Optimum power and rate allocation in cluster based video sensor networks

In a wireless video sensor network (WVSN), each video sensor node consumes a significant amount of power on video compression in addition to the required power for communication. Therefore, the power optimization is a more critical issue in WVSN. This paper presents a cross-layer algorithm for the minimization of the total power in a video sensor network organized in a clustered architecture. The algorithm minimizes the total power in the network by jointly optimizing the encoding and transmission powers, in addition to the source encoding rate at each video sensor node. Furthermore, the allocation of the MAC layer resources (time slots and frequency bands) considering flat fading channel is addressed. We formulate the problem as a non-linear optimization, and propose a solution based on Lagrange duality subject to video signal distortion and packet loss constraints. The simulation results show the trade-off between allocating power to the encoding process or the transmission process. Moreover, the interaction between the nodes competing for channel resources for both intra-cluster, and inter-cluster bases, and how this affects their power consumption and distortion levels is studied.