On the matched filter bound of transmit diversity techniques

Diversity transmission at the base station is an effective technique to combat the adverse effects of fading. This is suggested as an alternative to diversity at the terminal, thereby reducing the implementation complexity. We evaluate the matched filter bound (MFB) for two transmit diversity schemes with two transmit antennas: delay diversity and space-time block coding. Theoretical results show that even though the expected value of the matched filter bound is the same for both approaches, the diversity order exhibited by the space-time block coding approach is larger than that of delay diversity for any frequency selective channel with more than 1 tap. In fact for a frequency selective channel with L+1 taps with equal energy, the diversity order exhibited by the space-time coding MFB is 2×(L+1) while that of delay diversity is L+2