Minimising Complexity in Iterative Multiuser Detection Using Dynamic Decoding Schedules

Abstract

In this paper we utilize extrinsic information transfer (EXIT) chart analysis with unequal user power levels in a coded direct-sequence code-division multiple-access (DS-CDMA) multiuser receiver to derive a dynamic decoding schedule. Conventional receivers generally follow a static predetermined decoding schedule. However, decoding delay and complexity can be significantly reduced while maintaining BER performance through a dynamic decoding schedule optimized for a given load and transmit power configuration. Verified through simulations, we show that complexity savings of up to 50% can be achieved. We also derive the effective EXIT charts which can be used for the convergence analysis and performance predictions of unequal power CDMA systems.