WO2008000181A1

WO2008000181A1 - A method and system for retransmitting in transport layer

Info

Publication number: WO2008000181A1
Application number: PCT/CN2007/070140
Authority: WO
Inventors: Xiaoxiao Zheng
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-06-21
Filing date: 2007-06-20
Publication date: 2008-01-03
Also published as: CN101047484A; CN101047484B

Abstract

A method and system for retransmitting in transport layer is provided, that said method including: in evolution mobile access network system, a receiver transmits information of data blocks, which are received accurately, to a transmitter through control message; based on the received control message, the transmitter deletes the data blocks stored in it's buffer and received successfully by the receiver. The transmitter can transmit poll indication information to the receiver, and the receiver generates control message and transmits it to said transmitter after received the poll indication information and the predetermined condition is met.

Description

Transmission layer retransmission method and system

[1] Technical field

[2] The present invention relates to the field of network communication technologies, and in particular, to a transport layer retransmission method and system.

[3] Background of the invention

[4] In LTS (Long Term Evolution), both the sender and the receiver support AM.

(Acknowledge mode) service, that is, both the sender and the receiver support RLC (Radio Link Control) retransmission.

[5] In the AM service, two types of PDUs, that is, control PDUs and service PDUs, are transmitted between the transmitting entity and the receiving entity. The specific implementation process of the AM service is: the sending entity divides the SDUs received from the upper layer into RLC PDUs of appropriate size, or connects different SDUs into one RLC service PDU, and then attaches an RLC header to the RLC service PDU, and RLC Service PDU

It is placed in the transmit buffer and retransmission buffer and transmitted to the MAC sublayer of the receiving entity through one or two logical channels. All service PDUs sent by the sender

Both require confirmation from the peer entity to determine if a retransmission is required. The control PDU here includes: some PDUs for receiving services generated by the RLC entity itself

Status report, reset request, etc. The receiving entity receives the PDU from the MAC sublayer

And extract the carried status information from it, put it into the receiving buffer, and reorganize it into SDU after waiting for the complete PDU.

Send to the upper layer. The receiving entity may request the transmitting entity to resend the PDU by sending an erroneous reception confirmation to the transmitting side.

[6] in LTE

In the system, the receiving end trigger status report is based on the detection of the RLC PDU received or not received, that is, the receiving end is correctly receiving the RLC PDU.

When the status report is not sent. The sending window of the sender is updated and moved according to the timer, that is, the RLC PDU waiting to be retransmitted in the sender buffer.

If the retransmission is not required within a certain period of time, the sender considers that the RLC PDUs waiting to be retransmitted have been correctly received by the receiving end, and the transmitting end deletes the RLC that it has confirmed that it has been correctly received by the receiving end. PDU.

[7] In the LTE system, the sender can also use the HARQ (Hybrid Automatic Repeat) to trigger the local ACK to delete the RLC PDU in its cache. The specific implementation method is as follows: After receiving the ACK acknowledgement from the receiving end, the HARQ of the sending end sends a local ACK indication to the ARQ to delete the SDU after waiting for a period of time to prevent the NACK -> ACK phenomenon.

(Service Data Unit), or delete the corresponding RLC PDU stored in the cache.

[8] In the process of implementing the present invention, the inventors found that at least the following two problems exist in the prior art: [9] Problem 1 Since there is no RLC PDU correctly received between the receiving end and the transmitting end

Confirmation, therefore, the specific value of the sender's timer time is difficult to control, which may cause the RLC PDU to be retransmitted when the sender receives the status report.

It has been deleted, resulting in data loss. At the same time, the above method is used to implement ARQ (automatic request retransmission)

During retransmission, the transmit window of the sender and the receive window of the receiver are likely to be out of synchronization, resulting in data loss.

[10] Question 2, due to NACK -> ACK and DTX-> ACK

The detection method and detection time of the phenomenon are different. Therefore, the HARQ at the transmitting end

The waiting time is not easy to control, and the phenomenon of deleting the RLC PDU before detecting the NACK -> ACK and DTX-> ACK phenomenon occurs, resulting in data loss.

[11] Summary of the invention

[12] An embodiment of the present invention provides a transport layer retransmission method and system, which can obtain data that has been correctly received by a receiving end in a buffer of a transmitting end by using an acknowledgment of correct receiving data between the peer entities. Delete in time, and avoid data loss.

