A M-ary biorthogonal code SS multicarrier CDMA transmission scheme

In this paper a M-ary biorthogonal code spread-spectrum (SS) multicarrier code division multiple access (CDMA) transmission scheme is proposed. This scheme uses quadrature BPSK modulation and biorthogonal SS code to take data; channel estimation eliminates the ambiguities of amplitude and phase generated by channel fading, and avoids the identification problem of the single/dual SS code. In comparison with conventional multicarrier CDMA system, this scheme highly increases the data rate of up to 2 log/sub 2/ M times. Meanwhile, simulations are performed with the improved subspace tracking and least squares (LS) channel estimation algorithm in the case of different combining schemes, and show good system performance.