Achieving spectrum efficiency through signal design for ultra wide band sensor networks

In this paper, a novel approach is presented for ultra wide band signal design. The bottom up approach designs the signals that utilize the ultra wide band spectrum efficiently. 1st-6th derivative Gaussian pulses are linearly combined using a particle swarm optimization algorithm to form one single pulse. A binary PSO determines the order of the derivative of the pulses that are combined. The continuous PSO determines the time duration and amplitudes for different pulses in the composite pulse. The power spectral density (PSD) of the resultant pulse conforms to the FCC spectral mask and effectively exploits the allowable bandwidth and power. The particle swarm optimization algorithm achieves multiple orthogonal pulses. The newly designed pulses achieve higher spectral efficiencies which is shown theoretically and in simulations. The proposed method presents a flexible and effective way for generating UWB pulses that satisfy the FCC mask. The method can be generalized to design UWB pulses for any given spectral mask.