CN101594374B - Novel L2 structure in wireless communication system, corresponding communication method and communication system - Google Patents

Abstract

A data link layer communication method and system. The data link layer is divided into two sublayers L2-1 and L2-2. The method includes the following steps: at the sending side: at the L2-1 sublayer, receiving and buffering IP packets forwarded from the network layer, generating L2-1PDUs, and forwarding the generated L2-1PDUs to the L2-2 sublayer; L2-2 sublayer, multiplexes the L2-1PDU forwarded from the L2-1 sublayer to generate the corresponding L2-2PDU, and forwards the generated L2-2PDU to the physical layer; on the receiving side: at the L2-2 The sublayer receives the L2-2PDU forwarded from the physical layer, demultiplexes the received L2-2PDU, and forwards the L2-1PDU generated after demultiplexing to the L2-1 sublayer; at the L2-1 sublayer, receives The L2-1 PDU forwarded from the L2-2 sublayer forms an original IP packet, and forwards the formed original IP packet to the network layer. The communication method and system of the present invention realize L2 layer communication with less communication workload and buffer.

Description

New L2 structure and corresponding communication means and system in the wireless communication system

Technical field

The present invention relates to the wireless mobile communications field, more specifically, the present invention relates to a kind of new data link layer (L2) structure for wireless communication system and corresponding communication means and system.

Background technology

Current, along with developing rapidly of mobile multimedia and high-speed data service, 3-G (Generation Three mobile communication system) (3G) obtains application more and more widely.Wherein, senior international mobile communication (IMT-advanced) system is the mobile system that has above the ability of IMT-2000.The support of IMT-advanced system from low to high ambulant application and the data rate of wide range, satisfy user under the multiple user environment and professional demand.

Air interface refers to the interface between terminal and the Access Network, and in the 3GPP document, air interface is to describe in the standard of 25,36 series.Protocol stack mainly divides three layers, is from bottom to up: physical (L1), data link layer (L2) and network layer (L3).Wherein L2 is divided into several sublayers again: from control plane, comprise media access control layer (MAC) and wireless chain control layer (RLC); And on the user plane except these two sublayers, also comprise the packet data protocol convergence sublayer (PDCP) of handling Packet Service, it mainly is that grouped data is carried out head compression by the RLC bearer service, with the efficiency of transmission of raising air interface.About the more details of data link layer L2, can be with reference to the technical specification of 3GPP 25,36 series.

Current data link layer structure is known for a person skilled in the art, describes the schematic diagram of the transmitter side of current data link layer structure below with reference to Fig. 1, and has omitted the description to receiver side; Note, only be described at a logic channel among Fig. 1.

Fig. 1 shows the schematic diagram of the transmitter side of current data link layer (L2) structure.L2 is divided into PDCP sublayer, RLC sublayer and media access control sublayer.In the PDCP sublayer, IP grouping is cushioned (102) with the form of PDCPSDU, carry out head compression (104) then, and generation PDCP sequence number (SN) to be being encrypted (106), thereby to be forwarded to the RLC sublayer.In the RLC sublayer, receive the data of transmitting from the PDCP sublayer, and cushion (108) with the form of RLC SDU, carry out segmentation and/or cascade (110) then; Afterwards, produce and interpolation RLC sequence number (SN) (112), to be used for reordering of receiver side; The rlc protocol data cell (PDU) that produces is forwarded to media access control sublayer, also be cushioned simultaneously in case retransmit under the situation of needs and situation at inadequate resource under carry out heavily segmentation earlier and then be forwarded to media access control sublayer (114,116).In media access control sublayer, to carrying out multiplexing (120) from the data of RLC sublayer, in order to transmit to the L1 layer.

As can be seen, there is following shortcoming in said structure:

At first, the structure of three sublayers causes a large amount of interlayer communications, namely between PDCP sublayer and RLC sublayer, between RLC sublayer and the media access control sublayer and the communication between PDCP sublayer and media access control sublayer if possible.

