Full Diversity Spatial Modulators

This talk presents a new approach for achieving both full rate and full transmit diversity. The techniques in this talk work on a symbol by symbol basis and so are called spatial modulators. When there is only a single receive antenna, the goal is to design the modulator at each transmit antenna so that(even for the worst case realization of the channel coefficients) the scheme achieves the capacity of the single transmitter multiple receiver system with the same channel coefficients. The talk presents two approaches to modulator design. The first expands the constellation by using a set of random phase sequences to modulate the transmitted symbol at each antenna. The receiver thus sees an equivalent single antenna system with an expanded and distorted constellation. The second approach does not increase the constellation size and transmits different permutations of the same constellation from different antennas. The permutations can be designed either algebraically or numerically and the receiver thus sees a distorted constellation that depends on the channel realization. In addition to being full rate and full diversity (which is impossible for coventional spacetime codes except in special cases) these schemes are potentially very simple to implement.