PERFORMANCE ANALYSIS OF TURBO'CODES WITH APPLICATION IN MOBILE. SYSTEMS

Abstract

The mam concern ofthis thesis has been the study and analysis of Turbo codes as one of the error correcting codes that have been recently introduced. A further step has been taken by proposing a Turbo encoder to replace the existing convolutional encoder in the GPRS system. The code has been adapted to this special application resulting in a significant coding gain as proved by simulations.

Turbo encoders have been presented in Chapter 2 where different parameters that have been reported in the literature are reviewed to get a better understanding ofthe encoder elements. We have explained the recursive nature of the constituent encoder and its importance in the error floor enhancement. Rules for the interleaver design have been given and different interleavers' types were presented. T_he different terminating schemes have also been discussed, as well as the puncturing process. This chapter has gathered the results of different works done during the previous decade. During this overview, we concluded the importance of matched design elements where the components (constituent encoders and interleavers) must match each other, as well as the termination and puncturing schemes used, since any individual design of one element alone will certainly affect the overall performance.