It is well known that interleavers play a critical role in Turbo coding/decoding schemes, and contention-free inter-leaver design has become a serious problem in the parallelization of Turbo decoding, which is indispe...It is well known that interleavers play a critical role in Turbo coding/decoding schemes, and contention-free inter-leaver design has become a serious problem in the parallelization of Turbo decoding, which is indispensable to meet the demands for high throughput and low latency in next generation mobile communication systems. This paper unveils the fact that inter-leavers based on permutation polynomials modulo N are contention-free for every window size W, a factor of the interleaver length N, which, also called maximum contention-free interleavers.展开更多
This paper describes a new interleaver construction technique for turbo code. The technique searches as much as possible pseudo\|random interleaving patterns under a certain condition using genetic algorithms(GAs). Th...This paper describes a new interleaver construction technique for turbo code. The technique searches as much as possible pseudo\|random interleaving patterns under a certain condition using genetic algorithms(GAs). The new interleavers have the superiority of the S\|random interleavers and this interleaver construction technique can reduce the time taken to generate pseudo\|random interleaving patterns under a certain condition. The results obtained indicate that the new interleavers yield an equal to or better performance than the S-random interleavers. Compared to the S-random interleaver, this design requires a lower level of computational complexity.展开更多
In the investigation of turbo codes, either random interleavers or structured interleavers are used. Combined two kinds of interleavers in one turbo encoder, a hybrid interleaving mode is proposed in this paper. Compu...In the investigation of turbo codes, either random interleavers or structured interleavers are used. Combined two kinds of interleavers in one turbo encoder, a hybrid interleaving mode is proposed in this paper. Computer simulations show that the performance of turbo codes with the hybrid interleaving mode is better than that with the typical interleaving mode.展开更多
A new method to design interleaver based on Henon chaos model is presented. The designed interleaver is with rather random behavior. Experimental results show that the proposed S-henon interleaver make a magnitude of ...A new method to design interleaver based on Henon chaos model is presented. The designed interleaver is with rather random behavior. Experimental results show that the proposed S-henon interleaver make a magnitude of improvement in bit error rate (BER) performance by 0.4 dB compared with the S-random interleaver for AWGN channel respectively. The S-henon interleaver may be adapted to 3G mobile communication systems.展开更多
Coding techniques have always been a major area of scientific interest. Due to this interest, many coding schemes were invented. Eventually, their implementation in various systems contributed in the evolvement of Wir...Coding techniques have always been a major area of scientific interest. Due to this interest, many coding schemes were invented. Eventually, their implementation in various systems contributed in the evolvement of Wireless Communications. A breakthrough was definitely Turbo coding. Particularly, the concept of joining two or more convolutional encoders in parallel (PCCC) or in serial (SCCC), along with the iterative decoding technique, literally raised the expectations of the anticipated BER performance. In fact, Concatenated Convolutional Codes clearly outperform convolutional codes. Moreover, various systems, either under development or either for future use, will have high standards. The previous systems should present exceptional tolerance of noise effects and consequently a low overall number of received errors. For this purpose a new PCCC design was developed. The system’s performance analysis, using an AWGN channel, showed better results for various iterations compared to other schemes such as typical PCCC, SCCC and finally a Convolutional encoder with a Viterbi decoder.展开更多
In this paper,we study turbo codes from the digital signal processing point of view by defining turbo codes over the complex field.It is known that iterative decoding and interleaving between concatenated parallel cod...In this paper,we study turbo codes from the digital signal processing point of view by defining turbo codes over the complex field.It is known that iterative decoding and interleaving between concatenated parallel codes are two key elements that make turbo codes perform significantly better than the conventional error control codes.This is analytically illustrated in this paper.We show that the decoded noise mean power in the iterative decoding decreases when the number of iterations increases,as long as the interleaving decorrelates the noise after each iterative decoding step.An analytic decreasing rate and the limit of the decoded noise mean power are given.The limit of the decoded noise mean power of the iterative decoding of a turbo code with two parallel codes with their rates less than 1/2 is one third of the noise power before the decoding,which can not be achieved by any non-turbo codes with the same rate.From this study,the role of designing a good interleaver can also be clearly seen.展开更多
Based on the analysis of codeword Hamming distances, two parameters, i.e. self-interleaving distance and cross-interleaving distance, are proposed herein. To make these two distances as large as possible, a method to ...Based on the analysis of codeword Hamming distances, two parameters, i.e. self-interleaving distance and cross-interleaving distance, are proposed herein. To make these two distances as large as possible, a method to evaluate the efficiency of an interleaver produced and a new type of structured interleaver is proposed. Simulations show that turbo codes with the new type of structured interleaver can obtain a better performance compared with a random interleaver or a block interleaver.展开更多
Previously, the interleavers is generated randomly for users of Interleave Division Multiple Access (IDMA) systems. Therefore, transmitting the entire chip-level interleaver matrix or power interleaver generation is r...Previously, the interleavers is generated randomly for users of Interleave Division Multiple Access (IDMA) systems. Therefore, transmitting the entire chip-level interleaver matrix or power interleaver generation is required, which either adds redundancy or increases delay. In this paper, we propose to use deterministic chip-level interleavers for multiple users of IDMA systems. These chip-level interleavers are modified from single-user symbol-level interleavers for turbo codes. The receiver can generate the chip-level interleavers for user k automatically without the redundancy of transmitting the entire interleaver matrix or the delay of generating power interleavers. Simulation results show that the proposed deterministic–interleaver-based IDMA performance is better than Gold-code-based CDMA in the multipath environment.展开更多
基金Project (No. 60332030) supported by the National Natural ScienceFoundation of China
文摘It is well known that interleavers play a critical role in Turbo coding/decoding schemes, and contention-free inter-leaver design has become a serious problem in the parallelization of Turbo decoding, which is indispensable to meet the demands for high throughput and low latency in next generation mobile communication systems. This paper unveils the fact that inter-leavers based on permutation polynomials modulo N are contention-free for every window size W, a factor of the interleaver length N, which, also called maximum contention-free interleavers.
