Mathematical Analysis of IEEE 802.11 Energy Efficiency

Mobility and portability are the major advantages that IEEE 802.11 wireless networks offer over their traditional counter- parts, i.e. wired Ethernet networks. However, when nodes are mobile or portable units, power consumption becomes a primary issue since terminals are usually battery driven. In this paper we propose an analytical framework to investigate the energetic cost of communicating in a cluster of IEEE 802.11 DCF terminals. We propose a linear model describing all the different phases that a node goes through during its active period. Under independence hypothesis, we provide the complete statistical description of the power consumption process through a moment generating function. By this means, we can evaluate the average life of a terminal, that is the maximum number of packets which can be transmitted by a terminal competing in a cluster of nodes. Using our model, we develop a case study and provide interesting indications to mitigate the power consumption of IEEE 802.11 terminals.