CN107359968B

CN107359968B - Data transmission method and device for single-layer serial number

Info

Publication number: CN107359968B
Application number: CN201610304961.0A
Authority: CN
Inventors: 赵亚利; 谌丽; 刘佳敏; 鲍炜
Original assignee: China Academy of Telecommunications Technology CATT
Current assignee: China Academy of Telecommunications Technology CATT; Datang Mobile Communications Equipment Co Ltd
Priority date: 2016-05-10
Filing date: 2016-05-10
Publication date: 2020-05-26
Anticipated expiration: 2036-05-10
Also published as: CN107359968A

Abstract

The invention discloses a data transmission method and a device of a single-layer serial number, comprising the following steps: receiving a data packet issued by a high layer; assigning a unique serial number to each data packet; and transmitting the data packets according to the unique serial number, wherein in the transmission process, header compression/decompression and retransmission processing are carried out on each data packet according to the unique serial number of the data packet. The invention can overcome the problems of high standard complexity, certain repeatability of PDCP/RLC operation and the like in the data transmission of the LTE system designed based on the double-layer serial number.

Description

Data transmission method and device for single-layer serial number

Technical Field

The present invention relates to the field of wireless communication technologies, and in particular, to a data transmission method and apparatus for a single-layer SN.

Background

Fig. 1 is a schematic diagram of a user plane protocol stack of an existing LTE system, and as shown in the figure, in a user plane protocol stack of an LTE (Long term evolution ) system, main functions of each protocol layer are as follows:

PDCP (Packet Data Convergence Protocol):

the PDCP layer mainly functions to perform security-related operations (encryption/decryption, integrity protection/verification) and header compression/decompression processing. Fig. 2 is a schematic diagram of a PDCP layer data processing flow, and as shown in the figure, the detailed data processing flow of the PDCP layer includes:

after the sending PDCP entity processes the received IP packet, a PDCP PDU (Protocol data unit) is generated, and fig. 3 is a schematic diagram of a PDCP PDU structure, where as shown in the figure, a Sequence Number (SN) of a PCPC layer is included in a PDCP header.

Data delivered by the RLC layer to the PDCP layer is typically in-order, but for handover cases, the RLC is allowed to deliver to the PDCP layer on an as-needed basis. In this case, the PDCP SN may be used for reordering and duplicate detection.

RLC (Radio Link Control) layer processing:

the RLC layer has the main functions of completing segmentation, concatenation and sequential delivery of data and ARQ (Automatic repeat request). The RLC layer supports three modes: TM (Transparent Mode), UM (Unacknowledged Mode), and AM (Acknowledged Mode) modes. Fig. 4 is a schematic diagram of RLC tm mode data processing, fig. 5 is a schematic diagram of RLC UM mode data processing, fig. 6 is a schematic diagram of RLC AM mode data processing, and a schematic diagram of RLC processing for various RLC mode data is shown.

When the RLC layer is responsible for Reordering RLC data PDUs (Reordering, which is only applicable to UM and AM modes), HARQ (Hybrid Automatic repeat request) operation of the MAC (Media Access Control) layer may cause data arriving at the RLC layer to be out of order, so that the RLC layer is required to reorder data. Reordering orders RLC data PDUs according to the Sequence order of SN (Sequence Number).

For RLC TM mode, transparent transmission is performed in the RLC layer without adding an RLC header (without adding RLC sn). However, for RLC UM and AM modes, the RLC layer processes RLC SDUs (Service Data units) (i.e., PDCP PDUs) by segmenting and concatenating them based on scheduling information indicated by the MAC layer. Fig. 7 is a schematic diagram of RLC PDU generation, and as shown in the figure, in the process of generating RLC PDUs by segmentation/concatenation method for RLC SDUs, each RLC PDU needs to be allocated to an SN, and the SN is carried in an RLC PDU header.

And MAC layer processing:

the MAC mainly functions to perform uplink/downlink scheduling based on PHY (Physical layer) resources. For downlink scheduling, the MAC of the base station determines the scheduling information and then needs to notify the RLC organization RLC PDUs, and then the MAC layer multiplexes RLC PDUs from different logical channels of a terminal into one downlink MAC PDU. For uplink scheduling, after determining scheduling information, the MAC of the base station indicates the scheduling information to the terminal through a PDCCH (physical downlink control channel), and the terminal organizes an uplink MAC PDU through an uplink logical channel priority process.

PHY layer:

the PHY mainly functions to modulate and encode the MAC PDU generated by the MAC layer, and send the MAC PDU to the communication peer over the air interface.

The defects of the prior art are as follows: data transmission in current LTE systems is designed based on dual-layer SNs (PDCP SN and RLC SN). In future wireless communication systems, if the dual-layer SN design is still maintained, there are some problems, such as high standard complexity, some repeatability of PDCP/RLC operation, etc. Subsequent wireless communication system development needs to consider how to overcome the problems associated with the existing dual-layer SN.

Disclosure of Invention

The invention provides a data transmission method and device of a single-layer SN (service provider) and aims to solve the problem in data transmission of an LTE (long term evolution) system based on a double-layer SN design at present.

The embodiment of the invention provides a data transmission method of a single-layer SN, which comprises the following steps:

receiving a data packet issued by a high layer;

allocating a unique SN for each data packet;

and transmitting the data packets according to the unique SN, wherein the data packets are subjected to header compression/decompression and retransmission processing according to the unique SN of each data packet in the transmission process.

Preferably, the data packet sent by the upper layer is received by the AS layer;

each data packet is allocated with a unique SN, and each data packet is allocated with a unique SN at the AS layer.

