4G systems are expected to support data rates of the order of 100 Mbps in the outdoor environment and 1 Gbps in the indoor/stationary environment. In order to support such large payloads, the radio physical layer must employ receiver algorithms that provide a significant increase in spectrum efficiency (and hence capacity) over current wireless systems. Recently an explosion of MIMO studies have appeared with many journals presenting special issues on this subject. This has occured dur to the potential of MIMO to provide a linear increase in capacity with antenna numbers. Environmental conciderations and tower loads will often restrict the placing of large antenna spans on base stations. Similarly, customer device form factors also place a limit on the antenna numbers that can be placed with a mutual spacing of 0.5 wavelength. The use of crosspolarized antennas is widely used in modern cellular installtions as it reduces spacing needs and tower loads on base stations. Hence, this appr...
Mansoor Shafi, Min Zhang, Aris L. Moustakas, Peter