High-Throughput, High-Delivery Ratio MAC Protocol for Wireless VOIP Networks.

Existing duty-cycle MAC protocols for wireless voice-over-IP(VOIP) networks, such as S-MAC, mostly do not consider the influence of inherent traffic distribution characteristic derived from network infrastructure, leading to significant end-to-end delivery latency and poor medium contention handling in data gathering, where multiple data flows generated at sensor nodes converge to the sink. To mitigate these drawbacks, we propose a novel duty-cycle protocol. It adopts a static configuration strategy to configure nodes with un-uniform minimum contention window, in order to optimize application-level medium access fairness, avoiding packet loss and buffer overflow incurred by mismatches between un-uniform payload distribution and node-level fair medium access scheme adopted by current protocols. Our simulation results obtained on ns-2 show that it can better accommodate tree-based data gathering applications, providing high throughput and packet delivery ratio without sacrificing energy efficiency.