TCPW with bulk repeat in next generation wireless networks

Wireless links are error-prone. In Next Generation wireless networks, link capacities will still grow. It is known that in such configurations the performance of current TCP variants degrades severely. In this paper we propose a new retransmission strategy for TCP in high error situations – Bulk Repeat (BR). We apply BR to TCP Westwood (TCPW). BR has only three senderside modifications to TCP, i.e. Bulk Retransmission, Fixed Retransmission Timeout and Intelligent Window Adjustment. BR permits efficient recovery from multiple losses in the same congestion window. To discriminate error from congestion loss, a Loss Discrimination Algorithm (LDA), based on Spike and Rate Gap Threshold, is used. Simulation results in wireless network scenarios show that TCPW BR improves throughput performance up to an order of magnitude over TCPW and NewReno when the error rate is high (>5%). The results also show that TCPW BR has satisfactory fairness and friendliness to TCP NewReno.