Secondly, from the angle of standard, different sublayers needs three kinds of buffer modules altogether, and identical data payload is cushioned in PDCP sublayer and RLC sublayer respectively, and this has caused redundancy.

Again, need two kinds of sequence numbers (SN): PDCP SN is used for the encryption of PDCP sublayer, and the receiver side that RLC SN is used for the RLC sublayer reorders; This can increase header overhead.

Therefore, also exist and above-mentioned corresponding shortcoming at current L2 agreement designed communication means and system.Wish exploitation a kind of new L2 communication means and system, it utilizes less communication work amount to realize communicating by letter of L2 layer with buffer, can not influence the interface with existing L3 layer and L1 layer simultaneously.

Summary of the invention

In order to address the above problem, the present invention proposes a kind of new data link layer (L2) structure for senior international mobile communication (IMT-advanced) system and corresponding communication means and system.

Current L2 layer is responsible for the following 4 kinds of functions at the transmission of user's planning data: a compression, encryption, cascade and segmentation and L2 re-transmission, multiplexing, first three function is relevant with a logic channel, and then function is responsible for handling the data from all logic channels.So, first three function can be fused to a part, and a back function is fused to another part.This new data link layer (L2) is divided into two sublayers, i.e. L2-1 sublayer and L2-2 sublayer.L2-1 is responsible for the sublayer handling the data from a logic channel, and the data from all logic channels are responsible for handling in the L2-2 sublayer.

Therefore, according to a first aspect of the invention, provide a kind of data link layer L2 communication means, wherein data link layer L2 is divided into two sublayer L2-1 and L2-2, said method comprising the steps of:

At transmitter side:

In the L2-1 sublayer, receive and cushion the IP grouping of transmitting from network layer, produce L2-1 protocol Data Unit PDU, and transmit the L2-1 PDU that produces to the L2-2 sublayer;

In the L2-2 sublayer, the L2-1 PDU that transmits from the L2-1 sublayer is carried out multiplexing, producing corresponding L2-2 PDU, and transmit the L2-2 PDU that produces to physical layer.

Preferably, described method is further comprising the steps of:

At receiver side:

In the L2-2 sublayer, receive the L2-2 PDU that transmits from physical layer, to the L2-2PDU demultiplexing that receives, and transmit the L2-1 PDU that produces behind the demultiplexing to the L2-1 sublayer;

In the L2-1 sublayer, receive the L2-1 PDU that transmits from the L2-2 sublayer, form the initial IP grouping, and transmit formed initial IP grouping to network layer.

According to a further aspect in the invention, provide a kind of data link layer L2 communication system, wherein data link layer L2 is divided into two sublayer L2-1 and L2-2, and described system comprises:

Transmitter side equipment receives and cushions the IP grouping of transmitting from network layer, produces L2-2 PDU, and transmits the L2-2 PDU that produces to physical layer.

Preferably, described communication system also comprises:

Receiver side equipment receives the L2-2 PDU that transmits from physical layer, forms the initial IP grouping, and transmits formed initial IP grouping to network layer.

The advantage that the present invention has is:

-compare with current L2 structure, reduced interlayer communication effectively;

-need less buffer, and only to new IP buffering of packets once, this helps to simplify and optimize buffer state reports;

-only use a SN to carry out the encryption of transmitter side and reordering of receiver side, thus header overhead reduced;

-simple HO repeating process.

Description of drawings

By detailed description with the accompanying drawing hereinafter, above-mentioned and other features of the present invention will become more apparent, wherein:

Fig. 1 shows the schematic diagram of the transmitter side of current data link layer structure;

Fig. 2 shows the schematic diagram according to the transmitter side of data link layer structure of the present invention;

Fig. 3 shows the schematic diagram according to the receiver side of data link layer structure of the present invention;

Fig. 4 shows the flow chart according to data link layer transmitter side method of the present invention;

Fig. 5 shows the flow chart according to data link layer receiver side method of the present invention; And

Fig. 6 shows the block diagram according to data link layer communication system of the present invention.

