN), or a ciphering and integrity counter (counter) maintained by the PDCP layer. In addition, the second RLC PDU may be an unsegmented RLC PDU or a segmented RLC PDU.

The embodiment of the invention provides a basis for RLC PDU recombination by segmenting RLC PDU by L2 and using a segmentation sequence number with uniqueness in bearing.

As a possible implementation, a specific implementation that the segmented sequence number has uniqueness is provided: the segmentation sequence number is a sequence number of a PDCP PDU of the second RLC PDU.

In the present embodiment, the PDCP SN is used as the sequence number of the fragment, and the first node can obtain the SN contained in the PDCP PDU by parsing the PDCP PDU. It should be noted that the segmentation sequence number may not be obtained by the first node parsing the PDCP PDU, but may also be obtained, for example, by signaling or by various protocol headers included in the RLC PDU. This embodiment is not limited to this.

As one possible implementation, several possible delivery modes of the segment sequence number are provided:

the protocol header of the PDCP PDU contained in the second RLC PDU contains a segmentation sequence number;

or the protocol header of the second RLC PDU contains a segmentation sequence number;

or the protocol header of the packet contained in the second RLC PDU contains a segmentation sequence number;

or the protocol header of the packet containing the second RLC PDU contains a segmentation sequence number;

or the control signaling sent by the second node contains the segmentation sequence number, and the second node is the sending node of the second RLC PDU.

The second node is a sending node of RLC PDU, and the second node may be UE or base station in the relay network, and may also be a relay node having layer 3 (L3) function.

As a possible implementation manner, a specific implementation manner of including the segmentation sequence number in the protocol header of the second RLC PDU may be: the protocol header of the second RLC PDU includes Segmentation Information (SI), and if the SI indicates that the second RLC PDU carries an RLC Service Data Unit (SDU) that is not segmented and includes a segmentation sequence number, the segmentation sequence number field in the protocol header of the second RLC PDU includes the segmentation sequence number.

The SI referred to in this embodiment is expanded in function, and can be expressed more in meaning by adding bytes of the SI.

As a possible implementation, the step of including the segmentation sequence number in the protocol header of the packet including the second RLC PDU includes:

the second RLC PDU is encapsulated in a data packet containing a Medium Access Control (MAC) subheader containing a segment sequence number; alternatively, the first and second electrodes may be,

the second RLC PDU is encapsulated in a data packet containing an adaptation layer header containing a segmentation sequence number.

This embodiment provides a specific implementation manner of carrying the segmentation sequence number in the protocol header of the packet containing the second RLC PDU, one is the MAC subheader, and one is the adaptation layer header. If other specific packet protocol headers are modified to carry the segment sequence number, the embodiment of the present invention is not limited uniquely.

As one possible implementation, the control signaling includes:

a MAC Control Element (CE), the MAC CE and the second RLC PDU are in the same MAC packet.

This embodiment provides an alternative implementation of the control signaling, which may be the control information of L2, and besides the MAC CE, the control signaling may also be RLC control (control) PDU, etc., so the MAC CE should not be understood as a unique limitation to the control signaling.

As a possible implementation, the method further includes:

transmitting the segmented sequence number to the subordinate node under the condition that the first node transmits a second RLC PDU to the subordinate node;

alternatively, in the case where the first node is an upper node of the group packing node, the segment sequence number is transmitted or not transmitted to the group packing node.

This embodiment provides a scheme that the first node does not segment the RLC PDU and whether the segmentation sequence number needs to be sent to the lower node. The first node in the previous scheme may send the segmentation sequence number to a subordinate node as long as the first node does not segment the RLC PDU, regardless of whether the first node is the last hop, and the subordinate node may be a packet packaging node or not; under the condition that the first node determines that the first node is the last hop, the first node has two options, wherein one option is not to send the segmented sequence number, and the packet packaging node keeps the original processing mode under the condition; the other is to send the fragment sequence number, in which case the packet grouping node will not consider the disjointed sequence number upon receipt of the fragment sequence, and can directly ignore this information.

In addition to the above two schemes, there are other possible application scenarios, such as: the first node segments the RLC PDU, in which case the first RLC PDU is sent; carrying a segmentation sequence number in the first RLC PDU; at this point, if the segment sequence number is signaled, the first node may choose to continue forwarding the signaling to the subordinate node or not. This embodiment is not limited to this.

In another aspect, an embodiment of the present invention further provides a method for controlling packet segmentation, including:

a second node acquires a second RLC PDU, wherein the RLC SDU contained in the second RLC PDU is not segmented;

the second node sends the segmentation sequence number and a second RLC PDU to the first node;

the segmentation serial number is the segmentation serial number of a first RLC PDU, the first node is a layer2relay node, the segmentation serial number has uniqueness in the load bearing of the first RLC PDU, and the first RLC PDU is the segmentation of a second RLC PDU; the segmentation sequence number is used for the first node to send a first RLC PDU containing the segmentation sequence number.

The second node is a node that transmits the second RLC PDU, and may be a UE, a base station, or a relay node having a layer 3 (L3) function in the relay network. The uniqueness of the segment sequence number can refer to the foregoing description, and is not described herein again.

As a possible implementation manner, a specific implementation manner in which the second node sends the segment sequence number to the first node includes:

the protocol header of a second RLC PDU sent by the second node to the first node contains a segmentation sequence number; alternatively, the first and second electrodes may be,

the protocol header of a packet contained in a second RLC PDU sent by the second node to the first node contains a segmentation sequence number; alternatively, the first and second electrodes may be,

the protocol header of the packet containing the second RLC PDU sent by the second node to the first node contains a segmentation sequence number; alternatively, the first and second electrodes may be,

the second node sends control signaling to the first node, and the control signaling contains a segmentation sequence number.

In addition, the PDCP PDU may carry PDCP SNs, and the PDCP SNs may be used as the implementation of the segmentation sequence number, which may not require protocol modification at the second node side.

As a possible implementation, a specific implementation that the protocol header of the second RLC PDU includes a segmentation sequence number is also provided: the protocol header of the second RLC PDU includes an SI indicating that the second RLC PDU carries an RLC SDU that is not segmented and contains a segmentation sequence number.

the second RLC PDU is packaged in a data packet containing the MAC subheader, and the MAC subheader contains a segmentation serial number; alternatively, the first and second electrodes may be,

the second RLC PDU is encapsulated in a data packet containing an adaptation layer header, which contains the segmentation sequence number.

As one possible implementation, the control signaling includes:

and the MAC CE and the second RLC PDU are in the same MAC data packet.

In three aspects, an embodiment of the present invention further provides a data packet segmentation method, including;

the second node determines whether the second RLC PDU sent by the second node exceeds the Maximum Transmission Unit (MTU) of the transmission path where the second RLC PDU is located;

if the second node determines that the second RLC PDU exceeds the MTU, performing segmentation operation on the second RLC PDU;

the second node sends a first RLC PDU, which is a segment of a second RLC PDU.

In this embodiment, the second node determines whether the second RLC PDU will be segmented by a predictive manner, and if segmentation is possible, the second node pre-segmentation may reduce the possibility of segmentation at the first node, thereby reducing the problem caused by non-basis segmentation at the first node. The embodiment provides an implementation manner for determining whether the second RLC PDU is to be segmented, and the implementation manner is implemented by using MTU, wherein the MTU can be calculated by taking the signal quality of the transmission path of the second RLC PDU and the like as a reference. The MTU may be fed back from the first node to the second node.

As a possible implementation, the method further includes:

and the second node sends the MTU to the terminal, and the terminal is a receiving party of the first RLC PDU.

As a possible implementation manner, the second node is a terminal, and the method further includes: the second node receives configuration information for the MTU.

The embodiment provides two application scenarios, wherein the former is a scenario in which the second node serves as a sending node, and the terminal serves as a receiving node, and in this scenario, the sending node can send the MTU to the receiving node; in the latter case, the second node serves as a receiver and receives the configuration information of the MTU sent by the network side.

As a possible implementation manner, the manner of carrying the configuration information of the MTU may include: uplink Control Information (UCI), MAC CE, Radio Resource Control (RRC) signaling, F1 control plane signaling, or adaptation layer control information.

In a fourth aspect, an embodiment of the present invention further provides a method for controlling packet segmentation, including;

the first node does not segment the second RLC PDU when determining that the bearing corresponding to the second RLC PDU is in an unacknowledged mode or the second RLC PDU does not carry a segmented serial number;

and forwarding the second RLC PDU.

The present embodiment specifies two possible cases in which the relay node of L2 does not segment the RLC PDU. By prohibiting the L2 relay node from segmenting the RLC PDUs, the problem of an RLC PDU not carrying a segmented sequence number in unacknowledged mode not being able to correctly acquire the sequence number due to no sequence number is avoided. Meanwhile, the protocol flow is simplified.

In a fifth aspect, an embodiment of the present invention further provides a first node, including:

the processing unit is used for acquiring a segmentation serial number of a first Radio Link Control (RLC) Packet Data Unit (PDU), wherein the first node is a layer2relay node, the segmentation serial number has uniqueness in a bearing where the first RLC PDU is located, the first RLC PDU is a segment of a second RLC PDU, the second RLC PDU is an RLC PDU received by the first node, and the PDCP PDU contained in the second RLC PDU is not segmented;

a transmitting unit for transmitting a first RLC PDU containing a segmentation sequence number.

As a possible implementation manner, a specific implementation manner that the segmentation sequence number has uniqueness in the bearer in which the first RLC PDU is located includes:

the segmentation sequence number is a sequence number of a PDCP PDU of the second RLC PDU.

As a possible implementation manner, a carrying manner of the segmentation sequence number of the first RLC PDU is also provided, which specifically includes:

As a possible implementation, a specific implementation that the protocol header of the second RLC PDU includes a segmentation sequence number is also provided:

and the protocol header of the second RLC PDU comprises segmentation information SI, and if the SI indicates that the second RLC PDU carries the RLC SDU which is not segmented and contains a segmentation sequence number, the segmentation sequence number field in the protocol header of the second RLC PDU contains the segmentation sequence number.

As a possible implementation, a specific implementation is also provided in which the protocol header of the packet containing the second RLC PDU contains a segmentation sequence number:

the second RLC PDU is packaged in a data packet containing an MAC subheader, and the MAC subheader contains a segmentation serial number; alternatively, the first and second electrodes may be,

As one possible implementation, the control signaling includes:

and the MAC control element CE, wherein the MAC CE and the second RLC PDU are in the same MAC data packet.

