CN102201901A - Data retransmission method and device - Google Patents

Abstract

The invention discloses a data retransmission method and device. Wherein, the data retransmission method includes: setting the radio link control RLC layer data retransmission threshold; judging that the free space of the transmission block TB is less than the data retransmission threshold; using a new TB to retransmit the RLC Layer retransmission data. By setting the RLC layer data retransmission threshold, the present invention avoids improper splitting of retransmission data, effectively controls the length of PDU, saves uplink and downlink data transmission bandwidth, and reduces the complexity of RLC retransmission data processing.

Description

Data retransmission method and device

technical field

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

Background technique

The RLC (Radio Link Control, radio link control) protocol layer is located under the PDCP (Packet Data Convergence Protocol, packet data convergence protocol) layer in the LTE wireless interface protocol stack, and above the MAC (Media Access Control, media access control) layer , is a sublayer of the Layer 2 protocol used for error recovery and flow control in 3G systems. The RLC sublayer provides segmentation and retransmission services for user traffic data and control data. The functions of the RLC sublayer include link control, transfer of PDU (Protocol Data Unit, Protocol Data Unit) of the upper layer (RRC/PDCP), reassembly, segmentation, re-segmentation and concatenation, delivery of PDUs to the upper layer in sequence, ARQ (Automatic Repeat Request, automatic repeat request) error correction, repetition detection, flow control, protocol error detection and repair, RLC reconstruction, etc.

The functions of the RLC sublayer are implemented by RLC entities, and each RLC entity can be configured by RRC (Radio Resource Control, radio resource control) in three modes for performing data transmission: transparent mode (TM, Transparent Mode), unacknowledged mode (UM , Unacknowledged Mode) and confirmation mode (AM, Acknowledged Mode).

Among the three modes, the ARQ retransmission in the confirmation mode is to send a status report (Status Report) to the sender through the receiving end, and the sending end according to the ACK_SN (Acknowledgment Sequence Number) and NACK_SN (Negative Acknowledgment Sequence Number) in the status report To determine which PDUs have been confirmed by the receiving end, which PDUs or PDU fragments need to be retransmitted, so as to ensure the reliability of data transmission.

Data transmission in acknowledgment mode is usually performed using RLC AM PDU, and the structure of an RLCAM PDU is shown in Figure 1. In the prior art, when retransmitting a message, it can be infinitely split according to the size of the bandwidth. However, this will result in that when the remaining bandwidth is less than a certain value, the cost of splitting is greater than the cost of not splitting. For example, if there are 3 bytes left in the bandwidth, if the data of 3 bytes is split into TB (TransportBlock, transport block) blocks from the retransmission message, the RLC layer will cause the DMAC layer to overload the data when it passes the data to the DMAC layer. 2 bytes of DMAC header data. Therefore, when the RLC layer sends a retransmission message next time, there will be 2 more bytes of SO in the Segment structure of the RLC AM PDU, as shown in Figure 2. If the peer end needs to add 4 bytes of SOstart and SOend fields in the status report structure shown in Figure 3 after receiving the fragment, in order to send 3 bytes of data, 2 bytes of downlink data are added , adding 4 bytes of uplink data, wasting the bandwidth of uplink and downlink wireless links.

Contents of the invention

The main purpose of the present invention is to provide a data retransmission method and device to solve the problem of waste of wireless link bandwidth due to the shortage of the RLC layer in the retransmission data message construction process in the existing LTE system.

According to one aspect of the present invention, a data retransmission method is provided, including: setting the radio link control RLC layer data retransmission threshold; judging that the free space of the transport block TB is less than the data retransmission threshold; using a new The TB retransmits the retransmitted data of the RLC layer.

Further, the step of setting the RLC layer data retransmission threshold includes: obtaining 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 byte number.

Further, the data retransmission method further includes: judging that the free space of the TB is greater than the data retransmission threshold and greater than the length of the retransmission data; using the free space of the TB to retransmit the retransmission data of the RLC layer.

Further, the data retransmission method further includes: judging that the free space of the TB is greater than the data retransmission threshold and smaller than the length of the retransmitted data; Data; use TB of free space to retransmit sub-retransmission data.

Further, the value range of the data retransmission threshold is 4-8 bytes.

According to another aspect of the present invention, a data retransmission device is provided, including: a setting module for setting a radio link control RLC layer data retransmission threshold; a first judging module for judging the transmission block TB The free space is smaller than the data retransmission threshold; the first retransmission module is configured to use the new TB to retransmit the retransmission data of the RLC layer.

