In this paper, we propose a novel idea for improvement performances of the leader M-BCJR algorithm functioning in low complexity. The basic idea consists to localize error instant possibility, and then increase the co...In this paper, we propose a novel idea for improvement performances of the leader M-BCJR algorithm functioning in low complexity. The basic idea consists to localize error instant possibility, and then increase the complexity around this moment. We also propose an easy and important idea for early localisation of erroneous moments. We call this new algorithm Z-MAP. The simulations show that the improvement of performances is significant. The performances of Z-MAP turbo decoding are so close to full MAP-BCJR performances. Furthermore, the complexity is the same that of the M-BCJR. So, Z-MAP is an optimal version of M-BCJR algorithm.展开更多
In this paper, a new method to approximate the compensation term in the Jacobian logarithm used by the MAP decoder is proposed. Using the proposed approximation, the complex functions In（.） and exp（.） in the Exact...In this paper, a new method to approximate the compensation term in the Jacobian logarithm used by the MAP decoder is proposed. Using the proposed approximation, the complex functions In（.） and exp（.） in the Exact-log-MAP algorithm can be estimated with high accuracy and lower computational complexity. The efficacy of the proposed approximation is investigated and demonstrated by applying it to iteratively decoded BICM （Bit Interleaved Coded Modulation）.展开更多
This contribution proposes a new combination symbol mapper/8-ary constellation, which is a joint optimization of an 8-ary signal constellation and its symbol mapping operation, to improve the performance of Bit Interl...This contribution proposes a new combination symbol mapper/8-ary constellation, which is a joint optimization of an 8-ary signal constellation and its symbol mapping operation, to improve the performance of Bit Interleaved Coded Modulation with Iterative Decoding (BICM-ID). The basic idea was to use the so called (1,7) constellation (which is a capacitive efficient constellation) instead of the conventional 8-PSK constellation and to choose the most suitable mapping for it. A comparative study between the combinations most suitable mapping/(1,7) constellation and SSP mapping/conventional 8-PSK constellation has been carried out. Simulation results showed that the 1st combination significantly outperforms the 2nd combination and with only 4 iterations, it gives better performance than the 2nd combination with 8 iterations. A gain of 4 dB is given by iteration 4 of the 1st combination compared to iteration 8 of the 2nd combination at a BER level equal to 10-5, and it (iteration 4 of the 1st combination) can attain a BER equal to 10-7 for, only, a SNR = 5.6 dB.展开更多
首先从理论上分析了硬判决译码算法和软判决译码算法的性能然后对BCH(Bose,Ray-Chaudhuri,Hocquenghem)码的网格结构以及BCJR(Bahl,Cocke,Jelinek and Raviv)算法进行了详细地分析及推导。实验结果表明,在光信道环境中,在误比特率为10-5...首先从理论上分析了硬判决译码算法和软判决译码算法的性能然后对BCH(Bose,Ray-Chaudhuri,Hocquenghem)码的网格结构以及BCJR(Bahl,Cocke,Jelinek and Raviv)算法进行了详细地分析及推导。实验结果表明,在光信道环境中,在误比特率为10-5时,当仅提高最小汉明距离码率相同或者仅减小码率最小汉明距离相同时,BCJR算法相对于硬判决译码算法的编码增益分别在之前的编码增益基础上又增加了0.15dB和0.25dB。因此设计级联码方案时,应尽可能选择纠错能力较大的内码。此外也可以采用适当增加内码的冗余度相应减小外码的冗余度的方法,在获得更高的编码增益的同时保证整个系统的带宽利用率不变。展开更多
The layered maximum a posteriori （L-MAP） algorithm has been proposed to detect signals under frequency selective fading multiple input multiple output （MIMO） channels. Compared to the optimum MAP detector, the L-M...The layered maximum a posteriori （L-MAP） algorithm has been proposed to detect signals under frequency selective fading multiple input multiple output （MIMO） channels. Compared to the optimum MAP detector, the L-MAP algorithm can efficiently identify signal bits, and the complexity grows linearly with the number of input antennas. The basic idea of L-MAP is to operate on each input sub-stream with an optimum MAP sequential detector separately by assuming the other streams are Gaussian noise. The soft output can also be forwarded to outer channel decoder for iterative decoding. Simulation results show that the proposed method can converge with a small number of iterations under different channel conditions and outperforms other sub-optimum detectors for rank-deficient channels.展开更多
The concatenated codes are widely used in current communication systems, such as satellite communication systems and WiMAX system. The objective of this study was to present a low complexity iterative soft decoding al...The concatenated codes are widely used in current communication systems, such as satellite communication systems and WiMAX system. The objective of this study was to present a low complexity iterative soft decoding algorithm for concatenated codes. The concatenation was between a Reed-Solomon (RS) code and recursive systematic convolutional (RSC) code. The reduction in computational complexity was achieved by simplifying the Chase-2 decoder for RS codes with limited usage of test patterns. The processing of soft information between inner and outer decoders was also discussed. Simulation results showed that the proposed algorithm could achieve a good trade-off between complexity and performance.展开更多
文摘In this paper, we propose a novel idea for improvement performances of the leader M-BCJR algorithm functioning in low complexity. The basic idea consists to localize error instant possibility, and then increase the complexity around this moment. We also propose an easy and important idea for early localisation of erroneous moments. We call this new algorithm Z-MAP. The simulations show that the improvement of performances is significant. The performances of Z-MAP turbo decoding are so close to full MAP-BCJR performances. Furthermore, the complexity is the same that of the M-BCJR. So, Z-MAP is an optimal version of M-BCJR algorithm.
