Frequency Impact on the Indoor MIMO Channel Capacity between 2 and 12 GHz

The spectral efficiency of MIMO (multiple input multiple output) channels is limited by both the spatial correlation and rank deficiency of the channel. Precedent studies have focused less attention in how the frequency band affects these channel properties. In this paper, the results derived from an extensive measurement campaign performed between 2 and 12 GHz in an office scenario, show frequency band dependence on the MIMO channel capacity. Increasing the number of antenna elements under these correlated channels for different frequencies, we found frequency band dependence on both the ergodic and the 10% outage capacities. Taking into account the isolation of the path loss, a high SNR regime, equal electric separation between array elements, and the WSS (wide sense stationary) channel condition, remarkable changes on the magnitude spatial correlation coefficients and on the MIMO system eigenvalues were observed for different frequencies in line-of-sight (LOS) and non-line-of-sight (NLOS).