Sensor beamforming with distributed mobile elements in a wireless sensor network

Abstract

Sensor array beamforming performance using independently mobile antennas connected through a wireless sensor network is analyzed where a performance metric is proposed enabling mitigation of the perturbation of array factor formation caused by dynamic node positions. Wireless networking has expanded array design possibilities to include wirelessly connected elements; however, static positioning of elements remains central to determination and application of weights necessary for coherent array beam formation. Wireless networks allow for participant mobility, but applied weights must be reformed for each position update in order to maintain target focus. While deterministic motion allows easy weight translation, random element motion requires significant network energy to reform weights through position updates. The relationship between array factor and stochastic element motion is analyzed. A relationship is developed between motion and array factor magnitude probability towards the intended target vector. The relationship proposed is shown to be assessable and useful for reducing network traffic and processing overhead and while producing operationally acceptable gain towards the target. The result compares favorably against a constant position updating model in terms of sensor energy usage across the network.