Adaptive Equalization in a Turbo Loop

Turbo equalization has been an important topic in wireless communication for some time. Various approaches to incorporating the a priori information from the decoder into the equalization process have been developed. In this paper, we present and investigate an algorithm for adaptive equalization in a turbo loop. The algorithm exploits the soft information from the decoder directly in the adaptation process, while keeping the complexity of the resulting method on the same order as the original adaptive algorithm. The performance of the proposed turbo equalizer is compared with that of existing turbo methods to demonstrate its practical value. Real-world underwater communication data from the KAM11 experiment are used to characterize the performance.