On the Convergence of Iterative Receiver Algorithms Utilizing Hard Decisions
The convergence of receivers performing Iterative Hard Decision Interference Cancellation (IHDIC) is analyzed in a general framework for ASK, PSK, and QAM constellations. The authors first give an overview of IHDIC algorithms known from the literature applied to linear modulation and DS-CDMA-based transmission systems and show the relation to Hopfield neural network theory. It is proven analytically that IHDIC with serial update scheme always converges to a stable state in the estimated values in course of iterations and that IHDIC with parallel update scheme converges to cycles of length 2. Additionally, they visualize the convergence behavior with the aid of convergence charts.