  This paper considers cooperative spectrum sensing in Cognitive Radios. In our
previous work we have developed DualSPRT, a distributed algorithm for
cooperative spectrum sensing using Sequential Probability Ratio Test (SPRT) at
the Cognitive Radios as well as at the fusion center. This algorithm works
well, but is not optimal. In this paper we propose an improved algorithm-
SPRT-CSPRT, which is motivated from Cumulative Sum Procedures (CUSUM). We
analyse it theoretically. We also modify this algorithm to handle uncertainties
in SNR's and fading.