As a possible implementation manner, the sending unit is further configured to send the segmentation sequence number to the subordinate node in a case where the sending unit sends the second RLC PDU to the subordinate node;

alternatively, in the case where the first node is an upper node of the group package node, the segment sequence number is transmitted or not transmitted to the group package node.

In a sixth aspect, an embodiment of the present invention further provides a second node, including:

the device comprises an acquisition unit, a processing unit and a processing unit, wherein the acquisition unit is used for acquiring a second RLC PDU, and the RLC SDU contained in the second RLC PDU is not segmented;

a transmitting unit, configured to transmit the segmentation sequence number and the second RLC PDU to the first node;

As a possible implementation manner, a specific carrying manner for sending the segment sequence number to the first node is further provided as follows: the protocol header of a second RLC PDU sent to the first node contains a segmentation sequence number;

or, the protocol header of the packet contained in the second RLC PDU sent to the first node contains the segmentation sequence number; alternatively, the first and second electrodes may be,

the protocol header of the packet containing the second RLC PDU sent to the first node contains a segmentation sequence number; alternatively, the first and second electrodes may be,

the control signaling sent to the first node contains a segment sequence number.

As a possible implementation, a specific implementation is also provided in which a protocol header of a packet containing the second RLC PDU, which is sent to the first node, contains a segmentation sequence number:

a second RLC PDU sent to the first node is encapsulated in a data packet containing a MAC subheader, the MAC subheader containing a segmentation sequence number; alternatively, the first and second electrodes may be,

the second RLC PDU sent to the first node is encapsulated in a data packet containing an adaptation layer header containing the segmentation sequence number.

As one possible implementation, the control signaling includes:

and the MAC CE and the second RLC PDU are in the same MAC data packet.

In a seventh aspect, an embodiment of the present invention further provides a second node, including;

the processing unit is used for determining whether the second RLC PDU sent by the second node exceeds the MTU of the transmission path where the second RLC PDU is located; if the second RLC PDU is determined to exceed the MTU of the transmission path where the second RLC PDU is located, performing segmentation operation on the second RLC PDU;

a transmitting unit, configured to transmit a first RLC PDU, which is a segment of a second RLC PDU.

As a possible implementation manner, the sending unit is further configured to send the MTU to a terminal, where the terminal is a receiving side of the first RLC PDU.

As a possible implementation manner, the second node is a terminal, and the second node further includes:

and the receiving unit is used for receiving the configuration information of the MTU.

In an eighth aspect, an embodiment of the present invention further provides a packet segmentation control apparatus, used as a first node, including;

the segmentation control unit is used for not segmenting the second RLC PDU when the load corresponding to the second RLC PDU is determined to be in an unacknowledged mode or the second RLC PUD does not carry a segmentation serial number;

and the forwarding unit is used for forwarding the second RLC PDU.

In a ninth aspect, embodiments of the present invention further provide a communication apparatus, including a processor and a memory connected to the processor, where the processor further includes an interface connected to the transceiver, the transceiver is configured to transmit and receive signals and transmit and receive data, the memory is configured to store instructions, and the processor is configured to read and execute the instructions in the memory to control the communication apparatus to perform any one of the methods provided by the embodiments of the present invention.

In a tenth aspect, an embodiment of the present invention further provides a computer storage medium, where the computer storage medium stores instructions that, when executed by a processor, control a communication apparatus to perform any one of the methods provided by the embodiments of the present invention.

In an eleventh aspect, the present invention further provides a computer program product, where the computer program product includes instructions that, when executed by a processor, control a communication apparatus to perform any one of the methods provided by the embodiments of the present invention.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present invention, the drawings required to be used in the embodiments or the background art of the present invention will be described below.

FIG. 1 is a system architecture diagram according to an embodiment of the present invention;

FIG. 2 is a system architecture diagram according to an embodiment of the present invention;

FIG. 3 is a system architecture diagram according to an embodiment of the present invention;

FIG. 4 is a diagram of a system architecture and protocol stack according to an embodiment of the present invention;

FIG. 5 is a diagram of a system architecture and protocol stack according to an embodiment of the present invention;

FIG. 6 is a schematic flow chart of one embodiment of a method implemented by the present invention;

FIG. 7 is a schematic flow chart of a method embodying the present invention;

FIG. 8 is a schematic flow chart of one embodiment of a method implemented by the present invention;

FIG. 9 is a schematic flow chart of one embodiment of a method implemented by the present invention;

FIG. 10 is a diagram of a MAC subheader (subheader) without an L field according to an embodiment of the present invention;

fig. 11 is a schematic diagram of a MAC CE carrying SN according to an embodiment of the present invention;

FIG. 12 is a diagram of an RLC Control PDU with an SN according to an embodiment of the present invention;

FIG. 13 is a schematic flow chart of one embodiment of a method implemented in accordance with the present invention;

fig. 14 is a format example of an RLC SDU implemented by the present invention;

fig. 15 is a format example of an RLC SDU implemented by the present invention;

fig. 16 is a format example of an RLC SDU implemented by the present invention;

fig. 17 is a format example of an RLC SDU implemented by the present invention;

fig. 18 is a format example of an RLC SDU implemented by the present invention;

fig. 19 is a format example of an RLC SDU implemented by the present invention;

FIG. 20 is a schematic flow chart of one embodiment of a method implemented in accordance with the present invention;

FIG. 21 is a schematic flow chart of one embodiment of a method implemented in accordance with the present invention;

fig. 22 is a diagram illustrating a Downlink (DL) MAC PDU format in accordance with an embodiment of the present invention;

FIG. 23 is a schematic diagram of a format of a subheader with an L-field length of 8 bits according to an embodiment of the present invention;

FIG. 24 is a schematic diagram of a format of a 16-bit L-field subheader implemented in the present invention;

FIG. 25 is a diagram illustrating the format of a subheader without L field in accordance with an embodiment of the present invention;

FIG. 26 is a diagram illustrating the format of a subheader with an L-field length of 8 bits carrying SN according to an embodiment of the present invention;

fig. 27 is a schematic format diagram of a PDU of a general packet radio service tunneling protocol (GTP) implemented in the present invention;

FIG. 28 is a diagram illustrating a GTP user plane (GTP-U) header format in accordance with an embodiment of the present invention;

FIG. 29 is a diagram illustrating a PDU format according to an embodiment of the present invention;

FIG. 30 is a schematic diagram of a first node structure embodying the present invention;

FIG. 31 is a schematic diagram of a second node structure embodying the present invention;

FIG. 32 is a second node architecture diagram in accordance with the practice of the present invention;

FIG. 33 is a schematic diagram of a first node structure embodying the present invention;

FIG. 34A is a block diagram of a communication device in accordance with the present invention;

fig. 34B is a schematic structural diagram of a communication device implemented in the present invention.

Detailed Description

The embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a 5G system; in fig. 1, included in the present invention, a link between a donor base station/donor base station (donor next generation node B, DgNB) and a Relay Node (RN) is called a Backhaul (BH) link, and a link between the relay node and a UE is called an Access (AC) link. In a 5G system, a backhaul link may contain multiple RNs.

The network topology on the radio access network side can be regarded as a tree based topology, that is, the Relay Node (RN) and the base station (donor gbb, DgNB, which serves the relay node) have a clear hierarchical relationship, and each relay node regards the node providing backhaul service for the relay node as a parent node. For example, in fig. 2, RN1 provides backhaul service for RN2, and RN1 is the parent node of RN 2; similarly, the parent node of RN1 is DgNB. Accordingly, an uplink packet of a User Equipment (UE) served by RN2 is transmitted to the DgNB via RN2 and RN1 in sequence, and then sent to the gateway device by the DgNB. The gateway device may be a User Plane Function (UPF) in the 5G network. Accordingly, after the DgNB receives the downlink data packet from the gateway device, the downlink data packet is transmitted to the UE through the RN1 and the RN2 in sequence. In the network diagram shown in fig. 2, data transmission between the UE and the DgNB is referred to as two hops if two RNs pass through, three hops if three RNs pass through, and so on.

In the embodiment of the present invention, a downlink data packet refers to a data packet sent from a donor to a UE, a link used by the downlink data packet may be referred to as a downlink, and a behavior of sending the downlink data packet may be referred to as downlink sending/downlink transmission, etc.; accordingly, an uplink packet refers to a packet sent from the UE to the donor, a link used by the uplink packet may be referred to as an uplink, and a behavior of sending the uplink packet may be referred to as uplink transmission/uplink transmission or the like. This will not be described in the following embodiments.

Fig. 3 illustrates a multi-hop multi-connection networking scenario. Due to the introduction of multiple connections, one relay node may be served backhaul by two or even more access nodes (base stations or relay nodes). As shown in FIG. 3, RN1 and RN4 may simultaneously provide backhaul service for RN 2. Accordingly, uplink data of UE1 can be transmitted to DgNB through RN2 and RN1, or can be transmitted to DgNB through RN2, RN4 and RN 3; and vice versa. Thus, RN2, RN1, and DgNB are one path; RN2, RN3, RN3 and DgNB are additional paths.

The content specified in the LTE system protocol is mainly for coverage extension: the relay node of type 1 has the necessary RRC functions in order to support access control and mobility management of the UE. Both RN and eNB (LTE base station) of type 1 have scheduling capability, and this type of RN may be referred to as L3 RN.

Fig. 4 is a schematic diagram of a network system and its protocol stack. The user plane includes a UE, an RN, a DeNB, and a Serving Gateway (SGW)/public data network gateway (PGW) for serving the UE (denoted as SGW-UE/PGW-UE in fig. 4). The protocol stack of the UE includes, from top to bottom, an Internet Protocol (IP) layer, a PDCP layer, an RLC layer, an MAC layer, and a Physical (PHY) layer; the protocol stack for communication between the RN and the UE comprises a PDCP layer, an RLC layer, an MAC layer and a PHY layer from top to bottom, and the protocol stack for communication between the RN and the DeNB comprises a GTP-U layer, a User Datagram Protocol (UDP) layer, an IP layer, the PDCP layer, the RLC layer, the MAC layer and the PHY layer from top to bottom; the protocol stack for communication between the DeNB and the RN comprises a GTP-U layer, a UDP layer, an IP layer, a PDCP layer, an RLC layer, an MAC layer and a PHY layer from top to bottom; the protocol stack for communication between the DeNB and the SGW-UE/PGW-UE comprises a GTP-U layer, a UDP layer, an IP layer, an L2 layer and an L1 layer from top to bottom; the protocol stack of communication between the SGW-UE/PGW-UE and the DeNB comprises an IP layer, a GTP-U layer, a UDP layer, an IP layer, an L2 layer and an L1 layer from top to bottom. The user plane of the LTE system protocol also has a complete protocol stack, and can provide an air interface Data Radio Bearer (DRB) transmission service for the UE, and can aggregate data of a plurality of UEs and forward the aggregated data to the DeNB through a backhaul link.

