Research And Implementation On Turbo Code Of LTE Systems

To cope with the increasing demand for multimedia services, Long Term Evolution Systems(LTE) has been introduced and developed for the 3GPP in recent years.Turbo code is one of the key technologies of physical layer design for B3G/LTE system.It is particularly noticeable for its high error-correcting capabilities in high-noise application environments, especially for high data rate (HDR)/broadband transmission systems such as LTE. The adoption of 1/3-rate Turbo code as the mother code and the inner conflict-free internal interleaver not only enhances the LTE system's anti-jamming capability, but also reduces the complexity of its practical application.This paper first discusses the basic theory of channel coding, including the concepts and the characteristics of block codes and convolutional codes, and then studies the Turbo code encoding/decoding techniques as well as the principle of the inner interleaver.The paper details several improvements made to the existing LTE system Turbo codes, which include the use of inner conflict-free interleaver, and sectional decoding techniques for large code blocks.Other improvements include Turbo code rate matching and HARQ techniques. The modified Turbo codes were run in the LTE system simulated by MATLAB under different environments, such as with/without the presence of Turbo codes, under different decoding algorithms etc. Simulation data was analysed and presented in the later part.The results show that the performance of LTE system will be greatly improved by virtue of Turbo codes.Last but not least, the paper introduces the development tool - pico-chip, including its development process and its program language. Based on the DSP chip of the LTE system, the author develops several efficient Turbo code techniques, such as HARQ, Turbo code encoding/decoding rate matching etc. Following that, the paper also discusses the design of these three modules. The authtor tested the hardware implementation against the MATLAB simulations in order to verify the functional correctness of such techniques. Finally, the pico-chip of the Turbo decoding accelerator is tested to optimise system parameters to achieve the best performance of the LTE system.