[13] A transport layer retransmission method provided by an embodiment of the present invention includes:

[14] In the evolved mobile access network system, the transmitting end receives the control message sent by the receiving end, where the control message carries the data block information correctly received by the receiving end;

[15] The sender deletes the data block stored in the buffer and received by the receiver correctly according to the received control message.

[16] Embodiments of the present invention also provide A transmission layer retransmission system includes: a sending end and a receiving end, wherein the sending end is provided with a deleting module, and the receiving end is provided with a sending module;

[17] a sending module, configured to send the data block information correctly received by the receiving end to the sending end by using a control message;

[18] The delete module is configured to delete the data block stored in the sender buffer and received correctly by the receiver according to the control message received by the sender.

[19] According to the description of the foregoing technical solution, the transmitting end of the embodiment of the present invention deletes the buffered data block that has been correctly received by the receiving end by using the display signaling sent by the receiving end, thereby avoiding the sending end and the receiving end. The phenomenon of data loss and loss is avoided. Therefore, the phenomenon of data loss is avoided. Therefore, the technical solution provided by the present invention improves the buffer utilization of the transmitting end and improves the implementation process of the transport layer retransmission in the evolved mobile access network system.

[20] BRIEF DESCRIPTION OF THE DRAWINGS

1 is a flow chart of a method for retransmission of a transport layer according to an embodiment of the present invention.

[22] Mode for carrying out the invention

[23] In evolved mobile access network systems such as LTE systems, Evolved UMTS (Universal Mobile Telecommunication Systems)

In a general-purpose mobile communication system or the like, the data block that is buffered in the transmitting end and has been correctly received by the receiving end is deleted by explicit signaling sent by the receiving end. The data block deleted by the transmitting end may be any data block correctly received by the receiving end described in the explicit signaling, or may be a data block partially received by the receiving end as described in the explicit signaling. The data block here is RLC PDU or SDU

Etc., explicit signaling is a control message, such as a status report. That is, the receiving end triggers and generates a control message such as a status report according to a predetermined triggering principle, and sends the status report to the sending end, and the sending end caches the status message according to the received control message, such as the status report. The RLC PDU or SDU correctly received by the receiving end is deleted. In the following description, a status report is taken as an example for explanation.

[24] The above predetermined triggering principle and prior art LTE

The principle of the triggering status report of the receiving end in the system is completely different. In the prior art, the receiving end is detecting the RLC PDU.

If the error status is received or the status report is triggered without receiving, the status report of the receiving end is for receiving the RLC PDU with the receiving abnormality. Therefore, the status report in the prior art may be referred to as a status report based on the receiving abnormality. In the embodiment of the present invention, the predetermined triggering principle is not only for the receiving abnormal phenomenon, that is, the status report of the receiving end in the embodiment of the present invention. Mainly for receiving the correct data block, therefore, the state in the embodiment of the present invention includes a status report that can be referred to as receiving based on the correct.

[25] The main information included in the status report sent by the receiving end in the embodiment of the present invention is: information of the RLC PDU or SDU that the receiving end has correctly received, such as the RLC PDU that the receiving end has correctly received.

The serial number and so on. Of course, the status report may also include information of RLC PDUs or SDUs that are not correctly received.

[26] The receiving end in the embodiment of the present invention may periodically send a status report to the sending end according to a predetermined time interval, or may send a status report to the sending end after receiving the polling indication information sent by the sending end. The present invention can also set a predetermined condition in the receiving end in advance, so that after receiving the polling indication information sent by the transmitting end, the receiving end determines whether the predetermined condition is satisfied. If the receiving end determines that the predetermined condition is satisfied, triggering and generating a status report. The status report here contains the information of the data that has been correctly received. If the receiving end determines that the predetermined condition is not satisfied, the triggering and the generation of the status report are not performed. At this time, the receiving end may receive the next polling indication information. Then, the processing of the trigger status report is performed, and the receiving end may further determine whether the predetermined condition is satisfied, and until the predetermined condition is satisfied, the receiving end performs the processing of the trigger status report.

[27] That is to say, in order to avoid the phenomenon that the receiving end reports the air interface resource, the redundant retransmission status report, etc., the receiving end and the transmitting end can be controlled by using a timer, a counter, a sliding receiving window, and the like. The sending of the status report.

[28] In the embodiment of the present invention, the sending end sends the polling indication information in multiple manners, for example, the sending end sends the polling indication information to the receiving end according to a certain time interval, and the data stored by the sending end in the cache. When the amount reaches a certain amount, it sends a polling indication message to the receiving end, and so on. When the transmitting end sends the polling indication information according to the amount of data stored in the cache, it avoids that the sender accumulates a large number of data blocks such as RLC PDUs or SDUs in the cache because the status report is not received for a long time.

