FMAC: a highly flexible multiple-access protocol for wireless communications systems

Due to the limited bandwidth of wireless networks, an efficient medium-access control protocol is essential to meet the growing demand of wireless access. Most multiple-access protocols require contentions (collisions) in the process of acquiring the transmission medium. While collisions cannot be avoided, successive collisions that consist of the same group of active stations are totally unnecessary. Successive collisions not only waste bandwidth, but also raise the concern of saturation in the channel. In this paper, we solve the problem of repetitive contentions involving the same set of stations by using the theory of finite projective planes. Due to the property of single-point intersection for an arbitrary pair of sets in the finite projective plane, we can minimize the number of unnecessary collisions. Protocol finite projective plane-based medium access control (FMAC) is highly flexible and has many features including adaptation for a mobile environment, support for priority assignment and handoffs in cellular networks, and extension of asynchronous transfer mode (ATM) services to mobile users. A performance evaluation shows that the throughput of the system is higher than that of slotted ALOHA. By dynamically adjusting the retransmission probability and the order of the finite projective plane, protocol FMAC can be stabilized.