文摘In this paper, a new method to approximate the compensation term in the Jacobian logarithm used by the MAP decoder is proposed. Using the proposed approximation, the complex functions In（.） and exp（.） in the Exact-log-MAP algorithm can be estimated with high accuracy and lower computational complexity. The efficacy of the proposed approximation is investigated and demonstrated by applying it to iteratively decoded BICM （Bit Interleaved Coded Modulation）.
文摘This contribution proposes a new combination symbol mapper/8-ary constellation, which is a joint optimization of an 8-ary signal constellation and its symbol mapping operation, to improve the performance of Bit Interleaved Coded Modulation with Iterative Decoding (BICM-ID). The basic idea was to use the so called (1,7) constellation (which is a capacitive efficient constellation) instead of the conventional 8-PSK constellation and to choose the most suitable mapping for it. A comparative study between the combinations most suitable mapping/(1,7) constellation and SSP mapping/conventional 8-PSK constellation has been carried out. Simulation results showed that the 1st combination significantly outperforms the 2nd combination and with only 4 iterations, it gives better performance than the 2nd combination with 8 iterations. A gain of 4 dB is given by iteration 4 of the 1st combination compared to iteration 8 of the 2nd combination at a BER level equal to 10-5, and it (iteration 4 of the 1st combination) can attain a BER equal to 10-7 for, only, a SNR = 5.6 dB.
文摘首先从理论上分析了硬判决译码算法和软判决译码算法的性能然后对BCH(Bose,Ray-Chaudhuri,Hocquenghem)码的网格结构以及BCJR(Bahl,Cocke,Jelinek and Raviv)算法进行了详细地分析及推导。实验结果表明,在光信道环境中,在误比特率为10-5时,当仅提高最小汉明距离码率相同或者仅减小码率最小汉明距离相同时,BCJR算法相对于硬判决译码算法的编码增益分别在之前的编码增益基础上又增加了0.15dB和0.25dB。因此设计级联码方案时,应尽可能选择纠错能力较大的内码。此外也可以采用适当增加内码的冗余度相应减小外码的冗余度的方法,在获得更高的编码增益的同时保证整个系统的带宽利用率不变。
基金the National Natural Science Foundation of China (90604035)
文摘The layered maximum a posteriori （L-MAP） algorithm has been proposed to detect signals under frequency selective fading multiple input multiple output （MIMO） channels. Compared to the optimum MAP detector, the L-MAP algorithm can efficiently identify signal bits, and the complexity grows linearly with the number of input antennas. The basic idea of L-MAP is to operate on each input sub-stream with an optimum MAP sequential detector separately by assuming the other streams are Gaussian noise. The soft output can also be forwarded to outer channel decoder for iterative decoding. Simulation results show that the proposed method can converge with a small number of iterations under different channel conditions and outperforms other sub-optimum detectors for rank-deficient channels.
基金supported by the National High-Tech Research and Development Program of China (2006AA01Z263)the Research Fund of National Mobile Communications Research Laboratory,Southeast University (2008A10)
文摘The concatenated codes are widely used in current communication systems, such as satellite communication systems and WiMAX system. The objective of this study was to present a low complexity iterative soft decoding algorithm for concatenated codes. The concatenation was between a Reed-Solomon (RS) code and recursive systematic convolutional (RSC) code. The reduction in computational complexity was achieved by simplifying the Chase-2 decoder for RS codes with limited usage of test patterns. The processing of soft information between inner and outer decoders was also discussed. Simulation results showed that the proposed algorithm could achieve a good trade-off between complexity and performance.