Phenomenon of the embodiment of the present invention may also be in the RLC

When the amount of data stored in the layer cache reaches a certain limit value, the transmission of the new data block is stopped, and the polling indication information is sent to the receiving end. The sender receives the status report based on the correct reception and deletes the delay. After the data block stored in the memory, the transmission process of the new data block can be restored, so that the amount of data stored in the buffer of the sender is effectively controlled.

[29] The sending end may separately send the polling indication information to the receiving end, that is, the sending end sends the polling indication information through the signaling specially set for the polling indication information; the sending end may also carry the polling indication information in the user. Data such as service PDU

The sending end is sent to the receiving end; the sending end may also carry the polling indication information in the existing signaling and send it to the receiving end, where the signaling is physical layer control signaling, MAC layer control signaling, and the like.

[30] The content in the status report correctly received in the embodiment of the present invention may be: a maximum data block that is continuously received correctly, such as an RLC PDU or an SDU.

The serial number can also be: Bitmap information of the receiving block receiving the data block. The transmitting end can determine the data block correctly received by the receiving end and the data block that is not correctly received by the receiving end by using the above sequence number or bitmap information.

[31] Since the content in the status report of the embodiment of the present invention is not only for the data block correctly received by the receiving end, but also for the data block that is not correctly received by the receiving end, the transmitting end can not only receive the status report but also The data block stored in the sender buffer and correctly received by the receiver is deleted according to the information in the status report, and the retransmission process of the data block that is not correctly received may also be triggered.

[32] The following describes the invention by way of several specific embodiments.

The method provided by the embodiment will be described in detail. The transport layer, RLC, is described in the following embodiment.

[33] Example 1

The specific implementation process of the receiving end triggering according to the timer and generating the status report includes the following steps:

[34] Step 1. The receiving end establishes an RLC entity, and starts a first timer, and the first timer starts timing.

[35] Set the first timer to Timer_Status, the minimum time interval for the receiver to send status reports to Min_Status_Duration, and the maximum interval at which the receiver sends status reports is

Max_Status_Duration.

[36] to step 2

The receiving end determines whether it receives the polling indication sent by the transmitting end, and whether the current timing of the timer reaches Max_Status_Duration

If the receiving end receives the polling indication sent by the sending end, and the current timing of the timer has not yet been If Max_Status_Duration is reached, go to step 3.

[37] In step 3, the receiving end determines whether the current timing value of the timer is less than Min_Stat _US _D _U rati ₀ n , if the current timing value of Timer_Status is less than Min_Status_Duration, then to step 5, the receiving end waits for Min_Status_Duration and Timer_Status

After the time difference of the current timing value, go to step 4

, the receiver triggers and generates a status report, such as receiving a type

The status report fills in a status report, and the receiver sends the status report to the sender. At the same time, the receiver restarts the timer Timer_Status and the timer Timer_Status restarts. The specific implementation process of triggering and generating a status report at the receiving end ends.

[38] In step 3, if the current timing value of Timer_Status is not less than Min_Status_Duration, then to step 4, the receiving end triggers and generates a status report. If the receiving end selects a status report filling method to generate a status report, the receiving end will state the status. The report is sent to the sender. At the same time, the receiver restarts the timer Timer_Status and the timer Timer_Status restarts. The specific implementation process of triggering and generating a status report at the receiving end ends.

[39] In step 2, if the receiving end is always within the maximum time interval

The polling indication sent by the sender is not received, that is, the current timing value of the timer Timer_Status reaches Max_Status_Duration

When the receiving end still does not receive the polling indication sent by the sending end, go to step 4.

[40] In step 4, the receiver triggers and generates a status report, such as receiving a type

[41] Example 2

The specific implementation process of the receiving end triggering according to the counter and generating the status report includes the following steps:

[42] Step 1. The receiver establishes RLC

Entity, and start the counter, the counter is incremented by one each time a new block is received at the receiving end.

[43] Set the counter to Rev_Dat

, and the minimum number of received data blocks triggered by the receiver and generating the status report is Min_R _ev _Dat The maximum number of received data blocks that the receiver triggers and generates a status report is Ma _X _R _ev _Dat .