Further, the setting module includes: an acquisition module, used to obtain the number of bytes occupied by the offset byte of the RLC layer protocol data unit PDU; a threshold value setting module, used to set the data retransmission threshold value to be greater than or equal to The number of bytes.

Further, the data retransmission device further includes: a second judging module, configured to judge that the free space of the TB is greater than the data retransmission threshold, and greater than the length of the retransmitted data; a second retransmitting module, configured to use the TB The retransmission data of the RLC layer is retransmitted in the free space.

Further, the data retransmission device further includes: a third judging module, configured to judge that the free space of the TB is greater than the data retransmission threshold and smaller than the length of the retransmitted data; Splitting the sub-retransmission data whose length is less than or equal to the free space; the third retransmission module is used to retransmit the sub-retransmission data using the free space of TB.

Further, the value range of the data retransmission threshold is 4-8 bytes.

By setting the RLC layer data retransmission threshold, the present invention avoids improper splitting of retransmission data, effectively controls the length of PDU, saves uplink and downlink data transmission bandwidth, and reduces the complexity of RLC retransmission data processing.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is the structural representation of a kind of RLC AM PDU of prior art;

Fig. 2 is the structural representation of a kind of RLC AM PDU Segment of prior art;

Fig. 3 is a structure diagram of an RLC status report in the prior art;

FIG. 4 is a flow chart of the steps of an embodiment of a data retransmission method in the present invention;

FIG. 5 is a flow chart of steps of another embodiment of a data retransmission method in the present invention;

FIG. 6 is a flow chart of steps in another embodiment of a data retransmission method according to the present invention;

FIG. 7 is a structural block diagram of an embodiment of a data retransmission device according to the present invention;

Fig. 8 is a structural block diagram of another embodiment of a data retransmission device according to the present invention.

Detailed ways

Hereinafter, the present invention will be described in detail with reference to the drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

Referring to FIG. 4 , it shows a flow chart of the steps of an embodiment of a data retransmission method according to the present invention, which may specifically include the following steps:

Step 401: setting the radio link control RLC layer data retransmission threshold;

The data retransmission threshold can 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. Under the principle of saving uplink and downlink bandwidth resources, those skilled in the art can flexibly set according to the actual situation, and the present invention does not need to limit this.

Step 403: judging that the idle length of the transport block TB is less than the data retransmission threshold;

Step 405: Use the new TB to retransmit the retransmitted data of the RLC layer.

When the free space of the TB is smaller than the data retransmission threshold, the TB is abandoned to retransmit the retransmission data of the RLC layer, so as to avoid retransmission of small data volume data with a larger header, resulting in waste of bandwidth.

When retransmitting data in the prior art, even if the free space of TB is small, the retransmitted data will still be split and filled into the free space. However, in this way, less bytes will be occupied by the transmitted data, and more bytes will be occupied by the header bytes of the message, thus causing a waste of data transmission bandwidth. Through this embodiment, the deficiency of the RLC layer retransmission data message structure in the LTE system in the prior art can be solved, the uplink and downlink data transmission bandwidth can be effectively saved, and the complexity of RLC retransmission data processing can be reduced.

Referring to FIG. 5 , it shows a flow chart of steps of another embodiment of a data retransmission method according to the present invention. This embodiment takes the retransmission data of the RLC layer in the LTE system as an example. According to the implementation method of the prior art, when the data retransmission threshold is not set, in the downlink data, 2 bytes of RLC PDU will be wasted. Offset bytes, and in the uplink data, 4 RLC PDU offset bytes will be wasted.

Therefore, when setting the data retransmission threshold, first obtain the number of bytes occupied by the offset byte of the PDU of RLC, and then set the data retransmission threshold greater than or equal to the PDU of RLC according to the number of bytes. The number of bytes occupied by the offset bytes. In this embodiment, the number of bytes occupied by the offset byte of the PDU of the RLC is first acquired as 2 or 4 bytes, then the value range of the data retransmission threshold can be set as 4 to 8 bytes, Take selecting 5 bytes as an example. By setting the data retransmission threshold value according to the number of bytes occupied by the offset byte of the PDU, the algorithm is simple, the implementation is convenient, and the setting of the data retransmission threshold value is more reasonable. The value range of setting the data retransmission threshold value is 4 to 8 bytes, which can better adapt to the data retransmission of the RLC layer at the present stage, and provides a better setting reference for those skilled in the art. Of course, those skilled in the art Personnel can also be properly set as needed.

Assume that there are three retransmission data nodes in the RLC retransmission queue, which are DATA-1, DATA-2, and DATA-3, and the lengths are 500 bytes, 800 bytes, and 300 bytes respectively. The data retransmission in this embodiment may specifically include the following steps:

Step 501: The RLC receives the scheduling result of the MAC layer and the TB space available for retransmission this time.