Embodiment

Specifically describe data link layer of the present invention (L2) structure below in conjunction with accompanying drawing 2-3.

Fig. 2 shows the schematic diagram according to the transmitter side of data link layer of the present invention (L2) structure.As shown in Figure 2, L2 structure of the present invention comprises L2-1 sublayer and L2-2 sublayer.Be grouped in from the IP of core net (CN) and be cushioned (202) in the L2-1 sublayer.According to control judgement, the transmitted bit that allows in the L2-2 sublayer indication L2-1 sublayer current transmission time interval (TTI).Based on this judgement, which IP grouping the L2-1 sublayer selects to be sent out in current TTI according to the head of each IP grouping, current context and employed compression algorithm.Then, (204) are correspondingly compressed in these selected IP groupings.Simultaneously, the L2-1 sublayer produces a sequence number (SN) (208) successively, utilizes this SN that the IP grouping of all compressions is encrypted (206).Afterwards, the IP based on these encryptions divides into groups to carry out segmentation and/or cascade (210).Add the SN and the corresponding indication that produce, to produce L2-1 PDU (214), it is multiplexing to carry out that this L2-1 PDU is forwarded to the L2-2 sublayer.Simultaneously also this L2-1 PDU is cushioned (212), in order to retransmit as required and under the situation of inadequate resource, carry out heavily segmentation (216) earlier and then be forwarded to the L2-2 sublayer.Carry out multiplexing back (220) at the different L2-1 PDU to the logic channel that is scheduled from all, inserts corresponding producing corresponding L2-2 PDU, and it is forwarded to the L1 layer does further processing.

Fig. 3 shows the schematic diagram according to the receiver side of data link layer of the present invention (L2) structure.As shown in Figure 3, at first to the L2-2 PDU demultiplexing (302) from the L1 layer, then to the L2-1 PDU of L2-1 forwarding at each logic channel.For same logic channel, utilize the SN (312) of the L2-1 PDU that receives to come these PDU are reordered (304), be because mixed automatic repeat request (HARQ) re-transmission causes or loses forever with the L2-1 PDU that determines to lose.After the process of reordering, L2-1 PDU is recombinated (306), and L2-1PDU is separated cascade and/or recombinates to obtain corresponding IP grouping, and utilize this S that each IP grouping is decrypted (308).After finishing deciphering, carry out decompress (310) to produce the initial IP grouping.

In addition, in (HO) process of switching, for fear of loss of data, should be forwarded to goal systems to the incorrect data that receive to retransmit.In L2 structure of the present invention, only in the L2-1 sublayer with the IP buffering of packets once.Therefore, based on status report or other information, can easily determine and to forward a packet to goal systems to which IP.This is different from LTE: in LTE, cushion with PDCP PDU and the IP grouping of RLC PDU respectively in PDCP sublayer and RLC sublayer.Therefore, L2 structure of the present invention discuss need not be again in the LTE standardisation process should to the IP grouping still RLC PDU transmit.

As can be seen from the above, L2 structure of the present invention has following advantage:

-compare with current L2 structure, reduced interlayer communication effectively;

-in LTE, RLC and MAC be exchange message at first, and for example mixed automatic repeat request (HARQ) is fed back, and after RLC handles, the information that exchanges is forwarded to PDCP; The present invention is different therewith, because direct exchange message between L2-1 sublayer and the L2-2 sublayer, so can realize striding layer (cross-layer) optimization;

-need less buffer, and only to new IP buffering of packets once, this helps to simplify and optimize buffer state reports.Different with LTE, L2 structure of the present invention only can be reported new IP grouping and L2-1 retransmission packet.Yet in LTE, must know which data is new groupings, and which data cushions in RLC but do not send, which data in the RLC re-transmission buffer, etc.;

-only use a SN to carry out the encryption of transmitter side and reordering of receiver side, thus header overhead reduced;

-simple HO repeating process need not to spend extensive work discussion and should transmit still RLC PDU of IP grouping as in the LTE standardisation process.

