WO2005112489A1

WO2005112489A1 - A method of transmitting status report

Info

Publication number: WO2005112489A1
Application number: PCT/CN2005/000688
Authority: WO
Inventors: Xuezhi Yang; Yingzhe Ding
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2004-05-18
Filing date: 2005-05-18
Publication date: 2005-11-24
Also published as: CN1700627A; CN100359841C

Abstract

The present invention disclosed a method of transmitting status report, which is suitable for the communication entities which adopt automatic retransmission request mechanism to perform data communication, the method including : a, determining the length of status information unit used for carrying the status report that need to be transmitted currently; b, performing section/cascade processing on the traffic data which is to be transmitted in the communication unity, creating new data unit that need to be transmitted, and reserving fill byte that is larger than or equal to the length of said status information unit within the new-created data unit, the data unit is the data unit that can carry said status information unit; c, encapsulating the status information unit in the fill byte of the data unit which can carry said status information unit, and transmit the data unit in which encapsulating the status information unit. By using the method of the present invention, it can exert the benefit of the carry mechanism and improve the availability of the link resource.

Description

Method for sending status report

Technical field

The present invention relates to a data transmission technology for data communication, and in particular, to a method for sending a status report under an automatic repeat request (ARQ) mechanism of a communication entity. Background of the invention

At present, in a third generation mobile communication system, such as a wideband code division multiple access (WCDMA) system and a time division synchronous code division multiple access (TD-SCDMA) system, the wireless interface is divided into a physical layer, a data link layer, and a network layer. The data link layer further includes a medium access control (MAC) sublayer, a radio link control (RLC) sublayer, a packet data compression protocol (PDCP) sublayer, and a broadcast / multicast control (BMC) sublayer; a network layer It also includes a radio resource control (RRC) sublayer.

The RLC sublayer of the data link layer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). The RLC layer can implement functions such as segmenting, concatenating, filling, reorganizing, error control, flow control, and repeatability detection of data. Among them, the AM mode also has an ARQ mechanism for error control of data units.

The ARQ mechanism in AM mode is applicable to two RLC AM entities that communicate with each other. Each RLC AM entity includes two sides: a transmitting side (Transmitting side) and a receiving side (Receiving side). The sending side can schedule and send data units to the peer RLC AM entity; the receiving side can receive data units sent by the peer RLC AM entity, and is responsible for generating a status report according to the reception status of the data unit, and reporting the sending status to the sending side The transmitting side bears the status report in the status information unit, and sends the status information unit to the peer RLC AM entity. The status report is used to confirm that the RLC AM entity has correctly received the data unit, and is used to request the peer RLC AM entity to retransmit the RLC AM entity that it has not received. Data unit. The status report contains a positive confirmation that the data unit was received correctly

(ACK) information and contains a negative acknowledgement (NACK) 'message indicating that the data unit was not received correctly. If the status report carried by the status information unit received by the peer RLC AM entity contains NACK information, the peer RLC AM entity needs to retransmit the data unit that was not received correctly to ensure the correct transmission of the data unit.

FIG. 1 is a schematic diagram of a functional model of an RLC AM entity in the prior art. The following describes the processing process of the data unit by the sending side and the receiving side of the RLC AM entity in the WCDMA system according to FIG. 1.

The processing process of the data unit by the sending side of the RLC AM entity is:

The sending side of the RLC AM entity receives the service data unit (SDU) transmitted from the upper layer, and performs segmentation and / or concatenation processing on the received SDU. The segmented and / or concatenated SDU is then added to the RLC header to assemble a fixed-length acknowledge mode data (AMD) protocol data unit (PDU). According to actual needs, it is also possible to perform padding processing on the segmented and / or concatenated SDUs to fix the length of the AMD PDU. The generated AMD PDU is then placed in a retransmission buffer and a multiplexing device. The retransmission buffer determines the AMD PDUs that need to be retransmitted according to the NACK information in the status PDU from the peer RLC AM entity, and multiplexes them to the multiplexing device. The device sends these AMD PDUs that need to be retransmitted. The multiplexing device multiplexes the AMD PDUs transmitted from the retransmission buffer and the newly generated AMD PDUs by segmentation and / or concatenation processing, and places the multiplexed AMD PDUs into the sending buffer. Next, the status report transmitted from the receiving side is carried in a status information unit, where the status information unit is a status PDU, and a sending buffer is used to find whether there is an AMD PDU that can piggyback the status PDU, that is, the AMD PDU. If the length of the stuffing byte is greater than or equal to the length of the status PDU, it can be piggybacked, and the status PDU is encapsulated in the stuffing byte part of the AMD PDU, and sent as a piggyback; if all AMD PDUs in the sending buffer are sent If the length of the padding bytes is less than the length of the status PDU, the status PDU is not encapsulated. Then, for the AMD PDU, status The PDU and the control PDU from the RLC control unit are multiplexed, and the AMD PDUs therein are encrypted. Finally, the logical PDUs, such as one or two dedicated control channels (DCCH) or dedicated service channels (DTCH), are used. The multiplexed PDU is sent out.

