CN105681001A - Method and device for realizing RLC (Radio Link Control) layer retransmission - Google Patents

Abstract

The invention discloses a method and a device for realizing RLC (Radio Link Control) layer retransmission. The method comprises the following steps that: a media access control (MAC) layer of an evolved node B (eNodeB) transmits hybrid automatic repeat request (HARQ) new transmission to an MAC layer of user equipment (UE); and when the MAC layer of the eNodeB does not receive an acknowledgement (ACK) and a negative acknowledgement (NACK) of the MAC layer of the UE, the MAC layer of the eNodeB does not perform HARQ retransmission, and instructs an RLC layer to perform automatic repeat request (ARQ) retransmission. Through the scheme of the invention, delay of retransmission is shortened, and air interface resources are saved.

Description

A method and device for realizing RLC layer retransmission

technical field

The invention relates to an automatic retransmission technology, in particular to a method and a device for realizing retransmission of a radio link control (RLC, RadioLinkControl) layer.

Background technique

FIG. 1 is a schematic diagram of an air interface protocol stack of a Long Term Evolution (LTE, Long Term Evolution) network. Referring to Fig. 1, the LTE network guarantees the transmission reliability of the air interface from two aspects, one is the automatic repeat request (ARQ, AutomaticRepeatreQuest) of the RLC layer confirmation mode (AM, AcknowledgedMode); the other is the media access control (MAC, MediumAccessControl ) Layer Hybrid Automatic Repeat Request (HARQ, HybridARQ).

HARQ transmission is divided into new transmission and retransmission. If the HARQ retransmission exceeds the maximum number, the HARQ retransmission fails, and the RLC layer of the user equipment (UE, UserEquipment) notifies the RLC layer of the evolved node B (eNodeB, EvolvedNodeB) through a status report , and then the RLC layer of the eNodeB retransmits the corresponding message. Since ARQ retransmission involves a higher protocol level than HARQ retransmission, the time delay is also greater. In order to reduce the retransmission delay, after the HARQ fails, the MAC layer of the eNodeB can directly notify the RLC layer to perform ARQ retransmission without waiting for the status report of the UERLC layer.

The unit of HARQ transmission is TB, and a TB is a data block including a MAC message. The TB size is specified by the MCS index. The MCS index has 5 bits (bit), but only 29 combinations (0-28) are used, and the remaining 3 combinations (29-31) are reserved, and these 3 combinations Only used for retransmissions. Since the size of the transport block (TB, TransportBlock) is generally specified by the modulation and coding scheme (MCS, Modulation and Coding Scheme) index in the newly transmitted downlink control information (DCI, Downlink Control Information), and the TB size does not change when HARQ retransmits, so the retransmission The TB size is not re-indicated in the DCI. If the UE does not successfully receive the newly transmitted DCI, the UE fails to demodulate because it does not know the size of the TB after receiving the HARQ retransmitted message. After the UE fails to demodulate, it will send a non-acknowledgement response (NACK, Negative Acknowledgment) to the eNodeB, thereby triggering ARQ. Therefore, the delay of retransmission at the RLC layer is very long.

Contents of the invention

In order to solve the above problems, the present invention proposes a method and device for realizing RLC layer retransmission, which can reduce retransmission delay.

In order to achieve the above object, the present invention proposes a method for realizing radio link control RLC layer retransmission, including:

The medium access control MAC layer of the evolved node BeNodeB sends a HARQ new transmission to the MAC layer of the user equipment UE;

When the MAC layer of the eNodeB does not receive the acknowledgment response ACK and the non-acknowledgment response NACK of the MAC layer of the UE, the MAC layer of the eNodeB does not perform HARQ retransmission, and notifies the RLC layer to perform automatic retransmission request ARQ retransmission.

Preferably, when the MAC layer of the eNodeB receives a non-acknowledgment response NACK of the MAC layer of the UE, the method further includes:

The MAC layer of the eNodeB performs HARQ retransmission.

The present invention also proposes a device for realizing radio link control RLC layer retransmission, at least including:

A sending module, configured to send a hybrid automatic repeat request HARQ new transmission to the MAC layer of the user equipment UE;

The notification module is configured to not perform HARQ retransmission when the MAC layer does not receive the ACK and NACK of the MAC layer of the UE, and notify the RLC layer to perform automatic retransmission request ARQ retransmission.

Preferably, the sending module is also used for:

When the MAC layer receives a non-acknowledgment response NACK from the MAC layer of the UE, the MAC layer performs HARQ retransmission.

Compared with the prior art, the present invention includes: the MAC layer of the eNodeB sends a HARQ new transmission to the MAC layer of the UE; when the MAC layer of the eNodeB does not receive the ACK and NACK of the MAC layer of the UE, the MAC layer of the eNodeB does not perform HARQ retransmission, and notify the RLC layer to perform ARQ retransmission. Through the solution of the present invention, when the MAC of the eNodeB does not receive the ACK or NACK of the MAC layer of the UE, it immediately notifies the RLC layer to perform ARQ retransmission without continuing to perform HARQ retransmission, thereby reducing the time for retransmission. Delay, and save the meaningless HARQ retransmission, thus saving precious air interface resources.

