Channel capacity of 8×2 MIMO transmission due to antenna configurations in an actual cellular environment measurement

This paper investigated the channel capacity of a 9×2 MIMO channel in an actual cellular environment when the antenna polarization is set to vertical, vertical and horizontal, and slanted 45 degrees at both the base and the terminal stations. We first evaluated the spatial correlation characteristics. If the number of antennas is less than four when employing only vertical polarization, the spatial correlation becomes greater than 0.9. On the other hand, the antenna configuration employing orthogonal polarization reduced the spatial correlation value to less than 0.8 even if a 2×2 MIMO channel is used. We next evaluated the channel capacity due to the difference in the antenna configuration. The antenna configuration with the 45 degree slanted polarization obtains the highest channel capacity when the number of the array antennas is less than four at the SNR from 10 to 40 dB in an actual outdoor environment. Moreover, we confirmed that the most effective antenna configuration changes based on the SNR or the number of antennas at the base station.