An Opportunistic System to Counteract Fading and Gaussian Interference Effects Under Different Modulation Schemes

In this paper we propose an opportunistic transmission in which the fading characteristics and interference are considered. The opportunism is considered in the sense that transmissions are made just when the fading amplitude is above a threshold value. For this opportunistic system, it is considered that the estimated fading is sent through a feedback link using channel state information (CSI). Thereby, the receiver indicates to the transmitter when it should transmit. To analyze the performance of the opportunistic system, we consider the presence of additive white Gaussian noise, flat and slow Rayleigh fading and co-channel interference. The performance analysis is based on the mean bit error rate as a function of the signal-to-noise ratio for different modulation schemes. For this, analytical expressions are established. The accuracy of these expressions is verified by Monte-Carlo simulations. Moreover, a comparison between the opportunistic system and an ordinary system is made in terms of the mean bit error rate.