  In this paper we present a model for the lifetime of wireless sensor
networks. The model takes into consideration several parameters such as the
total number of sensors, network size, percentage of sink nodes, location of
sensors, the mobility of sensors, and power consumption. A definition of the
life time of the network based on three different criteria is introduced;
percentage of available power to total power, percentage of alive sensors to
total sensors, and percentage of alive sink sensors to total sink sensors. A
Matlab based simulator is developed for the introduced model. A number of
wireless sensor networks scenarios are presented and discussed.
