M-ary orthogonal modulation for multi-carrier spread-spectrum uplink transmission

We investigate the application of M-ary orthogonal modulation for multi-carrier spread spectrum (MCSS) uplink transmission over a Rayleigh fading indoor channel. Different coherent detection strategies with perfectly known channel coefficients are analyzed. Furthermore, we present a decision-directed estimation receiver to apply channel phase estimation. With decision-directed estimation no redundancy like training data is required to be transmitted. Simulation results show no performance loss for low E¯_b/N₀ and only a moderate degradation for high E¯_b/N₀ in comparison to ideal phase equalization. Moreover, the results are always contrasted with BPSK performance. Applying M-ary orthogonal modulation is revealed to outperform BPSK with respect to bit error rate and spectral efficiency, even if ideal equalization is considered for BPSK and decision-directed estimation for M-ary orthogonal modulation. The results are generally valid, whereas in this paper, they are based on the European HIPERLAN/2-standardization