Biorthogonal pulse shape modulation for ultra-wideband wireless communications

We propose a wireless communications ultra-wideband (UWB) multiple access spread spectrum scheme based on biorthogonal pulse shape modulation (BPSM). Unlike classical UWB that employs bit-by-bit spreading, this scheme utilizes symbol-by-symbol spreading which effectively reduces the multiple access interference. Compared to orthogonal UWB using symbol-by-symbol spreading the proposed BPSM technique minimizes the receiver complexity, while causing a negligible performance degradation. The proposed system performance is investigated in a realistic multipath channel. The expressions of the desired, interference and noise signals at the output of the selective Rake combiner, the conditional bit error rate as well as its upper bound are also derived. Results reveal that the proposed BPSM based UWB receiver holds a great promise for practical implementation both from the performance and complexity perspectives.