According to this new L2 structure of the present invention, can design corresponding communication means and system.Be specifically addressed below with reference to Fig. 4-6.

Fig. 4 shows the flow chart according to data link layer transmitter side method of the present invention.As shown in Figure 4, method begins at S400.At S402, receive and cushion the IP grouping from high level.At S403, judge whether to exist data retransmission.If then method proceeds to S405, to select data retransmission.Then, judge at S407 whether resource is enough.If resource is not enough, then in the L2-1PDU heavily segmentation of S409 to buffering, and method proceeds to S418, hereinafter will introduce in detail; Otherwise if resource is enough, then method directly advances to S418 on the one hand, and current L2-1PDU is transmitted to the L2-2 sublayer, gets back to S403 on the other hand, continues to judge whether to exist data retransmission.When not having data retransmission, show and to transmit new data that this quadrat method proceeds to S406, formation sequence SN.Then, judge whether to exist remaining segment at S411.If then method proceeds to S413 with the selection remaining segment, and judge at S415 whether resource is enough.If resource is enough, then method proceeds to S404, hereinafter will introduce in detail; Otherwise if resource is not enough, then method proceeds to S410, is described in detail below equally.

At S404, select the IP grouping and the head compression is carried out in the selected IP grouping that will send.At S408, the SN that utilizes in the S406 generation is encrypted the IP grouping of all compressions.At step S410, based on the IP of these encryptions grouping and carry out segmentation and/or cascade.At step S412, add the SN that produces and indicate to produce L2-1 PDU accordingly, and cushion this L2-1 PDU.At step S418, the L2-1 PDU that produces is transmitted to the L2-2 sublayer.At step S420, L2-1PDU is carried out multiplexing, insert corresponding head to produce corresponding L2-2 PDU.At last, transmit the L2-2 PDU that produces to the L1 layer at step S422.This method finishes at step S424 place.

Fig. 5 shows the flow chart according to data link layer receiver side method of the present invention.As shown in Figure 5, method begins at S500.At S502, receive the L2-2 PDU from the L1 layer.Next at S504, to the L2-2 PDU demultiplexing that receives, transmit the L2-1 PDU at each logic channel then to the L2-1 sublayer.At S506, at same logic channel, utilize the SN of the L2-1 PDU that receives to come these PDU are reordered.At S508, the L2-1 PDU after reordering is recombinated and it is separated the reorganization of cascade and/or IP grouping bag.At S510, utilize this SN that each IP grouping among the L2-1 PDU after recombinating is decrypted.At S512, grouping is carried out and is decompressed to form original IP grouping to the IP after the deciphering.At step S514, divide into groups to the initial IP that the output of L3 layer produces.This method finishes at step S516 place.

Fig. 6 shows the block diagram according to data link layer communication system of the present invention.This L2 communication system 1000 comprises transmitter side equipment and receiver side equipment.Wherein, transmitter side equipment comprises: IP buffering of packets module 600, data retransmission processing module 601, a compression module 602, remaining segment processing module 603, encrypting module 604, SN generation module 606, segmentation/cascade module 608, L2-1PDU buffer module 610, L2-1 PDU generation module 612, heavy segmentation module 614, scheduling/control module 616 and Multiplexing module 618.Receiver side equipment comprises: demultiplexing module 620, the module that reorders 622, recombination module 624, deciphering module 626 and decompression module 628.

