Performance Evaluation of QAM-Based BICM: An Analytical Approach

We present an analytical approach to determine the performance of bit-interleaved coded modulation (BICM) transmission over unfaded Gaussian channels. In particular, we derive expressions for bit-error rate and cutoff rate assuming general quadrature amplitude modulation (QAM) constellations. Different from previously proposed methods, our analysis is valid for arbitrary labeling rules and results in simple closed-form expressions. The key idea is to utilize a simplification to estimate the probability density function of reliability metrics, which is tight for signal-to-noise ratio regions of interest for BICM systems with moderate coding complexity such as, e.g., convolutional coded BICM systems. The usefulness of the proposed analytical approach is validated through numerical and simulation results for a number of BICM transmission examples.