WO2011116577A1

WO2011116577A1 - Data retransmission method and apparatus

Info

Publication number: WO2011116577A1
Application number: PCT/CN2010/076030
Authority: WO
Inventors: 任泰云
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-03-22
Filing date: 2010-08-16
Publication date: 2011-09-29
Also published as: CN102201901A

Abstract

Disclosed are a data retransmission method and apparatus. Wherein, the data retransmission method includes: setting a data retransmission threshold for a Radio Link Control (RLC) layer; judging whether the spare space of a Transport Block (TB) is smaller than the data retransmission threshold, and if yes, waiting for a next new TB to retransmit the RLC layer retransmission data. The present invention, by setting a data retransmission threshold for the RLC layer, avoids inappropriate segmentation of retransmission data, controls the length of Protocol Data Units (PDUs) effectively, saves uplink and downlink data transmission bandwidth and reduces the complexity of processing RLC retransmission data.

Description

The present invention relates to the field of wireless communication technologies, and in particular, to a data retransmission method and apparatus for an LTE (Long Term Evolution) system. Background technique

The RLC (Radio Link Control) protocol layer is located under the PDCP (Packet Data Convergence Protocol) layer in the LTE radio interface protocol stack, above the MAC (Media Access Control) layer. , is a sublayer of Layer 2 protocols for error recovery and flow control in 3G systems. The RLC sublayer provides segmentation and retransmission services for user service data and control data. The functions of the RLC sublayer include link control, delivery of upper layer (RRC/PDCP) PDUs (Protocol Data Units), reassembly, segmentation, re-segmentation and cascading, sequential delivery of PDUs, ARQ ( Automatic Repeat Request, Automatic Repeat Request) Error Correction, Repeatability Detection, Flow Control, Protocol Error Detection and Repair, RLC Reconstruction, etc. The functionality of the RLC sublayer is implemented by RLC entities, and each RLC entity can be RRC (Radio

Resource Control, configured in three modes for data transfer: Transparent Mode (TM, Transparent Mode), Unacknowledged Mode (UM), and Acknowledged Mode (AM, Acknowledged Mode). In the three modes, the ARQ retransmission in the acknowledge mode is to send a status report to the sender through the receiver, and the sender is based on the ACK_SN (Acknowledgement Sequence Number) and NACK-SN (Native-Acknowledgement Sequence) in the status report. Number) ^p determines that PDU has been connected) to terminal indeed less, PDU or PDU segments which need to be retransmitted, so as to ensure reliability of data transmission. The data transmission of the acknowledgment mode is usually performed using the Radio Link Control Acknowledgement Mode Protocol Data Unit RLC AM PDU. The structure of an RLC AM PDU field (Segment) is as shown in FIG. Figure 1 shows the case of an odd number of LI fields, where K is used to identify how many LI fields are in total, where it is assumed that the meaning of K >= 3 is that the LI field following the braces exists. Figure 2 shows the case of an even number of LI fields. In the prior art, when retransmitting a message, the bandwidth can be used. Unlimited split down. However, this will cause the cost after splitting to be greater than the cost of not splitting when the remaining bandwidth is less than a certain value. For example, if the bandwidth is 3 bytes, if the 3 bytes of data are split from the retransmission message to the TB (Transport Block) block, the RLC layer will cause the DMAC layer when passing the data to the DMAC layer. More than 2 bytes of DMAC header data. Therefore, when the RLC layer sends the retransmission packet next time, the field structure of the RLC AM PDU will have 2 bytes of SO field data, as shown in Figure 2. If the peer receives the fragment, it needs to increase the SOstart and SOend fields in the status report structure shown in Figure 3 by 4 bytes. In order to send 3 bytes of data, 2 bytes of downlink data are added. , adding 4 bytes of uplink data, wasting bandwidth of uplink and downlink wireless links. SUMMARY OF THE INVENTION A main object of the present invention is to provide a data retransmission method and apparatus, which solves the problem that the bandwidth of the radio link is wasted due to the deficiencies in the process of constructing the RLC layer in the LTE existing system due to retransmission of data packets. According to an aspect of the present invention, a data retransmission method is provided, including: setting a radio link control RLC layer data retransmission threshold; determining whether a free space of the transport block TB is less than a data retransmission threshold; The result is yes, waiting for the retransmission data of the RLC layer to be retransmitted using the next new TB. Further, the step of setting the RLC layer data retransmission threshold includes: acquiring the number of bytes occupied by the offset byte of the RLC layer protocol data unit PDU; setting the data retransmission threshold to be greater than or equal to the number of bytes . Further, after the RLC layer data retransmission threshold is set, the data retransmission method further includes: determining whether the TB free space is greater than a data retransmission threshold, and greater than a length of the retransmitted data; Yes, the retransmission data of the RLC layer is retransmitted using the free space of the TB. Further, after the RLC layer data retransmission threshold is set, the data retransmission method further includes: determining whether the TB free space is greater than a data retransmission threshold, and less than a length of the retransmitted data; If yes, the retransmission data of the free space whose length is less than or equal to TB is split from the retransmission data; and the retransmitted data is retransmitted by using the free space of the TB. Further, the data retransmission threshold has a value ranging from 4-8 bytes. According to another aspect of the present invention, a data retransmission apparatus is provided, including: a setting module, The first retrieving module is configured to determine whether the free space of the transport block TB is smaller than a data retransmission threshold; the first retransmission module is used to be in the first When the judgment result of the determination module is YES, it is waiting to use the retransmission data of the next new TB retransmission RLC layer. Further, the setting module includes: an acquiring module, configured to acquire an RLC layer protocol data unit

