Capacity of different MIMO systems based on indoor measurements at 5.2 GHz

We compared the average capacities of measured 8 × 8, 4 × 4 and 2 × 2 systems with fixed array size in an indoor office scenario at different receive positions. As expected, correlation either at the transmit or receive side is limiting the MIMO capacity. While the 2 × 2 system reaches mostly the capacity of an i.i.d. Rayleigh fading channel, the 4 × 4 and particularly the 8 × 8 system does not. When we tried to fit the capacity of the measured MIMO channel, based on the estimated receiver and transmitter correlation matrices, to a popular stochastic MIMO correlation model, considerable discrepancy arose.