Comparison of beam selection and antenna selection techniques in indoor MIMO systems at 5.8 GHz

The comparison of beam selection and antenna selection techniques in conjunction with the multiple-input-multiple-output (MIMO) architecture is provided for measured channels. The channels, captured on a 3D MIMO measurement system based on the virtual antenna array technology, are centered at 5.8 GHz with a frequency span of 500 MHz. Both flat- and frequency-selective fading are considered. The selection techniques can be applied to either the transmit end or both ends of the communication links, and both cases are considered. Shannon capacity is employed as the comparison criterion throughout the paper. The presence of the line-of-sight (LOS), and the correlation of interference are shown to impact the performances of both kinds of selection techniques. The use of beams does not eliminate the need for stream control, which is the regulation of the number of data streams when MIMO links interfere. The results show that in the indoor environment, the beam selection is only slightly better than the antenna selection in both narrowband and wideband channels when stream control is used. However, without stream control, beam selection offers a significant improvement over antenna selection.