The number of bytes occupied by the offset byte of the PDU. The threshold value setting module is configured to set the data retransmission threshold to be greater than or equal to the number of bytes. Further, the data retransmission device further includes: a second determining module, configured to determine whether a free space of the TB is greater than a data retransmission threshold, and greater than a length of the retransmitted data; and a second retransmission module, configured to When the judgment result of the second judging module is YES, the retransmission data of the RLC layer is retransmitted using the free space of the TB. Further, the data retransmission apparatus further includes: a third determining module, configured to determine whether a free space of the TB is greater than a data retransmission threshold, and less than a length of the retransmitted data; and a splitting module, configured to be in the third If the judgment result of the determination module is yes, the retransmission data of the free space whose length is less than or equal to TB is split from the retransmission data; the third retransmission module is used for retransmission of the free space using TB. Retransmit the data. Further, the data retransmission threshold has a value ranging from 4-8 bytes. By setting the RLC layer data retransmission threshold, the invention avoids the inappropriate splitting of the retransmitted data, effectively controls the length of the PDU, saves the uplink and downlink data transmission bandwidth, and reduces the complexity of the RLC retransmission data processing. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a schematic structural diagram of an RLC AM PDU Segment of the prior art; FIG. 2 is a schematic structural diagram of another RLC AM PDU Segment of the prior art; FIG. 3 is a RLC of the prior art. Status report structure diagram; 4 is a flow chart showing the steps of an embodiment of the data retransmission method of the present invention; FIG. 5 is a flow chart showing the steps of another embodiment of the data retransmission method of the present invention; FIG. 6 is another data weight of the present invention. Figure 7 is a block diagram showing the structure of an embodiment of a data retransmission apparatus of the present invention; and Figure 8 is a block diagram showing the structure of another embodiment of the data retransmission apparatus of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. Referring to FIG. 4, a flow chart of steps of an embodiment of a data retransmission method according to the present invention is shown. Specifically, the method may include the following steps: Step 401: Set a radio link control RLC layer data retransmission threshold; The pass threshold may be set to be greater than or equal to the number of bytes occupied by the offset byte of the RLC AM PDU, or greater than or equal to the number of bytes occupied by the offset byte of the RLC status report structure. Those skilled in the art can flexibly set according to actual conditions under the principle of saving uplink and downlink bandwidth resources, and the present invention does not need to be limited. Step 403: Determine whether the idle length of the transport block TB is less than the data retransmission threshold. If the determination result is yes, go to step 405; Step 405: Wait for the retransmission data of the RLC layer to be retransmitted by the next new TB. When the TB free space is smaller than the data retransmission threshold, the TB retransmits the retransmission data of the RLC layer by using the TB to avoid retransmission of small data volume by using a large header, thereby causing bandwidth waste. In the prior art, when retransmitting data, even if the TB has a small free space, the retransmitted data is still split and filled into the free space. However, this will cause the transmitted data to occupy a smaller number of bytes, and the header bytes of the message occupy a larger number of bytes, thereby causing a waste of data transmission bandwidth. With the embodiment, the deficiencies of the RLC layer retransmission data in the LTE system in the prior art can be solved, the uplink and downlink data transmission bandwidth is effectively saved, and the complexity of the RLC retransmission data processing is reduced. Referring to Figure 5, there is shown a flow chart of the steps of another embodiment of the data retransmission method of the present invention. In this embodiment, the retransmission data of the RLC layer in the LTE system is taken as an example. According to the prior art implementation, when the data retransmission threshold is not set, in the downlink data, a 2-byte RLC PDU is wasted. The offset byte, in the uplink data, wastes 4 RLC PDU offset bytes. Therefore, when the data retransmission threshold is set, the number of bytes occupied by the offset byte of the PDU of the RLC is first obtained, and then the PDU whose data retransmission threshold is greater than or equal to the RLC is set according to the number of bytes. The number of bytes occupied by the offset byte. In this embodiment, the number of bytes occupied by the offset byte of the PDU of the RLC is 2 or 4 bytes, and the data retransmission threshold may be set to be 4 to 8 bytes. Take 5 bytes as an example. By setting the data retransmission threshold according to the number of bytes occupied by the offset byte of the PDU, the algorithm is simple and convenient to implement, and the data retransmission threshold setting is more reasonable. The value of the data retransmission threshold is set to be 4 to 8 bytes, which can better adapt to the data retransmission of the current RLC layer, and provides a good setting reference for those skilled in the art. Of course, the technology in the field Personnel can also be set as needed. ^ii. There are three retransmitted data nodes in the RLC retransmission queue, which are DATA-l, DATA-2, respectively.

