Efficient pilot carrier acquisition and tracking in detect and avoid signal processing

For the detect and avoid operation in cognitive radio systems, there is often a requirement to rapidly acquire a pilot carrier in a large frequency uncertainty band. This paper presents a method for rapid pilot carrier acquisition with extremely low computational complexity. A low latency, iterative frequency estimation algorithm is introduced, which accurately determines the pilot carrier frequency and initializes a phase locked loop center frequency. The phase locked loop, with essentially no initial frequency error, is then able to rapidly acquire the pilot signal. Because a narrow band phase locked loop can be used, extremely good phase error tracking performance is achievable with small acquisition time.