CN108429607B

CN108429607B - HARQ retransmission processing method in communication system

Info

Publication number: CN108429607B
Application number: CN201710077502.8A
Authority: CN
Inventors: 刘波
Original assignee: Potevio Information Technology Co Ltd
Current assignee: Potevio Information Technology Co Ltd
Priority date: 2017-02-14
Filing date: 2017-02-14
Publication date: 2021-05-14
Anticipated expiration: 2037-02-14
Also published as: CN108429607A

Abstract

The application discloses a HARQ retransmission processing method in a communication system, which comprises the following steps: after data receiving equipment receives or sends re-authorization, an MAC layer of the equipment does not clear an HARQ process, if HARQ process data sent before re-authorization needs to be retransmitted and the size of a TB (transport block) of the data to be retransmitted stored in the HARQ process is different from the size of a TB currently transmitted, when an RLC layer of the equipment is in an AM (access control) mode, the MAC layer informs the RLC layer of retransmitting the data which is lost and needs to be retransmitted in the HARQ process; and after receiving the notice of the retransmission data, the RLC layer analyzes the instructed retransmission data and adds the retransmission data into an RLC retransmission queue for retransmission. By applying the method and the device, the time delay of data retransmission can be reduced, and the maximum retransmission phenomenon of the RLC can be avoided as much as possible.

Description

HARQ retransmission processing method in communication system

Technical Field

The present invention relates to communication technologies, and in particular, to a hybrid automatic repeat request (HARQ) retransmission processing method in a communication system.

Background

In wireless communication systems such as GPRS/WCDMA/TD-SCDMA/LTE, a media access Control Layer (MAC) provides functions of channel mapping, uplink and downlink scheduling, data multiplexing, retransmission processing of (HARQ hybrid automatic Repeat Request) and the like, wherein when the HARQ retransmission is in charge of data errors of the MAC Layer, retransmission is attempted to transmit data to an opposite terminal function again; RLC (radio Link control) refers to a radio Link control layer Protocol, where the RLC layer is located above the MAC layer and provides segmentation and retransmission services for users and control Data, and in an RLC Acknowledged Mode (AM) Mode, a sending end retransmits RLC Data according to a received status Protocol Data Unit (PDU) and a POLL retransmission timer sent from a receiving end.

In summary, HARQ retransmission of the MAC layer and retransmission of the RLC layer provide a retransmission scheme for data transmission loss, and if air interface data transmission is wrong or lost, HARQ of the MAC layer is retransmitted first, and if retransmission is still unsuccessful, detection is performed by the RLC layer, and data retransmission is sent to the opposite end.

At present, in a wireless communication system, after a MAC layer receives and transmits Downlink Control Information (DCI), a next radio frame starts, and air interface data needs to transmit data according to a new Transport Block (TB) size, especially before re-authorization, because MCS (modulation and Coding scheme) is high and a current air interface cannot carry the modulated data, an error occurs in air interface transmission, and at this time, a Modulation and Coding Scheme (MCS) needs to be reduced by re-authorization to transmit data with a smaller TB Block. In the conventional method, the UE clears the uplink HARQ process when receiving the uplink re-authorization, the base station (eNB) clears the data of the downlink HARQ process when sending the downlink re-authorization, and if the data transmission before the DCI is re-authorized is incorrect, the HARQ process is cleared after re-authorization, and there is no retransmission opportunity, so that the lost data can be retransmitted only by depending on the RLC layer through the status PDU or POLL retransmission timer, and particularly, under the condition that the RLC layer has segments, if some segment is lost due to the MAC, all segments may need to be retransmitted. In addition, the RLC retransmission can determine whether RLC layer retransmission is needed or not because status PDU report from the opposite end or the POLL timer of the RLC retransmission is overtime, and the like, which causes problems of certain time delay, repeated transmission and the like for the transmission of air interface data, and even causes the phenomenon of RLC maximum retransmission.