Preferably, a unique SN is allocated to each data packet, and the SN is allocated after receiving a data packet sent by a higher layer, or allocated for the data packet in units of PDUs after determining the size of the PDU transmitted by a lower layer.

Preferably, after determining the size of the PDU transmitted in the bottom layer, the method allocates a unique SN for the packet in units of PDUs, including:

after receiving a data packet sent by a high layer, caching the data packet according to a first-in first-out mode;

when the PDU size transmitted by the bottom layer is determined according to the scheduling information of the next layer and the PDU encapsulation is carried out, the encapsulated PDU is organized according to the first-in first-out principle, and SN is distributed to each PDU.

Preferably, the SN is maintained at the highest layer of the user plane protocol stack.

Preferably, the SN is maintained at layer 3 or layer 2 of a three-layer user plane protocol stack, and the SN is maintained at layer 2 of a two-layer user plane protocol stack.

Preferably, when transmitting the data packet according to the unique SN, the method includes:

after each data packet is allocated with a unique SN, storing the mapping relation between the data packet and the SN;

performing PDU encapsulation according to the scheduling information of the next layer;

and transmitting the transmission encapsulated PDU.

Preferably, in the three-layer user plane protocol stack, after a unique SN is allocated to each data packet, the mapping relationship between the data packet and the SN is stored in layer 3, and the scheduling information is sent out in layer 2.

Preferably, the header of the encapsulated PDU includes one or a combination of the following information:

the PDU comprises SN corresponding to data contained in the PDU, a data domain length indication domain corresponding to each SN, positions of the data corresponding to each SN in all data corresponding to the SN, and information used for indicating whether the information corresponding to the SN is data or next SN;

the length of the data field corresponding to each SN indicates the position of the data corresponding to the first and last SN in all the data corresponding to the SN, and the SN is used for indicating whether the information corresponding to the SN is data or information corresponding to the next SN;

the number of the SNs contained in the PDU, the first SN corresponding to the data contained in the PDU, and the positions of the data corresponding to the first SN and the last SN contained in the PDU in all the data corresponding to the SN.

Preferably, further comprising:

when the discard timer is overtime and loses packets, the discarded SN and/or SF + HFN is notified to one end for receiving the transmission.

Preferably, if ARQ is supported, re-segmentation is performed on the encapsulated PDU, and the RLC header during re-segmentation includes one or a combination of the following information:

the SN corresponding to the RLC PDU which is segmented again, the data domain length indicating domain corresponding to the segmentation again, and the position indicating information of the data corresponding to each SN in all the data corresponding to the SN.

Preferably, further comprising:

when the transmission is carried out, if the discard timer is overtime and loses packets, discarding the data packets which are not distributed with SN.

Preferably, when the data packet is received and transmitted according to the unique SN, after HARQ demultiplexing, the correctly received PDU is delivered to the upper layer to perform duplicate detection and reordering.

Preferably, in a three-layer user plane protocol stack, HARQ demultiplexing is performed at layer 2 and duplicate detection and reordering is performed at layer 3.

Preferably, the duplicate detection is based on window duplicate detection, and if the SN included in the received PDU is outside the window or the same as the SN included in the received PDU, the PDU is duplicate data, where the window lower boundary is the last SN +1 that is currently received and consecutive, and the window upper boundary is the lower boundary + SN/2.

Preferably, the reordering comprises:

and when the PDU is received, sequencing according to the SN, if the SN in the out-of-sequence state exists, starting a reordering timer, and sequencing after waiting for HARQ retransmission.

Preferably, if the corresponding SN is not received after the reordering timer expires while waiting for the HARQ retransmission, the method further includes:

taking the data corresponding to the SN as lost data, and informing one end for transmitting and transmitting the data to retransmit the data or the data segments corresponding to the SN;

or, determining whether the end performing the transmission is a packet loss due to the discard timer being overtime, if so, not notifying the end performing the data transmission to retransmit the data or the data segment corresponding to the SN, and if not, notifying the end performing the data transmission to retransmit the data or the data segment corresponding to the SN.

Preferably, further comprising:

and when determining that the UE for data transmission is switched, sending a status report carrying a PDU downlink SN sending status and an uplink SN receiving status to a node for providing service for the switched UE.

Preferably, in the three-layer user plane protocol stack, each protocol layer includes functions as follows:

layer 1: channel mapping, modulation, coding and radio frequency transmission processing, layer 2: scheduling and HARQ, layer 3: SN management, security correlation, header compression, duplicate detection, reordering, ARQ, and packet dropping; alternatively, layer 1: channel mapping, modulation, coding and radio frequency transmission processing, layer 2: scheduling, HARQ, SN management, duplicate detection, reordering, ARQ, and packet dropping, layer 3: security correlation and header compression;

or, in the two-layer user plane protocol stack, each protocol layer includes each function as follows:

layer 1: scheduling, HARQ channel mapping, modulation, coding, and radio frequency transmission processing, layer 2: SN management, security correlation, header compression, repetition detection, reordering, ARQ, and packet dropping.

The embodiment of the invention provides a data transmission device of a single-layer SN, which comprises:

the receiving module is used for receiving the data packet sent by the high layer;

the distribution module is used for distributing a unique SN for each data packet;

and the transmission module is used for transmitting the data packets according to the unique SN, wherein in the transmission process, header compression/decompression and retransmission processing are carried out on the data packets according to the unique SN of each data packet.