In IP buffering of packets module 600, receive and cushion the IP grouping from high level, and under the scheduling/control of scheduling/control module 616, select the IP that will send to divide into groups.In data retransmission processing module 601, judge whether to exist data retransmission; If exist, then it is carried out and above handle corresponding processing in conjunction with the described data retransmission of Fig. 4.SN generation module 606 formation sequence SN.In remaining segment processing module 603, judge whether to exist remaining segment; If exist, then it is carried out and above handle corresponding processing in conjunction with the described remaining segment of Fig. 4.Compression module 602 receives the IP grouping that will send, and to its Executive Head compression.Afterwards, encrypting module 604 uses the IP grouping of the sequence number SN that is generated by SN generation module 606 to be encrypted.IP after the encryption is grouped in and carries out segmentation and/or cascade in segmentation/cascade module 608.Divide into groups according to SN and the IP after segmentation/cascade module 608 is handled from SN generation module 606, L2-1 PDU generation module 612 produces L2-1 PDU, and is cushioning in L2-1 PDU buffer module 610 under the scheduling/control of scheduling/control module 616.The L2-1 PDU that produces directly is forwarded to Multiplexing module 618.Multiplexing module 618 carries out multiplexingly under the scheduling/control of scheduling/control module 616 to L2-1 PDU, insert corresponding head producing corresponding L2-2 PDU, and it is forwarded to the L1 layer.

In receiver side equipment, enter demultiplexing module 620 from the L2-2 PDU of L1 layer.Demultiplexing module 620 is carried out demultiplexing, and output needle is to the L2-1 PDU of each logic channel.The module that reorders 622 utilizes the SN of the L2-1 PDU that receives to come these PDU are reordered.Then, the PDU after being reordered by 624 pairs of recombination modules carries out reorganization.Each IP grouping among the PDU after deciphering module 626 utilizes SN to reorganization is decrypted.After finishing deciphering, decompression module 628 is carried out and is decompressed to produce the initial IP grouping.

Although below show the present invention in conjunction with the preferred embodiments of the present invention, one skilled in the art will appreciate that under the situation that does not break away from the spirit and scope of the present invention, can carry out various modifications, replacement and change to the present invention.Therefore, the present invention should not limited by above-described embodiment, and should be limited by claims and equivalent thereof.

Claims (18)

