Copyright © 2008 Perttu Salmela et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In the advent of very high data rates of the upcoming 3G long-term evolution telecommunication systems, there is a crucial need for efficient and flexible turbo decoder implementations. In this study, a max-log-MAP turbo decoder is implemented as an application-specific instruction-set processor. The processor is accompanied with accelerating computing units, which can be controlled in detail. With a novel memory interface, the dual-port memory for extrinsic information is avoided. As a result, processing one trellis stage with max-log-MAP algorithm takes only 1.02 clock cycles on average, which is comparable to pure hardware decoders. With six turbo iterations and 277 MHz clock frequency 22.7 Mbps, decoding speed is achieved on 130 nm technology.