A QoS guaranteed low energy packet transmission technique for the IEEE 802.11 WLAN

This work presents an energy efficient packet transmission algorithm that exploits the multi-rate transmission technique used by the link adaption algorithm of the IEEE 802.11 standard. The proposed algorithm adapts both the transmission data rate and the transmission power to optimize energy consumption of a WLAN transmitter under specific Quality of Service (QoS) constraints. The proposed algorithm introduces a new cost function for data rate mapping based on a dual parameter approach, where both transmission delay and queue length are used for data rate selection. Transmitters always choose the lowest possible data rate that satisfies the QoS objective in order to minimize energy consumption; as the system load and the congestion increases, the required data rate to satisfy the QoS objective is increased to adapt to the network load condition. The developed algorithm requires minimum signaling feedback and introduces low computational load. Simulation results show that the proposed protocol can introduce significant energy savings compared to well-known Rate First Channel Driven Rate/Power adaptation (CDRPA) and Miser approaches while still maintaining the QoS at the required level. An OPNET based simulation model is used for the performance analysis.