In embodiments of the present invention, NR may introduce layer2relay (L2 RN), which may have part of the layer2 protocol stack, e.g. the forwarding of data between UE, L2RN and DgNB is based on PDCP/RLC/MAC PDUs. Accordingly, the processing of the protocol layer can be reduced in the transmission process of the data in the relay node, so that the time delay is shorter and the signaling overhead is smaller.

Fig. 5 shows a possible system and protocol stack structure for layer2 relay.

In the system shown in fig. 5, the peer entity of the UE PDCP may be in a donor (donor) node, i.e., DeNB; entities such as UE RLC, MAC and PHY are in RN.

Forwarded between the relay nodes in the system shown in fig. 5 are PDCP PDUs;

the PDCP PDU is processed by an Adaptation Layer (Adaptation Layer) added between the PDCP and RLC layers.

Taking downlink transmission as an example:

the DeNB encapsulates the PDCP PDU into an adaptation layer PDU and then delivers the adaptation layer PDU to the RLC layer, and the adaptation layer adds information such as UE ID, DRB ID and the like;

and the RN selects the corresponding UE DRB to process the data according to the UE ID and the DRB ID and then sends the data to the UE.

In fig. 5, add refers to an adaptation layer (adaptation layer) for identifying the UE to which the data belongs and the DRB of the UE when the data is forwarded between the RN and the DgNB; service Data Adaptation Protocol (SDAP) in the third generation partnership project (3 GPP)37.324 protocol is a protocol layer newly introduced by NR with respect to LTE for handling mapping of quality of service (QoS) flow to DRB. It should be noted that fig. 5 is a protocol stack architecture in which an adapt sublayer is added above the RLC layer. In one possible implementation, the adapt. sublayer may also be below the RLC layer; the adapt may also be used as a sublayer of RLC or PDCP or MAC. The illustration in fig. 5 should therefore not be construed as an exclusive limitation of adpt.

The interface between the RN and the DeNB may also be F1 control plane signaling (for example, F1application protocol (F1 AP), please refer to 3GPP 38.473 protocol), a GTP tunnel, or an F1AP with extended functions, a GTP tunnel, etc. embodiments of the present invention are not limited to this.

In addition, according to the specification of the 5G NR protocol, that is, the 3GPP 38.323 protocol, if Radio Link Control (RLC) Unacknowledged Mode (UM) is used for Data transmission, the PDU may be referred to as an Unacknowledged Mode (UMD) PDU.

For convenience of the following description, the name and meaning of the data packet used by the RLC layer are defined. Generally, a data packet of an upper layer received by the RLC layer or a data packet obtained by the RLC layer after the data packet received by the RLC layer from a lower layer is processed by the RLC layer is called an RLC Service Data Unit (SDU), and from the viewpoint of an upper protocol of the RLC layer, the RLC SDU is also called a PDU of the upper protocol. For example, if there is a PDCP layer above the RLC layer, the RLC SDU and PDCP PDU are the same, and if there is an adapt layer above the RLC layer, the RLC SDU is also adapt. A packet transmitted to or received from the lower layer of the RLC layer is called an RLC PDU. The lower layer of the RLC layer may be, for example, a MAC layer, or may be an adapt layer, which depends on the protocol definition, but is not limited in this application. It should be understood that, in the present application, when the upper layer of the RLC is the PDCP layer, the RLC SDU refers to PDCP PDU, and when the upper layer of the RLC is the adapt. layer, the RLC SDU refers to adapt. PDU; the RLC layer sends out or receives packets from other nodes (usually from the MAC layer or the adapt. layer), called RLC PDUs. In this application, the RLC PDU is not segmented means that the RLC PDU generated by a device (e.g. a terminal) or received from a lower layer of the RLC layer is not segmented, that is, the RLC SDU included in the RLC PDU is not segmented.

The RLC UM mode for NR is introduced as follows:

according to the specification in the 5G NR protocol, i.e. the 3GPP 38.323 protocol, if RLC unacknowledged mode is used for data transmission, for its data PDU, i.e. the unacknowledged mode data UMD PDU:

1) data field:

the data part of the UMD PDU/RLC PDU carries RLC SDUs or segments of SDUs-RLC SDUs correspond to PDUs of the PDCP layer.

2) Processing of SN field:

adding SN to RLC PDU only when it contains RLC SDU segment;

and, the SN of the segmentation of the same RLC SDU is the same;

3) processing of Segment Offset (SO) field:

no SO is carried for the RLC PDU containing the first segment of the RLC SDU;

for the middle segment, or the last segment, SO represents the offset of the starting byte of the Data part of the RLC PDU relative to the original starting position of the RLC SDU carried thereby. For example, an RLC SDU is divided into two segments, where the first segment is 10 bytes long, the first segment contains no SO, and the SO of the second segment indicates an offset value of 10.

4) The SI field is specifically shown in table 1:

TABLE 1

The above-mentioned complete RLC SDU is an RLC SDU that is not segmented, and the complete RLC PDU is an RLC PDU that is not segmented in the subsequent embodiments, which will not be described again in the subsequent embodiments.

In the following embodiments, taking the network system shown in fig. 2 as an example, the PDCP peer entity of the UE may be deployed in the donor (i.e., DgNB), and may also be deployed in L3 RN; in the following embodiments, the PDCP peer entity of the UE may be deployed in the donor as an example.

For uplink transmission, the UE performs integrity protection and/or ciphering on the PDCP SDU to generate a PDCP PDU, and the donor receives the PDCP PDU to perform integrity verification and/or deciphering to obtain the PDCP SDU. Again, since the PDCP peer entity of the UE is deployed in the donor in this embodiment, during uplink transmission, the donor performs integrity check and/or decryption of the PDCP PDU, where the UE may be referred to as a sending node and the donor may be referred to as a receiving node; accordingly, for downlink transmission, the UE is the receiving node.

For downlink transmission, the donor is a transmitting node, the RN is a relay node, and the UE is a receiving node.

In the embodiment of the present invention, if considering that the PDCP peer entity of the UE is deployed at RNx, when transmitting in downlink, RNx is the transmitting node and the UE is the receiving node. This RNx represents any relay node between the donor node and the UE. In addition, in this embodiment, the relay node may have a function of performing integrity check/protection and/or decryption/ciphering on the PDCP PDU; for convenience of description, in the embodiment of the present invention, if no special description is provided, the relay node refers to a relay node that does not perform integrity check/protection and/or decryption/encryption on the PDCP PDU, and details thereof are not repeated in the subsequent embodiments.

As shown in any one of fig. 2, 6, 8, 13, 20 and 21, which is a schematic diagram of downlink transmission; standing at the angle of RN1, donor (i.e., DgNB) is the previous hop and RN2 is the next hop. If uplink transmission is received, the station is in the angle of RN1, RN2 is the previous hop, and donor (i.e., DgNB) is the next hop.

As described earlier, in NR, SN is added to RLC PDU only when the RLC PDU contains RLC SDU segments. If the RLC PDU is not segmented, the SN is not included in the header of the RLC PDU. However, when the relay node performs RLC PDU transmission, it needs to consider adapting the size of the transport block of the air interface to improve transmission efficiency, and may perform segmentation on the RLC PDU not including SN.

To this end, the present application provides a data packet segmentation method, including: the method comprises the steps that a first node obtains a segmentation serial number of a first Radio Link Control (RLC) Packet Data Unit (PDU), the first node is a layer2relay node, the segmentation serial number has uniqueness in a bearing where the first RLC PDU is located, the first RLC PDU is a segment of a second RLC PDU, the second RLC PDU is the RLC PDU received by the first node, and the first node sends the first RLC PDU containing the segmentation serial number.

Wherein, the uniqueness of the segmentation sequence number in the bearer where the first RLC PDU is located comprises: the packet data convergence protocol PDCP PDU contained in the second RLC PDU is not segmented, and the segmentation sequence number is the sequence number of the PDCP PDU of the second RLC PDU.

The above-mentioned first node obtaining the segmentation sequence number of the first RLC PDU includes: the first node obtains a segmentation sequence number from a PDCP PDU protocol header contained in the second RLC PDU; or, obtaining a segmentation sequence number from a protocol header of the second RLC PDU; or, obtaining a segmentation sequence number from a protocol header of a packet included in the second RLC PDU; or, obtaining a segmentation sequence number from a protocol header of a packet containing the second RLC PDU; or, the first node receives a control signaling sent by the second node, the control signaling contains a segmentation sequence number, and the second node is a sending node of the second RLC PDU.

Based on the foregoing description, an embodiment of the present invention provides a method for segmenting a data packet, as shown in fig. 7, including:

701: the second node sends a second RLC PDU to the first node;

the second node may be the sending node of the second RLC PDU in the foregoing embodiment, for example: donor, UE, may also be a relay node of L3. The second RLC PDU may or may not carry RLC SN, and the RLC SN may be information carried together with the second RLC PDU when carrying RLC SN; under the condition that the second RLC PDU does not carry RLC SN, a separate control signaling can be used for carrying, which is not limited uniquely by the embodiment of the present invention.

702: if the RLC SDU contained in the second RLC PDU is not segmented, the first node acquires a segmentation serial number of the first RLC PDU;

the first node is a layer2relay node, the segmented sequence number has uniqueness in a load where the first RLC PDU is located, the first RLC PDU is a segment of a second RLC PDU, and the second RLC PDU is an RLC PDU received by the first node. The first node may be any L2 relay node that performs RLC PDU segmentation, and the specific location in the relay network is not limited by the embodiment of the present invention.

In this embodiment, the relay node does not refer to a node that performs the transparent transmission function, and may be a relay node of L2 in the relay network. The segmentation sequence number may be equal to the PDCP SN or referred to as the sequence number of the PDCP PDU, or may be another sequence number that can ensure that the segmentation sequence number has uniqueness in the bearer of the RLC PDU, which is not uniquely limited in this embodiment.

703: the first node transmits the first RLC PDU including the segmentation sequence number.

The embodiment of the invention segments the RLC PDU by the L2, provides a basis for the recombination of the RLC PDU by using the segmentation serial number with uniqueness in the load, and can avoid the problem that the RLC PDU can not be segmented by the first node due to lack of the segmentation serial number.

The manner of obtaining the segment sequence number and transmitting the segment sequence number is described in the foregoing, and please refer to the foregoing, which is not described herein again.