In this embodiment, the space length of the retransmitted TB block this time is 1303 bytes.

Step 503: Determine whether there is data in the retransmission queue, if not, end the process; if yes, execute step 505.

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 retransmitting data node, if yes, execute step 509; if not, execute step 511.

Step 509: copy the retransmission data of the retransmission data node to the TB, go to step 503.

Step 511: Determine whether the free space of the TB is smaller than the data retransmission threshold, if yes, execute step 513; if not, execute step 515.

Step 513: Use the new TB copy to retransmit the data.

Step 515: Split and retransmit the data node, fill up the idle TB, and send the TB.

In this embodiment, the space length of the retransmitted TB block this time is 1303 bytes. First, obtain the retransmission data node DATA-1 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 to the TB block. The calculated TB free space is 803 bytes, which is 5 bytes larger than the data retransmission threshold. Obtain the 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 to the TB block, and calculate the free space of TB as 3 bytes. It is judged that the free space of the TB is less than the retransmission data threshold value of 5 bytes, the retransmission message construction is completed, and the data of the TB is retransmitted.

Then, the RLC receives the rescheduling result from the MAC, and retransmits the TB block again with 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 less than the space length of the retransmission TB. Copy the data of DATA-3 to the TB block, and calculate the free space for retransmission TB to be 700 bytes. Judging that the free space of the retransmission TB is greater than the data retransmission threshold value of 5 bytes, continue to copy the new retransmission data to the retransmission TB until the retransmission TB is filled, and then retransmit the retransmission TB .

Through 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 retransmitted data is directly copied to the TB for retransmission, which effectively improves the data retransmission speed and efficiency.

Referring to FIG. 6 , it shows a flow chart of steps in another embodiment of a data retransmission method according to the present invention. This embodiment still takes the retransmission data of the RLC layer in the LTE system as an example, and selects the data retransmission threshold as 5 bytes. Assume that there are three retransmission data nodes in the RLC retransmission queue, which are DATA-1, DATA-2, and DATA-3, and the lengths are 500 bytes, 800 bytes, and 300 bytes respectively.

The data retransmission in this embodiment may specifically include the following steps:

Step 601: RLC receives the scheduling result of the MAC layer, and the space for retransmitting TB this time 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 to a TB block, and calculate the free space of TB as 1003 bytes.

Step 605: Obtain the 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 to the TB block, and calculate the free space of TB as 203 bytes.

Step 607: Judging that the free space of TB is greater than the retransmission data threshold of 5 bytes, but less than the data length of DATA-3 of 300 bytes.

Step 609: Split DATA-3 into two parts, the first sub-retransmission data part is equal to 203 bytes of free space in TB, and the remaining second sub-retransmission data part is 97 bytes.

Step 611: Copy the first sub-retransmission data of DATA-3 into a TB, and retransmit the TB.

Step 613: The RLC receives the rescheduling result from the MAC, and retransmits the TB again with a space length of 1000 bytes.

Step 615: The RLC acquires the second sub-retransmission data of the retransmission node DATA-3 from the retransmission queue, copies it into the TB, and calculates that the free space of the retransmission TB is 903 bytes.

Step 617: Continue to copy the new retransmission data to the retransmission TB, and retransmit the retransmission TB.

Through 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 retransmitted data is reasonably split, which improves the data retransmission speed and efficiency.

Referring to FIG. 7, it shows a structural block diagram of an embodiment of a data retransmission device according to the present invention, which may specifically include:

The setting module 701 is used to set the data retransmission threshold of the radio link control RLC layer.

The first judging module 703 is configured to judge that the free space of the transport block TB is smaller than the data retransmission threshold.

The first retransmission module 705 is configured to use the new TB to retransmit the retransmission data of the RLC layer.

The setting module 701 sets the RLC layer data retransmission threshold, such as any one of 4-8 bytes. The first judging module 703 judges that the free space of the TB (eg, 3 bytes) is smaller than the data retransmission threshold (eg, 5 bytes). The first retransmission module 705 gives up using the TB to retransmit the retransmission data of the RLC layer, and uses a new TB to retransmit the retransmission data.

Through this embodiment, the deficiency of the RLC layer retransmission data message structure in the LTE system in the prior art can be solved, the uplink and downlink data transmission bandwidth can be effectively saved, and the complexity of RLC retransmission data processing can be reduced.

Referring to FIG. 8 , it shows a structural block diagram of another data retransmission device embodiment of the present invention, which may specifically include:

The setting module 801 is configured to set the data retransmission threshold of the radio link control RLC layer.