[44] Go to step 2, the receiving end determines whether it receives the polling indication sent by the transmitting end, and the counter

Whether the current count value of Rev_Dat reaches Max_Rev_Dat

, if the receiving end receives the polling indication sent by the sender, and the counter Rev_Dat

The current count value has not reached Max_Rev_Dat, then go to step 3.

[45] In step 3, the receiving end determines whether the current count value of the counter Rev_Dat is less than Min_R _ev _Dat

If the current count value of Rev_Dat is less than Min_Rev_Dat, the receiver receives it again.

After the difference between the number of Min_Rev_Dat and the current count value of Rev_Dat, the data is sent to step 4, the receiver triggers and generates a status report, such as the receiver selects a type.

The status report filling method generates a status report, and the receiving end sends the status report to the sending end, and at the same time, the receiving end restarts the counter, counting

The device restarts counting. The specific implementation process of triggering and generating a status report at the receiving end ends.

[46] In step 3, if the current count value of Rev_Dat is not less than Min_Rev_Dat, the receiver triggers and generates a status report, such as the receiver selects a type

The status report fills in a status report, and the receiver sends the status report to the sender. At the same time, the receiver restarts the counter Rev_Dat.

. The specific implementation process of triggering and generating a status report at the receiving end ends.

[47] In step 2, if the number of new data blocks received by the receiver reaches Ma _X _R _ev _Dat

, and the receiving end has not received the polling indication sent by the sending end, to step 4.

[48] In step 4, the receiver triggers and generates a status report, such as receiving a type

The status report fills in a status report, and the receiver sends the status report to the sender. At the same time, the receiver restarts Rev_Dat.

[49] Embodiment 3, the sender deletes the data stored in the cache, and

The specific implementation process of sending a polling indication to the receiving end according to the timer includes the following steps:

[50] Step 1. The sender establishes an RLC entity and starts a timer. The timer starts timing.

[51] Set the timer to Timer_Poll

The time interval at which the sending end sends the polling indication information is the timer duration of the timer. And the maximum number of data blocks stored in the sender buffer is a predetermined number.

[52] Go to step 2, the sender judges whether the timer is

The timeout, the number of data blocks in the transmission window, that is, the number of data blocks in the sender's buffer, reaches a predetermined number. If the timer expires, regardless of whether the number of data blocks in the transmission window reaches a predetermined number, go to step 3.

[53] In step 3

The sending end sends a polling indication to the receiving end, so that the receiving end sends a status report to it, and if the sending end detects that the timer Timer_Poll is timing, the transmitting end restarts the timer Timer_Poll, and the timer Timer_Poll restarts timing. This sender

The specific implementation process of sending a polling indication to the receiving end ends.

[54] In step 3

If the timer expires and the number of data blocks in the transmission window does not reach the predetermined number, the transmitting end continues to send a new data block to the receiving end.

[55] In step 2

Regardless of whether the timer expires or not, as long as the number of data blocks in the transmission window reaches a predetermined number, then step 4 is reached.

[56] In step 4

The transmitting end suspends the transmission process of the new data block. Then, the transmitting end continues to determine whether the timer expires until the timer expires, and the sending end sends a polling indication to the receiving end, so that the receiving end sends a status report to the receiving end. The specific implementation process of sending the polling indication to the receiving end is terminated.

[57] In the above description process, if the sender receives the RLC based on the receiver

The status report of the information, the sending end deletes the data block that has been correctly received by the receiving end according to the content in the status report, for example, the data block between the two serial numbers in the status report indicates that the receiving end has been correctly received, at this time, the transmitting end Data blocks within the two serial numbers of their cache should be deleted. Data blocks other than the two sequence numbers indicate data blocks that have not been correctly received by the receiving end. After deleting the buffered data block, the sender needs to detect whether the sending process of the new data block is suspended. If the sending process is suspended and the number of data blocks stored in the buffer is less than a predetermined number, the transmitting end restores the new one. The transmission process of the data block, the sender continues to send a new data block to the receiving end; if the sending process is suspended, and the data stored in the buffer If the number of blocks is not less than the predetermined number, the transmitting end does not resume the transmission process of the new data block; if the transmission process is not suspended, the transmitting end continues the transmission process of the new data block.

[58] Embodiment 4, the sender deletes the data stored in the cache, and

The specific implementation process of sending a polling indication to the receiving end according to the counter includes the following steps:

[59] Step 1, the sender establishes RLC

Entity, and start counter, the sender increments one counter each time a data block is sent, and one counter is decremented by one for each data block deleted in the sender buffer.

