Major problems in the Medium Access Control (MAC) of Wireless Sensor Networks (WSNs) are: sleep/wake-up scheduling and its overhead, idle listening, collision, and the energy used for retransmission of collided packets. This paper focuses on these problems and proposes an adaptive quorum-based MAC protocol, Queen-MAC. This protocol independently and adaptively schedules nodes wake-up times, decreases idle listening and collisions, increases network throughput, and extends network lifetime. Queen-MAC is highly suitable for data collection applications. A new quorum system, dygrid is proposed that can provide a low duty cycle, View the MathML source, for adjusting wake-up times of sensor nodes. Theoretical analysis demonstrates the feasibility of dygrid and its superiority over two commonly used quorum systems (i.e., grid and e-torus). A lightweight channel assignment method is also proposed to reduce collision and make concurrent transmissions possible. Simulation results indicate that Queen-MAC prolongs the network lifetime while increasing the average delivery ratio and keeping the transmission latency low.

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