Novel overlay/underlay cognitive radio waveforms using SD-SMSE framework to enhance spectrum efficiency- part i: theoretical framework and analysis in AWGN channel. - Vasu Chakravarthy; Xue Li 002; Zhiqiang Wu 001; Michael A. Temple; F. Garber; Rajgopal Kannan; Athanasios V. Vasilakos (IEEE Trans. Commun., 2009)