Optimal transmit power and packet size in wireless sensor networks in lognormal shadowed environment
Arnab Nandi, Sumit Kundu · International Journal of Sensor Networks · 2012
In this paper, an optimum packet based transmission scheme for WSN (Wireless Sensor Network) where packet size is varied depending on the node density and channel condition is discussed. A WSN based on a square grid topology is investigated. This optimum size packet yields highest energy efficiency for a particular network condition. Optimum packet length is evaluated under several network conditions in presence of shadowing. Impact of severity of shadowing on optimal packet size is also investigated. Energy expenditure for optimum packet based scheme is compared with that of an arbitrary fixed packet size based transmission. Further impact of severity of fading on energy consumption is also studied. An infinite ARQ (Automatic Repeat reQuest) scheme between adjacent nodes has been considered to successfully deliver a file. Optimal transmit power is also derived for the above network. Optimal transmit power is the minimum transmit power used by all nodes to guarantee network connectivity with a prefixed BER (Bit Error Rate) threshold. Further impacts of lognormal shadowing on optimal transmit power, route BER and energy efficiency are studied for such WSN.