Based on the different carrying manners of the segment sequence numbers, the following embodiments provide three application examples. In the following embodiments, the first node takes RN of L2 as an example, the second node may be a donor, may also be an L3 functional node, and may also be a UE, and the second node is a donor in the following embodiments.

First, PDCP SNs are obtained from PDCP PDUs as RLC SNs.

Fig. 8 is a schematic diagram illustrating an exemplary downlink transmission flow according to an embodiment of the present invention.

The network shown in fig. 8 includes 3 relay nodes RN 1-RN 3, donor and UE, where RN 1-RN 3 may all be L2 relay nodes, or may be nodes having L3 function, and in the following embodiments, all are L2 relay nodes, donor is a transmitting node, and UE is a receiving node.

1. Transmitting node (donor):

and transmitting data according to a mode defined by the 3GPP protocol.

2. A relay node:

since L2RN does not deploy the PDCP layer. Thus, if the relay node RN1 or RN2 were to segment RLC PDUs, the RN would need to obtain the segmentation sequence number, which here would need to be unique in the bearer in which the segmented RLC PDUs are located. For example: two data in fig. 8, assuming that two data of PDCP SN (also referred to as PDCP PDU SN) of 7 and PDCP SN of 9, the transmitting node and the receiving node thereof are the same and use the same bearer; then the two data cannot be segmented using the same segmentation sequence number, which may be referred to as the RLC SN. In this embodiment, the RLC SN may be equal to the PDCP SN, or may be other segmentation sequence numbers, as long as the segmentation sequence number is required to have uniqueness in the bearer where the segmented RLC PDU is located.

And after the relay node performs segmentation, sending segmented data to a lower node. For example: the RN1 segments the PDCP SN-7 data, and then transmits the segmented data to the RN 2.

In addition, in the embodiment of the present invention, obtaining the segment sequence number is generally performed in a case where it is determined that segmentation is possible. Therefore, the present embodiment further provides that the specific conditions for the relay node to determine to perform segmentation are as follows:

acquiring an RLC mode corresponding to a bearer (bearer) where data to be segmented (RLC SDU/PDU) is located, if the bearer is in an UM mode, when a packet provided by an MAC layer can only transmit part of the data to be segmented, namely the whole data to be segmented cannot be transmitted, segmenting the data to be segmented, otherwise, not segmenting the data to be segmented. It should be noted that whether to segment the data to be segmented may also be determined according to, for example, data transmission capability of the relay node, which is not limited uniquely in the embodiment of the present invention. In addition, judgment can also be added, if the data to be segmented (RLC SDU) is segmented (can be determined according to the received RLC PDU carrying the RLC SN), segmentation can be determined, otherwise segmentation cannot be determined; or whether the RLC SDU has been segmented by other nodes or not.

3. The receiving node:

the method defined by the 3GPP 38.322 protocol is adopted for processing.

In this embodiment, if the segmentation sequence number (RLC SN) is equal to the PDCP SN, the RLC layer of the RN is required to have the capability of acquiring the PDCP SN. This function may be deployed in the RLC layer or adaptation layer of the RN. The adaptation layer may be an independent protocol layer, or may be a sublayer of an existing protocol layer of a New Radio (NR) protocol. In addition, for Data Radio Bearer (DRB), the header of the PDCP PDU is not encrypted, and the PDCP SN therein can be directly read.

In the example shown in fig. 8, only at the UE, the RLC PUD segmented packet is reassembled, and assuming that the data with PDCP SN of 9 is segmented at RN1 and the data with PDCP SN of 7 is segmented at RN2, RN1 and RN2 add RLC SNs to the segmented RLC PDUs, respectively, and in fig. 8, the RLC SNs are as follows:

at time T1, the RLC PDU sent by RN1 to RN2 carries packets with PDCP SN of 7 (PDCP PDU), and the RLC PDU sent by donor to RN1 carries packets with PDCP SN of 9 (PDCP PDU) -these PDCP PDUs (i.e. RLC SDUs) are not segmented and do not carry RLC SN.

At time T2, the RN in this embodiment has the capability of acquiring PDCP SNs of PDCP PDUs, and then adds RLC SNs to PDCP SNs when RLC layer segmentation is performed.

For example, the RN2 divides the data packet into two segments according to the link condition, where the RLC SN added to the RLC PDU corresponding to the first segment is 7, the length of the carried data is 10 bytes, the RLC SN added to the RLC PDU corresponding to another segment to be transmitted is 7, SO indicates that the offset value is 10, and SI indicates that the segment is the last segment;

similarly, RN1 divides the data packet addressed to RN2 into two segments, where the RLC PDU corresponding to the first segment adds RLC SN of 9, carries data length of 20 bytes, the RLC PDU corresponding to another segment to be transmitted adds RLC SN of 9, SO indicates its offset value to be 20, and SI indicates that it is the last segment.

When the data packet reaches the UE, the packet discarding caused by misjudgment can not occur.

In addition, this embodiment also provides two alternative descriptions of the above relay node, which are respectively: the RN performs two schemes of RLC SDU segmentation and re-segmentation of RLC SDU segmentation, and assumes that RLC SN ═ PDCP SN specifically is as follows:

scheme 1(Case 1): the RN performs RLC SDU segmentation:

the scheme comprises the following steps (operation of an RN internal RLC entity or an RLC layer):

step 1: if the RLC layer of the RN needs to execute RLC SDU segmentation, whether PDCP PDU analysis is triggered is judged according to the following conditions, for example, the PDU header (header) is analyzed, and PDCP SN is obtained:

acquiring an RLC mode corresponding to a bearer (bearer) where data to be segmented (RLC SDU/PDU) is located, and if the RLC mode is an UM mode, triggering the PDCP PDU to analyze and acquire a PDCP SN.

In the scheme, if the RLC SDU has been segmented or the RLC PDU carries RLC SN, the operation of analyzing the PDCP PDU may not be triggered, otherwise, the PDCP PDU may be triggered to analyze and obtain the PDCP SN.

In the present solution, the condition for determining whether the operation of analyzing the PDCP PDU needs to be triggered may be set as needed, and the determination sequence may be set arbitrarily, which is not limited by the present invention.

Step 2: the RN takes the acquired PDCP SN as the RLC SN of the RLC PDU, and processes other fields, such as SI, SO and data fields, according to the existing protocol; and then transmits the processed RLC PDU to the lower node.

Case 2: the RN performs re-segmentation of RLC SDU segmentation:

in the scheme, the RLC UM is subjected to function expansion: considering that in the Relay network, the link quality among the multiple hops is different, and the size of the data packet which can be transmitted by each hop is different, therefore, the segmentation re-capability can be introduced into the UM of the RN, and the data packet transmitted among the multiple hops is segmented again according to the link quality, so that the utilization rate of resources can be improved.

Correspondingly, the re-segmentation operation of RLC SDU segmentation (PDU process of generating RLC) comprises:

the RLC SN remains unchanged, i.e.: RLC SN obtained in case1 segmentation operation, or RLC SN set in RLC PDU at the time of segmentation by the transmitting node;

the SI is set according to the segmentation condition defined by the protocol;

and after the RLC SDU segmentation is performed with re-segmentation, the data field of the PDU is put into the RLC SDU segmentation.

The SO is set according to the result of the re-segmentation.

In addition, the embodiment of the invention can exchange RLC configuration information through RLC configuration and inform the information of the RLC mode and/or the RLC SN length. It should be noted that the RLC mode and/or RLC SN length may be pre-configured.

According to the definition of 3GPP 38.322 protocol, RLC has multiple modes, and RLC SN length may have different options, and RLC PDU format may be different due to different RLC modes or different RLC SN lengths. Therefore, the length of the RLC mode and the RLC SN may be used to determine a format used when the RLC PDU is generated; accordingly, the relay node or the receiving node may attempt to parse and process each field of the RLC PDU according to the RLC mode and the PDU format corresponding to the RLC SN. For example: the RLC SN related to the embodiment of the invention is extracted. Examples of PDU formats are provided in the subsequent embodiments.

The relay node needs to know the mode of the RLC mode/RLC bear; in addition, for the same Radio bearer (Radio bearer) of the same UE, the RLC bearer or QoS flow usually uses the same RLC mode. The relay network RLC configuration, in particular the configuration of the RLC mode, may be generated by the donor RN, and the RLC configuration interaction may be as follows:

case 1: donor generates RLC mode:

the donor sends the generated RLC configuration (including RLC mode) to each RN.

Case 2: the RN generates an RLC mode, if the RLC configuration of the UE bearer is generated by the RN, for example: RN generation (RN 2 in fig. 2) for direct access UE, there are two possibilities:

case2.1, the RN generating the RLC configuration sends the RLC configuration to the rest of RNs (RN 1 in FIG. 2)

Case2.2, the RN generating the RLC configuration sends the RLC configuration to the donor; the remaining RNs (RN 1 in FIG. 2) are informed by donor of the RLC configuration

The RLC configured transmission mode:

the RLC configuration interaction may be performed in a bearer configuration or reconfiguration process, and specifically, the RLC configuration may be sent as follows: RRC signaling, or layer2 signaling such as MAC CE, or RN and donor and the interface between RN and RN, e.g. adaptation layer or F1AP interface.

The receiving node of the RLC configuration may store this information.

In the 3GPP 38.322 protocol, the RLC mode includes:

transparent Mode (TM), Acknowledged Mode (AM), and UM Mode.

Since UM mode currently supports different sequence number lengths (e.g., 12bit and 6bit), the RLC SN may be specified in the RLC configuration to keep the nodes consistent. Avoid the situation that the RLC SN is inconsistent with the actual RLC SN due to sequence number truncation (e.g., 12bit to 6 bit).

In this embodiment, if the RLC SN adopts the PDCP SN, since the PDCP SN is usually maintained by the UE and the donor, and the relay node adopts the sequence number when setting the RLC SN of the RLC PDU, it can be ensured that the sequence number of the RLC PDU has uniqueness in multi-hop transmission, and packet discarding caused by using the same RLC SN when different PDCP PDUs are forwarded in multi-hop is avoided.

And II, signaling to transfer the RLC SN.

The former embodiment provides obtaining PDCP SN from PDCP PDU as RLC SN, and the present embodiment provides a scheme of using signaling to transfer RLC SN. In this embodiment, two cases are included, namely segmentation and non-segmentation performed at the RN.

Case 1: the RN performs segmentation.

As shown in FIG. 9, for downlink transmission, RLC SN may be carried when donor forwards data to RN1 or RN1 forwards data to RN 2. The RLC SN may be carried using L2 signaling, with no RLC SN (without SN) in the RLC PDU.

