Location fingerprinting has received considerable attention as a practical solution to the indoor localization problem. Specifically Received Signal Strength (RSS) based fingerprinting has been studied extensively and some improvements in performance have been reported for certain pattern recognition algorithms. Recently channel impulse response (CIR) based fingerprinting received attention due to its potential for significant improvements in accuracy. The performance evaluation of CIR fingerprinting, however, has not been addressed adequately in literature. This paper presents the performance evaluation of CIR location fingerprinting in an indoor environment. A simulation framework has been developed using the Ray-Tracing software to emulate the indoor wireless channel. The CIR-based simulation results showed noticeable improvements in the location estimation compared to the RSSbased approach. The paper highlights new findings for some parameters that affect the performance of the CIR-based fingerprinting with respect to the system bandwidth and training point spacing.

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Channel‐based radio‐frequency fingerprinting such as a channel impulse response (CIR), channel transfer function (CTF), and frequency coherence function (FCF) have been recently proposed to improve the accuracy at the physical layer; however, their empirical performance, advantages, and limitations have not been well reported. This paper provides a comprehensive empirical performance evaluation of RF location fingerprinting, focusing on a comparison of received‐signal strength, CIR‐, CTF‐, and FCF‐based fingerprinting using the weighted k‐nearest neighbor pattern recognition technique. Frequency domain channel measurements in the IEEE 802.11 band taken on a university campus were used to evaluate the accuracy of the fingerprinting types and their robustness to human‐induced motion perturbations of the channel. The localization performance was analyzed, and the results are described using the spatial and temporal radio propagation characteristics. In particular, we introduce the coherence region to explain the spatial properties and investigate the impact of the Doppler spread in time‐varying channels on the time coherence of RF fingerprint structures.