Disclosure of Invention

The application provides a HARQ retransmission processing method in a communication system, which can reduce retransmission time delay and avoid the phenomenon of maximum RLC retransmission as much as possible.

In order to achieve the purpose, the following technical scheme is adopted in the application:

a HARQ retransmission processing method in a communication system comprises the following steps:

after a data receiving device receives or sends re-authorization, an MAC layer of the device does not clear a corresponding HARQ process, if the HARQ process data sent before re-authorization needs to be retransmitted and the size of a Transport Block (TB) of the data to be retransmitted stored in the HARQ process is different from the size of the TB currently transmitted, when an RLC layer of the device is in an AM mode, the MAC layer informs the RLC layer of retransmitting the data which is lost and needs to be retransmitted in the HARQ process;

and after receiving the notice of the retransmission data, the RLC layer analyzes and adds the lost data indicated by the HARQ process into an RLC retransmission queue for retransmission.

Preferably, the data receiving device is a terminal, and the HARQ process data is uplink data transmission; or, the data receiving device is a base station, and the HARQ process data is downlink data transmission.

Preferably, the RLC layer parsing and adding the HARQ process data indicated by the MAC layer to an RLC retransmission queue for retransmission includes:

and the RLC layer analyzes the retransmission HARQ process data indicated by the MAC, adds the analyzed data into the RLC retransmission queue in a mode of receiving NACK of the status PDU and waits for the next data transmission.

According to the technical scheme, after the data receiving equipment receives or sends the re-authorization, the MAC layer of the equipment does not clear the HARQ process, if some HARQ process data sent before the re-authorization needs to be retransmitted and the size of the data TB to be retransmitted stored in the HARQ process is different from the size of the currently transmitted TB, when the RLC layer of the equipment is in an AM mode, the MAC layer informs the RLC layer to retransmit the HARQ process data; after receiving the notice of the retransmission data, the RLC layer analyzes the data indicated by the notice and adds the data into an RLC retransmission queue for retransmission. By the mode, the MAC layer indicates retransmission to the RLC layer, and the RLC layer directly adds retransmission data into a retransmission queue, so that retransmission time delay is shortened, and the phenomenon of maximum retransmission of the RLC is avoided as much as possible.

Drawings

Fig. 1 is a flowchart of a HARQ retransmission processing method in an embodiment of the present application;

fig. 2 is a flowchart of RLC layer processing in the embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical means and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings.

The invention provides a method for HARQ retransmission processing in a wireless communication system, which is used for uplink HARQ retransmission processing of UE and downlink HARQ retransmission processing of eNB, and comprises the following steps:

after receiving and transmitting re-authorization, the MAC layer does not clear the related HARQ process, but continues to wait for the feedback of air interface data; if the feedback of a certain HARQ process is NACK, indicating that the transmission of air interface data is wrong, needing to perform HARQ retransmission processing, comparing the size of a data TB block to be retransmitted stored by the HARQ with the size of a currently scheduled transmission TB block, if the size of the data TB block is equal to the size of the currently scheduled transmission TB block, indicating that the size of the TB block is not changed, directly retransmitting the air interface data stored by the HARQ at the air interface, if the size of the air interface data is not equal to the size of the currently scheduled transmission TB block, indicating that the transmission TB block is changed, and the current air interface cannot transmit PDU data stored by the HARQ process, needing to send the data PDU to an RLC layer of the module.

After receiving the data retransmission instruction, the RLC layer analyzes the data, processes the data according to the NACK state PDU sent by the corresponding receiving terminal, analyzes the data and re-adds the data into the RLC retransmission queue, waits for the next wireless frame MAC layer to reschedule, and preferentially forms the data in the retransmission queue into the PDU to be sent to an air interface, so that the retransmission processing of data loss errors is accelerated, and the problems of too large time delay and the like of an application layer or an RRC layer are avoided.

