In this article, the problems studied are to optimize the life of the network of sensors covering mobile targets by minimizing the energy consumption of the network. Indeed, wireless sensor networks have received particular attention in recent years, as their applications are common today, such as vehicle tracking or battlefield monitoring. In a wireless sensor network, the sensor battery plays an important role. The function of the sensor depends on the battery life. Replacement of batteries becomes impossible once deployed in a remote or unattended location. A set of randomly placed sensors monitors targets moving in an area. Each sensor has a limited lifetime and two states: Active or Inactive. An active sensor can monitor targets in its monitoring sub-area at a necessary energy consumption cost. To model these problems, we use a mathematical model based on linear programming with mixed integer variables. AMPL is used to formulate the model and MINOS for its resolution and the numerical results allowed to obtain an adequate activation scheduling of the sensors by improving their lifetime.

Integration of wireless and mobile networks to new generations constitutes a heterogeneous system, this is the case of LTE and WiFi networks. In this paper, we study and analyze the optimal performances of this system regarding the SINR(Signal Interference Noise Ration), the blocking probability and the user communication loss. The user mobility is represented by random wayPoint(RWP) model and users terminals equipped with multiple accesses interfaces. We have established a Markov chain to assess and analyze the performances obtained from the heterogeneous networks system. So we have proposed an average value of the signal power emitted in down-ling voice, the blocking probability of system connections.

Networks LTE(4G) and Wi-Fi complementarity establish a heterogeneous system of wireless and mobile networks. We study and analyze the optimal performances of this heterogeneous system based on the bit rate, the blocking probability and user connection loss. Random Waypoint is the user mobility model. User’s provided mobile terminal equipped with multiple accesses interfaces. We have developed a Markov chain to estimate the performances obtained from the heterogeneous networks system, which allowed us to propose an average bit rate value in a sub-zone of this system then the average blocking probability user connection in this zone. We have also proposed a sensitivity factor of maximal decrease of these selection network parameters. This factor informs about the heterogeneous networks congestion and dis-congestion system.