High performance non-line-of-sight identification using MIMO-OFDM space frequency correlation statistics

This paper proposes a non-line-of-sight (NLOS) identification technique that exploits statistics of space-frequency correlation of multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Here, space correlation refers to the correlation across antenna elements and frequency correlation refers to the correlation across subcarriers. In this technique, the mean value and standard deviation of space-frequency correlation over multiple transmit and receive antenna combinations are used to identify NLOS conditions. The technique requires minimal variation of spatial correlation across different multi-path components. The channel model satisfying this requirement is studied and the performance of the proposed technique is investigated.