Preferably, the receiving module is further configured to receive, at the AS layer, a data packet delivered by a higher layer;

the allocation module is further configured to allocate a unique SN to each data packet at the AS layer.

Preferably, the allocating module is further configured to allocate a unique SN to each data packet after receiving a data packet sent by a higher layer, or allocate a unique SN to each data packet in units of PDUs after determining the size of the PDU transmitted by the lower layer.

Preferably, the allocating module is further configured to, when determining the size of the PDU transmitted by the underlying layer and allocating a unique SN for the data packet in units of PDUs, include:

Preferably, the transmission module is further configured to, when transmitting the data packet according to the unique SN, include:

and transmitting the transmission encapsulated PDU.

Preferably, the transmission module is further configured to, in the three-layer user plane protocol stack, after allocating a unique SN to each data packet, store the mapping relationship between the data packet and the SN at layer 3, and send the scheduling information at layer 2.

Preferably, the transmission module is further configured to include, at the header of the encapsulated PDU, one or a combination of the following information:

Preferably, the transmission module is further configured to notify the end receiving the transmission of the dropped SN and/or SF + HFN when the discard timer times out and loses packets while the transmission is being performed.

Preferably, the transmission module is further configured to perform re-segmentation on the encapsulated PDU if ARQ is supported, where the RLC header in the re-segmentation includes one or a combination of the following information:

Preferably, the transmission module is further configured to discard the data packet to which the SN is not allocated when the discard timer times out and loses the packet during transmission.

Preferably, the transmission module is further configured to deliver the correctly received PDU to a higher layer for performing duplicate detection and reordering after HARQ demultiplexing when the data packet is received and transmitted according to the unique SN.

Preferably, the transmission module is further configured to perform HARQ demultiplexing at layer 2 and duplicate detection and reordering at layer 3 in a three-layer user plane protocol stack.

Preferably, the transmission module is further configured to perform repetition detection based on a window, and if an SN included in the received PDU is outside the window or the same as an SN included in the received PDU, the PDU is repeated data, where a lower boundary of the window is a last SN +1 that is currently received and consecutive, and an upper boundary of the window is a lower boundary + SN/2.

Preferably, the transmission module is further configured to, when reordering, include:

Preferably, the transmission module is further configured to, if the corresponding SN is still not received after the reordering timer times out while waiting for HARQ retransmission, take the data corresponding to the SN as lost data, and notify the end performing data transmission to retransmit the data or the data segment corresponding to the SN; or, determining whether the end performing the transmission is a packet loss due to the discard timer exceeding, if so, notifying the end performing the data transmission to retransmit the data or the data segment corresponding to the SN, and otherwise, notifying the end performing the data transmission to retransmit the data or the data segment corresponding to the SN.

Preferably, further comprising:

and the sending module is used for sending a status report carrying a PDU downlink SN sending status and an uplink SN receiving status to a node providing service for the switched UE when the UE for data transmission is determined to be switched.

The invention has the following beneficial effects:

in the technical solution provided by the embodiment of the present invention, after receiving a data packet delivered by a higher layer, a unique SN is assigned to each data packet, and then the data packet is transmitted according to the unique SN. Due to the fact that the single-layer SN data transmission scheme is provided, the problems in data transmission of an LTE system based on the double-layer SN design, such as high standard complexity, certain repeatability of PDCP/RLC operation and the like, are solved.

Further, the embodiment of the present invention also provides an implementation manner of a data transmission mechanism related to a single-layer SN when a user plane performs data transmission based on the single-layer SN, which specifically includes at least: a user plane protocol stack corresponding to the single-layer SN, how to organize the PDUs based on the single-layer SN, a duplicate detection mechanism based on the single-layer SN, a reordering mechanism based on the single-layer SN, a packet dropping mechanism based on the single-layer SN, and the like.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic diagram of a user plane protocol stack of a conventional LTE system in the background art;

FIG. 2 is a diagram illustrating a process of PDCP layer data processing in the prior art;

FIG. 3 is a diagram illustrating a PDCP PDU structure in the background art;

FIG. 4 is a diagram illustrating RLC TM mode data processing in the background art;

FIG. 5 is a diagram illustrating RLC UM mode data processing in the prior art;

FIG. 6 is a diagram illustrating RLC AM mode data processing in the background art;

FIG. 7 is a diagram illustrating RLC PDU generation in the background art;

FIG. 8 is a schematic diagram illustrating an implementation flow of a data transmission method for a single-layer SN according to an embodiment of the present invention;

FIG. 9 is a diagram illustrating a three-layer protocol stack structure in an embodiment of the present invention;

FIG. 10 is a diagram illustrating a two-layer protocol stack structure according to an embodiment of the present invention;

FIG. 11 is a schematic diagram illustrating an implementation flow of data processing at a transmitting end in the case of a single SN layer according to an embodiment of the present invention;

FIG. 12 is a diagram illustrating L3PDU segment concatenation according to an embodiment of the present invention;

fig. 13 is a schematic diagram of a data transmission flow of a sending end under a single-layer SN condition in the embodiment of the present invention;

FIG. 14 is a schematic diagram illustrating a processing flow at a receiving end according to an embodiment of the present invention;

FIG. 15 is a diagram illustrating a single-layer SN data transmission device according to an embodiment of the present invention;

fig. 16 is a schematic diagram of a base station structure according to an embodiment of the present invention.

Detailed Description

Data transmission of the current LTE system is designed based on a dual-layer SN (PDCP SN and RLC SN). In future wireless communication systems, if the dual-layer SN design is still maintained, there are some problems, such as:

with the increasing peak rate requirements, the SN length needs to be extended. The design of the bi-layer SN necessarily increases the standardization complexity.

