Methods for Preventing Protocol Stalling in UMTS Radio Link Control

The Radio Link Control (RLC) for Universal Mobile Telecommunication Systems (UMTS) is an acknowledgment based retransmission protocol. Protocol stalling and deadlock might happen under certain circumstances and thus reduce the system efficiency. In this paper, we propose and investigate three alternative mechanisms with spontaneous retransmissions to prevent protocol stalling. We compare the performance of the three approaches with simulation results. Our results indicate that all three methods can prevent protocol stalling quite effectively. In addition, the combined retransmission of the last or the earliest transmitted packet has the best throughput and delay performance and outperforms the other two methods.