Implementation of a Turbo Decoder on a Configurable Computing Platform

(ABSTRACT) Turbo codes are a new class of codes that can achieve exceptional error performance and energy efficiency at low signal-to-noise ratios. Decoding turbo codes is a complicated procedure that often requires custom hardware if it is to be performed at acceptable speeds. Configurable computing machines are able to provide the performance advantages of custom hardware while maintaining the flexibility of general-purpose microprocessors and DSPs. This thesis presents an implementation of a turbo decoder on an FPGA-based configurable computing platform. Portability and flexibility are emphasized in the implementation so that the decoder can be used as part of a configurable software radio. The system presented performs turbo decoding for a variable block size with a variable number of decoding iterations while using only a single FPGA. When six iterations are performed, the decoder operates at an information bit rate greater than 32 kbps. iii Acknowledgements There are several people who deserve recognition for the assistance they provided in the successful completion of my graduate work. First and foremost, I would like to thank my advisor, Dr. Peter Athanas, for his help and guidance in not only this effort, but in all of the projects we have attempted in the three-and-a-half years of our association. His friendly demeanor, keen insight, and amazingly upbeat attitude in the face of adversity continue to inspire his students and colleagues alike. I would also like to thank the other members of my committee, Dr. Mark Jones and Dr. Jeff Reed, for their suggestions and support throughout this effort and for serving on my committee. Special thanks goes out to Dr. Brian Woerner, my committee member-by-proxy, who was more than willing to help out on short notice and also provided many useful suggestions. I am also grateful to my fellow students Yufei Wu and Matt Valenti for their support in helping me understand the theory of turbo codes. I am doubly grateful to Yufei for the invaluable debugging support she provided during the latter days of this project. Wendy Akers and Martha McCollum provided priceless administrative and emotional support throughout my time with the Configurable Computing team, and without their help, this document would still have colons used improperly. My wonderful parents and friends have given me the support I needed to complete what at times seemed to be an insurmountable task. Their simultaneous desires for my success and my sanity gave me much-needed support when …