Biorthogonal pulse position modulated direct-sequence CDMA for wireless local communications

The author proposes a biorthogonal code-division multiple-access (CDMA) scheme based on biorthogonal pulse position modulated signature sequences. Unlike classical CDMA using bit-by-bit spreading, this scheme utilises symbol-by-symbol spreading which effectively reduces multiple-access interference. Compared to the orthogonal CDMA using symbol-by-symbol spreading, the proposed biorthogonal CDMA minimises the receiver complexity, while it causes negligible performance degradation. Its simple receiver structure will be suitable for use in CDMA wireless local communications. For a proper symbol size M, the biorthogonal CDMA proposed shows great promise for practical implementation both from the performance and complexity points of view