A recent result of Zheng and Tse states that over a quasi-static channel, there exists a fundamental tradeoff, referred to as the diversity-multiplexing gain (D-MG) tradeoff, between the spatial multiplexing gain and the diversity gain that can be simultaneously achieved by a space-time (ST) block code. This tradeoff is precisely known in the case of i.i.d. Rayleigh-fading, for T nt + nr - 1 where T is the number of time slots over which coding takes place and nt, nr are the number of transmit and receive antennas respectively. For T < nt + nr - 1, only upper and lower bounds on the D-MG tradeoff are available. In this paper, we present a complete solution to the problem of explicitly constructing D-MG optimal ST codes, i.e., codes that achieve the D-MG tradeoff for any number of receive antennas. We do this by showing that for the square minimum-delay case when T = nt = n, cyclic-division-algebra (CDA) based ST codes having the non-vanishing determinant property are DMG optimal. W...
Petros Elia, K. Raj Kumar, Sameer A. Pawar, P. Vij