Bandwidth Efficiency of Practical MIMO-OFDM Systems with Adaptive MIMO Schemes

This paper considers the practical multiple-input multiple-output systems with orthogonal frequency division multiplexing (MIMO-OFDM) and bit-interleaved coded modulation (BICM) in spatially correlated broadband channels. Using link adaption techniques, the MIMO scheme that better exploits the space and frequency characteristics of the encountered channel condition is selected. It is shown that the bandwidth efficiency is increased compared to systems with fixed MIMO schemes in all propagation scenarios, while maintaining a predefined link quality. Furthermore, the adaptive transmission in channels with low spatial correlation can attain the complete multiplexing gain, whereas the finite set of modulation and coding schemes restricts the multiplexing gain that can be extracted when the spatial correlation is large.