[60] Set the sender to send a polling indication when the number of data blocks it has buffered reaches a predetermined maximum.

[61] to step 2

The sender determines whether the number of data blocks buffered reaches a predetermined maximum value and a predetermined alert value. If the predetermined maximum value is reached, regardless of whether the number of data blocks in the cache reaches a predetermined alert value, go to step 3.

[62] In step 3

The transmitting end sends a polling indication to the receiving end, so that the receiving end sends a status report thereto, and at the same time, the counter continues to count the new data block sent by the transmitting end.

[63] In step 3

If the number of data blocks in the buffer of the sender reaches a predetermined maximum value and the predetermined alarm value has not been reached, the sender continues to send a new data block to the receiver.

[64] In step 2, if the number of data blocks in the sender's buffer reaches the predetermined alert value, go to step 4.

[65] In step 4, the sender hangs the transmission process of the new data block.

[66] In the above description process, if the sender receives the RLC based on the RSR

The status report of the information, the sending end deletes the data block that has been correctly received by the receiving end according to the content in the status report, for example, the data block between the two serial numbers in the status report indicates that the receiving end has been correctly received, at this time, the transmitting end The data block within the two serial numbers of its cache should be deleted. Correspondingly, the counter value should be reduced by the corresponding amount. The data blocks other than the two sequence numbers in the status report indicate that the data blocks have not been correctly received by the receiving end. After deleting the buffered data block, the sender needs to detect whether the sending process of the new data block is suspended, if the sending process is suspended, and the number of data blocks stored in the buffer is small. At the predetermined alert value, the transmitting end resumes the transmission process of the new data block, and the transmitting end continues to send the new data block to the receiving end; if the sending process is suspended, and the number of data blocks stored in the buffer is not less than the predetermined alert value , the transmitting end does not resume the transmission process of the new data block; if the sending process is not suspended, the transmitting end continues the transmission process of the new data block.

[67] In the description of the above four embodiments, Embodiment 1 and Embodiment 2

Is a description of the receiving end, Embodiment 3 and Embodiment 4

It is a description of the transmitting end, and the receiving end can adopt Embodiment 1 and Embodiment 2

In any of the embodiments, the transmitting end may adopt Embodiment 3 and Embodiment 4

Any of the embodiments, that is, the embodiment 1 and the embodiment 2 can be used in any combination with the embodiment 3 and the embodiment 4.

[68] In LTE, HARQ can trigger ARQ retransmission, and ARQ can trigger ARQ itself.

Retransmission, the two ARQ retransmissions triggered by different reasons affect each other. That is, the ARQ entity at the receiving end does not know whether the missing PDU has been triggered by the HARQ. If the ARQ entity triggers the status report for the missing PDU, Causes redundant retransmission of data blocks.

[69] In order to coordinate the ARQ triggered by the lower layer HARQ of the transport layer in the LTE system

Retransmission, and ARQ of the transport layer's upper layer ARQ itself triggered by sequence number detection

Retransmission, preventing redundancy of data blocks ARQ

Retransmission, the embodiments of the present invention provide the following specific implementation methods.

[70] Method 1: Since DTX is mistaken for ACK

The error probability is very low. Therefore, the sender does not need to add an additional mechanism for detection. At the receiving end, there is a timer-controlled reception status report, and then the missing SN

It will be notified to the sender and will also trigger a retransmission. But the trigger time is not well controlled, it only depends on the sender RLC

Status reporting period. It may cause the trigger to lead to unnecessary redundant status reporting and retransmission too early. If the trigger is too late, it will bring a certain delay.

[71] Method 2: Use a timer to control redundant ARQ retransmission of data blocks.

[72] When the receiving end RLC finds a missing PDU/SDU,

That is, when the data block of the serial number is not consecutively, the RLC is not directly triggered. The status report, but its trigger is controlled by a timer, and the validity of this status report is guaranteed for a predetermined period of time. This timer needs to be the timer of the receiver itself, Timer-Status.

The status of the control reports coordination because they trigger the same status report format.

[73] The specific implementation process of the above method 2 is described in detail below.

[74] Step 1

When the receiving end detects that the data block sequence number is discontinuous, triggering the second timer for the discontinuous data block

, that is, the timer Timer_MisPDU, the timer Timer_MisPDU starts timing.

[75] Set the data block number that is not continuously received SN=N , where N

The sequence number of the data block that is received by the receiving end and is not consecutive.

