Object-Oriented Implementation of LTE Turbo Codes

Object-Oriented Implementation of LTE Turbo Codes by Anusha Gangadi Master of Science in Electrical Engineering West Virginia University Matthew C. Valenti, Ph.D., Chair Turbo codes are a popular form of error correction codes as they perform close to the Shannon limit. Turbo codes have interesting features like parallel code concatenation, nonuniform interleaving, and an iterative decoding algorithm. Because of these features, turbo codes are adopted by various standards like NASA’s for deep space communications, third generation cellular standards like UMTS and cdma2000, and the latest mobile network technology called 3GPP LTE (Long Term Evolution). The main objective of this problem report is to study the implementation and behavior of the LTE turbo codes. An object-oriented approach is considered for the implementation of the turbo codes. To achieve the objectives of this report, a previously developed library called the Coded Modulation Library (CML), which was developed at West Virginia University’s Wireless Communications Research Laboratory (WCRL), is extended to support the turbo codes specified in the LTE standard in an object-oriented fashion. This report begins with a brief overview of communication and coding theory, and discusses the use of object-oriented programming for simulating communication systems. Next, a clear study of convolutional and turbo codes is presented, including a discussion of the encoding and decoding of the codes. An object-oriented Matlab implementation of LTE Turbo codes is also discussed in detail. Simulation results are obtained using the LTE turbo code class developed in this report along with a class from Matlab’s Communication Toolbox called the Error Rate Test Console. Results are shown that illustrate the influence of key parameters such as codeword length and the choice of decoding algorithm.