DATA-3, the length is 500 bytes, 800 bytes, 300 bytes. The data retransmission in this embodiment may include the following steps: Step 501: The RLC receives the scheduling result of the MAC layer, and the space for retransmitting the TB. In this embodiment, the space length of the retransmission TB block is 1303 bytes. Step 503: Determine whether there is data in the retransmission queue. If not, the process ends; if yes, step 505 is performed. Step 505: Obtain a retransmission data node from the retransmission queue. Step 507: Determine whether the free space of the TB is greater than the data length of the retransmitted data node. If yes, go to step 509; if no, go to step 511. Step 509: Copy the retransmitted data of the retransmitted data node to the TB, and go to step 503. Step 511: Determine whether the free space of the TB is less than the data retransmission threshold, and if yes, perform step 4 513; if not, perform step 4 515. Step 513: Retransmit the data using the new TB copy. Step 515: Split the retransmitted data node, fill the idle TB, and send the TB. In this embodiment, the space length of the retransmission TB block is 1303 bytes. First, the retransmission data node DATA-1 is obtained from the retransmission queue. The data length of DATA-1 is 500 bytes, which is less than the length of TB, and DATA-1 is copied into the TB block. The free space for calculating TB is 803 bytes, which is greater than the data retransmission threshold of 5 bytes. The second retransmitted data node DATA-2 is obtained from the retransmission queue. The data length of DATA-2 is 800 bytes, which is less than the free space of TB. The DATA-2 is copied into the TB block, and the free space of the TB is calculated to be 3 bytes. It is determined that the free space of the TB is less than 5 bytes of the retransmission data threshold, and the retransmission packet construction ends, and the data of the TB is retransmitted. Then, the RLC receives the rescheduling result of the MAC, and retransmits the TB block again to have a space length of 1000 bytes. The RLC obtains the retransmission node DATA-3 from the retransmission queue. The data length of DATA-3 is 300 bytes, which is smaller than the space length of retransmitting TB again. The data of DATA-3 is copied into the TB block, and the free space for retransmitting TB is 700 bytes. It is determined that the free space of the retransmission TB is greater than the data retransmission threshold of 5 bytes, and the new retransmission data is continued to be copied to the TB again, until the retransmission TB is filled, and the retransmission is retransmitted. . In this embodiment, when the free space of the TB is greater than the data retransmission threshold and greater than the length of the retransmitted data, the retransmission data is directly copied to the TB for retransmission, which effectively improves the data retransmission speed and efficiency. Referring to Figure 6, a flow chart of the steps of another embodiment of the data retransmission method of the present invention is shown. In this embodiment, the retransmission data of the RLC layer in the LTE system is taken as an example, and the data retransmission threshold is selected to be 5 bytes. Suppose there are three retransmission data nodes in the retransmission queue of RLC, which are DATA-1, DATA-2, DATA-3, respectively, which are 500 bytes, 800 bytes, and 300 bytes. The data retransmission in this embodiment may include the following steps: Step 601: The RLC receives the scheduling result of the MAC layer, and the space for retransmitting the TB is 1503 bytes. Step 603: Obtain a retransmission data node DATA-1 from the retransmission queue. The data length of DATA-1 is 500 bytes, which is less than the space length of TB. Copy DATA-1 into the TB block, and calculate the free space of TB to be 1003 bytes. Step 605: Obtain a second retransmission data node DATA-2 from the retransmission queue. The data length of DATA-2 is 800 bytes, which is less than the free space of TB. Copy DATA-2 into the TB block. The free space for calculating TB is 203 bytes. Step 607: Determine whether the free space of the TB is greater than 5 bytes of the retransmission data threshold, but less than 300 bytes of the data length of the DATA-3. If the determination result is yes, step 609 is performed. Step 609: Split DATA-3 into two parts, the split first retransmission data part is equal to TB free space 203 bytes, and the remaining split second retransmission data part is 97 bytes. Step 611: Copy the first retransmission data of the DATA-3 into the TB, and retransmit the