Due to the dual-layer SN design, SN-related operations (such as mechanisms for repetitive detection, reordering, packet dropping, etc.) need to be performed separately at the PDCP/RLC layer with some repeatability.

In view of simplifying system design and standardizing complexity, a data transmission scheme based on a single-layer SN is provided in the embodiments of the present invention, and the following describes a specific embodiment of the present invention with reference to the drawings.

Fig. 8 is a schematic flow chart of an implementation of a data transmission method for a single-layer SN, which may include the following steps:

step 801, receiving a data packet issued by a high layer;

step 802, allocating a unique SN for each data packet;

and 803, transmitting the data packets according to the unique SNs, wherein header compression/decompression and retransmission processing are performed on each data packet according to the unique SN of the data packet during transmission.

In the implementation, the data packet sent by the higher layer is received, and the data packet sent by the higher layer can be received at the AS layer;

each data packet is allocated with a unique SN, which may be allocated with a unique SN at the AS layer.

In the implementation, a unique SN is allocated to each data packet, and the SN may be allocated after receiving a data packet sent by a higher layer, or allocated for the data packet in units of PDUs after determining the size of the PDU transmitted by a lower layer.

Specifically, in a data transmission scheme based on a single-layer SN, an AS (Access Stratum) layer allocates a unique SN to each data packet delivered by a higher layer, and the SN allocation timing may be immediately allocated after the AS layer receives the data packet delivered by the higher layer, or may be allocated to the PDU after determining the size of the PDU transmitted by the bottom layer.

When the user plane performs data transmission based on the single-layer SN, the embodiment of the present invention further provides an implementation manner of a data transmission mechanism based on the single-layer SN, which may specifically include: a user plane protocol stack corresponding to the single-layer SN, how to organize PDUs based on the single-layer SN, a duplicate detection mechanism based on the single-layer SN, a reordering mechanism based on the single-layer SN, and a packet discarding mechanism based on the single-layer SN, etc., which are described below with reference to examples.

Example 1:

this embodiment will explain an implementation of a user plane protocol stack structure corresponding to a single-layer SN.

In implementation, the SN may be maintained at the highest layer of the user plane protocol stack.

Specifically, the highest layer of the user plane protocol stack depends on the design scheme of the last user plane protocol stack, and is determined according to the actual user plane protocol stack in implementation.

The user plane protocol stack structure corresponding to the single-layer SN can be a three-layer structure or a two-layer structure, and the SN maintenance can be processed at the highest layer of the user plane protocol stack no matter which protocol stack structure is adopted.

(1) Three-layer protocol stack

Fig. 9 is a schematic diagram of a three-layer protocol stack structure, and as shown in the diagram, fig. 9 shows a basic three-layer user plane protocol stack, and a communication peer may be a UE and a base station (eNB), or a UE and a TRP (Transmission Point), or a UE and a UE.

The basic functions of the respective protocol layers may include some or all of the following functions:

l1: channel mapping, modulation, coding, radio frequency transmission processing, and the like.

L2: scheduling, HARQ, etc.

L3: SN management (allocation & maintenance), security correlation, header compression, duplicate detection, reordering, ARQ, packet dropping, etc.

Or:

L2: scheduling, HARQ, SN management (allocation & maintenance), duplicate detection, reordering, ARQ, packet dropping, etc.

L3: security related, header compression, etc.

(2) Two-layer protocol stack

Fig. 10 is a schematic diagram of a two-layer protocol stack structure, and as shown in the diagram, fig. 10 shows a basic two-layer user plane protocol stack, and a communication peer may be a UE and a base station (eNB), or a UE and a TRP, or a UE and a UE.

l1: scheduling, HARQ channel mapping, modulation, coding, radio frequency transmission processing, and the like.

L2: SN management (allocation & maintenance), security correlation, header compression, duplicate detection, reordering, ARQ, packet dropping, etc.

Example 2:

this embodiment will describe a data transmission flow of a sending end in a single-layer SN situation, specifically, an example is a situation where an AS allocates an SN first after receiving a higher-layer data packet.

In the implementation, when the data packet is transmitted according to the unique SN, the method comprises the following steps:

and transmitting the transmission encapsulated PDU.

Fig. 11 is a schematic diagram of a data processing implementation flow of a sending end under a single-layer SN condition, and illustrates a data processing scheme of the sending end under the single-layer SN condition by taking a three-layer protocol stack structure and dividing the protocol layer functions into examples according to the first dividing manner described in embodiment 1, as shown in the figure. The dotted line part of the figure indicates that this operation is performed optionally. In a specific implementation, if the two-layer protocol stack structure is adopted, the L1 and the L2 of the three-layer protocol stack structure are processed and combined, which is easily known by those skilled in the art, and therefore, the three-layer protocol stack structure is mainly taken as an example for explanation, and the two-layer protocol stack structure is not described in detail.

In the specific implementation, for the sending end, the difference from the existing wireless communication processing is mainly that the sending end is a single-layer SN, the data packet enters L3, that is, the corresponding relationship between the data packet and the SN is determined, the data packet is stored in the cache after being processed by L3, and the mapping relationship between the data packet and the SN needs to be stored when the data packet is stored in the cache, but the data packet and the SN are not encapsulated together. The data in the buffer waits for the scheduling information of L2, and the encapsulation of L3PDU is performed according to the scheduling information of L2.

