On achieving fairness and efficiency in high-speed shared medium access

Channel access has been an active research area for the past two decades. Several protocols have been proposed in the literature to utilize channel bandwidth efficiently. Some of the recently proposed protocols achieve a near-ideal channel utilization. However, the efficiency in utilization comes at the expense of certain unfairness in delay characteristics. A new channel-access protocol, called access mechanism for efficient sharing in broadcast medium networks (AMES-BM), is developed based on a deterministic binary tree-splitting technique to achieve efficient sharing of bandwidth. In AMES-BM, the stations are dynamically mapped to leaf nodes of a binary tree. The stations are then divided into smaller groups that mimic the behavior of an ideal transmission queue. Collisions are allowed to occur within these groups and are resolved using a variation of the conventional binary tree-splitting technique. The performance of AMES-BM is similar to that of a collision-based protocol under low loads and to that of a collision-free protocol under high loads. Besides achieving a near-optimal channel utilization, the proposed protocol also guarantees fairness with respect to delay for messages of varying lengths. The deterministic nature of the protocol makes it more attractive for real-time applications.