NLOS Channel Identification and Mitigation in UltraWideband ToA-Based Wireless Sensor Networks

Recently, Ultra Wideband (UWB) Time of Arrival (ToA)-based localization in Wireless Sensor Networks (WSNs) have received considerable attention. For a typical WSN operating in indoor environments, the localization performance can be degraded considerably due to the existence of Non-Line-of-Sight (NLOS) channel conditions between the sensor nodes. In these channel conditions the ranging accuracy is degraded due to the attenuation and/or loss of the Direct Path (DP) signal which ultimately imposes a positive bias on the ToA-based distance estimation. As a result there is a need for robust algorithms that have the capability to identify and mitigate those NLOS ranging conditions.