Preferably, the value range of the data retransmission threshold may be 4-8 bytes.

Preferably, the setting module 801 may include: an acquisition module 8011, which is used to obtain the number of bytes occupied by the offset byte of the RLC layer PDU; a threshold value setting module 8013, which is used to set the data retransmission threshold value to be greater than or equal to the number of bytes.

The first judging module 803 is configured to judge that the free space of the transport block TB is smaller than the data retransmission threshold.

The first retransmission module 805 is configured to use the new TB to retransmit the retransmission data of the RLC layer.

Preferably, the data retransmission device may further include:

The second judging module 807 is configured to judge that the free space of the TB is greater than the data retransmission threshold and greater than the length of the retransmitted data.

The second retransmission module 809 is configured to use the free space of TB to retransmit the retransmission data of the RLC layer.

Preferably, the data retransmission device may further include:

The third judging module 811 is configured to judge that the free space of the TB is larger than the data retransmission threshold and smaller than the length of the retransmitted data.

The splitting module 813 is configured to split the sub-retransmission data whose length is less than or equal to the free space from the retransmission data.

The third retransmission module 815 is configured to use the free space of TB to retransmit sub-retransmission data.

The obtaining module 8011 of the setting module 801 obtains the number of occupied bytes of the offset byte of the RLC layer PDU. The threshold value 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. During data retransmission, if the first judgment module 803 judges that the free space of the TB is less than the data retransmission threshold, the first retransmission module 805 uses the new TB to retransmit the retransmission data of the RLC layer; if the second judgment module 807 Judging that the free space of the TB is greater than the data retransmission threshold and greater than the length of the retransmission data, the second retransmission module 809 uses the free space of the TB to retransmit the retransmission data of the RLC layer; if the third judgment module 811 judges that the TB The free space of is greater than the data retransmission threshold value and less than the length of the retransmission data, then the splitting module 813 splits the sub-retransmission data whose length is less than or equal to the free space from the retransmission data, and the third retransmission module 815 uses TB of free space to retransmit the sub-retransmission data.

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned present invention can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed in a network formed by multiple computing devices Alternatively, they may be implemented in program code executable by a computing device so that they may be stored in a storage device to be executed by a computing device, and in some cases in an order different from that shown here The steps shown or described are carried out, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps among them are fabricated into a single integrated circuit module for implementation. As such, the present invention is not limited to any specific combination of hardware and software.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A data retransmission method, characterized in that, comprising: Set the radio link control RLC layer data retransmission threshold; Judging that the free space of the transport block TB is less than the data retransmission threshold; The retransmission data of the RLC layer is retransmitted using the new TB. 2. method according to claim 1, is characterized in that, the step of described setting RLC layer data retransmission threshold value comprises: Obtain the number of bytes occupied by the offset byte of the RLC layer protocol data unit PDU; Set the data retransmission threshold to be greater than or equal to the number of bytes. 3. The method according to claim 1, characterized in that the method further comprises: Judging that the free space of the TB is greater than the data retransmission threshold and greater than the length of the retransmission data; retransmitting the retransmission data of the RLC layer using the free space of the TB. 4. The method according to claim 1, wherein the method further comprises: Judging that the free space of the TB is greater than the data retransmission threshold and less than the length of the retransmission data; Splitting sub-retransmission data whose length is less than or equal to the free space from the retransmission data; retransmitting the sub-retransmission data using the free space of the TB. 5. The method according to claim 1, wherein the value range of the data retransmission threshold is 4-8 bytes. 6. A data retransmission device, comprising: Setting module, used to set the radio link control RLC layer data retransmission threshold; A first judging module, configured to judge that the free space of the transport block TB is smaller than the data retransmission threshold; The first retransmission module is configured to use the new TB to retransmit the retransmission data of the RLC layer. 7. The device according to claim 6, wherein the setting module comprises: An acquisition module, configured to acquire the number of bytes occupied by the offset byte of the RLC layer protocol data unit PDU; A threshold value 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 judging module, configured to judge that the free space of the TB is greater than the data retransmission threshold and greater than the length of the retransmitted data; The second retransmission module is configured to use the free space of the TB to retransmit the retransmission data of the RLC layer. 9. The device according to claim 6, further comprising: A third judgment module, configured to judge that the free space of the TB is greater than the data retransmission threshold and less than the length of the retransmission data; A splitting module, configured to split the sub-retransmission data whose length is less than or equal to the free space from the retransmission data; The third retransmission module is configured to use the free space of the TB to retransmit the sub-retransmission data. 10. The device according to claim 6, wherein the value range of the data retransmission threshold is 4-8 bytes.

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