An energy-efficient QoS-aware media access control protocol for wireless sensor networks

We present an innovative MAC protocol (Q-MAC) that minimizes the energy consumption in multi-hop wireless sensor networks (WSNs) and provides quality of service (QoS) by differentiating network services based on priority levels. The priority levels reflect application priority and the state of system resources, namely residual energy and queue occupancies. The Q-MAC utilizes both intra-node and inter-node arbitration. The intra-node packet scheduling is a multiple queuing architecture with packet classification and weighted arbitration. We also introduce the power conservation MACAW (PC-MACAW) - a power-aware scheduling mechanism that, together with the loosely prioritized random access (LPRA) algorithm, govern the inter-node scheduling. Performance evaluation are conducted between Q-MAC and S-MAC with respect to two performance metrics: energy consumption and average latency. Simulation results indicate that the performance of the Q-MAC is comparable to that of the S-MAC in non-prioritized traffic scenarios; when packets with different priorities are present, Q-MAC supiors in average latency differentiation between the classes of service, while maintaining the same energy level as that of S-MAC