Memory-Efficient Scheme for RLC Data Buffer Management in Radio Access Networks

The RAN (Radio Access Network) has undergone significant changes to meet the diverse requirements of various use cases. These changes include rewriting the network architecture, protocols, and algorithms to optimize performance and efficiency. The Radio Link Control (RLC) layer offers Automatic Repeat Request (ARQ) for error recovery and reliable packet delivery in Acknowledgement Mode (AM). In AM mode, the RLC receiver uses a t-Reassembly timer to allow time for recovery and reordering at lower layers. Additionally, a t-StatusProhibit timer is employed to prevent excessive transmission of Status Reports and to allow sufficient time for the MAC layer to recover errors through HARQ retransmissions and to update the ACK/NACK status to the transmitter side. In the AM Mode, data packets at RLC transmitter are only freed after receiving an acknowledgment of successful reception through a Status Report from the RLC receiver. In low-memory systems, delays in transmitting the Status Report caused by a high t-StatusProhibit timer value can lead to significant consumption of packet buffer memory. This paper introduces a solution that focuses on minimizing the packet buffer memory requirement at the transmitter RLC, facilitating the design of cost-effective and memory-efficient devices. Experimental results demonstrate that the proposed solution decreases the transmitter RLC packet data buffer memory requirement by approximately 50%, with one additional status report within a t-StatusProhibit timer interval without affecting the RLC protocol's functional requirements.