Multi-band Wavelet-Based Spectrum Agile Communications for cognitive radio secondary user communication

This paper proposes a novel technique for the opportunistic, secondary user, communication using wavelet domain processing to aid agile spectrum re-use. Deploying cognitive radio (CR) principles, the paper investigates the joint operation of direct sequence spread spectrum (DSSS) modulation and discrete wavelet packet transforms (DWPT) for signal shaping. Specifically, wavelet-based spectrum agile communication (WBSAC) is introduced where the detection of the primary user spectrum is carried out in the DWPT domain, and the insertion of the secondary user signal into opportunistic spectrum locations is carried out using spreading sequences and DWPT signal shaping. Simulation results are presented for different primary user spectrum occupancies and secondary user performance metrics to document the impact of different parameters in the wavelet domain on the overall performance of WBSAC.