Step 1, the donor sends the SN corresponding to the data, that is: the RLC SN of the RLC SDU is transmitted.

In this embodiment, the donor is an originating node of data, the originating node of the data on the RAN side during downlink transmission may be the donor or RN, and the originating node of the data during uplink transmission may be the UE or RN. The specific implementation process is similar, and this embodiment exemplifies the case where the data originating node is a donor, in the following transmission.

Optionally, in this step, the donor may send its corresponding RLC SN only for the unsegmented RLC SDU (PDCP PDU) through L2 signaling.

And step 2, when the RN executes the RLC SDU segmentation, acquiring the RLC SN contained in the L2 signaling as the RLC SN of the segmented RLC PDU.

In this embodiment, the RN is an RLC entity/RLC layer, and RLC SDU segmentation may be performed. The conditions under which the RN triggers the acquisition of RLC SN carried by the L2 signaling, which requires the acquisition of RLC SN before RLC SDU segmentation is performed, may be as follows:

1) RLC mode: if the RLC mode corresponding to the acquired RLC SDU/PDU (bearer) is the UM mode, the RLC SN carried by the L2 signaling is triggered and acquired.

2) The segmentation condition is as follows: the RLC SDU has been segmented before being sent by the originating node or forwarded by the relay node, or whether the RLC PDU sent in the previous hop already carries RLC SN, which if not segmented or not, may trigger the acquisition of RLC SN carried by L2 signaling.

In this step, the RN may obtain the RLC SN from the RLC layer, or may obtain the RLC SN from the MAC layer. For the former, after receiving the MAC CE carrying RLC SN, the MAC layer of RN delivers MAC layer data (MAC SDU) to the RLC layer together with SN information in the MAC CE.

Step 3, if the RLC SN is acquired, RN1 sets the RLC SN of the RLC PDU segment to the acquired RLC SN.

In addition, the L2 signaling in step 1 may include, in addition to the RLC SN, SN related information of the RLC, such as: the Identification (ID) of the corresponding relation between the RLC SN and the RLC PDU; the ID is used to associate the RLC PDU with the RLC SN. The ID may be a UE ID such as a cell radio network temporary identifier (C-RNTI), a UE bearer ID, a Logical Channel Identifier (LCID), an RN bearer ID, and the like.

In addition, in the embodiment of the present invention, the RLC SN may be set arbitrarily as long as it satisfies that the bearer in which the transmitted data is located has uniqueness; the RLC SNs can be PDCP SNs, ciphered and guaranteed counters maintained by the PDCP layer, SNs of GTP-Us, and the like. Among them, the counter may contain Hyper Frame Number (HFN) and SN. The above-mentioned globally unique RLC SN may be generated by the sending node, and the relay node simply uses or forwards the RLC SN without modifying the SN. In this embodiment, the RLC SN is generated by the transmitting node, for example, by the UE at the time of uplink transmission and by the base station at the time of downlink transmission.

In this embodiment, the RLC SN carried by the L2 signaling may be associated with RLC PDU/RLC SDU by ID. For example: when the relay node processes the RLC SDU of a bearer of a certain UE, the L2 signaling is searched according to the UE ID and the bearer ID, and the SN provided by the signaling is read. In addition, other schemes such as a scheme using a dual-layer RLC may be adopted to associate the RLC SN with the RLC PDU, and the embodiment of the present invention is not limited uniquely.

The above L2 signaling may be MAC CE, RLC control PDU, etc. The L2 signaling may be sent with the MAC PDU that sent the RLC PDU so that the RN can acquire the SN in time when performing segmentation.

In this embodiment, if the MAC CE carries the RLC SN, the MAC CE in the 3GPP 38.321 protocol may be designed and a corresponding MAC sub header may be selected. The method comprises the following specific steps:

the existing MAC subheader format may be used. For example, a MAC subheader that may indicate a fixed length MAC CE is selected. The format of the MAC header will be explained in the following embodiments.

The format of the MAC CE and the LCID corresponding to the MAC CE may also be newly defined, that is: the type and format of the MAC CE are determined by the LCID carried by the MAC subheader, namely, the MAC CE carries the RLC SN.

LCID may select a field reserved by the current protocol, for example, '100001', and it should be understood that 100001 is only an example, and may also be other reserved fields, which is not limited in this embodiment; the MAC CE needs to include information of RLC SN and ID, as shown in fig. 10, the MAC CE carries RLC SN (length is 16 bits), and may further include UE ID (length is 8 bits) and bearer ID (length is 8 bits); fig. 10 shows a MAC sub-header without L field, and fig. 11 shows a MAC CE carrying SN. It should be understood that this is only an example, and for SNs with different lengths, the length of the SN field may be different, which depends on the configuration specifically, and this embodiment is not limited and will not be described again.

If the RLC Control PDU carries SN, an RLC Control PDU format can be newly defined in the 3GPP 38.322 protocol. The RLC Control PDU and the RLC PDU carrying the data packet are transmitted in the same bearer, and no ID is needed to associate the RLC Control PDU with the RLC PDU transmitting the data, so that only RLC SN information may be included, as shown in fig. 12 (assuming that SN is 16 bits), where fig. 12 is the RLC Control PDU carrying SN.

Case2, RN does not perform fragmentation.

The present embodiment differs from the previous embodiment in that the previous embodiment focuses on performing segmentation at the RN, and in the present embodiment, if the RLC SDU has been segmented, the RLC SN is already included in the RLC PDU sent by the RN; if the RLC SDU is not segmented, then the RN may also consider the forwarding of the RLC SN when transmitting data. As shown in fig. 13, the originating provides the SN through signaling, and the unfragmented last hop does not forward the SN.

Step 1, denor provides RLC SN.

This step is the same as the step of case1, and is not described herein again.

Step 2, RN determines that RLC SDU is not segmented and decides whether to forward RLC SN or not.

The steps are specifically divided into the following conditions:

1) for example, RN1 shown in fig. 13, RLC SDU is not segmented in RN1 (RLC PDU does not carry RLC SN), RN1 is not the last hop, RN1 performs the following procedure:

if the RLC SDU is not segmented, the RLC SN and related information thereof are continuously forwarded; if segmented, the SN-related information is not forwarded. The specific contents and manner of forwarding the RLC SN and the related information thereof are described in step 1, and are not described herein again. The above-mentioned related information refers to the information mentioned in the foregoing that there may be an ID; since the information of the ID does not necessarily exist, the related information may not exist.

2) For example, RN2 shown in fig. 13, in RN2, RLC SDU is not segmented (RLC PDU does not carry RLC SN), RN1 is the last hop, and RN1 performs the following procedure: the RLC SN may be forwarded. The RLC SN may not be transmitted. The RLC SN may not be included in the L2 signaling if it is not sent.

And step 3, receiving the UE.

Two cases of forwarding or not forwarding the RLC SN can be selected according to the last hop in the foregoing step 2, and there are two corresponding processing cases on the UE side, as follows:

if the last hop RN forwards L2 signaling, but the RLC SDU is not segmented; in this case, the UE receives an RLC SDU which is not segmented, ignores the RLC SN provided by the L2 signaling, and then processes the complete RLC SDU according to the existing protocol. If the RLC PDU is segmented, the RLC PDU carries the RLC SN and the UE performs the packetization process according to the existing protocol.

In this embodiment, the sending node provides the RLC SN with uniqueness to the relay node through L2 signaling, and the relay node uses the RLC SN carried in L2 signaling when performing segmentation, so that the RN can obtain a segmentation sequence number when performing segmentation, which provides a basis for the relay node in the L2 layer to segment the RLC PDU.

Third, the previous embodiment provides a scheme for transferring RLC SN using L2 signaling. In this embodiment, a scheme for carrying RLC SN in RLC PDU is provided.

Before describing the specific flow of this embodiment, first, an implementation scheme that specifically carries the RLC SN in the RLC PDU is described as follows:

according to the specification of 3GPP 38.322 protocol, the RLC segment carries SN, specifically: the format of UMD PDU containing SN is defined, and the SN number is carried only by UMD PDU containing RLC SDU segmentation or RLC UMD PDU or RLC PDU. And, the SI field of the PDU is used to indicate various fragmentation conditions:

the data part of the PDU carries the first segment of the RLC SDU, e.g., the SI field is set to '01';

the data part of the PDU carries the last segment of the RLC SDU, e.g., the SI field is set to '10';

the data part of the PDU carries the middle segment of the RLC SDU, e.g., the SI field is set to '11';

if the data part of the PDU carries a complete RLC SDU, the SI field is set to '00', and the corresponding UMD PDU does not carry SN.

Please refer to table 1 above, and the values and corresponding meanings of SI are not described herein.

Based on the above description, in this embodiment, taking RLC UMD PDU with SN length of 6bit as an example, the following different PDU formats are adopted for different SI or segmentation cases:

the RLC SDU is unsegmented, i.e., contains a complete RLC SDU, for example, with the SI field set to '00', and adopts the following format, SN-free field and SO-free field, as shown in fig. 14, and is referred to herein as format1 for convenience of description.

The first segment of the RLC SDU, for example, the SI field is set to '01', and the following format is used, without the SO field, as shown in fig. 15, and referred to herein as format2 for convenience of description.

The middle segment, or the last segment, contains both SI and SO fields, with the SI field set to '10' or '11', as shown in fig. 16, and referred to herein as format3 for convenience of description.

The embodiment considers that SN information is carried based on the existing UMD PDU format, and is divided into three alternatives of Alt 1-Alt 3. Wherein, the cases that Alt1 contains 'complete RLC SDU' and 'complete SDU + SN' exist at the same time; alt2, all packets carry SNs.

Note that the specific values of the PDU format or field defined by various options may be used only for donor and Integrated Access and Backhaul (IAB) nodes, or between an IAB node and an IAB node. When the donor communicates with the UE, or the IAB node communicates with the UE directly, the PDU format defined by the existing protocol may be adopted. Another option is to use only the updated PDU of the present invention, whether communicating with the UE or with the IAB node. The IAB node, the RN and the relay node in the foregoing are all nodes in a relay network, and are located between the donor and the UE to perform a relay function. The IAB node, RN and relay node are network entities with the same function in the relay network.

Alt1：

And extending the SI, redefining the PDU format, and indicating that the data field contains the complete RLC SDU by using a specific value of the SI. For example: the SI of 3bit is defined, and the value '111' indicates that the PDU includes SI, SN and data fields, and the data field includes a complete RLC SDU. Optionally, the PDU may further include an SO field. Specifically, the following Alt1.1 and Alt1.2 schemes may be included.