Figure 2 shows the data structure of the sent AMD PDU. As shown in FIG. 2, where D in the first byte indicates that the AMD PDU is a data PDU; the serial number of the AMD PDU is placed in the first and second bytes; P in the second byte indicates The query bit is used to request the peer RLC AM entity to send a status report; HE is a graph extension type, indicating that the following bytes are a data field or a length indicator (LI, Length Indicator) field; the LI field is used to define the SDU in the AMD PDU. Boundary; the bytes following the data field are padding bytes or piggybacked status PDUs.

The following describes the process of the data unit on the receiving side of the RLC AM entity:

The demultiplexing / routing unit sends the received AMD PDU to the decryption unit; sends the received control PDU to the RLC control unit, and sends the received status PDU to the retransmission buffer of the sending side of the RLC AM entity Area. The decryption unit decrypts the AMD PDU and places it in the receiving buffer. The repetitive management mechanism of the receiving buffer generates a status report according to the reception status of the AMD PDU, and sends the status report to the sending side of the RLC AM entity for sending. Then, analyze the AMD PDU in the receiving buffer to determine whether the RLC SDU can be recombined. 'If a complete RLC SDU can be recombined, remove the RLC header from the AMD PDU and perform the recombination operation. The obtained RLC SDU is submitted to the upper layer. At the same time, the status PDU carried by the AMD PDU is extracted, and the status PDU is sent to the retransmission buffer on the sending side of the RLC AM entity.

As described above, in the current ARQ mechanism, piggybacking is allowed when sending a status report of a data unit, that is, if the length of a status PDU to be sent is equal to or less than the padding byte of the AMD PDU to be sent, the status is used The PDU replaces the stuffing byte of the AMD PDU, is encapsulated in the AMD PDU, and is sent together with the AMD PDU. The piggybacked state PDU technology can reduce unnecessary padding bytes, thereby improving link utilization. However, the prior art method of using the piggyback mechanism to send a status report has the following disadvantages:

After receiving the SDU from the upper layer, the RLC AM entity immediately performs segmentation and / or concatenation processing, assembles it into a fixed-length AMD PDU, and then uses the padding bytes of the AMD-PDU to piggyback the status PDU, and the length of the padding bytes needs to be Greater than or equal to the length of the status PDU. This processing method depends on the length of the padding bytes of the AMD PDU after segmentation and / or concatenation. If the length of the padding bytes is less than the length of the status PDU, it can only form an independent status PDU to carry the status report. Therefore, the benefits brought by the piggyback mechanism cannot be fully utilized, resulting in a waste of link resources.

In the prior art, especially in a burst service mode that requires a large number of cascading processes, the probability that AMD PDUs have padding bytes will be small, so there is not enough padding byte space to carry status PDUs, which is more likely to cause Waste of link resources.

The above disadvantages are particularly prominent when the status PDU is relatively short but frequently sent, and the number of AMD PDUs allowed to be transmitted per unit time is small. In this case, sending a small amount of status reports will occupy more links. Resources, which further affect the sending of AMD PDUs by the same RLC AM entity, resulting in transmission blocking. SUMMARY In view of this, a main object of the present invention is to provide a method for sending a status report, so as to improve link resource utilization of a communication entity of an ARQ mechanism.

In order to achieve the foregoing objective, the technical solution of the present invention is specifically implemented as follows: A method for sending a status report, a communication entity suitable for data communication using an automatic retransmission mechanism, the method includes:

a. Determine the length of the status information unit used to carry the current status report; b. Segment and / or cascade the service data to be sent in the communication entity, generate a new data unit to be sent, and Reserved in the newly generated data unit is greater than or equal to the stated A padding byte of the length of the status information unit, and the data unit that is greater than or equal to the padding byte of the length of the status information unit is a data unit that can carry the status information unit;

C. Encapsulating the status information unit in a padding byte in the data unit that can carry the status information unit, and sending the data element encapsulated with the status information unit.

Preferably, after step a and before step b, the method further includes:

Find whether there is a data unit that can carry the status information unit in the data unit of the communication entity that needs to be retransmitted, and if found, go to step c; otherwise, go to step 13. .

The data unit that can piggyback the status information unit is a data unit with padding bytes, and the length of the padding byte is greater than or equal to the length of the piggybacked status information unit.

