Suboptimal space-frequency waveform design for MIMO-OFDM systems

In this paper, a new transmit waveform design algorithm for MIMO-OFDM systems is proposed. The algorithm is based on a geometric channel model consisting of different paths, where the geometric channel parameters are assumed to be known. Using the spatial channel information at the transmitter, the frequency selective MIMO channel is transformed into a number of uncoupled flat-fading SISO channels. This suboptimal algorithm significantly simplifies the computational complexity of the optimal joint space-frequency water-filling (JSF-WF) algorithm. The performance of the proposed algorithm is evaluated and compared to the JSF-WF algorithm via simulations in terms of bit-error-rate and bit-rate, and it is shown to be low complex with suboptimal performance.