Alt1.1, retaining multiple formats:

the SI of the formats 1-3 introduced above is extended to 3bit, and the new formats are as follows:

corresponding to Format1 'of Format1, as shown in fig. 17, Format 1' carries unsegmented SDUs without SN, and SI takes the value '000', and SI uses a reserved bit as compared to the previous Format 1.

As shown in fig. 18, the Format2 'carries the SI value' 001 'of the first segment or the complete SDU + SN, and the SI value' 111 ', which corresponds to the Format 2' of the Format2, and after SI extension, a reserved bit is added to ensure byte alignment, compared to the Format 2.

As shown in fig. 19, Format3 'corresponding to Format3, Format 3' carries a middle segment and a last segment, and includes an SO field, and the value of SO is the same as that in the foregoing, which is not described herein again; format 3' after SI expansion relative to Format3 above, a reserved bit as shown in FIG. 19 is added to ensure byte alignment.

The advantage of this scheme is that the definition of SO does not need to be changed.

Based on the newly defined PDU format, the values of the fields under various RLC SDU segmentation conditions are shown in table 2 below:

TABLE 2

Alt1.2, only one SN format is used, for example, format 3' of alt2.1 is used, and values of fields are shown in the following table, where SI distinguishes different schemes (cases), and values of SO are related to whether there is an SN and values of SI, as shown in table 3 below.

TABLE 3

The advantage of this scheme is that only one PDU is defined for the IAB network.

Alt2, the newly defined PDU does not distinguish between "complete packet" and "complete RLC SDU + SN", i.e. the PDU carrying a complete RLC SDU always carries SN. The classification into alt2.1 and alt2.2 is as follows:

alt2.1, the "complete RLC SDU + SN" is represented by SI '00', and since the PDU includes complete RLC SDU, SO value does not need to be considered in packet parsing, SO value of SO can be arbitrarily chosen. As shown in table 4:

TABLE 4

The scheme is slightly modified compared with the existing protocol.

Alt2.2, on the basis of alt1.2, delete the table with the first row, i.e.: the Format 1' is removed.

Based on the foregoing description, a specific scheme for using RLC PDUs to carry RLC SNs has been specified. Based on the description based on Alt1, when the RN forwards data, the following two schemes are available:

case 1: when the RN forwards data, if the RN does not perform a fragmentation operation, SN and SO fields set by the transmitting node may be reserved.

Case 2: when the last hop RN forwards data, if the last hop RN does not perform segmentation operation, the SN and SO fields set by the sending node can be removed. That is, the last hop relay node sends format1 to the UE, and the relay node sends the complete RLC SDU specified by format3+ SO.

The embodiment of the invention also provides an implementation scheme for the relay node to determine whether the relay node is the last hop:

according to the route of the IAB network, when the donor sends data or signaling to the IAB node accessing the UE, the donor may add the identifier of the IAB node to the data packet as the destination address of the route. For example, the IAB network may implement routing through the adaptation layer, and then the packet header of the adaptation layer may carry the destination IAB node scheduling identifier when sending the data packet. When the relay node processes the data packet, whether the data packet needs to be processed at the relay node can be judged according to the identifier carried by the adaptation layer packet header; if the scheduling identifier is consistent with the identifier of the node, the node is considered to need processing, namely the node is a last hop relay node; if the scheduling identification is inconsistent with the node, the data is required to be forwarded further, and then the next hop for data transmission is selected based on the scheduling identification.

In the following embodiments, specific implementation flows including two schemes will be described.

In Case1, RN does not remove SN and SO, as shown in FIG. 20, the processing steps are as follows:

step 1, a sending node (donor) adds SN and SO when sending RLC SDU.

In this step, even if a complete RLC SDU is transmitted, SN is obtained to be filled in the RLC PDU, and the SI or SO field takes a specific value indicating that "Data field carries one complete RLC SDU". The SN is an RLC SN, and has uniqueness in the bearer in which the RLC SDU is located.

Wherein, the SN may be a PDCP SN, a ciphering and integrity counter maintained by the PDCP layer.

And 2, forwarding operation of the relay node. RLC SDUs may or may not be segmented at the relay node, e.g., Alt1 and Alt2, respectively, as follows:

alt1 if the RLC SDU is segmented or re-segmented.

The SI takes values according to the protocol definition and according to the RLC SDU segmentation carried therein, and the specific values are as shown in table 4 above.

As shown in table 4, if not segmented then SI 00; if segmentation is performed, the first segment SI is 01, the middle segment SI is 11, and the last segment SI is 10. The value of the fragment SN is present and remains unchanged from the received SN value.

SN remains unchanged, i.e.: the RLC SN is equal to a unique SN, such as a PDCP SN.

SO is calculated according to the protocol definition and RLC SDU/replacement is put in; as shown in table 4, if not segmented, the relay node may only need to forward the received data, where for the SI 00 case, the RLC PDU may not contain SO; if the segmentation is carried out, the SI value in the segmentation is modified, the SO value corresponds to the modification of the SI value, for example, the first segmentation does not contain the SI value, and the SO values of the middle segmentation and the last segmentation can both conform to the 3GPP 38.323 protocol.

The Data field (Data field) puts the corresponding RLC SDU segment.

Alt2, if the RLC SDU is not segmented, the values of the fields of the RLC PDU are kept unchanged during forwarding. In this case transparent transmission.

And step 3, the node of the receiving node (or the node with the RLC SDU recombination function) processes the RLC PDU according to the SI and SO fields. The method comprises the following specific steps:

if the SI indicates that the complete RLC SDU is contained, no further RLC SN needs to be obtained; if SI or SI and SO indicate RLC PDU contains a complete RLC SDU together, if include complete RLC SDU, submit to the upper strata after removing the packet header, otherwise, according to the existing protocol, carry on the processing of RLC PDU according to SI value.

Case2, as shown in fig. 21, using RLC PDU to carry SN, if not segmented, deleting SN and SO in the last hop, and the processing steps are as follows:

step 1, a sending node:

the details of the processing are the same as step 1 of case1 and will not be described herein.

Step 2, processing of the relay node RN:

alt1, if RLC SDU is segmented or RLC SDU is re-segmented, refer to Case1 in the previous embodiment, and will not be described herein again.

Alt2, if RLC SDU is not segmented, RN determines whether it is the last hop of the path where RLC SDU is located, if SO, removes SN and SO fields in RLC PDU, that is: the PDU containing the complete RLC SDU as defined by the existing protocol is used for data transmission. Otherwise, the value of each field of the transmitted RLC PDU and each field of the RLC PDU of the previous hop node remain unchanged, or the information carried by the RLC PDU of the previous hop is adopted, including SI, SO, and the like, that is, transparent transmission is performed.

Note that, the RN determines whether it is the last hop, and the specific scheme has been described above, which is not described in this embodiment again.

And step 3, receiving the node.

The processing of the receiving node follows the existing protocol and is not described in detail here.

In this embodiment, when each node processes an RLC SDU, it may first determine whether a bearer corresponding to the data is in an RLC UM mode, and if not, the procedure of the embodiment of the present invention need not be executed.

In this embodiment, SN is transmitted together with Data without segmentation of RLC SDU, so that the relay node can use the SN as RLC SN, thereby avoiding the problem of being unable to determine the SN that should be used correctly in segmentation due to lack of SN. The SN carried in the RLC SDU can be provided by a sending node, and the SN of the same RLC PDU keeps unchanged in the whole transmission path, so that the uniqueness of the SN can be ensured. In this embodiment, the existing PDU format may be multiplexed, the RN does not need to have the capability of reading the PDCP header, and the L2 signaling for interacting SN does not need to be newly defined, and the RLC SDU and its corresponding SN are transmitted together, which does not need to indicate the corresponding relationship between the SN carried in the L2 signaling and the RLC SDU.

The foregoing embodiments provide a scheme for carrying SN in a protocol layer header, i.e., a scheme for transmitting the SN-carrying header together with data/RLC PDUs. In the following embodiments, the protocol header will be described in more detail.

As shown in fig. 22, DL MAC PDU is defined for 3GPP 38.321 protocol.

As shown in fig. 22, one MAC PDU of NR may contain a plurality of MAC sub PDUs; each sub PDU may be of the form:

sub-only (including padding);

subheader + MAC CE (control element);

subheader+MAC SDU；

subheader + padding.

In the 3GPP protocol, the subheader is as follows: the difference is whether there is L field and the length of L field is different; if an L field is present, then an F field is needed to refer to the length of the L field:

a subheader with the length of the L field being 8bit is used for MAC SDU and variable-length MAC CE; as shown in fig. 23, is a subheader with an L field length of 8 bits;

a subheader with the length of the L field being 16bit is used for MAC SDU and variable-length MAC CE; as shown in fig. 24, is a subheader with an L field length of 16 bits;

a subheader without L field for MAC CE with fixed length or padding; the length is implicitly provided for padding, e.g., the transport block size minus the length of all Sub-PDUs. As shown in FIG. 25, is a subheader without L fields.

The values of the fields are as follows:

logical Channel Identification (LCID);

l (length) for indicating the length of SDU or MAC CE in the current sub PDU;

f, for indicating the length of the L field, for example, 0 is used to indicate the L field of 8 bits, and 1 is used to indicate the L field of 16 bits;

and an R field of 0 by default.

The embodiment of the invention can provide a technical scheme based on a 3GPP 38.321 protocol, wherein, the RLC PDU is upper layer data relative to an MAC layer and can be sent together with a subheader as an MAC SDU. Correspondingly, SN may be carried in the MAC subheader, and specifically, the subheader of the NR may be extended, and a field carrying SN is added, for example, 16 bits (2 bytes) is added.

Taking the subheader with the length of L being 8 bits as an example, the format after the expansion is shown in fig. 26, which is a schematic diagram of the subheader with the length of L being 8 bits carrying SN.

Further, if the R field is set to 1, it can be used to indicate that the corresponding subheader carries SN. The other fields, such as LCID, F, L, are defined to take values according to the existing protocol, and are not described herein again.

Extension 1, in the adaptation layer (no specific protocol yet) header, possibly described in 3GPP technical report 38.874 for IAB; assuming that the adaptation layer is deployed below the RLC layer, after the RLC PDU is sent to the adaptation layer, the adaptation layer may add a header, where the header at least includes SN corresponding to the RLC PDU.

In the extension 2, a GTP (General Packet Radio System (GPRS) tunneling Protocol) header specified in the 3GPP 29.281 Protocol is used. If the RLC PDU passes through a GTP-U (user plane) tunnel when delivered to the lower layer, the corresponding interface can be F13 GPP 38.470 protocol/Xn 3GPP 38.420 protocol/NG 3GPP 38.410 protocol/S13 GPP 36.410 protocol/X23 GPP 36.420 protocol, etc., and the GTP-U packet header can carry SN information at this time.