Preferably, after step a and before step b, the method further includes:

Determine whether the status information unit can be piggybacked according to a preset piggybacking threshold. If the length of the status information unit is greater than the piggybacking threshold, the status information unit cannot be piggybacked, and the status information unit is directly sent. To end the process; if the length of the status information unit is less than or equal to the piggyback threshold, the status information unit can piggyback and execute steps

The piggyback threshold is a product of a predetermined length of the data unit to be transmitted and a coefficient a. The value of the coefficient a is 0.0625.

Preferably, after step a and before step b, the method further includes:

It is determined whether there is service data to be sent in the communication entity, and if so, step b is performed, otherwise, the status information unit is directly sent, and the process ends.

The communication entity has a service data buffer, and the service data to be sent is temporarily stored in the service data buffer before segmentation and / or cascading processing.

Preferably, the communication entity is a communication entity in a broadband code division multiple access system, or a communication entity in a time division synchronous code division multiple access system.

The method is applied in a broadband code division multiple access communication entity or a time division synchronous code division multiple access communication entity that implements an automatic retransmission mechanism in an acknowledgement mode of a radio link control protocol. The data unit that can carry the status information unit is: a protocol data unit for confirming the mode data.

Preferably, the communication entity is a communication entity in a CDMA2000 system.

The method is applied to a CDMA2000 communication entity that implements an automatic retransmission mechanism in an automatic retransmission request sublayer of a link access control protocol.

Because the method of the present invention first determines the length of the status information unit carrying the status report, and then performs segmentation and / or concatenation processing on the data to be sent according to the length of the status information unit, and generates a padding byte length greater than or equal to the status information. A data unit of unit length, and then using the data unit to piggyback the status information unit, so the present invention can improve the probability of piggybacking the status information unit, making full use of the benefits brought by the piggybacking mechanism, and improving the communication chain The utilization of network resources improves the working efficiency of communication entities and reduces costs indirectly.

In the case where the length of the status information unit is relatively small but is frequently sent and the number of data units allowed to be transmitted per unit time is small, since the present invention makes full use of the piggybacking mechanism, the number of status information units sent separately can be reduced. Reduce the probability of sending blocking.

Because the present invention can further determine whether there is a data unit that has been subjected to segmentation and / or cascade processing before the data is segmented and / or cascaded, the status information unit can be piggybacked. If it exists, the data unit is directly used The data unit carries a status information unit, so the transmission speed can be further increased, and the processing load of the communication entity can be reduced. Brief Description of the Drawings Figure 1 is a schematic diagram of a functional model of an RLC AM entity in the prior art;

Figure 2 is a data structure diagram of an AMD PDU;

FIG. 3 is a flowchart of sending a status report by using the piggyback mechanism in the method according to the present invention. Party implementing the invention,

The following describes the implementation method of the present invention with reference to the drawings and specific embodiments. '' The communication system to which the present invention is applicable includes at least two communication entities, each communication entity includes a transmitting side and a receiving side, and the communication between the two communication entities uses an automatic retransmission request

(A Q) mechanism. Here, the communication system may be a WCDMA system, a TD-SCDMA system, or a code division multiple access (CDMA) 2000 system. For WCDMA systems or TD-SCDMA systems, the automatic retransmission request mechanism is implemented in the AM mode of the RLC protocol; for CDMA2000 systems, the automatic retransmission request mechanism is implemented in the ARQ sublayer of the Link Access Control (LAC) protocol.

The core idea of the present invention is: segment / cascade the upper-layer service data, that is, the SDU, according to the length of the status information unit to be piggybacked, generate a data unit that can hold the status information unit, and encapsulate the status information unit in the Piggybacked in the data unit.

The following embodiments use the AM mode of the RLC layer in the Universal Terrestrial Radio Access Network (UTRAN) of the WCDMA system as an example to describe the method of the present invention.

FIG. 3 is a flowchart of sending a status report by using the piggyback mechanism in the method according to the present invention. As shown in FIG. 3, the status report sending method described in this embodiment includes the following steps:

Step 301: The sending process of the status report is triggered, and the receiving side of the RLC AM entity generates a status report that needs to be sent according to the reception status of the PDU, and further generates a carrier of the status report, that is, at least one status information unit, and the status information here. The unit is a status PDU. Send the status PDU to the sending side of the RLC AM entity, and determine the length of the status PDU.

In the RLC protocol, there are multiple mechanisms for triggering status reports. For example, the Timer- Status- Prohibit mechanism can trigger status reports and control the frequency of sending status reports.

The following steps are the processes on the sending side of the RLC AM entity: Step 302: Determine whether the length of the status PDU is less than or equal to a preset piggyback threshold of the RLC PDU. If yes, the status PDU can be piggybacked, and step 303 is performed; otherwise, the status PDU cannot be piggybacked, and step 308 is performed. In this embodiment, the piggybacking threshold may be a product of a predetermined length L of the RLC PDU and a coefficient a, and a value of the coefficient a may be 0.0625.

