Enhancing TCP Performance in AMC Based Broadband Wireless Access Networks

In this paper, we study wireless links that are enhanced using adaptive modulation and coding (AMC) techniques. In particular, we consider a cross-layer protocol approach that modifies the behavior of the Transmission Control Protocol (TCP) using AMC techniques. An application of the proposed system for an IEEE 802.16 (WiMAX) based Wireless Metropolitan Area Network (WMAN) is presented. The performance of the system has been studied using discrete event simulation models in ns2 and compared to TCP-Reno and TCP-Tahoe schemes. The results indicate that in our system, queueing delay and packet drops that result due to buffer overrun are minimized. We also show that our system achieves better throughput fairness when multiple flows share a bottle-necked access link.