The following describes a specific implementation of the present application with a specific embodiment. In this embodiment, a UE is taken as an example to describe a HARQ retransmission processing procedure when receiving uplink feedback after receiving uplink re-authorization due to MCS level transmission change. Fig. 1 is a schematic diagram of a corresponding process. As shown in fig. 1, the process is as follows:

step 101, after receiving the re-authorization, the UE does not clear the HARQ process, and after receiving the uplink feedback, acquires the HARQ process N corresponding to the feedback, if the feedback is determined to be ACK, it is a normal processing flow, which indicates that the uplink air interface data has been received and processed by the eNB, and then executes the processing in step 104; if the feedback is NACK, the retransmission process is performed on the nth HARQ process, and step 102 is executed.

102, judging whether the size of the TB block transmitted by the PUSCH stored in the HARQ process is consistent with the current transmission, if not, indicating that the size of the TB block transmitted by the PUSCH is changed after receiving the re-authorization and the current scheduling can not send the PUSCH data PDU stored in the HARQ process at the air interface, and executing the processing of 105; if yes, step 103 is executed to perform the processing.

Step 103, if the size of the retransmission TB block is consistent with the current scheduling, it is determined whether the HARQ retransmission number reaches the maximum value, if so, step 104 is executed to continue the processing, otherwise, the stored data PDU of the HARQ process is retransmitted in the scheduling period, and the process is ended.

And step 104, the MAC layer clears the data of the current HARQ process, acquires the data from the RLC layer by using the current TB block transmission capability, and forms a MAC PDU for transmission, and meanwhile, stores the data into the HARQ process so as to perform retransmission processing on the data in the subsequent process.

Step 105, sending the PDU data saved in HARQ to RLC, notifying RLC layer that the data needs to be retransmitted, and continuing to execute step 106.

And step 106, after receiving the retransmission instruction of the MAC layer, the RLC layer adds the retransmission data into an RLC retransmission queue for retransmission when the RLC working mode is AM.

Specifically, the comprehensive processing flow for each case after the RLC layer receives the MAC layer data is as shown in fig. 2:

after receiving MAC layer data, RLC judges whether it is the indicated retransmission data, if not, carries on PDU analysis according to the existing flow, and processes the following flow, otherwise, it goes to 2 processes;

2. judging whether the RLC working mode corresponding to the data is AM, if so, turning to 3 processing, otherwise, not processing and ending the flow;

3. analyzing and processing the data which is indicated as retransmission from the MAC, adding the data into a retransmission queue of the RLC according to the NACK flow of the received status PDU, and waiting for the next uplink transmission of the data; the processing of this step is the operation of step 106 described above.

The sequence of the RLC sending data is that the status PDU is sent preferentially, the data in the retransmission queue is sent again, and the data is new data at last, so that if the transmission TB block is changed due to sending of the re-authorization and the HARQ retransmission is carried out subsequently, the packet data can be sent to the air interface again by the fastest frame descending.

The foregoing is a specific implementation of the HARQ retransmission processing method in the present application. In the description of the above embodiment, the UE is taken to send uplink data transmission as an example, and in fact, the processing method of the present application is also applicable to eNB downlink data transmission, and the difference is that the eNB does not clear the HARQ process after sending the downlink re-authorization and determines whether the received downlink data feedback information is NACK, and the subsequent processing is the same as that of the UE side, and is not repeated here.

Through the processing of the application, after re-authorization, if data is lost or wrong, the data can be retransmitted as soon as possible; the transmission time delay of an application layer and the like is reduced to a certain extent; the occurrence of the maximum RLC retransmission phenomenon under the condition of the original mechanism is reduced; meanwhile, the processing mode of the method does not damage the original protocol architecture and hierarchical division, is clear, can realize low complexity and has better compatibility.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A HARQ retransmission processing method in a communication system is characterized by comprising the following steps:

2. The method of claim 1, wherein the data receiving device is a terminal, and the HARQ process data is uplink data transmission; or, the data receiving device is a base station, and the HARQ process data is downlink data transmission.

3. The method of claim 1 or 2, wherein the RLC layer parsing the HARQ process data indicated by the MAC layer into an RLC retransmission queue for retransmission comprises: