Measurement and characterization of the time variation of indoor and outdoor MIMO channels at 2.4 and 5.2 GHz

The extent of time variation of measured multiple-input multiple-output (MIMO) wireless channels is explored. A prototype MIMO channel sounder developed at Brigham Young University, capable of probing 8x8 MIMO channels from 28 GHz with up to 100 MHz of instantaneous bandwidth, is used to measure representative indoor and outdoor scenarios at 2.4 and 5.2 GHz. New metrics are proposed to quantify the time variation observed in the channel measurements: eigenvalue level crossing rate, eigenvalue fade duration, rate of eigenvector angular deviation, and temporal capacity degradation. Two different models are used to fit the measurements: (1) a simple random matrix model and (2) a physical time-varying cluster model. The performance of these models is assessed in terms of their ability to reproduce the measured time-variation metrics.