L2 performs scheduling processing on each bearer or flow based on the physical resources of L1, determines the resources that can be allocated to each bearer or flow, and then notifies L3 of the resource allocation of each bearer or flow.

L3 organizes L3 PDUs for each bearer or flow, respectively, based on the scheduling information of L2. L3 may segment, concatenate, etc. packets. Fig. 12 is a schematic diagram of L3PDU segment concatenation, and a specific segment concatenation manner can be seen in fig. 12.

In an implementation, the header of the encapsulated PDU may include one or a combination of the following information:

Specifically, the header of the L3PDU needs to be able to indicate which SN corresponding data, the length of the data field corresponding to each SN, and the segment indication information of the data field corresponding to the first and/or last SN are included in the L3 PDU. The specific header design can be implemented in several ways:

mode 1:

the most straightforward design, namely, the following fields are included in the L3PDU header:

the SN indication field (SN) corresponding to each data portion.

A data field length indication field (LI) corresponding to each SN, wherein LI: a length indication field indicating a length of bytes in the data field.

The position (such as head, middle or tail) of the data corresponding to each SN in all the data corresponding to the SN (FI), where FI: indicating whether a PDU is divided at the start or end of the data field.

Adding indication information (E) in front of each SN indication domain for indicating whether SN/LI/FI is followed by data or information of the next SN, wherein E: and (4) spreading bits.

Mode 2:

due to the fact that the SNs have continuity, for example, m +1, m +2 … and the like, optimization is conducted based on the mode 1, for the first SN, the E/SN/LI/FI needs to be indicated, the following SNs are omitted, for the indication corresponding to the non-last SN, the E/LI is included, and the indication domain corresponding to the last SN is the E/LI/FI.

Mode 3:

a further simplification is based on mode 2, namely that for the first SN, the indication field comprises E/SN/LI/FI, and further Nbit indicates the number of consecutive SNs, for each subsequent SN (except the last SN) only the LI field needs to be indicated, and for the last SN the LI/FI field needs to be indicated.

For example, 2 bits are used to indicate the number of consecutive SNs, which may be specifically as follows;

2bit SDU number indication	Means of
		00	Represents 1 SDU
01	Representing 2 SDUs in succession
		10	Representing 3 SDUs in succession
11	Representing 4 SDUs in succession

In the implementation, the method may further include:

Specifically, in order to avoid the situation that SN at the receiving end is not continuously waiting for a time-out packet loss due to a time-out packet loss of the originating discard timer, after the time-out packet loss of the originating discard timer, the receiving end needs to be notified of the discarded SN and/or SF + HFN (Hyper Frame Number).

Example 3:

this embodiment will describe a data transmission flow of a transmitting end under a single-layer SN condition, specifically a condition of allocating SNs according to a size of a PDU to be scheduled.

In an implementation, the determining the size of the PDU transmitted in the bottom layer and then allocating a unique SN to the packet in units of PDUs may include:

In particular, if security-related mechanisms are involved, such AS integrity protection and ciphering, and the transfer to higher layer processing is possible independently of the SN, the packet arrives at the AS layer and may be buffered in L3 in a first-in-first-out manner. When receiving the scheduling information of L2, L3 PDUs are organized according to the first-in-first-out principle, and a SN is assigned to each L3 PDU. Fig. 13 is a schematic diagram of a data transmission flow of a sending end under a single-layer SN condition, and specifically, fig. 13 shows an implementation without considering header compression and a security mechanism.

In implementation, if ARQ is supported, the encapsulated PDU is re-segmented, and the RLCheader during re-segmentation may include one or a combination of the following information:

Specifically, if ARQ is supported, L3PDU needs to be re-segmented, and the RLC header when L3PDU is re-segmented may carry the following information:

re-segmented RLC PDU corresponding (SN)

The data field length indication field (LI) corresponding to the re-segmented section

The data corresponding to each SN is at the position (such as head, middle or tail) of all the data corresponding to the SN (FI)

In the implementation, the method may further include:

Specifically, for this case, only L3 data to which SN is not assigned is discarded upon expiration of the discard timer, and L3 PDUs to which SN is assigned are not discarded.

Example 4:

the present embodiment will explain the receiving-end processing.

The receiving end processing mode is suitable for distributing SN after AS receives a high-level data packet or distributing SN based on the size of PDU scheduled. Fig. 14 is a schematic diagram of a receiving-end processing flow, and the receiving-end processing flow can be specifically shown in fig. 14, where a dotted schematic part indicates an optional behavior.

In implementation, when a data packet is received and transmitted according to the unique SN, after HARQ demultiplexing, the correctly received PDU is delivered to a higher layer to execute repeated detection and reordering.

Specifically, after HARQ demultiplexing, all correctly received L3 PDUs will be delivered to the higher layer. Duplicate detection and reordering based on a single layer SN is performed by L3.

In the implementation, the duplicate detection is based on a window, and if the SN included in the received PDU is outside the window or the same as the SN included in the received PDU, the PDU is duplicate data, where the window lower boundary is the last SN +1 that is currently received and consecutive, and the window upper boundary is the lower boundary + SN/2.

Specifically, the repetitive detection process may be as follows:

and carrying out repeated detection operation based on the window, wherein the lower boundary of the window is the currently received and continuous last SN + 1. The upper window boundary is the lower boundary + SN/2. If the SN(s) included in the L3PDU received from L2 is outside the duplicate detection window or is duplicated with the SN that has been currently received, it is regarded as duplicate data and is directly deleted.