In the current 3GPP 29.281 protocol, there is PDU of GTP, as shown in fig. 27, where t (transport) -PDU is the payload of GTP PDU, i.e. user data packet, such as IP packet, or RLC PDU mentioned in the present invention. The GTP-U header, as shown in FIG. 28, may have two alternatives:

and the Alt1 uses the GTP-U packet header and utilizes the existing SN field to carry the SN corresponding to the T-PDU/RLC PDU.

Alt2, the added field is used to carry SN corresponding to the RLC PDU. For example: the 16-bit SN does not meet the requirements or the SN is used for packet management of GTP-U. The updated PDU is shown in fig. 29 below.

Further, the R field set to "1" may be used to indicate that the header carries the sequence number of the corresponding T-PDU.

In contrast to the previous embodiment, the SN of this embodiment is transmitted together with the RLC PDU in the header of a different protocol layer. This ensures that the RN performing the fragmentation can accurately know the SN in time.

The foregoing embodiments are all performed by RLC PDU segmentation at the relay node, and this embodiment provides RLC PDU segmentation at the transmitting node, that is: the transmitting node is segmented in advance, and the existing PDU containing RLC SDU segmentation of the protocol is utilized to provide the SN number for the RN, and the UMD PDU is described in the previous embodiment and is not described again here. In this embodiment, since the pre-segmentation is performed at the transmitting node, it is not necessary to define a specific value of the field SO or to extend the SI field.

In this embodiment, the transmitting node may segment the UM mode RLC SDU in any case. In addition, in order to reduce the overhead increase caused by fragmentation, a judgment criterion may be further introduced, and fragmentation is performed at the transmitting node only when data is forwarded at each hop RN, thereby reducing unnecessary fragmentation.

The specific judgment rule may be as follows:

the maximum transmission capability of the RN is defined, for example, as Maximum Transmission Unit (MTU), and if the RLC SDU is larger than the maximum transmission capability, it means that the RN will segment the RLC SDU when it is processed. Therefore, the transmitting node may segment the RLC SDU in advance before transmitting data to the RN or if the MTU of the RN is smaller than the RLC SDU.

In the foregoing, the MTU needs to be used, and therefore, the MTU needs to be obtained through information interaction between the sending node and the receiving node. In addition, the MTU for uplink transmission may be different from the MTU for downlink transmission, and thus the uplink MTU and the downlink MTU may be configured separately.

The nodes perform interaction information, for example: RN and donor, RN and UE, RN and RN. Optionally, only a sending node of data, or a node with segmentation capability, such as UE in uplink transmission, or donor in downlink transmission, obtains the maximum transmission capability of the RN. For example,

during uplink transmission, UE or RN needs to know the MTU value of each hop and each path of RN;

during downlink transmission, the donor or RN node needs to know the MTU value of the RN on each path.

The specific information interaction mode may be as follows:

MTU information can be directly interacted among all nodes, or MTU information can be configured to RN or UE after a certain node/centralized control node such as a donor collects MTU.

Further, donor may send all received MTUs to the remaining nodes. Or based on certain criteria, such as screening out the minimum MTU value and then sending it to the remaining nodes.

It is considered that the present embodiment provides a new characteristic with respect to 3GPP Release15, i.e., that the UE of Release15 cannot recognize the MTU. Therefore, no matter the nodes are directly interacted, or the mode of firstly collecting and then configuring is centralized, the following distinction can be made when selecting the receiving node of the MTU:

if the UE is the UE of release15, only sending the MTU to RN and donor;

if the UE is the UE of release16, the MTU can be sent to UE, RN, donor.

The signaling used for information interaction may be: layer 1, layer2, layer 3, F1 control plane, Adaptation layer (Adaptation layer) control signaling.

Layer 1 may report the MTU by UCI, please refer to 3GPP 38.213 protocol;

layer2, a specific MAC CE may be defined for reporting MTU; please refer to 3GPP 38.321 protocol;

layer 3, RRC signaling may be defined for reporting MTU, which may refer to 3GPP 38.331 protocol;

f1 control plane signaling, such as the gNB Data Unit (DU) Configuration Update (Configuration Update) message of F1AP to carry MTUs;

control information of the adaptation layer, for example: status report information of the adaptation layer.

Further, the interaction triggering condition for the MTU may be that the interaction of the MTU information is triggered periodically; event triggering may also be used, for example, when the RN determines that the current MTU exceeds a certain threshold relative to the last MTU, the MTU interaction is triggered. Optionally, when event-triggered, to avoid frequent MTU updates, a timer may be configured to control the minimum time between event triggers, thereby reducing the frequency of event triggers.

The generation process of the MTU value may be: the protocol is used to stipulate the calculation mode of the MTU and necessary parameters. For example: and the RN determines the MTU value of the RN when the RN sends data to the previous hop node or the next hop node/UE according to the parameter information such as the link quality and the load of the uplink/downlink.

After the sending node obtains the MTU information, the sending node executes the following contents:

step 1, in the UMD mode, the donor determines whether to segment the RLC SDU according to the MTU.

Wherein, donor is a sending node, and triggers the segmentation operation of RLC SDU according to the following conditions:

case1, the length of the RLC SDU is larger than the MTU of a single RN, such as the MTU of the next hop RN/the last hop RN.

In Case2, the length of RLC SDU is greater than Min (MTU) on the transmission path, i.e. greater than the minimum value of MTU of each hop.

And 2, carrying out RLC SDU segmentation operation by the donor according to the existing protocol, setting RLC SN, and submitting the RLC PDU to a lower layer.

Since the donor is the sending node, it can ensure the uniqueness of the RLC SN in its bearer.

The processing of the relay node is as follows:

if the relay node does not segment the RLC SDU, then the values of the fields of the entire RLC PDU remain unchanged, for example: the RLC SN keeps unchanged, or the value of each field of the generated RLC PDU is consistent with that of the RLC PDU of the previous hop. In this case, the relay node transparently transmits the received data.

The receiving node processes according to the existing protocol definition, which is not described in detail in this embodiment.

In this embodiment, the pre-segmentation is triggered by the MTU interacting between the nodes, so that the RLC SN can be provided by using the existing protocol scheme, and then the relay node of L2 may not perform the segmentation operation any more.

The embodiment provides a method for RLC SDU segmentation control by an RN, which is applied to a relay node. Unlike the previous 4 embodiments, the present embodiment avoids the relay node to segment the RLC SDU according to the criteria.

Since the relay node does not have a segmentation sequence number when segmenting the "RLC packet without SN", the processing manner of this embodiment is to not segment the forwarded data. That is, if the segmentation of data at the relay node can be avoided, the problem that the relay node of the L2 layer cannot segment the RLC PDU due to the lack of RLC SN at present can be avoided.

However, the purpose of segmentation is to adapt the link conditions, for example: when the channel quality is degraded, less data can be transmitted, so that the bottom layer can carry more redundant information to improve reliability. In order to make link adaptation as possible, decision criteria can be introduced, and no segmentation operation is performed only for specific RLC SDUs.

In one possible scheme, the relay node may define, by a protocol, that the RLC SDU is not segmented, for example, the relay node does not segment RLC data packets not carrying RLC SN, but may segment RLC data packets carrying RLC SN. In this scheme, when the relay node performs data forwarding, it needs to consider scheduling a certain RLC data packet during scheduling.

In another possible scheme, the donor node may segment the UM mode RLC SDU by configuring the relay node whether the relay node is allowed. Specifically, the donor node may configure RLC UM mode segmentation indication to each relay node, and the RLC UM mode segmentation indication may be node-level configuration, that is, the relay node does not segment RLC SDUs of all RLC UM modes, or does not segment RLC data packets not carrying RLC SNs. The segmentation indication of RLC UM mode may also be UE-level, i.e. no segmentation is performed on configured RLC UM mode packets for UEs, or RLC SN not carried RLC packets for UEs. The segmentation indication of RLC UM mode may also be bearer level, i.e. no segmentation is performed on RLC UM mode packets of configured bearers, or RLC SN not carried bearers. The specific configuration depends on the protocol definition or configuration, and the application is not limited.

Based on the above description, as an example, the present embodiment is executed at a relay node, and the specific steps are as follows:

step 1, when the RN forwards the data packet, judging whether to segment or re-segment according to at least one rule as follows:

if the corresponding load of the RLC data packet is in an UM mode, the segmentation is not carried out;

if the RLC data packet does not carry the RLC SN, the segmentation is not carried out;

and step 2, the RN forwards the data out/the RLC entity submits the RLC PDU to a lower layer.

In the embodiment, a decision condition is introduced, and for RLC SDUs which are not in UM mode and/or do not carry RLC SN, no segmentation/re-segmentation operation is performed at the time of intermediate node forwarding. Thereby avoiding the problem of being unable to segment due to lack of RLC SN numbers.

The embodiment of the present invention further provides a first node, which may refer to the detailed description in the foregoing method embodiment, and is not described herein again, as shown in fig. 30, including:

a processing unit 3001, configured to obtain a segmentation sequence number of a first radio link control RLC packet data unit, PDU, where the first node is a layer2relay node, the segmentation sequence number has uniqueness in a bearer where the first RLC PDU is located, the first RLC PDU is a segmentation of a second RLC PDU, the second RLC PDU is an RLC PDU received by the first node, and a PDCP PDU included in the second RLC PDU is not segmented;

a transmitting unit 3002, configured to transmit the first RLC PDU including the segmentation sequence number.

the segmented sequence number is a sequence number of a PDCP PDU of the second RLC PDU.

As a possible implementation, a specific implementation is also provided in which the protocol header of the packet containing the second RLC PDU contains the above-mentioned segmentation sequence number:

the second RLC PDU is encapsulated in a data packet containing an adaptation layer header containing a segmentation sequence number. As a possible implementation manner, the control signaling includes:

and the MAC control element CE, the MAC CE and the second RLC PDU are in the same MAC data packet.

As a possible way of realisation,

the transmitting unit 3002 is further configured to transmit the segmentation sequence number to a lower node when the transmitting unit 3002 transmits the second RLC PDU to the lower node;

alternatively, when the first node is a higher node of a group packet node, the segment sequence number is transmitted to or not transmitted to the group packet node.

