TCP over wireless with link level error control: analysis and design methodology

This paper considers the problem of supporting TCP, the Internet data transport protocol, over a lossy wireless link whose quality varies over time. In order to prevent throughput degradation, it is necessary to "hide" the losses and the time variations of the wireless link from TCP. A number of solutions to this problem have been proposed in previous studies, but their performance was studied on a purely experimental basis. This paper presents an approximate analysis, validated by computer simulations, for TCP performance over wireless links. The analysis provides the basis for a systematic approach to supporting TCP over wireless links. The specific case of a Rayleigh-faded wireless link and automatic repeat request-based link-layer recovery is considered for the purpose of illustration. The numerical results presented for this case show that a simple solution, that of using an appropriately designed link-layer error-recovery scheme, prevents excessive deterioration of TCP throughput on wireless links.