Step 303: Determine whether there is an AMD PDU to be transmitted in the retransmission buffer, and if there is, execute step 304; otherwise, perform step 305.

Step 304: Check the padding bytes of each AMD PDU to be sent in turn. If there is a padding byte of an AMD PDU that is larger than the length of the status PDU, the AMD PDU is a data unit that can carry the status report. And select the AMD PDU as the carrier of the status PDU, and perform step 307; otherwise, perform step 305.

Step 305: Determine whether there are high-level SDUs in the SDU buffer that have not been segmented and / or concatenated yet to be sent, and if so, go to step 306; otherwise, go to step 308. After receiving the SDU in the upper layer, the RLC AM entity described in the present invention does not immediately segment and / or concatenate the SDU, but places the SDU in the SDU buffer, which needs to be piggybacked in the stateful PDU. The SDU is then segmented and / or cascaded.

Step 306: Segment and / or cascade the unprocessed SDUs according to the length of the status PDU, generate a new AMD PDU, and reserve in at least one newly generated AMD PDU greater than or equal to the status PDU. A padding byte of length, and the newly generated AMD PDU is an AMD PDU that can carry the status PDU.

Step 307: Encapsulate the status PDU in a padding byte in the AMD PDU that can piggyback the status PDU, and send the AMD PDU with the status PDU encapsulated, and end the process.

Step 308: Send the status PDU without piggybacking the status PDU, and end the process. The above are only the preferred embodiments of the present invention. In the present invention, the steps are described

Step 302, step 303 and step 304, or step 305 are optional steps. The present invention can also perform step 306 directly after performing step 301.

The protection scope of the present invention is not limited to the above solutions. Any person familiar with the technology can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

Claim

1. A method for sending a status report, which is suitable for a communication entity that uses an automatic retransmission mechanism for data communication, and is characterized in that the method includes:

a. Determine the length of the status information unit used to carry the current status report; b. Segment and / or cascade the service data to be sent in the communication entity, generate a new data unit to be sent, and The newly generated data unit reserves a padding byte that is greater than or equal to the length of the status information unit, and the data unit that is greater than or equal to the length of the status information unit is filled with data that can carry the status information unit. Unit

c. Encapsulate the status information unit in a padding byte in the data unit that can piggyback the status information unit, and send the data unit encapsulated with the status information unit.

2. The method for sending a status report according to claim 1, further comprising: after step a and before step b, further comprising:

Find whether there is a data unit that can carry the status information unit in the data unit of the communication entity that needs to be retransmitted, and if found, perform step c; otherwise, perform step ¾ ».

3. The method for sending a status report according to claim 2, wherein the data unit that can carry the status information unit is a data unit with padding bytes, and the length of the padding bytes is greater than or equal to The length of the piggybacked status information unit.

4. The method for transmitting a status report according to claim 1, further comprising: after step a and before step b, further comprising:

Determine whether the status information unit can be piggybacked according to a preset piggybacking threshold value. If the length of the status information unit is greater than the piggybacking threshold value, the status information unit cannot be piggybacked, and the status information unit is directly sent. End If the length of the status information unit is less than or equal to the piggybacking threshold, the status information unit can piggyback and execute steps

5. The method for sending a status report according to claim 4, characterized in that: The threshold value of the band is the product of the predetermined length of the data unit to be transmitted and the coefficient a.

6. The method for transmitting a status report according to claim 5, wherein the value of the coefficient a is 0.0625.

7. The second method for sending a status report according to claim 1, wherein after step a and before step b, further comprising:

8. The method for transmitting a status report according to claim 7, wherein the communication entity has a service data buffer, and the service data to be transmitted is temporarily stored before segmentation and / or cascade processing. The business data buffer.

9. The method for transmitting a status report according to claim 1, wherein the communication entity is a communication entity in a wideband code division multiple access system, or a communication entity in a time division synchronous code division multiple access system.

10. The method for transmitting a status report according to claim 9, wherein the method is a broadband code division multiple access communication entity or time division synchronization implementing an automatic retransmission mechanism in an acknowledgement mode of a radio link control protocol. Application in code division multiple access communication entity.

11. The method for sending a status report according to claim 10, wherein the data unit capable of carrying the status information unit is: a protocol data unit for confirming mode data.

12. The method for transmitting a status report according to claim 1, wherein the communication entity is a communication entity in a CDMA2000 system.

13. The method for transmitting a status report according to claim 12, wherein the method is applied to a CDMA2000 communication entity that implements an automatic retransmission mechanism in an automatic retransmission request sublayer of a link access control protocol.