Lower Bound on Averages of the Product of L Gaussian Q-Functions over Nakagami-m Fading

This paper is concerned with performance analysis (in terms of bounds and approximations to the average symbol error probability (ASEP)) of a product and power of Gaussian Q-functions over Nakagami-m fading. The results are valid for arbitrary product/power order. This is done by first deriving a family of new, simple lower bounds on the Gaussian Q-function, which is obtained as a sum of products of an exponential function and cx where c is a constant. These lower bounds can be made arbitrarily tight as the number of summation terms increases, and thus, can be used to approximate the Gaussian Q-function accurately. Their applications to the evaluation of the ASEP are then presented. Some advantages of the results derived here over those given in the literature are briefly discussed.