Control Mechanism to Solve False Blocking Problem at MAC Layer in Wireless Sensor Networks

Contention based MAC protocols for wireless sensor networks (WSNs) suffer from the problem of false blocking of channel access due to unsuccessful attempts of RTS transmission by their neighboring nodes. This does not only reduce the network throughput, but also results in inconsistent and unpredictable data packet transmission pattern, which is unacceptable for real-time applications. A control mechanism that solves the false blocking problem is designed and introduced in this paper. In this approach, an additional control signal, called clear channel (CC), is used to facilitate the medium access decision. The proposed solution works for single-stream as well as multi-stream communication scenarios. Simulation results show that the solution helps the network to provide consistent and predictable delay performance while maintaining similar network throughput and energy consumption as compared to other general purpose MAC protocols for WSNs. With this solution, wireless sensors can be used in real-time sensor data communication.