[76] When the receiver receives a discontinuous packet less than N, it stops the timer Timer_MisPDU.

[77] Go to step 2, Receiver RLC entity judgment timer Timer_Status

The first timer is the timeout state of the two timers Timer-Status, if the receiving end

RLC entity controlled timer Timer_Status

Timeout, that is, when the receiver needs to send a status report, or the timer Timer_Status

When reset, the timer Timer-MisPDU has not timed out, that is, the protection time of missi ng PDU detection has not arrived yet, then go to step 3.

The receiving end triggers and generates a status report. The contents of the status report mainly include: The SN of the data block is smaller than the missing data block number N

The correct reception of those data blocks. The receiver then sends a status report to the sender. Receiver restart timer Timer_Status

. Of course, the embodiment of the present invention does not exclude the case where the receiving end reports the missing data block sequence number in the status report, and does not exclude the case where the correctly received data block and the missing data block sequence number are reported.

[78] In step 2, if the timer Timer_Status expires or resets, the timer Timer_MisPDU has not timed out until the timer Timer_MisPDU times out, to step 4

The receiver triggers and generates a status report. The contents of the status report mainly include: The slave PDU is N

The receipt of the identified missing data block begins with the reception of those data blocks between the next discrete data block. The receiver then sends the status report to the sender. Receiver restart timer Timer_Status. The receiver stops the timer Timer_MisPDU.

[79] In step 2, if the timer Timer_MisPDU times out before the Timer_Status expires or resets, go to step 5.

The receiving end triggers and generates a status report. The content in the status report mainly includes: the receiving status of all the data blocks before the next lost data block number, where the next missing data block number is: PDU SN is N The next missing block number after the identified missing block. The receiver then sends a status report to the sender. The receiver restarts the timer Timer_Status. The receiver stops the timer Timer_MisPDU.

[80] For a specific example, if the PDUs with sequence numbers 1 and 2 are correctly received by the receiving end, the PDUs with sequence numbers 3 and 4 are not correctly received by the receiving end, but the receiving end receives the PDU with sequence number 5, and the shell N =5, the timer Timer_MisPDU corresponding to the PDU with sequence number 5

Start timing, set the receiver to receive the data block with the sequence number 6, 7, 9, if the receiver RLC entity controls the timer Timer_Status before the timer Timer_MisPDU

If the timeout occurs, the content of the status report in step 3 is: The sequence number is 1, 2

The reception of the data block. If the timer Timer_Status controlled by the receiving RLC entity times out first, then when the timer Timer_MisPDU times out, step 4

The contents of the status report are: Serial number 3, 4, 5, 6, 7

The reception of the data block. If the timer Timer_MisPDU precedes the receiver RLC

The entity-controlled timer Timer_Status expires, then the content of the status report in step 5 is: The reception of the data block of sequence number 1, 2, 3, 4, 5, 6, and 7.

[81] In general, the timer duration of the timer Timer_MisPDU < the timer duration of the timer Timer_Status. In this way, the receiver can be based on the Timer_MisPDU.

A status report is triggered each time a lost data block is detected.

[82] Method 3: When the HARQ of the receiving end triggers the corresponding status report, the status report records the HARQ TB arrival time and other information, and the HARQ of the receiving end will be HARQ TB.

The ARQ entity is notified to the receiving end, and the ARQ entity determines whether the sequence number of the missing PDU/SDU is SN according to the received HARQ TB arrival time and other information.

Generate a status report or wait for an ongoing RLC retransmission. [83] Method 4: The problem of redundant retransmission is solved by the sender.

[84] In this method, the receiving end still performs missing PDU/SDU

Detection, and after detecting the missing PDU/SDU, the receiver triggers and generates a status

report. After receiving the status report, the sender limits the retransmission process of the data block, that is, the sender cannot continuously perform the same PDU.

Retransmission. This control can be done by a timer or counter. That is to say, the transmitting end does not retransmit the same data block within a predetermined time interval, or in the predetermined number of retransmitted data blocks, the same data block cannot be retransmitted.

The system for transmitting layer retransmission provided by the embodiment of the present invention includes: a sending end and a receiving end, wherein the sending end is provided with a deleting module and a polling module, and the receiving end is provided with a sending module.

