Analysis of Energy Detector in Cooperative Relay Networks for Cognitive Radios

In this paper, performance of the energy detector is analyzed in blind cooperative relay networks operating over independent and identically distributed (IID) Rayleigh fading channels. First, utilizing the closed-form expression of the probability density function (PDF) of the dual-hop relay link along with an alternative series form representation of the generalized marcum-Q function, exact average detection probability expression is obtained for the dual-hop blind relay link. After that, a closed-form PDF expression is derived for the total received signal-to-noise ratio (SNR) of the combined received signal, received via the relay path and direct path, at the destination, which is assumed to be equipped with selection combiner (SC) and energy detector. Finally, within the same analytical framework, as established for the analysis of the relay link, an exact average detection probability expression for the cooperative system is derived. Since the obtained expressions are in the form of infinite summation series, therefore, respective series truncation error bounds are also calculated, which can be used to compute the number of terms required to achieve a given figure of accuracy. In the end, analytical expressions are validated with the help of computer simulations. It is expected that these analysis will be helpful in quantifying the future communication networks such as cognitive radio networks.