Non-line-of-sight identification via space-frequency correlation in MIMO-OFDM systems: A preliminary study

This paper presents a preliminary study on a non-line-of-sight (NLOS) identification technique that exploits space-frequency correlation features of multiple-output 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, a measure, subcarrier correlation difference (SCD), is introduced and used to identify NLOS conditions. SCD is defined as the difference of cross-antenna subcarrier correlation and single antenna subcarrier correlation. The impact of the fading channel K-factor, spatial subchannel correlation and channel estimation error on the proposed techniques is investigated.