In this paper, we investigate the application of M­ary orthogonal modulation for multicarrier 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 decision­directed estimation receiver to apply channel phase es­timation. With decision­directed estimation no redundancy like training data is required to be transmitted. Simulation results show no performance loss for low E b =N 0 and only a moder­ate degradation for high E b =N 0 in comparison to ideal phase equalization. Moreover, the results are always contrasted with BPSK performance. Applying M­ary orthogonal modulation reveals to outperfom BPSK with respect to bit error rate and spectral efficiency, even if ideal equalization is considered for BPSK and decision­directed estimation for M­ary orthogonal modulation.

The results are generally valid, whereas in this paper, they are based on the European HIPERLAN/2­standardization.