TB. Step 4: 613: The RLC receives the rescheduling result of the MAC, and retransmits the TB space length to 1000 bytes. Step 615: The RLC obtains the split second retransmission data of the retransmission node DATA-3 from the retransmission queue, copies it to the TB, and calculates that the free space for retransmitting the TB is 903 bytes. Step 617: Continue to copy the new retransmission data to retransmit the TB again, and retransmit the TB again. In this embodiment, when the free space of the TB is greater than the data retransmission threshold and less than the length of the retransmitted data, the retransmission data is reasonably split, thereby improving data retransmission speed and efficiency. Referring to FIG. 7, a structural block diagram of an embodiment of a data retransmission apparatus of the present invention is shown. Specifically, the method may include: a setting module 701, configured to set a radio link control RLC layer data retransmission threshold. The first determining module 703 is configured to determine whether the free space of the transport block TB is less than a data retransmission threshold. The first retransmission module 705 is configured to wait for the retransmission data of the next new TB retransmission RLC layer to be used if the determination result of the first judging module 703 is YES. The setting module 701 sets an RLC layer data retransmission threshold, such as any one of 4-8 bytes. The first determining module 703 determines that the free space (eg, 3 bytes) of the TB is less than the data retransmission threshold (eg, 5 bytes). The first retransmission module 705 relinquishes retransmission data using the TB retransmission RLC layer, and retransmits the retransmission data using the new TB. With the embodiment, the RLC layer retransmission data of the LTE system in the prior art can be solved. Insufficient manufacturing, effectively save uplink and downlink data transmission bandwidth, and reduce the complexity of RLC retransmission data processing. Referring to FIG. 8, a structural block diagram of another embodiment of a data retransmission apparatus of the present invention is shown. Specifically, the method may include: a setting module 801, configured to set a radio link control RLC layer data retransmission threshold. Preferably, the data retransmission threshold may be in the range of 4-8 bytes. Preferably, the setting module 801 may include: an obtaining module 8011, configured to acquire an occupied byte number of an offset byte of the RLC layer PDU; and a threshold value setting module 8013, configured to set the data retransmission threshold to be greater than or Equal to the number of bytes. The first determining module 803 is configured to determine that the free space of the transport block TB is smaller than a data retransmission threshold. The first retransmission module 805 is configured to retransmit the retransmission data of the RLC layer by using the new TB. Preferably, the data retransmission device may further include: a second determining module 807, configured to determine whether the free space of the TB is greater than a data retransmission threshold, and greater than a length of the retransmitted data. The second retransmission module 809 is configured to retransmit the retransmission data of the RLC layer by using the free space of the TB if the determination result of the second judging module 807 is YES. Preferably, the data retransmission apparatus may further include: a third determining module 811, configured to determine whether a free space of the TB is greater than a data retransmission threshold, and less than a length of the retransmitted data. The splitting module 813 is configured to, when the determination result of the third determining module 811 is YES, split the retransmission data of the free space whose length is less than or equal to TB from the retransmission data. The third retransmission module 815 is configured to retransmit the split retransmission data by using the free space of the TB. The obtaining module 8011 of the setting module 801 acquires the occupied byte number of the offset byte of the RLC layer PDU. The threshold setting module 8013 sets a data retransmission threshold according to the number of bytes, and the data retransmission threshold is greater than or equal to the number of bytes. When the data is retransmitted, if the first determining module 803 determines

