Ranging in multi-band communication systems

We present a new scheme to refine the range and time resolution of multi-band communication systems. The resolution of range or delay estimation in any communication system is inversely proportional to the bandwidth of the transmitted signal. In a multi-band system where only a portion of the total bandwidth is available to any transmission, the resolution appears to be proportional to the inverse of the bandwidth of a sub-band. In this paper we describe a scheme that coherently processes received signals from different sub-bands to achieve a resolution proportional to the inverse of the total system bandwidth. We show that in the high signal to noise ratio regime this scheme outperforms conventional schemes, such as averaging the estimates from different sub-bands to reduce the effect of noise. In particular, we show that the resolution we achieve is inversely proportional to the number of sub-bands while that of traditional schemes is inversely proportional to the square root of the number of sub-bands. We provide simulation results to show the performance of the scheme in additive white Gaussian noise. We also study the effect of oscillator phase mismatches that occur when switching from one sub-band to another.