Research On Precoded Turbo Coding With Unequal Error Protection Ability

With the rocketing development of communication technology, people are more and more need to rely on it. So it’s the supreme goal of each communication researchers to provide efficient and reliable information transmission with maximum efforts. Information theory and coding technology play a more important role as a branch in the field of communication. Therefore, it is one of the ways to achieve the goal by looking for superior channel coding scheme for scientific researchers. At the end of20th century, Turbo code is putted forward with the glory of superstar. Since it has incomparable advantage in the high speed data transmission compared with traditional channel coding. It becomes one channel coding standard of the third generation mobile communication.In real communication, different information always has different importance. So it becomes an excellent choice that designing unequal error protection (UEP) scheme based on Turbo code with high performance. Also, the precoding technique can improve the performance of Turbo code effectively. Therefore, in order to achieve more efficient and more reliable delivery of information, this paper proposes a new precoded Turbo coding scheme with unequal error protection ability by the combination between unequal error protection technique and precoding thought.In this paper, a reasonable precoded Turbo coding scheme is designed according to different level of importance of information. And it also studies a new soft-in and soft-out(SISO) iterative decoding algorithm on the new coding scheme. The different schemes with different coding rate and different importance classification are simulated, and compare with the classical Turbo code in performance. In addition to this, this paper also analyses the iterative decoding process of the precoded Turbo coding scheme by the extrinsic information transfer (EXIT) chart. In the paper, the main content is divided into five parts:1. The development and current situations of the channel coding are described, and the research backgrounds of Turbo code, UEP technique and precoding thought are respectively introduced. 2. The structure and principles of Turbo coding and decoding are elaborated. The decoding algorithm are derived in detail. And the influences of different coding parameters on Turbo code’s performance are studied.3. A new precoded Turbo coding scheme with unequal error protection ability is designed and the structures of coding, decoding and the new SISO decoding algorithm are described. Different new schemes are carried on the simulation and performance analysis.4. The extrinsic information transfer properties of the iterative decoding on the component codes are analyzed, and the EXIT chart is introduced. Then the EXIT chart is used to estimate the iterative decoding of the classic Turbo code and precoded Turbo code.5. Summarizes the article and prospects the development of Turbo code.