FAFS: a new MAC protocol for wireless ATM

Wireless ATM (WATM) is being envisaged as the next-generation wireless solution for meeting the demands of the users. Besides supporting high data transfer rates, it also provides QoS (quality of service) guarantees to the connections. Since the wireless channel is error-prone (bit error rate >10^-3) and bandwidth is scarce, it becomes an important design issue to efficiently allocate bandwidth among users. The MAC (medium access control) layer arbitrates the channel access to the wireless medium and is also responsible for bandwidth allocation to different users. We present a new MAC protocol, FAFS (fair access fair scheduling), which provides a new contention scheme along with a novel scheduling algorithm that allocates data slots to the sources based on their packet queues, negotiated traffic requirements, signal intensity and the last time when the channel was granted to the connection (for best-effort service only). Our results show that the delay probability of the real-time packets is decreased using the techniques mentioned. We also provide improved service to the best-effort sources by avoiding large queues at the mobile terminal