Power control for collaborative beamforming in wireless sensor networks

Energy-efficient communication in wireless sensor networks (WSNs) is addressed in the physical layer by implementing collaborative beamforming (CB). CB achieves directional gain and at the same time distributes the corresponding energy consumption over the collaborative sensor nodes. However, sensor nodes in practice may have different energy budgets assigned to CB transmission. Thus, equal power CB can deplete energy from sensor nodes with smaller energy budget faster than the rest of sensor nodes. In this paper, CB with power control is developed to prolong the lifetime of a cluster of collaborative sensor nodes by balancing the sensor node lifetimes. A novel strategy is proposed to utilize the residual energy information (REI) available at each sensor node. Power control adjusts the energy consumption rate at each sensor node while achieving the required average signal-to-noise ratio (SNR) at the destination. Simulation results show that CB with power control outperforms equal power CB in terms of prolonging the lifetime of a cluster of collaborative nodes.