In an implementation, reordering comprises:

In the implementation, if the corresponding SN is not received after the reordering timer expires while waiting for the HARQ retransmission, the method further includes:

Specifically, the reordering process may be as follows:

when receiving the L3PDU, sorting according to SNs, if there is an out-of-order SN, starting a reordering timer, waiting for retransmission of the HARQ first, and once the time for possible retransmission of the HARQ elapses, that is, the corresponding SN is still not received after the reordering timer times out, the process may be as follows:

if the data at the SN gap is considered to be lost, a status report may be organized to inform the sending end to retransmit the data or data segment corresponding to the lost SN. (corresponding to example 3SN distribution mode)

Judging whether the SN is discarded due to overtime of the originating discard timer, if so, not organizing the state report, otherwise, organizing the state report again, and informing the sending end to retransmit the data or the data segment corresponding to the lost SN. (corresponding example 2SN distribution mode)

In implementation, the packet loss status report can be divided into two types:

the SN number may be carried if the SN is not received in the entire data field.

For partial loss of the data field corresponding to the SN, the SN number may be carried, along with location indication information of the lost segment, such as 0-a byte, a-B byte, or B-last byte, to indicate which segment was lost.

Example 5:

the present embodiment will explain processing at the time of transmission node switching of the UE.

In the implementation, the method may further include:

Specifically, when the UE moves, the UE moves out of the service range of the current transmission node, and the transmission node of the UE needs to be switched. At this time, the process of the network side is that the source node stops serving the UE and notifies the target node to start serving the UE. In order to ensure service continuity, the source node needs to send a status report to the target node. Wherein, the sending state of the downlink SN and the receiving state of the uplink SN of the L3PDU need to be carried.

Based on the same inventive concept, the embodiment of the invention also provides a single-layer SN data transmission device, and because the principles of solving the problems of the devices are similar to the single-layer SN data transmission method, the implementation of the devices can be referred to the implementation of the method, and repeated details are not repeated.

Fig. 15 is a schematic structural diagram of a data transmission device with a single SN layer, which may include:

a receiving module 1501, configured to receive a data packet sent by a higher layer;

an allocating module 1502, configured to allocate a unique SN for each data packet;

a transmission module 1503, configured to transmit the data packets according to the unique SN, where in the transmission process, header compression/decompression and retransmission processing are performed on each data packet according to the unique SN of the data packet.

In implementation, the receiving module is further configured to receive, at the AS layer, a data packet delivered by a higher layer;

In implementation, the allocating module is further configured to allocate a unique SN to each data packet after receiving a data packet sent by a higher layer, or allocate a unique SN to each data packet in units of PDUs after determining the size of the PDUs transmitted by the lower layer.

In an implementation, the allocating module is further configured to, when determining a PDU size transmitted by the underlying layer and allocating a unique SN for the data packet in units of PDUs, include:

In implementation, the SN is maintained at the highest layer of the user plane protocol stack.

In the implementation, the SN is maintained at layer 3 or layer 2 of a three-layer user plane protocol stack, and the SN is maintained at layer 2 of a two-layer user plane protocol stack.

In an implementation, the transmission module is further configured to, when transmitting the data packet according to the unique SN, include:

and transmitting the transmission encapsulated PDU.

In implementation, the transmission module is further configured to, in a three-layer user plane protocol stack, after allocating a unique SN to each data packet, store a mapping relationship between the data packet and the SN at layer 3, and send scheduling information at layer 2.

In an implementation, the transmission module is further configured to include, at the header of the encapsulated PDU, one or a combination of the following information:

In an implementation, the transmission module is further configured to notify, when the discard timer times out and loses a packet, the discarded SN and/or SF + HFN to a terminal receiving the transmission.

In an implementation, the transmission module is further configured to perform re-segmentation on the encapsulated PDU if ARQ is supported, where an RLC header in the re-segmentation includes one or a combination of the following information:

In an implementation, the transmission module is further configured to discard a data packet to which the SN is not allocated, when the discard timer times out and loses a packet during transmission.

In implementation, the transmission module is further configured to deliver the correctly received PDU to a higher layer for performing duplicate detection and reordering after HARQ demultiplexing when receiving and transmitting the data packet according to the unique SN.

In an implementation, the transmission module is further configured to perform HARQ demultiplexing at layer 2 and duplicate detection and reordering at layer 3 in a three-layer user plane protocol stack.

In an implementation, the transmission module is further configured to perform repetition detection based on a window, and if an SN included in the received PDU is outside the window or the same as an SN included in the received PDU, the PDU is repeated data, where a lower boundary of the window is a last SN +1 that is currently received and is continuous, and an upper boundary of the window is a lower boundary + SN/2.

In an implementation, the transmission module is further configured to, when reordering, include:

In implementation, the transmission module is further configured to, if the reordering timer still does not receive the corresponding SN after timeout while waiting for HARQ retransmission, take the data corresponding to the SN as lost data, and notify the end performing data transmission to retransmit the data or the data segment corresponding to the SN; or, determining whether the end performing the transmission is a packet loss due to the discard timer exceeding, if so, notifying the end performing the data transmission to retransmit the data or the data segment corresponding to the SN, and otherwise, notifying the end performing the data transmission to retransmit the data or the data segment corresponding to the SN.

In an implementation, the method further comprises the following steps:

For convenience of description, each part of the above-described apparatus is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware in practicing the invention.

When the technical scheme provided by the embodiment of the invention is implemented, the implementation can be carried out as follows.