[86] The polling module in the sender is mainly used to send polling indication information to the receiver. The polling module may periodically send polling indication information to the receiving end according to a predetermined time interval, or may send polling indication information to the receiving end when the number of data blocks in the sending window exceeds a predetermined value. Specifically as described in the above method

[87] The sending module of the receiving end is mainly configured to receive the polling indication information at the receiving end, and after the predetermined condition is satisfied, generate a control message, and transmit the control message to the sending end. In this way, the deleting module in the sending end can delete the data block stored in the sending end buffer and correctly received by the receiving end according to the control message received by the sending end.

[88] The sending module of the receiving end can control the sending of the status report by using a timer, a counter, a sliding receiving window, etc., to avoid the phenomenon that the receiving end reports the air status resource too frequently, which is as in the above method. description.

[89] According to the description of the foregoing specific implementation manner, the sending end deletes the buffered data block that has been correctly received by the receiving end by using the display signaling sent by the receiving end, thereby avoiding the loss of transmission and reception between the transmitting end and the receiving end. The phenomenon of steps, therefore, avoids the phenomenon of data loss; the transmitting end and the receiving end control the transmission of the status report by using a timer, a counter, a sliding receiving window, etc., thereby avoiding the wasteful transmission of the status report by the receiving end and wasted The phenomenon of the air interface resource enables the data block stored in the buffer of the sender to be correctly received by the receiver to be deleted in time, thereby avoiding the phenomenon that the data storage in the sender cache is excessive and the storage resources of the sender are wasted; The way to solve the low-level retransmission of the transport layer The HARQ-triggered retransmission and the transport layer high-level retransmission conflicts between the ARQ retransmissions triggered by the ARQ's own error detection, so that the status report is not repeatedly transmitted, and the status report and the redundant retransmission of the data block are avoided; Embodiments of the invention also avoid ignoring DTX false positives ACK

The data loss phenomenon caused by the error; thus, the technical solution provided by the present invention realizes the transmission layer retransmission in the mobile access network system that provides system transmission reliability, improves air interface resource utilization, improves transmission buffer utilization, and improves evolution. The purpose of the realization process.

While the invention has been described by the embodiments of the invention, it will be understood that

Claims

Claim

[1] 1. A transport layer retransmission method, characterized in that the method comprises the steps of:

In the evolved mobile access network system, the sending end receives the control message sent by the receiving end, where the control message carries the data block information correctly received by the receiving end;

The transmitting end deletes the data block stored in the buffer and received by the receiving end correctly according to the received control message.

[2] 2. The method according to claim 1, wherein the step of the receiving end receiving the control message sent by the receiving end comprises:

The sending end sends the polling indication information to the receiving end;

After receiving the polling indication information and satisfying the predetermined condition, the receiving end generates a control message and transmits the control message to the transmitting end.

[3] The method according to claim 2, wherein the polling indication information is carried in the transport layer user data, or carried in the existing signaling, or through the polling indication information. The set signaling is sent separately.

[4] The method of claim 2, wherein the sending, by the sending end, the polling indication information to the receiving end comprises:

The transmitting end sends the polling indication information to the receiving end according to the predetermined time interval; and/or the transmitting end sends the polling indication information to the receiving end when the number of the data blocks in the sending window exceeds a predetermined value.

[5] 5. The method according to claim 4, wherein the predetermined value is: a predetermined alert value and

I or a predetermined maximum value;

When the number of data blocks in the transmission window exceeds a predetermined alert value, the transmitting end does not stop the transmission process of the new data block;

When the number of data blocks in the transmission window exceeds a predetermined maximum value, the transmitting end stops the transmission process of the new data block, resumes the transmission process of the new data block when the transmitting end stops, and detects that the predetermined recovery transmission condition is satisfied, and restores the new The transfer process of the data block.

[6] 6. The method according to claim 2 or 3 or 4 or 5, wherein the predetermined condition is: a first timer set for generating a control message times out, and the receiving end is receiving Polling instruction letter And after the predetermined condition is met, generating a control message and transmitting to the sending end includes:

Receiving, by the receiving end, the polling indication information, and when determining that the timing value of the first timer exceeds the minimum time interval of the control message, generating a control message, and transmitting the control message to the transmitting end, and simultaneously, the first timer is reset, and Start timing again.

