Wireless communications cannot know the state of medium. Thus, the retransmission strategy is the very important and medium access control is critical issue in wireless communications.
CSMA/CA uses the well-known BEB algorithm for retransmission. Capture effect exists in the conventional BEB algorithm as a problem; the pre-emptive terminal has a higher likelihood to send its data successively. This induces the wasteful attempts and delays. Most of all, capture effect doesn``t give the multiple access fair opportunity.
In this thesis, we propose a MCA-BEB(Modified Capture Avoidance Binary Exponential Backoff) algorithm to improve multiple access fairness for Optical Wireless LAN. Conventional backoff algorithm used for multiple access in wired and wireless LAN doesn``t give the fair opportunity to transmit data. MCA-BEB algorithm, which can improve the fairness of multiple access, uses "Attempt History Variable". AHV is the sum of last success attempts and each terminal``s attempting history with different weighting factors. This eliminates wasteful attempts and lowers the likelihood that pre-emptive terminal sends its data successively. Simulation results reveal that MCA-BEB algorithm improves fairness of multiple access 120% ~ 200% compared with conventional BEB algorithm.