If the TB free space is smaller than the data retransmission threshold, the first retransmission module 805 uses the new TB retransmission. Retransmission data of the RLC layer; if the second judging module 807 determines that the free space of the TB is greater than the data retransmission threshold and is greater than the length of the retransmitted data, the second retransmission module 809 retransmits the RLC layer using the free space of the TB. If the third judging module 811 determines that the free space of the TB is greater than the data retransmission threshold and is less than the length of the retransmitted data, the splitting module 813 splits the length from the retransmitted data to be less than or equal to the free space. The retransmission data, the third retransmission module 815 retransmits the split retransmission data using the free space of the TB. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A data retransmission method, comprising:

Set the radio link control RLC layer data retransmission threshold;

Determining whether the free space of the transport block TB is smaller than the data retransmission threshold; if the judgment result is yes, waiting for the next new TB to retransmit the retransmission data of the RLC layer.

The method according to claim 1, wherein the step of setting an RLC layer data retransmission threshold comprises:

Obtaining, by the number of bytes occupied by the offset byte of the RLC layer protocol data unit PDU; setting the data retransmission threshold to be greater than or equal to the number of bytes.

The method according to claim 1, wherein after the setting the RLC layer data retransmission threshold, the method further includes:

Determining whether the free space of the TB is greater than the data retransmission threshold and greater than the length of the retransmitted data;

If the result of the determination is yes, the retransmission data of the RLC layer is retransmitted using the free space of the TB.

The method of claim 1, wherein after the setting of the RLC layer data retransmission threshold, the method further comprises:

Determining whether the free space of the TB is greater than the data retransmission threshold and less than the length of the retransmitted data;

If the result of the determination is yes, the retransmission data of the free space whose length is less than or equal to the TB is split from the retransmission data;

The split retransmission data is retransmitted using the free space of the TB.

The method according to claim 1, wherein the data retransmission threshold has a value ranging from 4-8 bytes.

6. A data retransmission device, comprising: a setting module, configured to set a radio link control RLC layer data retransmission threshold; a first determining module, configured to determine whether a free space of the transport block TB is smaller than the data retransmission threshold;

The first retransmission module is configured to wait for the retransmission data of the RLC layer to be retransmitted using the next new TB if the judgment result of the first judging module is yes.

The device according to claim 6, wherein the setting module comprises:

An acquiring module, configured to acquire an occupied byte number of an offset byte of the RLC layer protocol data unit PDU;

a threshold setting module, configured to set the data retransmission threshold to be greater than or equal to the number of bytes.

8. The device according to claim 6, further comprising:

a second determining module, configured to determine whether a free space of the TB is greater than the data retransmission threshold, and greater than a length of the retransmitted data;

And a second retransmission module, configured to retransmit the retransmission data of the RLC layer by using the free space of the TB if the determination result of the second determining module is yes.

9. The device according to claim 6, further comprising:

a third determining module, configured to determine whether a free space of the TB is greater than the data retransmission threshold, and less than a length of the retransmitted data;

a splitting module, configured to: when the determination result of the third determining module is yes, split the retransmission data whose length is less than or equal to the free space of the TB from the retransmission data; And a transmitting module, configured to retransmit the split retransmission data by using the free space of the TB.

10. The apparatus according to claim 6, wherein the data retransmission threshold has a value ranging from 4-8 bytes.