Comparison of layered and diversity approaches for increasing WCDMA data rates in frequency-selective MIMO channels

Multiple-input multiple-output (MIMO) channels have been shown to offer significant increase in system capacity (bit/s/Hz) when compared to conventional single-input single-output (SISO) systems. The current trend in the 3rd generation WCDMA system evolution is towards higher user data rates which can be achieved using MIMO techniques. So-called layered techniques increase the user data rate but they suffer from high receiver complexity. We propose a low-complexity diversity MIMO scheme which achieves a higher data rate by heavily puncturing the channel code. The proposed diversity scheme is compared to two different layered MIMO schemes in frequency-selective Rayleigh fading channels. The user data rate can be at least doubled by using (2, 2) MIMO techniques while less transmission power is required when compared to a conventional SISO system offering only single data rate.