Title: Implementing a Cooperative MAC Protocol: Performance and Challenges in a Real Environment
Authors: Thanasis Korakis, Sathya Narayanan, Shivendra Panwar (Polytechnic, Panasonic, Polytechnic) Poster II, 18

ABSTRACT

In wireless LANs that provide multi-rate support (IEEE 802.11a, 802.11b) stations that experience poor channel quality tend to use low transmission rates to reduce the bit-error-rate (BER) of each transmission. This phenomenon usually leads to fairness problems between the stations with good channel quality and those without. This fairness problem has been shown to result in throughput degradation for the whole network. Our cooperative MAC protocol addresses this issue using an efficient scheme. Under this scheme, remote stations are assisted by a high rate station in its transmissions. With such assistance, the remote station will be able to transmit data at a higher rate in a two hop manner using the helper station. We implemented this new protocol in a Linux testbed. In this poster we describe the assumptions, implementation process as well as the challenges we came across. We evaluated the protocol using our testbed through experiments. We also investigated the helper positions and other circumstances under which its participation in the transmission process is efficient. The implementation of the protocol shows that it performs efficiently in supporting TCP as well as UDP applications, for several combinations of two-hop data rates.