Enhanced energy detection receiver for OOK signals using Gaussian approximation

Equal-gain combining (EGC) is a conventional linear combining scheme used in non-coherent energy detection receiver for ultra-wideband (UWB) signals. However, due to the nonlinear nature of decision boundary, the EGC results in a suboptimal test statistic. In this paper, we propose a new design for a nonlinear combining energy detector based on Gaussian approximation, in which the energy detection problem becomes a general Gaussian signal detection problem with unequal-mean and unequal-variance. Numerical results indicate that the proposed detector exhibits better performance than the conventional energy detector. Introduction Impulse radio (IR) UWB has been considered as a promising solution for supporting low-cost and low-data-rate wireless communication. The energy detection receivers are favored for their simple implementation and good performance-complexity tradeoffs for UWB systems. The conventional energy detection receiver is known as the EGC (square-law combining) receiver, which recovers the transmitted symbol by comparing the combined output to a decision threshold [1,2]. However, it was shown in [3] that EGC for conventional energy detector is not optimal unless the signal-to-noise ratio (SNR) is infinitesimally small. Since the decision boundary is nonlinear [3], the implementation of optimal energy detector involves nonlinear functional operation, which not only complicates the detector structure, but also makes the exact evaluation of the average BER difficult to obtain analytically. In this letter, we propose a new design for a suboptimal energy detector based on Gaussian approximation. The goal of the suboptimal detector design is to reduce the complexity while preserving the performance very close to the optimal detector. Numerical results using the IEEE 802.15.4a channel models show that the proposed detector can effectively improve bit error rate (BER) performance without significantly increase of the system complexity, as compared to the conventional energy detector. System model Let the received UWB signal after the Rx antenna can be represented as