A Rate Adaptive Hybrid MAC Protocol for Wireless Cellular Networks

Efficient medium access control (MAC) protocol plays a critical role in wireless mobile networks. In this paper, we propose a rate adaptive hybrid MAC (RAH-MAC) protocol to support differential services in wireless cellular networks. RAH-MAC is a hybrid of polling and contention MAC protocol. In RAH-MAC, when a mobile terminal (MT) has data to send, it first uses the contention time slot to join the BS polling list. The contention time is dynamically allocated based on the system traffic load. An MT with high priority services has high priority to access the contention channel. The BS allocates a data transmission time slot for a registered MT. The time slot duration is based on the MT´s demanded service class. An MT transmits data after it receives the polling message from the BS. The data transmission rate is adaptively adjusted based on the channel conditions. The simulation results show that RAH- MAC is superior to the existing MAC protocols.