Method for enhancing transmission reliability of RLC AM mode

Abstract

The application discloses a method for enhancing transmission reliability of a radio link control acknowledgement (RLC AM) mode. By testing a retransmission receiving correct situation via an RLC layer of a receiving terminal, and optionally actively retransmitting certain PDU by a transmitting terminal according to an unoccupied degree of send windows, a situation of RLC status feedback loss is recognized by the RLC layer of the receiving terminal. Furthermore, by exchanging cross-layer information of MAC and RLC, the MAC layer of each of sending and receiving terminals purposefully performs adjustment of MCS transmission according to the status where RLC ARQ retransmission and feedback in. The transmission quality of ARQ retransmission of PDU and RLC status feedback of PDU are improved; the transmission accuracy of ARQ retransmission and RLC status feedback is increased. The method is beneficial for enhancing transmission reliability of a down link of the RLC AM mode.

Description

technical field [0001] The present application relates to the technical field of wireless communication, and in particular to a method for enhancing transmission reliability in a Radio Link Control Acknowledgment (RLC AM) mode. Background technique [0002] In the 3G / 4G wireless communication system, the data packets received by the base station and the core network first pass through the Packet Data Convergence Protocol (PDCP, Packet Data Convergence Protocol) layer, and then transfer to the radio link control (RLC) layer after IP header compression and encryption. , Radio Link Control) layer, after segmentation and concatenation according to the transmission requirements of the Media Access Control (MAC, Media Access Control) layer, then transfer to the MAC layer, and finally form a wireless signal from the air interface and send it out. [0003] According to the characteristics and requirements of business transmission, transmission is divided into transmission with conne...

AI Technical Summary

Problems solved by technology

Once there is a channel quality detection error, channel quality tracking is not timely, avoid frequently changing the modulation and coding strategy (MCS, Modulation and Coding Schem) and cause authorization overhead, etc., the adaptive modulation and coding (AMC, Adaptive Modulation and Coding) of the MAC layer Even the transmission quality assurance mechanism cannot guarantee an absolutely low block error rate at any time

The time-varying characteristics of the channel may cause the jitter of the channel transmission quality in a short period of time and the sudden packet error

In addition, because the MAC layer algorithm is only set for the transmission index of the MAC layer, it does not specifically consider the situation of RLC layer retransmission and status feedback.

Once the transmission of the status feedback PDU fails due to poor link conditions, or the T_reordering timer setting at the receiving end is unreasonable or the scheduling resource allocation causes the transmission delay, it will affect the speed of the sending window advancement, which may lead to the sending window being full. Affects the sending of new data

Once the sending window is full, it will trigger the sending end to actively retransmit the PDU, and it is more likely that the maximum RLC retransmission will be reached and the risk of RRC reconstruction will be performed.

Since the receiving end cannot identify whether the status feedback PDU is lost, nor can it distinguish and judge whether the specific reason why the RLC PDU is not received correctly is due to service transmission failure or feedback failure, it can only follow the normal feedback information sending process or passively let the sending end take turns. Inquiry for status feedback, cannot perform corresponding status feedback PDU reliability enhancement processing according to the reverse link transmission quality

The RLC sending side does not perform corresponding advance processing according to the free status of the sending window. It only performs polling and active retransmission processing when the sending window is full. Perform active retransmission, the protocol does not clearly stipulate

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