Distributed CS-CDMA Wireless Sensor Networks in Frequency Selective Channel

This paper proposes orthogonal communication between sensors and a data fusion center through a transmission scheme referred here as chip spread code-division multiple-access (CS-CDMA). The fusion performance is investigated in the presence of channel errors due to both frequency selective fading and noise. We derive the optimum Bayesian data fusion receiver for such CS-CDMA based distributed wireless sensor network whose complexity is exponential with the number of sensors. To provide a low-complexity solution, a data fusion receiver that performs multi-sensor matched filter detection followed by majority rule data fusion decision is proposed. The simulation results indicate that this low-complexity receiver performs close to the optimum fusion receiver. Comparisons with a direct sequence CDMA based distributed wireless sensor network are also included.