Wavelet Packet Multi-carrier modulation MIMO architecture for spectrum pooling systems
M. K. Lakshmanan, I. Budiarjo, H. Nikookar · 2009
In this paper we demonstrate the operation of a wavelet packet multi-carrier modulation (WPMCM) based cognitive radio (CR) on a multiple-input and multiple-output (MIMO) platform. The wavelet packets are derived from multistage tree-structured paraunitary filter banks. To enable the WPMCM system to co-exist with other licensed users (LU), the WPMCM transmission waveform characteristics are shaped to communicate in the idle time-frequency gaps of the LUs. This is done by vacating WPMCM carriers in and near the region of the LU spectrum. Furthermore, a spectrum estimation unit is tagged to the WPMCM transceiver structure by exploiting the filter bank infrastructure used for wavelet packet demodulation. Thus spectrum analysis is done at no additional cost. Through simulation studies the effectiveness of the system is demonstrated.