[7] 7. The method according to claim 6, wherein the method further comprises:

Receiving, by the receiving end, the polling indication information, and when determining that the timing value of the first timer does not exceed the minimum time interval for transmitting the control message, continuing to receive the data block transmitted by the transmitting end until the timing value of the first timer exceeds Sending a minimum time interval for the status report, the receiving end generates a control message and transmits it to the transmitting end, and at the same time, the first timer is reset, and the timing is restarted; and/or

Until the timeout value of the first timer reaches the maximum time interval of the transmission status report, the receiving end does not receive the polling indication information sent by the sending end, and the receiving end generates a control message and transmits the control message to the sending end. At the same time, the first timer is reset and the timing is restarted.

[8] 8. The method according to claim 2 or 3 or 4 or 5, wherein the predetermined condition is: a first timer set for generating a control message, and /

Or the second timer set for the lost data block times out, the first timer resets and restarts timing when the receiving end sends a control message, and when the second timer receives the discontinuous data block at the receiving end, Start timing, and when the receiving end receives the lost data block, stop timing, and the receiving end generates a control message after receiving the polling indication information, and after the predetermined condition is satisfied, and transmits the control message to the sending The steps at the end include:

Before the second timer expires, when the first timer is reset or timed out, the receiving end generates a control message for the data block smaller than the lost data block sequence number, and transmits the control message to the transmitting end, and at the same time, the first timer is reset. And restart the timing;

Before the second timer expires, when the first timer is reset or timed out, and the second timer expires, the receiving end generates a control message for starting from the data block of the sequence number of the lost data block to the next discontinuous data block. And transmitting to the transmitting end, at the same time, the first timer is reset, and the timing is restarted, and the second timer is stopped; When the second timer expires before the first timer is reset or timed out, the receiving end generates a control message for all data blocks smaller than the next lost data block sequence number, and transmits the control message to the transmitting end, and at the same time, the first timer Reset, and restart timing, the second timer stops.

[9] 9. The method according to claim 2 or 3 or 4 or 5, wherein the predetermined condition is: the number of received data blocks exceeds a predetermined number, and the receiving end receives the polling Instructing information, and after the predetermined condition is satisfied, generating a control message and transmitting to the transmitting end includes: receiving, by the receiving end, the polling indication information, and when determining that the number of data blocks it receives exceeds a predetermined number, A control message is generated and transmitted to the sender.

[10] The method of claim 9, wherein the method further comprises:

Receiving, when receiving the polling indication information, and determining that the number of data blocks it receives does not exceed the predetermined number, the receiving end continues to receive the data block transmitted by the transmitting end until the number of data blocks it receives exceeds a predetermined number, and receives And generating a control message, and transmitting to the sending end; and/or receiving the polling indication information sent by the sending end, and receiving the polling indication information sent by the sending end, and receiving The terminal generates a control message and transmits it to the sender.

[11] The method of claim 1, wherein the method further comprises:

Connect

When the lower layer retransmission unit of the receiving end layer triggers and generates a control message, the upper layer retransmission unit of the transmitting layer of the receiving end is notified;

The high-level retransmission unit of the receiving end transport layer limits the repeated transmission of the same data block status report according to the notification of the lower layer retransmission unit.

[12] 12. The method according to claim 1, wherein the step of deleting the data block by the transmitting end comprises:

The transmitting end deletes the buffered data block that has been correctly received by the receiving end according to the received status report, and retransmits the data block that is not correctly received by the receiving end; the retransmitted data that is not correctly received by the receiving end The block is a data block whose sequence number is smaller than the maximum sequence number indicated in the control message.

[13] 13. The method according to claim 12, wherein the step of retransmitting a data block that is not correctly received by the receiving end comprises: The transmitting end limits the repeated retransmission of the same data block when retransmitting the data block that is not correctly received by the receiving end.

[14] 14. The method according to claim 13, wherein the step of limiting repeated retransmission of the same data block comprises:

The transmitting end prohibits repeated retransmission of the same data block within a predetermined time interval; or the transmitting end prohibits repeated retransmission of the same data block during retransmission of a predetermined number of data blocks.

[15] 15. A system for retransmission of a transport layer, comprising: a transmitting end and a receiving end, wherein: the sending end is provided with a deleting module, and the receiving end is provided with a sending module;

a sending module, configured to send data block information correctly received by the receiving end to the sending end by using a control message;

The deleting module is configured to delete, according to the control message received by the sending end, the data block stored in the sending end buffer and received by the receiving end correctly.

[16] The system of claim 15, wherein the sending end is further configured with: a polling module, configured to send polling indication information to the receiving end;

The transmitting module at the receiving end receives the polling indication information at the receiving end, and after the predetermined condition is satisfied, generates a control message and transmits the control message to the transmitting end.