MAC queue size and energy-efficient of IEEE 802.11e EDCA in Wireless Multimedia Sensor Networks

The Wireless Multimedia Sensor Networks (WMSN) are confronted with two basic constraints that are the strong constraint of the energy consumption, and the strong constraint of the traffic performance (Delay, Throughput, etc.). To try to satisfy these two constraints, the IEEE 802.11e Enhanced Distributed Channel Access (EDCA) has been used at the MAC layer in the WMSN. The EDCA access method maintains four MAC queues of type Drop-Tail which corresponds to four Access Categories (AC). Knowing that WMSN are limited in terms of memory, the size of these four MAC queues must be well adjusted to avoid wasting memory space, and at the same time for not increasing the packet delay to ensure better traffic performance. In this paper we will not try to find the optimum value of these four MAC queues of type Drop-Tail used by EDCA. By against, we study the existence or absence of influence of the size of these four queues on energy consumption. The results show that the size of these four queues has a very low impact (negligible) on energy consumption, but directly influences the delay, with a small increase in Packet Delivery Rate (PDR) and a variation of the throughput.