Abstract: In this paper, a M-ary biorthogonal code spread spectrum (SS) high data rate multicarrier code division multiple access (CDMA) system is proposed. The system uses quadrature BPSK modulation and biorthogonal SS code to take data bits. Channel estimation eliminates the ambiguities of the phase generated by channel fading, and avoids the identification problem of the single/dual SS code. We use a modified subspace tracking channel estimation algorithm and simulate the system BER performance under different channel estimation approaches and combining methods.

Key words: multicarrier CDMA, M-ary biorthogonal code spectrum spread, CDMA, OFDM