IMPACT OF PARAMETER SELECTION IN SOFT-DECISION FEEDBACK TURBO EQUALIZATION

Abstract

In wireless communication systems, turbo equalization has been used to mitigate the intersymbol interference caused by dispersive channels. Despite its computational complexity, turbo equalization achieves high performance compared to systems that implement the equalization and coding processes separately. The large performance gain achieved through turbo equalization comes from exchanging soft information between the equalizer and decoder in an iterative manner. However, the computational complexity of turbo equalization can be a significant challenge for systems with limited hardware capabilities. This paper examines the performance gain versus computational complexity trade-off for a soft-decision feedback turbo equalizer (SDFTE).We show how to select parameters that achieve a desired performance specification, while minimizing implementation overhead. Sample results are presented from a simulation of a system using a Proakis channel exhibiting severe ISI using QPSK, 8PSK and 16QAM modulation schemes.