Analysis of Kurtosis-Based LOS/NLOS Identification Using Indoor MIMO Channel Measurement

The location of a mobile station (MS) can be estimated from distance measures between an MS and several base stations (BSs). However, distance measure accuracy is degraded due to the complicated indoor environment, particularly non line-of-sight (NLOS) propagation. To improve the accuracy of wireless localization, knowledge of whether the BS-MS path is line-of-sight (LOS) or NLOS may be of significant importance. Several papers have proposed the use of kurtosis for NLOS identification in ultrawideband systems. In this paper, we investigate the kurtosis of different channel impulse response (CIR) forms and explore the potential of kurtosis for LOS/NLOS identification with two sets of bandwidth and number of frequency tap configurations in terms of simulations. A statistical analysis of kurtosis is also conducted with an extensive set of multiple-input-multiple-output (MIMO) channel measurement data collected at Aalto University, Finland. Both simulation and measurement results indicate that using decibels of CIR amplitude in kurtosis calculation provides consistent information about the LOS/NLOS condition regardless of system parameters. The results also show that average kurtosis over MIMO channels, when available, gives a better indication of LOS/NLOS conditions.