Fig. 16 is a schematic structural diagram of a base station, as shown in the figure, the base station includes:

the processor 1600, which is used to read the program in the memory 1620, executes the following processes:

allocating a unique SN for each data packet;

a transceiver 1610 configured to transmit data under control of the processor 1600, the following processes being performed:

receiving a data packet issued by a high layer;

In the implementation, the data packet sent by the high layer is received at the AS layer;

In the implementation, a unique SN is allocated to each data packet, and the SN is allocated after receiving a data packet sent by a higher layer, or allocated for the data packet in units of PDUs after determining the size of the PDU transmitted by a lower layer.

In the implementation, after determining the size of the PDU transmitted in the bottom layer, the unique SN allocated to the data packet in units of PDUs includes:

In the implementation, when the data packet is transmitted according to the unique SN, the method includes:

and transmitting the transmission encapsulated PDU.

In implementation, in a three-layer user plane protocol stack, after a unique SN is allocated to each data packet, the mapping relationship between the data packet and the SN is stored in layer 3, and scheduling information is sent out in layer 2.

In an implementation, the header of the encapsulated PDU includes one or a combination of the following information:

In an implementation, the method further comprises the following steps:

In the implementation, if ARQ is supported, the encapsulated PDU is re-segmented, and the RLCheader during re-segmentation includes one or a combination of the following information:

In an implementation, the method further comprises the following steps:

In implementation, when the data packet is received and transmitted according to the unique SN, after HARQ demultiplexing, the correctly received PDU is delivered to the upper layer to perform duplicate detection and reordering.

In implementation, in a three-layer user plane protocol stack, HARQ demultiplexing is performed at layer 2 and duplicate detection and reordering is performed at layer 3.

In implementation, the duplicate detection is based on window duplicate detection, and if the SN included in the received PDU is outside the window or the same as the SN included in the received PDU, the PDU is duplicate data, where the window lower boundary is the last SN +1 that is currently received and continuous, and the window upper boundary is the lower boundary + SN/2.

In an implementation, the reordering comprises:

In an implementation, the method further comprises the following steps:

In fig. 16, among other things, the bus architecture may include any number of interconnected buses and bridges, with one or more processors represented by the processor 1600 and various circuits of the memory represented by the memory 1620 linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The transceiver 1610 can be a plurality of elements including a transmitter and a transceiver providing a means for communicating with various other apparatus over a transmission medium. The processor 1600 is responsible for managing the bus architecture and general processing, and the memory 1620 may store data used by the processor 1600 in performing operations.

In summary, the embodiment of the present invention provides a data transmission scheme based on a single-layer SN, that is, an AS layer allocates a unique SN to each data packet delivered by a higher layer, and the SN allocation time may be immediately allocated after the AS layer receives the data packet delivered by the higher layer, or may be allocated to a PDU after determining the size of the PDU transmitted by a bottom layer.

Specifically, also provided are:

and (3) distribution mode of single-layer SN. And the protocol stack structure corresponding to the single-layer SN. PDU organization format for single layer SN. Packet dropping mechanism for single layer SN. Based on single-layer SN structure, receiving end state report sending mode. Based on the single-layer SN structure, the contents of the status report at the time of switching. The sending end needs to inform the receiving end of the mechanism when the packet is lost after overtime.

The data transmission scheme based on the single-layer SN provided by the embodiment of the invention can simplify the system design and standardization complexity by changing the double-layer SN into the single-layer SN.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A data transmission method of a single-layer Serial Number (SN) is characterized by comprising the following steps:

receiving a data packet issued by a high layer;

allocating a unique SN for each data packet;

transmitting the data packets according to the unique SN, wherein in the transmission process, header compression/decompression and retransmission processing are carried out on the data packets according to the unique SN of each data packet;

the method comprises the steps that a unique SN is distributed to each data packet after the data packet sent by a high layer is received, or the data packet is distributed by taking a Protocol Data Unit (PDU) as a unit after the size of the PDU transmitted by a bottom layer is determined.

2. The method of claim 1, wherein the receiving of the data packets sent by the higher layer is receiving the data packets sent by the higher layer at an Access Stratum (AS) layer;

3. The method of claim 1, wherein the assigning a unique SN for the packet in units of PDUs after determining the size of the PDUs transmitted by the underlying layer comprises:

4. The method of claim 1, wherein the SN is maintained at a highest layer of a user plane protocol stack.

5. The method of claim 4, wherein the SN is maintained at layer 3 or layer 2 of a three-layer user plane protocol stack, and wherein the SN is maintained at layer 2 of a two-layer user plane protocol stack.

6. The method of claim 1, wherein transmitting the data packet with the unique SN comprises:

and transmitting the transmission encapsulated PDU.

7. The method of claim 6, wherein after assigning a unique SN to each packet in a three-layer user plane protocol stack, storing the mapping relationship between the packet and the SN at layer 3, and sending scheduling information at layer 2.

8. The method of claim 5 or 6, wherein the header of the encapsulated PDU includes one or a combination of the following information:

the PDU comprises SN corresponding to data, a data domain length indication domain corresponding to each SN, positions of data corresponding to the first SN and the last SN in all data corresponding to the SN, and information used for indicating whether the information corresponding to the SN is data or next SN;

9. The method of claim 6 or 7, further comprising:

when transmission is carried out, if the discard timer exceeds the time-out packet loss, the discarded SN and/or SF + hyper frame number HFN is notified to one end for receiving transmission.

