Multiband time-of-arrival positioning technique using an ultra-high-frequency bandwidth availability model for cognitive radio

In this study, the authors present a multiband time-of-arrival (TOA) positioning model and validate the performance in a practical dynamic spectrum access scenario according to results obtained from an ultra-high-frequency (UHF) spectrum occupancy measurement campaign. The statistical analysis of the measured data shows a distinguishable difference between the unoccupied and occupied portion of the UHF band. The bandwidth availability for the UHF band is shown to follow a Gaussian distribution according to the measurement results. The positioning model is verified using the non-linear least squares, linear least squares and two-step maximum-likelihood location estimation algorithms. The root-mean-square error (RMSE) performance evaluation of the proposed model revealed the advantage of utilising five discrete bands to perform TOA estimation, especially in poor signal-to-noise ratio (SNR) conditions ranging from – 10 to 0 dB. At a fixed SNR of 0 dB, an average RMSE improvement of 74 and 82% was observed for a double- and triple-band system when compared with a conventional single-band TOA system. This particular positioning technique can enable improved location estimation in a dynamic spectrum access environment.