TCP Over the IEEE 802.15.3 MAC: Analysis and Simulation

Abstract

High data rate wireless technologies are now becoming a reality, and have spurred the development of new applications that were previously hindered by the lack of capacity. In particular, it is now possible to stream high definition movies from a laptop to a sound system and flat screen television seamlessly. One of the key enablers of such applications is the IEEE 802.15.3 medium access control (MAC) protocol, which is designed to support bandwidth intensive applications in wireless personal area networks (WPANs). A key observation is that a significant number of multi-media applications rely on the transmission control protocol (TCP). Unfortunately, little works have conducted a thorough performance study of TCP over the IEEE 802.15.3 MAC. Moreover, the IEEE 802.15.3 specification does not specify any strategies for allocating time slots. This paper therefore contributes to the current state-of-the-art in the following manners. From our extensive analytical and simulation studies, we reveal the impacts of different channel time allocation methods and acknowledgment policies on the performance of TCP, with particular attention on round trip time, congestion window growth, and packet recovery. We then present the following guidance to application developers: (1) channel time allocations (CTAs) should be distributed evenly over the superframe and have durations determined by TCP’s maximum congestion window, (2) CTA positioning has no impact on TCP’s performance, and (3) the specified delayed acknowledgment policy needs to be augmented with an adaptive algorithm that adjusts its burst size dynamically to varying bit error rate (BER).