An embodiment of the present invention further provides a second node, as shown in fig. 31, including:

an obtaining unit 3102, configured to obtain a second RLC PDU, where an RLC SDU included in the second RLC PDU is not segmented;

a transmitting unit 3101 configured to transmit the segmentation sequence number and the second RLC PDU to the first node;

the segmented sequence number is a segmented sequence number of a first RLC PDU, the first node is a layer2relay node, the segmented sequence number has uniqueness in a load where the first RLC PDU is located, and the first RLC PDU is a segment of the second RLC PDU; the segmentation sequence number is used for the first node to transmit the first RLC PDU including the segmentation sequence number.

As a possible implementation manner, a specific carrying manner for sending the segment sequence number to the first node is further provided as follows:

the protocol header of the second RLC PDU sent to the first node contains the segmentation sequence number;

or, the protocol header of the packet included in the second RLC PDU sent to the first node includes the segment sequence number; alternatively, the first and second electrodes may be,

a protocol header of a packet containing the second RLC PDU, which is transmitted to the first node, contains the segmentation sequence number; alternatively, the first and second electrodes may be,

the control signaling sent to the first node includes the segment sequence number.

As a possible implementation, a specific implementation that the protocol header of the second RLC PDU includes the above-mentioned segmentation sequence number is also provided:

the protocol header of the second RLC PDU includes an SI indicating that the second RLC PDU carries an RLC SDU that is not segmented and contains a segmentation sequence number.

As a possible implementation manner, the control signaling includes:

and the MAC CE, the MAC CE and the second RLC PDU are in the same MAC data packet.

An embodiment of the present invention further provides a second node, as shown in fig. 32, including;

a processing unit 3201, configured to determine whether the second RLC PDU sent by the second node exceeds an MTU of a transmission path where the second RLC PDU is located; if the second RLC PDU is determined to exceed the MTU of the transmission path where the second RLC PDU is located, performing segmentation operation on the second RLC PDU;

a transmitting unit 3202 is configured to transmit a first RLC PDU, where the first RLC PDU is a segment of the second RLC PDU.

As a possible implementation manner, the sending unit 3202 is further configured to send the MTU to a terminal, where the terminal is a receiving side of the first RLC PDU;

a receiving unit 3203 is configured to receive configuration information of the MTU.

An embodiment of the present invention further provides a first node, as shown in fig. 33, including;

a segmentation control unit 3301, configured to determine that a bearer corresponding to a second RLC PDU is in an unacknowledged mode, or if the second RLC PDU does not carry a segmentation sequence number, not segment the second RLC PDU;

a forwarding unit 3302, configured to forward the second RLC PDU.

Referring to fig. 34A and 34B, fig. 34A and 34B are two schematic structural diagrams of a communication device according to an embodiment of the present invention, where the communication device includes a processor 3401, a memory 3402, and a transceiver 3403, and the processor 3401, the memory 3402, and the transceiver 3403 may be connected to each other through a bus.

The Memory 3402 includes, but is not limited to, a Random Access Memory (RAM), a Read-Only Memory (ROM), an Erasable Programmable Read-Only Memory (EPROM), or a Compact Disc Read-Only Memory (CD-ROM), and the Memory 3402 is used for storing related instructions and data. The transceiver 3403 is used to receive and transmit data.

The processor 3401 may be one or more Central Processing Units (CPUs), and in the case where the processor 3401 is one CPU, the CPU may be a single-core CPU or a multi-core CPU.

The processor 3401 in the communication device is configured to read the program code stored in the memory 3402 and execute the method steps provided by the embodiment of the present invention. The method steps can be referred to the previous method embodiments and are not described herein again.

The memory 3402 stores a program code;

it is understood that, based on the foregoing description of the transceiver 3403 for transmitting and receiving signals and transmitting and receiving data, the memory 3402 is used for storing instructions, and the processor 3401 is used for reading and executing the instructions in the memory 3401 to control the communication device to perform any one of the methods provided by the embodiments of the present invention. Please refer to the foregoing, which is not described herein again.

The transceiver 3403 in the present embodiment may correspond to a transmitting unit, a receiving unit, and a forwarding unit in the foregoing apparatus; the functions of the other units in the foregoing device can all correspond to the processor 3401.

The communication apparatus of this embodiment can be used as a communication device, and in this case, the transceiver 3403 can be a device for communicating with the outside, such as a radio frequency antenna; in the case where the communication device is in the form of a chip or an integrated circuit, the transceiver 3403 may be an inter-chip communication interface of the communication device.

An embodiment of the present invention further provides a storage medium, where the storage medium stores a program code, where the program code includes program instructions, and when the program instructions are executed by a processor, the processor cooperates with a transceiver to perform any one of the methods described above according to the embodiment of the present invention.

Embodiments of the present invention further provide a computer program product, which includes program instructions, and when executed by a processor, the program code causes the processor to cooperate with a transceiver to perform any one of the methods described above.

Those of ordinary skill in the art will appreciate that the various illustrative elements and method steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the communication apparatus and the unit described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, method and apparatus may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the above-described division of units is only one type of division of logical functions, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The procedures or functions described above in accordance with the embodiments of the invention may be generated, in whole or in part, when the computer program instructions described above are loaded and executed on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored on or transmitted over a computer-readable storage medium. The computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more of the available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a Digital Versatile Disk (DVD)), a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

One of ordinary skill in the art will appreciate that all or part of the processes in the methods of the above embodiments may be implemented by hardware related to instructions of a computer program, which may be stored in a computer-readable storage medium, and when executed, may include the processes of the above method embodiments. And the aforementioned storage medium includes: various media that can store program codes, such as a read-only memory (ROM) or a Random Access Memory (RAM), a magnetic disk, or an optical disk.

Claims

1. A method for packet segmentation, comprising:

if an RLC Service Data Unit (SDU) contained in a second Radio Link Control (RLC) grouped data unit (PDU) is not segmented, a first node acquires a segmentation serial number of a first RLC PDU, the first node is a layer2relay node, the segmentation serial number has uniqueness in a bearing where the first RLC PDU is located, the first RLC PDU is the segmentation of the second RLC PDU, the second RLC PDU is the RLC PDU received by the first node, and the segmentation serial number is the serial number of the PDCP PDU of the second RLC PDU;

the first node transmits the first RLC PDU including the segmentation sequence number.

2. The method of claim 1,

the protocol header of the PDCP PDU contained in the second RLC PDU contains the segmentation sequence number;

or, the protocol header of the second RLC PDU includes the segmentation sequence number;

or, the protocol header of the packet included in the second RLC PDU includes the segmentation sequence number;

or the protocol header of the packet containing the second RLC PDU contains the segmentation sequence number;

or, the control signaling sent by the second node includes the segmentation sequence number, and the second node is the sending node of the second RLC PDU.

3. The method of claim 2,

and the protocol header of the second RLC PDU comprises segmentation information SI, and if the SI indicates that the second RLC PDU carries an RLC SDU which is not segmented and contains the segmentation sequence number, the segmentation sequence number field in the protocol header of the second RLC PDU contains the segmentation sequence number.

4. The method of claim 2, wherein the including the segmentation sequence number in the protocol header of the packet containing the second RLC PDU comprises:

the second RLC PDU is encapsulated in a data packet containing a MAC subheader containing the segmentation sequence number; alternatively, the first and second electrodes may be,

5. The method of claim 2, wherein the control signaling comprises:

6. A method for packet segmentation control, comprising:

the second node sends a segmentation sequence number and the second RLC PDU to the first node;

the segmented sequence number is a segmented sequence number of a first RLC PDU, the first node is a layer2relay node, the segmented sequence number has uniqueness in a load where the first RLC PDU is located, and the first RLC PDU is a segment of a second RLC PDU; the segmentation sequence number is used for the first node to send the first RLC PDU containing the segmentation sequence number, and the segmentation sequence number is a sequence number of a PDCP PDU of the second RLC PDU.

7. The method of claim 6,

the protocol header of the second RLC PDU sent by the second node to the first node contains the segmentation sequence number;

or, the protocol header of the packet included in the second RLC PDU sent by the second node to the first node includes the segmentation sequence number; alternatively, the first and second electrodes may be,

the second node sends a packet containing the second RLC PDU to the first node, wherein the protocol header of the packet contains the segmentation sequence number; alternatively, the first and second electrodes may be,

and the second node sends control signaling to the first node, wherein the control signaling contains the segmentation serial number.

8. The method of claim 7,

and the protocol header of the second RLC PDU comprises segmentation information SI, and the SI is used for indicating that the second RLC PDU carries the RLC SDU which is not segmented and contains the segmentation sequence number.

9. The method of claim 7, wherein the including the segmentation sequence number in the protocol header of the packet containing the second RLC PDU comprises:

10. The method of claim 7, wherein the control signaling comprises:

and the MAC CE and the second RLC PDU are in the same MAC data packet.

11. A first node, comprising:

a processing unit, configured to obtain a segmentation sequence number of a first radio link control RLC packet data unit, PDU, where the first node is a layer2relay node, the segmentation sequence number has uniqueness in a bearer where the first RLC PDU is located, the first RLC PDU is a segment of a second RLC PDU, the second RLC PDU is an RLC PDU received by the first node, and a packet data convergence protocol PDCP PDU included in the second RLC PDU is not segmented, and the segmentation sequence number is a sequence number of a PDCP PDU of the second RLC PDU;

a transmitting unit, configured to transmit the first RLC PDU including the segmentation sequence number.

12. The first node of claim 11,

13. The first node of claim 12,

14. The first node of claim 13, wherein the inclusion of the segmentation sequence number in a protocol header of the packet containing the second RLC PDU comprises:

15. The first node of claim 14, wherein the control signaling comprises:

16. A second node, comprising:

a sending unit, configured to send a segmentation sequence number and the second RLC PDU to a first node;

17. The second node of claim 16,

or, the protocol header of the packet included in the second RLC PDU sent to the first node includes the segmentation sequence number; alternatively, the first and second electrodes may be,

the protocol header of the packet containing the second RLC PDU sent to the first node contains the segmentation sequence number; alternatively, the first and second electrodes may be,

18. The second node of claim 17,

the protocol header of the second RLC PDU includes segmentation information SI, which is used to indicate that the second RLC PDU carries an RLC SDU that is not segmented and contains the segmentation sequence number.

19. The second node of claim 17, wherein the inclusion of the segmentation sequence number in a protocol header of the packet containing the second RLC PDU sent to the first node comprises:

the second RLC PDU sent to the first node is encapsulated in a data packet containing a MAC subheader containing the segmentation sequence number; alternatively, the first and second electrodes may be,

the second RLC PDU sent to the first node is encapsulated in a data packet containing an adaptation layer header, the adaptation layer header containing the segmentation sequence number.

20. The second node of claim 17, wherein the control signaling comprises:

and the MAC CE and the second RLC PDU are in the same MAC data packet.