文摘This paper describes a new interleaver construction technique for turbo code. The technique searches as much as possible pseudo\|random interleaving patterns under a certain condition using genetic algorithms(GAs). The new interleavers have the superiority of the S\|random interleavers and this interleaver construction technique can reduce the time taken to generate pseudo\|random interleaving patterns under a certain condition. The results obtained indicate that the new interleavers yield an equal to or better performance than the S-random interleavers. Compared to the S-random interleaver, this design requires a lower level of computational complexity.
文摘In the investigation of turbo codes, either random interleavers or structured interleavers are used. Combined two kinds of interleavers in one turbo encoder, a hybrid interleaving mode is proposed in this paper. Computer simulations show that the performance of turbo codes with the hybrid interleaving mode is better than that with the typical interleaving mode.
基金Supported by the National High Technology Re-search and Development Program of China(2001AA123053)
文摘A new method to design interleaver based on Henon chaos model is presented. The designed interleaver is with rather random behavior. Experimental results show that the proposed S-henon interleaver make a magnitude of improvement in bit error rate (BER) performance by 0.4 dB compared with the S-random interleaver for AWGN channel respectively. The S-henon interleaver may be adapted to 3G mobile communication systems.
文摘Coding techniques have always been a major area of scientific interest. Due to this interest, many coding schemes were invented. Eventually, their implementation in various systems contributed in the evolvement of Wireless Communications. A breakthrough was definitely Turbo coding. Particularly, the concept of joining two or more convolutional encoders in parallel (PCCC) or in serial (SCCC), along with the iterative decoding technique, literally raised the expectations of the anticipated BER performance. In fact, Concatenated Convolutional Codes clearly outperform convolutional codes. Moreover, various systems, either under development or either for future use, will have high standards. The previous systems should present exceptional tolerance of noise effects and consequently a low overall number of received errors. For this purpose a new PCCC design was developed. The system’s performance analysis, using an AWGN channel, showed better results for various iterations compared to other schemes such as typical PCCC, SCCC and finally a Convolutional encoder with a Viterbi decoder.
文摘In this paper,we study turbo codes from the digital signal processing point of view by defining turbo codes over the complex field.It is known that iterative decoding and interleaving between concatenated parallel codes are two key elements that make turbo codes perform significantly better than the conventional error control codes.This is analytically illustrated in this paper.We show that the decoded noise mean power in the iterative decoding decreases when the number of iterations increases,as long as the interleaving decorrelates the noise after each iterative decoding step.An analytic decreasing rate and the limit of the decoded noise mean power are given.The limit of the decoded noise mean power of the iterative decoding of a turbo code with two parallel codes with their rates less than 1/2 is one third of the noise power before the decoding,which can not be achieved by any non-turbo codes with the same rate.From this study,the role of designing a good interleaver can also be clearly seen.
文摘Based on the analysis of codeword Hamming distances, two parameters, i.e. self-interleaving distance and cross-interleaving distance, are proposed herein. To make these two distances as large as possible, a method to evaluate the efficiency of an interleaver produced and a new type of structured interleaver is proposed. Simulations show that turbo codes with the new type of structured interleaver can obtain a better performance compared with a random interleaver or a block interleaver.
文摘Previously, the interleavers is generated randomly for users of Interleave Division Multiple Access (IDMA) systems. Therefore, transmitting the entire chip-level interleaver matrix or power interleaver generation is required, which either adds redundancy or increases delay. In this paper, we propose to use deterministic chip-level interleavers for multiple users of IDMA systems. These chip-level interleavers are modified from single-user symbol-level interleavers for turbo codes. The receiver can generate the chip-level interleavers for user k automatically without the redundancy of transmitting the entire interleaver matrix or the delay of generating power interleavers. Simulation results show that the proposed deterministic–interleaver-based IDMA performance is better than Gold-code-based CDMA in the multipath environment.
