Exploring full multipath diversity block transmission system based on direct sequence spreading and frequency domain equalization

If the signal receiver simply relies on linear equalization, itis difficult for the block transmission system to obtain the full multipath diversity gains of the wireless channel. To achieve this, we propose a single carrier block transmission system based on direct sequence spreading and maximum ratio combination frequency domain equalization. The direct sequence spreading of transmission signals in the time domain results in signal repetition and interleaving in the frequency domain. Through maximal ratio combination frequency domain equalization, the despreading and equalization are carried out simultaneously in the frequency domain. The simulation results, given in Figs. 2, 3 and 4, and their analysis show preliminarily that: (1) the block transmission system we proposed can obtain full multipath diversity gains (2) it has lower computational complexity and bit error rate than the conventional linear frequency domain equalizer.