1. A data link layer L2 communication method, wherein the data link layer L2 is divided into two sublayers L2-1 and L2-2, said method comprising the following steps: On the sending side: In the L2-1 sublayer, receive and buffer the IP packets forwarded from the network layer, generate the L2-1 protocol data unit PDU, and forward the generated L2-1PDU to the L2-2 sublayer, only for the IP packets to be sent and generate a serial number; At the L2-2 sublayer, the L2-1 PDUs forwarded from the L2-1 sublayer are multiplexed to generate corresponding L2-2 PDUs, and the generated L2-2 PDUs are forwarded to the physical layer. 2. The method according to claim 1, further comprising the steps of: On the receiving side: At the L2-2 sublayer, receive the L2-2PDU forwarded from the physical layer, demultiplex the received L2-2PDU, and forward the demultiplexed L2-1PDU to the L2-1 sublayer; In the L2-1 sublayer, receive the L2-1PDU forwarded from the L2-2 sublayer, form the original IP packet, and forward the formed original IP packet to the network layer. 3. The method according to claim 1, wherein in the step of generating L2-1PDU, select an IP packet and perform header compression on the selected IP packet, encrypt the compressed IP packet by using the sequence number, and encrypt the compressed IP packet. The encrypted IP packets are fragmented and/or concatenated, and L2-1 PDUs are generated based on the sequence numbers and the fragmented and/or concatenated IP packets. 4. The method according to claim 3, wherein at the receiving side, the L2-1PDUs are reordered using the sequence numbers, the reordered L2-1PDUs are reassembled, and the reassembled L2-1PDUs are deconcatenated and and/or recombined to obtain IP packets, decrypting each IP packet using the sequence number, and then decompressing the decrypted IP packets to form the original IP packets. 5. The method of claim 1, wherein the method further comprises: At the time of transmission, according to the scheduling result or other control information, perform retransmission data processing; and perform remaining segmentation processing before selecting IP packets for header compression. 6. The method of claim 3, wherein the step of selecting an IP packet comprises: IP packets are selected according to the header of each IP packet, the current context, and the compression algorithm used. 7. The method according to any one of claims 1-6, further comprising: During handover, IP packets that were not received correctly are forwarded to the target system. 8. The method of claim 7, wherein incorrectly received IP packets are forwarded to the target system based on status report information. 9. The method according to any one of claims 1-6, wherein the method is applied in the field of wireless communication. 10. A data link layer L2 communication system, wherein the data link layer L2 is divided into two sublayers L2-1 and L2-2, said system comprising: The sending side device receives and buffers the IP packet forwarded from the network layer, generates L2-2PDU, and forwards the generated L2-2PDU to the physical layer, The sending side equipment includes: The sequence number generating module is used for generating only one sequence number for the IP packet to be sent. 11. The communication system of claim 10, further comprising: The receiving side device receives the L2-2PDU forwarded from the physical layer, forms an original IP packet, and forwards the formed original IP packet to the network layer. 12. The communication system according to claim 10, wherein the sending side device further comprises: The IP packet receiving module is used to receive and buffer the IP packet forwarded from the network layer; a scheduling/control module for selecting IP packets; and The header compression module is used for performing header compression on the selected IP packet. 13. The communication system according to claim 12, wherein the sending side device comprises: Encryption module, utilizes described serial number to encrypt the compressed IP packet; Segmentation/concatenation module, segmenting and/or concatenating encrypted IP packets; The L2-1PDU generation module generates an L2-1PDU according to the sequence number and the segmented and/or concatenated IP packets, and forwards the generated L2-1PDU to the L2-2 sublayer; and The multiplexing module, according to the scheduling/control of the scheduling/control module, multiplexes the L2-1PDUs forwarded from the L2-1 sublayer to generate corresponding L2-2PDUs, and forwards the generated L2-1PDUs to the physical layer. 2 PDUs. 14. The communication system according to claim 13, wherein the receiving side device comprises: The demultiplexing module is used to receive the L2-2PDU forwarded from the physical layer, demultiplex the received L2-2PDU, and forward the L2-1PDU generated after demultiplexing to the L2-1 sublayer; The reordering module uses the sequence number to reorder the L2-1PDU generated after demultiplexing; The reassembly module reassembles the reordered L2-1PDU; A decryption module, using the sequence number to decrypt the IP packet in the reassembled L2-1PDU; and The decompression module decompresses each IP packet in the decrypted L2-1PDU to form an original IP packet, and forwards the formed original IP packet to the network layer. 15. The communication system of claim 13, further comprising: The retransmission data processing module interacts with the IP packet receiving module, the serial number generation module and the multiplexing module, and performs retransmission data processing; The remaining segment processing module interacts with the IP packet receiving module, sequence number generating module, header compression module and segment/concatenation module, and performs remaining segment processing. 16. The communication system according to claim 12, wherein the IP packet receiving module selects the IP packets according to the header of each IP packet, the current context and the compression algorithm used. 17. A data link layer L2 sending side device, wherein the data link layer L2 is divided into two sublayers L2-1 and L2-2, and the sending side device includes: Scheduling/control module; An IP packet receiving module, configured to receive and buffer IP packets forwarded from the network layer, and select IP packets according to the scheduling/control of the scheduling/control module; A header compression module, configured to perform header compression on selected IP packets; A sequence number generation module, used to generate only one sequence number for the selected IP grouping; Encryption module, utilizes described serial number to encrypt the compressed IP packet; Segmentation/concatenation module, segmenting and/or concatenating encrypted IP packets; The L2-1PDU generation module generates an L2-1PDU according to the sequence number and the segmented and/or concatenated IP packets, and forwards the generated L2-1PDU to the L2-2 sublayer; and The multiplexing module, according to the scheduling/control of the scheduling/control module, multiplexes the L2-1PDUs forwarded from the L2-1 sublayer to generate corresponding L2-2PDUs, and forwards the generated L2-1PDUs to the physical layer. 2 PDUs. 18. The sending-side device according to claim 17, wherein the sending-side device further comprises: The retransmission data processing module interacts with the IP packet receiving module, the serial number generation module and the multiplexing module, and performs retransmission data processing; The remaining segment processing module interacts with the IP packet receiving module, sequence number generating module, header compression module and segment/concatenation module, and performs remaining segment processing.

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