Performance of TCP and UDP protocols in multi-hop multi-rate wireless networks

An interesting feature of IEEE 802.11 wireless LAN cards is that they support multiple transmission modes. For example, the 802.11b cards support four transmission modes of I, 2, 5.5 and 11 Mbps, whereas, the 802.11a cards support eight transmission modes, up to a maximum of 54 Mbps. In this paper, we study layer four protocols over multi-rate multi-hop wireless networks and attempt to answer the question whether higher bandwidth links necessarily outperform lower bandwidth links in these networks. We examine this question by taking into account the transport layer protocols such as the TCP and UDP. While network capacity is a topic of active interest in the research community, a comparative study of the ad hoc network throughput at the different link bandwidths has not been made. We then propose a bandwidth-based ad hoc routing protocol and look at how to integrate QoS with routing.