Description of drawings

The accompanying drawings in the embodiments of the present invention are described below. The accompanying drawings in the embodiments are used for further understanding of the present invention and are used together with the description to explain the present invention, and do not constitute a limitation to the protection scope of the present invention.

Fig. 1 is the schematic diagram of the air interface protocol stack of existing LTE network;

Fig. 2 is the flowchart of the method for realizing RLC layer retransmission of the present invention;

FIG. 3 is a flow chart of a specific embodiment of the method for implementing RLC layer retransmission in the present invention.

detailed description

In order to facilitate the understanding of those skilled in the art, the present invention will be further described below in conjunction with the accompanying drawings, which cannot be used to limit the protection scope of the present invention. It should be noted that, in the case of no conflict, the embodiments in the present application and various manners in the embodiments can be combined with each other.

Referring to Fig. 2, the present invention proposes a method for realizing RLC layer retransmission, including:

Step 200, the MAC layer of the eNodeB sends a HARQ new transmission to the MAC layer of the UE.

In this step, the HARQ new transmission includes DCI and corresponding data.

The MAC layer of the UE first detects the DCI, and acquires data according to the detected DCI. When the MAC layer of the UE obtains the data successfully, it sends an ACK to the eNodeB; when the MAC layer of the UE fails to obtain the data, it sends a NACK to the eNodeB.

When the MAC layer of the UE does not detect DCI, the MAC layer of the UE will not send ACK and NACK to the eNodeB.

Step 201, when the MAC layer of the eNodeB does not receive the acknowledgment response (ACK, Acknowledgment) and NACK of the MAC layer of the UE, the MAC layer of the eNodeB does not perform HARQ retransmission, and immediately sends a message to notify the RLC layer to perform ARQ retransmission.

In this step, when the MAC layer of the eNodeB receives the NACK of the MAC layer of the UE, the MAC layer of the eNodeB performs HARQ retransmission.

The method of the present invention will be described in detail below through specific examples.

As shown in Figure 3, the method includes:

Step 300, the eNodeBRLC layer sends an RLC protocol data unit (PDU, ProtocolDataUnit) to the MAC layer.

In this step, the RLC PDU is ARQ new transmission or ARQ retransmission.

Step 301, the MAC layer of the eNodeB sends a MAC PDU to the UE MAC layer.

In this step, the MAC PDU is the new transmission of the HARQ.

Step 302: If the eNodeBMAC layer does not receive the ACK and NACK from the MAC layer of the UE, the MAC layer of the eNodeB does not perform HARQ retransmission, and immediately notifies the RLC layer of the eNodeB to retransmit the corresponding RLC PDU.

In this step, if the eNodeBMAC layer receives the NACK from the MAC layer of the UE, the MAC layer of the eNodeB performs HARQ retransmission.

The present invention also proposes a device for realizing RLC layer retransmission, at least including:

A sending module, configured to send a new transmission of HARQ to the MAC layer of the UE;

The notification module is configured to not perform HARQ retransmission when the MAC layer does not receive the ACK and NACK of the MAC layer of the UE, and notify the RLC layer to perform ARQ retransmission.

In the device of the present invention, the sending module is also used for:

When the MAC layer receives the NACK from the MAC layer of the UE, the MAC layer performs HARQ retransmission.

It should be noted that the above-described embodiments are only for the convenience of those skilled in the art to understand, and are not intended to limit the protection scope of the present invention. Any obvious replacements and improvements made by the invention are within the protection scope of the present invention.

Claims (4)

1. A method for realizing radio link control RLC layer retransmission, characterized in that, comprising: The medium access control MAC layer of the evolved node BeNodeB sends a HARQ new transmission to the MAC layer of the user equipment UE; When the MAC layer of the eNodeB does not receive the acknowledgment response ACK and the non-acknowledgment response NACK of the MAC layer of the UE, the MAC layer of the eNodeB does not perform HARQ retransmission, and notifies the RLC layer to perform automatic retransmission request ARQ retransmission. 2. The method according to claim 1, wherein when the MAC layer of the eNodeB receives a non-acknowledgment response NACK of the MAC layer of the UE, the method further comprises: The MAC layer of the eNodeB performs HARQ retransmission. 3. A device for realizing radio link control RLC layer retransmission, characterized in that it at least includes: A sending module, configured to send a hybrid automatic repeat request HARQ new transmission to the MAC layer of the user equipment UE; The notification module is configured to not perform HARQ retransmission when the MAC layer does not receive the ACK and NACK of the MAC layer of the UE, and notify the RLC layer to perform automatic retransmission request ARQ retransmission. 4. The device according to claim 3, wherein the sending module is also used for: When the MAC layer receives a non-acknowledgment response NACK from the MAC layer of the UE, the MAC layer performs HARQ retransmission.