High-Resolution Low-Complexity Cognitive-Radio-Based Multiband Range Estimation: Concatenated Spectrum vs. Fusion-Based

This paper, incorporating the principles of cognitive radios and utilizing the available bandwidth, proposes an active range estimation method with the properties of high precision and low complexity in wireless environments. Here, the cognitive radio concatenates the available narrow-band white spaces to increase the precision of a range estimation system. Two scenarios are investigated. First, signals are transmitted over an available spectrum either simultaneously (parallel concatenation) or sequentially (serial concatenation). Low complexity radio designs that handle the concatenation process sequentially and in parallel are introduced. To improve the range estimation performance, two new high-resolution time-of-arrival (TOA) estimation algorithms that are applicable to multiband scenarios are investigated. The first algorithm estimates the TOA over each subband and then optimally fuses the estimated TOAs. In the second technique, channels estimated over subbands are concatenated and a TOA estimation method is applied to the whole available spectrum. The TOA estimation error Cramer-Rao bounds of both approaches are computed. The performances of the proposed algorithm are investigated via simulations. The complexities of the introduced techniques are compared.