Analysis of heuristic-based MAC protocols for ad hoc networks

In the last years, there has been an increasing interest in developing and testing Medium Access Control (MAC) protocols for ad hoc networks based on optimal methods. The solutions already proposed in several works are generally hard to implement because they require extensive message passing among the nodes. Moreover, a relaxation for the optimal solution is generally needed to achieve an implementable algorithm from the optimization problem solution. These disadvantages decrease the performance of the optimal-based algorithms, often translated into a less than expected throughput. This is the main reason why several MAC protocols, such as IEEE 802.11, use simple heuristics to control the access of the nodes to the medium. Generally, the adoption of heuristics in MAC protocols turns its formal performance analysis very difficult. The motivation of this work is to assess the validity of a formal method that analyzes the throughput of heuristic-based MAC protocols. This work starts to introduce the method that characterizes the node's medium access satisfaction. This method is used to compare the heuristics used to control the medium access. We describe and compare several heuristics by applying the formal analysis, which is later validated through simulations. The method here described can be applied at MAC design stage, since the designer can evaluate the performance of a given heuristic by comparison with others.