10. The method of claim 6, wherein the encapsulated PDU is re-segmented if automatic repeat request ARQ is supported, and wherein a radio link control, RLC, header at the time of re-segmentation includes one or a combination of the following information:

11. The method of claim 10, further comprising:

12. The method of claim 1, wherein upon a received transmission of a data packet with said unique SN, a correctly received PDU is delivered to a higher layer for duplicate detection and reordering after HARQ demultiplexing.

13. The method of claim 12, wherein HARQ demultiplexing occurs at layer 2 and duplicate detection and reordering occurs at layer 3 in a three-layer user plane protocol stack.

14. The method according to claim 12 or 13, wherein the duplicate detection is a duplicate detection based on a window, and if the SN included in the received PDU is outside the window or the same as the SN included in the received PDU, the received PDU is duplicate data, wherein the window lower boundary is the last SN +1 that is currently received and consecutive, and the window upper boundary is the lower boundary + SN/2.

15. The method of claim 12 or 13, wherein the reordering comprises:

16. The method of claim 15, wherein if the corresponding SN is not received after a reordering timer expires while waiting for a HARQ retransmission, further comprising:

17. The method of claim 1, further comprising:

18. A method according to claim 5, 7 or 13, wherein in the three-layer user plane protocol stack, each protocol layer comprises functions as follows:

layer 1: channel mapping, modulation, coding and radio frequency transmission processing, layer 2: scheduling and HARQ, layer 3: SN management, security correlation, header compression, duplicate detection, reordering, ARQ, and packet dropping; alternatively, layer 1: channel mapping, modulation, coding and radio frequency transmission processing, layer 2: scheduling, HARQ, SN management, duplicate detection, reordering, ARQ, and packet dropping, layer 3: security concerns and header compression.

19. The method of claim 5, wherein in the two-layer user plane protocol stack, each protocol layer includes functions as follows:

20. A single-layer SN data transmission apparatus, comprising:

the transmission module is used for transmitting the data packets according to the unique SN, wherein in the transmission process, header compression/decompression and retransmission processing are carried out on the data packets according to the unique SN of each data packet;

the distribution module is further used for distributing a unique SN for each data packet after receiving the data packet sent by the high layer, or distributing a unique SN for each data packet by taking the PDU as a unit after determining the size of the PDU transmitted by the bottom layer.

21. The apparatus of claim 20, wherein the receiving module is further configured to receive a data packet sent by a higher layer at the AS layer;

22. The apparatus of claim 20, wherein the assigning module, when determining the size of the PDU transmitted by the underlying layer, is further configured to assign a unique SN to the packet in units of PDUs, the assigning module is further configured to:

23. The apparatus of claim 20, wherein the SN is maintenance processed at a highest layer of a user plane protocol stack.

24. The apparatus of claim 23, wherein the SN is maintenance processed at layer 3 or layer 2 of a three-layer user plane protocol stack, and wherein the SN is maintenance processed at layer 2 of a two-layer user plane protocol stack.

25. The apparatus of claim 20, wherein the transmission module is further configured to, when transmitting the data packet according to the unique SN, include:

and transmitting the transmission encapsulated PDU.

26. The apparatus of claim 25, wherein the transmission module is further configured to store a mapping relationship between the data packets and SNs at layer 3 and send the scheduling information at layer 2 after assigning a unique SN to each data packet in a three-layer user plane protocol stack.

27. The apparatus of claim 25 or 26, wherein the transmission module is further configured to include one or a combination of the following information in a header of the encapsulated PDU:

28. The apparatus according to claim 25 or 26, wherein the transmission module is further configured to notify the end receiving the transmission of the discarded SN and/or SF + HFN if the discard timer times out and loses packets while the transmission is in progress.

29. The apparatus of claim 25, wherein the transmission module is further configured to re-segment the encapsulated PDU if ARQ is supported, and the RLC header in re-segmentation includes one or a combination of the following information:

30. The apparatus of claim 29, wherein the transmission module is further configured to discard a packet without SN assignment if the discard timer times out to discard while transmitting.

31. The apparatus of claim 20, wherein the transmission module is further configured to deliver correctly received PDUs to higher layers for duplicate detection and reordering after HARQ demultiplexing when a received transmission is received for a data packet with the unique SN.

32. The apparatus of claim 31, wherein the transmission module is further for performing HARQ demultiplexing at layer 2 and duplicate detection and reordering at layer 3 in a three-layer user plane protocol stack.

33. The apparatus according to claim 31 or 32, wherein the transmission module is further configured to perform a duplicate detection based on a window, and if a received PDU includes a SN outside the window or the same as a SN included in an already received PDU, the received PDU is duplicate data, wherein a window lower boundary is a last SN +1 that is currently received and consecutive, and a window upper boundary is a lower boundary + SN/2.

34. The apparatus of claim 31 or 32, wherein the transmission module, when reordering, is further configured to:

35. The apparatus of claim 34, wherein the transmission module is further configured to, if the corresponding SN is still not received after the reordering timer expires while waiting for HARQ retransmission, regard the data corresponding to the SN as lost data, and notify a data transmitting end to retransmit the data or data segment corresponding to the SN; or, determining whether the end performing the transmission is a packet loss due to the discard timer being overtime, if so, not notifying the end performing the data transmission to retransmit the data or the data segment corresponding to the SN, and if not, notifying the end performing the data transmission to retransmit the data or the data segment corresponding to the SN.

36. The apparatus of claim 20, further comprising:

37. The apparatus according to claim 24, 26 or 32, wherein in the three-layer user plane protocol stack, each protocol layer comprises functions as follows:

38. The apparatus of claim 24, wherein in the two-layer user plane protocol stack, each protocol layer comprises functions as follows: