The effects of adaptive modulation on the TCP performance

To increase the link layer throughput, 802.16 Working Group defines the application of adaptive modulation in Broadband Wireless Access System (BWA). On the other hand.. the transport layer performance can be specified, for example, by Transmission Control Protocol (TCP) throughput. In this paper we analyse the link layer throughput by using adaptive modulation, as well as the TCP performance. Furthermore, the joint consideration of the data link layer and transport layer performance over a BWA network is discussed. The simulation results showed that the adaptive modulation in link layer could improve the TCP throughputs. In addition, criteria for the modulation selection considering both transport layer and link layer is given.