A novel Code-Matched interleaver is proposed which decreases the number of the low weight codewords to improve the performance of the Turbo code. The modified design can adapt more kinds of Turbo codes determined by t...A novel Code-Matched interleaver is proposed which decreases the number of the low weight codewords to improve the performance of the Turbo code. The modified design can adapt more kinds of Turbo codes determined by the generator matrix, while it doesn＇t decrease the bit error rate performance of Turbo codes at moderate to high signal to noise ratio. At the same time, in Rayleigh fading channel, the new Code-Matched interleaver can also debase the error floor.展开更多
Let G_(n)([-1]^(i))denote the set of all connected graphs on n vertices having distance eigenvalue-1 of multiplicity i.By using the distribution of the third largest distance eigenvalue and the second least distance e...Let G_(n)([-1]^(i))denote the set of all connected graphs on n vertices having distance eigenvalue-1 of multiplicity i.By using the distribution of the third largest distance eigenvalue and the second least distance eigenvalue of a connected graph,in this paper we completely characterize the graphs in G_(n)([-1]^(i)),where i=n-1,n-2,n-3 or n-4.展开更多
As is known, distributed Turbo coding （DTC） performs close to the theoretic outage probability bound of a relay channel when correct decoding is assumed at the relay. However, decoding error is inevitable in practic...As is known, distributed Turbo coding （DTC） performs close to the theoretic outage probability bound of a relay channel when correct decoding is assumed at the relay. However, decoding error is inevitable in practical fading channels due to the error-prone feature of radio channels, and the decoding error propagation in DTC scheme will severely degrade the error performance of the relay system. As a result, it is necessary to evaluate the error performance of the DTC scheme in multi-hop relaying wireless systems in practical fading channels. Moreover, the theoretical method of analysis provides an effective tool for obtaining the error performance besides lengthy simulations. In this article, the concept of equivalent signal-to-noise ratio （SNR） of the two-hop relay channel and the method of computing equivalent SNR are developed, and then the upper bound on the bit error probability （BEP） of DTC relay systems is analyzed by use of Turbo code＇s distance spectrum, the concept of uniform interleaver, the limit-before-averaging technique, and the union bound method. Both theoretical analysis and numerical simulation are implemented for relay systems with DTC scheme over quasi-static Rayleigh fading channels. The results show that the upper bound approaches the simulation results in the medium to high SNR region.展开更多
文摘A novel Code-Matched interleaver is proposed which decreases the number of the low weight codewords to improve the performance of the Turbo code. The modified design can adapt more kinds of Turbo codes determined by the generator matrix, while it doesn＇t decrease the bit error rate performance of Turbo codes at moderate to high signal to noise ratio. At the same time, in Rayleigh fading channel, the new Code-Matched interleaver can also debase the error floor.
基金This work is supported by the National Natural Science Foundation of China(12061074).
文摘Let G_(n)([-1]^(i))denote the set of all connected graphs on n vertices having distance eigenvalue-1 of multiplicity i.By using the distribution of the third largest distance eigenvalue and the second least distance eigenvalue of a connected graph,in this paper we completely characterize the graphs in G_(n)([-1]^(i)),where i=n-1,n-2,n-3 or n-4.
基金supported by the National Key Technology R&D Program of China (2009ZX03005-003-00)the National Science Foundation of China (60802082)Fundamental Research Funds for Central Universities (2009RC0102)
文摘As is known, distributed Turbo coding （DTC） performs close to the theoretic outage probability bound of a relay channel when correct decoding is assumed at the relay. However, decoding error is inevitable in practical fading channels due to the error-prone feature of radio channels, and the decoding error propagation in DTC scheme will severely degrade the error performance of the relay system. As a result, it is necessary to evaluate the error performance of the DTC scheme in multi-hop relaying wireless systems in practical fading channels. Moreover, the theoretical method of analysis provides an effective tool for obtaining the error performance besides lengthy simulations. In this article, the concept of equivalent signal-to-noise ratio （SNR） of the two-hop relay channel and the method of computing equivalent SNR are developed, and then the upper bound on the bit error probability （BEP） of DTC relay systems is analyzed by use of Turbo code＇s distance spectrum, the concept of uniform interleaver, the limit-before-averaging technique, and the union bound method. Both theoretical analysis and numerical simulation are implemented for relay systems with DTC scheme over quasi-static Rayleigh fading channels. The results show that the upper bound approaches the simulation results in the medium to high SNR region.
