Simple Calculation of Thresholds for Adaptive Modulation in Middleton Class A Noise

Abstract

This paper proposes a simple method of calculating the signal to noise ratio (SNR) thresholds for an adaptive modulation in Middleton class A noise for a given target symbol error rate (SER). Adaptive modulation is commonly used for increasing spectral efficiency by adaptively switching the modulation order of the transmission along with the channel quality variation. A communication system in military is susceptible to impairment by impulsive noise that degrades performance of the communication system, and there are a large mount of needs for adaptive modulation in the environment. But there are little outcomes about the SNR thresholds for adaptive modulation used in impulsive noise due to the complicated SER equation expressed with infinite terms. Therefore, this paper proposes a simple method of calculating the SNR thresholds for adaptive modulation in impulsive noise environment. To derive the SNR thresholds, we analyse the performance of the various modulations in impulsive noise to further reach an approximation, and then the difference between the exact analysis and the approximation is investigated. Simulation results illustrate that the proposed SNR thresholds allow adaptive modulation to perform well in impulsive noise environment with various impulsiveness parameters.