A new adaptive MAC protocol with QoS support based on IEEE 802.11 in ad hoc networks

With the expanding of applications, the demand of quality of service (QoS) has become strongly increased in ad hoc networks. Since the efficient and reasonable MAC protocol is a key factor for providing QoS in ad hoc networks, in this paper we propose an adaptive QoS MAC protocol (AMP) based on IEEE 802.11. In AMP, we introduce the concept of transmission license, where only the node which holds transmission license can participate in the channel contention for changing the number of licenses according to the load of the network adaptively, controlling the number of the nodes that participate in the channel contention, and ensuring the nodes with licenses share the channels through contention. In addition, AMP assigns different priority classes for different traffic according to the special characteristics and performance types of the different networks, and it sets the different contention parameters for the different priorities services for guaranteeing these services performances to have advantages in the channel contention. Simulation shows that compared to IEEE 802.11 protocol, AMP not only can meet the QoS requirement with high priority in the networks but also can well solve the hidden terminal problems and the fairness issues between different network nodes; that is, it can satisfy the high efficiency, pertinence, spatial-reuse, etc. to the largest extent at the same time in limited channels.