This paper addresses the application of turbo codes for third-generation wireless services. It describes the specific characteristics of high-rate data applications in third-generation wide-band code-division multiple-access (CDMA) systems that make turbo codes superior to convolutional codes. In particular, it shows the positive effect of fast power control employed in these systems on the rel...

Recently, turbo codes have received great attention due to their outstanding performance. Unfortunately, a high performance is associated with large transmission delays prohibiting an application for speech transmission. Hence, the aim of this paper is the comparison of turbo codes employing short interleavers with convolutional codes in terms of bit error rate performance and computational eff...

nels was computed. Wiberg [3] in his dissertation has W e model the density of extrinsic information in iterative turbo decoders by Gaussian density functions. This model is verified by experimental measurements. We consider evolution of these density functions through the iterative turbo decoder as a nonlinear dynamical system with feedback. Iterative decoding of turbo codes and of serially co...

Turbo code is recommended as a channel coding scheme, which has been shown to be capable of performing close to the Shannon Limit. In this paper, we compare the performance of both convolutional and block turbo codes over AWGN and Rayleigh fading channels. It is observed that the performance of convolutional turbo code is slightly better in the water fall region and the coding gain ranges from ...

Introduction: Recently, there has been a surge of interests in the design of the so called \space{time" codes which take advantage of both the spatial diversity provided by multiple antennas and the temporal diversity available with time{varying fading. The previous proposed space{time codes were mainly based on trellis codes or orthogonal block codes. In those codes, the number of transmitter ...

Space-time block codes provide substantial diversity advantages for multiple transmit antenna systems at a low decoding complexity. In this paper, we concatenate space-time codes with Convolutional Codes (CC), Turbo Convolutional codes (TC), Turbo BCH codes (TBCH), Trellis Coded Modulation (TCM) and Turbo Trellis Coded Modulation (TTCM) schemes for achieving a high coding gain. The associated p...

The selection of the component codes of turbo codes has a major influence on the performance of these codes. In this paper we propose a new type of asymmetric turbo codes for medium length of interleaver, based on the selection algorithm for the generating polynomials matched to a largest spread QPP interleaver. From the performance results one can observe that the new asymmetric turbo codes pe...

Turbo codes are usually constructed using systematic recursive convolutional codes (SRCC’s) as constituent codes. In this paper, we introduce a new class of turbo codes that uses nonsystematic recursive convolutional codes (NSRCC’s) as constituent codes. A systematic constituent code then becomes a particular case of this more general class. The use of this larger class of constituent codes enh...

This thesis studies a new method of combining Turbo Codes with various modulation techniques to take advantage of inherent trade-o s between BER performance, code rate, spectral e ciency and decoder complexity. Our new method, which we call Symbol-Based Turbo Codes, parses the parallel data streams of the Turbo Code encoder into n-bit symbols and maps each symbol to a point in a 2n-ary signal s...