Saturation throughput of IEEE 802.11 using carrier sense mechanism in backoff intervals

Most modifications on IEEE 802.11 DCF (distributed coordination function) so far have focused on updating of the CW (Contention Window) value and the carrier sense mechanism during a backoff interval is not considered. In this paper, we propose two novel schemes for DCF, which effectively utilize the carrier sense mechanism during backoff interval. The proposed schemes can be applied to any conventional ones, such as DCF and SD (slow CW decrease). Saturation throughput of the proposed schemes is analyzed by means of Bianchi´s Markovian model. Computer simulation validates the accuracy of the analysis. Numerical results based on IEEE 802.11b show that up to 10-20% improvement of saturation throughput can be achieved by combining the proposed schemes with DCF or SD.