A new design method interleavers, 2-dimension interleavers, are proposed for interleave division multiple access (IDMA) systems. With a same interleaving rule named I', the row indices and column indices of a tradi...A new design method interleavers, 2-dimension interleavers, are proposed for interleave division multiple access (IDMA) systems. With a same interleaving rule named I', the row indices and column indices of a traditional block interleaving matrix are scrambled to obtain an interleaver, which is marked as the master interleaver. F is produced by a loworder PN sequence generator. Two ways are provided for generating different interleavers. One is that all interleavers are generated by the circular shifting master interleaver. The other is that different inter leavers are generated by different Ts. Besides, we prove that the minimum distance between two adjacent bits resulted from 2-dimension interleaves is much larger than that of other schemes, such as random interleavers, power interleavers, and shiffting interleaves. The simulation results show that 2-dimension interleavers can achieve much better performance with much less resource consumption than random interleavers in IDMA systems.展开更多
High spectral efficiency is essential in design of multimedia communication systems such as L-band mobile in addition to various requirements of transmission quality. Time-interleaved A/D converter (TI-ADC) is an ef...High spectral efficiency is essential in design of multimedia communication systems such as L-band mobile in addition to various requirements of transmission quality. Time-interleaved A/D converter (TI-ADC) is an effective candidate to implement wide-band ADC with relatively slow circuits accounting for digital spectrum management. However, practical performance of TI-ADC is largely limited because of mismatches between different channels originated from manufacturing process variations. In this paper, a blind adaptive method is proposed to correct gain mismatch errors in TI-ADC, and it is verified through simulations on a two-channel TI-ADC. In proposed method, gain mismatch error is estimated and corrected in an adaptive scheme. Proposed compensated T1-ADC architecture is structurally very simple and hence suitable for realiza- tion in integrated circuits. Besides, proposed digital compensation algorithm not only is computationally efficient but also provides an improvement of 32.7 dB in the performance of two-channel TI ADC.展开更多
有效的多用户多址接入方式一直是水声通信网络研究的重点与难点;在十分有限的水声可用带宽条件下常规的基于频分技术的多址接入方式并不适用;而基于CDMA的码分多址接入方式则又存在着严重的难以克服的远近效应问题,且水声信道的多途效...有效的多用户多址接入方式一直是水声通信网络研究的重点与难点;在十分有限的水声可用带宽条件下常规的基于频分技术的多址接入方式并不适用;而基于CDMA的码分多址接入方式则又存在着严重的难以克服的远近效应问题,且水声信道的多途效应使接收信号产生严重的码间窜扰(ISI)。针对以上问题,本文提出了基于交织分多址接入(IDMA)的自适应Turbo迭代接收机技术的研究。接收机采用联合均衡过程和译码过程的Turbo迭代接收机,通过迭代的方式获得反馈的外信息从而提高系统性能。针对未知参数的信道,采用递归最小二乘(RLS)自适应均衡算法对信道参数迭代估计,从而指导均衡器消除码间窜扰(ISI)。RLS算法利用每次迭代译码器反馈的外信息再次估计信道参数,直接的增加了除训练序列外的可利用数据长度,从而提高估计精度。通过仿真得出在未知信道条件下接收机的性能比已知信道系统接收机的性能降低0.4 d B。展开更多
基金supported by the National Key Lab. Research Foundation of China under Grant No.2007CB310604
文摘A new design method interleavers, 2-dimension interleavers, are proposed for interleave division multiple access (IDMA) systems. With a same interleaving rule named I', the row indices and column indices of a traditional block interleaving matrix are scrambled to obtain an interleaver, which is marked as the master interleaver. F is produced by a loworder PN sequence generator. Two ways are provided for generating different interleavers. One is that all interleavers are generated by the circular shifting master interleaver. The other is that different inter leavers are generated by different Ts. Besides, we prove that the minimum distance between two adjacent bits resulted from 2-dimension interleaves is much larger than that of other schemes, such as random interleavers, power interleavers, and shiffting interleaves. The simulation results show that 2-dimension interleavers can achieve much better performance with much less resource consumption than random interleavers in IDMA systems.
基金Iran’s Telecommunication Research Center(ITRC)(No.500/3653)
文摘High spectral efficiency is essential in design of multimedia communication systems such as L-band mobile in addition to various requirements of transmission quality. Time-interleaved A/D converter (TI-ADC) is an effective candidate to implement wide-band ADC with relatively slow circuits accounting for digital spectrum management. However, practical performance of TI-ADC is largely limited because of mismatches between different channels originated from manufacturing process variations. In this paper, a blind adaptive method is proposed to correct gain mismatch errors in TI-ADC, and it is verified through simulations on a two-channel TI-ADC. In proposed method, gain mismatch error is estimated and corrected in an adaptive scheme. Proposed compensated T1-ADC architecture is structurally very simple and hence suitable for realiza- tion in integrated circuits. Besides, proposed digital compensation algorithm not only is computationally efficient but also provides an improvement of 32.7 dB in the performance of two-channel TI ADC.
基金Project supported by the"863"National High-Tech Research and Development Program of China(No.2008AA01 Z211)the International Science and Technology Cooperation Program(No.2008DFA11630)
文摘有效的多用户多址接入方式一直是水声通信网络研究的重点与难点;在十分有限的水声可用带宽条件下常规的基于频分技术的多址接入方式并不适用;而基于CDMA的码分多址接入方式则又存在着严重的难以克服的远近效应问题,且水声信道的多途效应使接收信号产生严重的码间窜扰(ISI)。针对以上问题,本文提出了基于交织分多址接入(IDMA)的自适应Turbo迭代接收机技术的研究。接收机采用联合均衡过程和译码过程的Turbo迭代接收机,通过迭代的方式获得反馈的外信息从而提高系统性能。针对未知参数的信道,采用递归最小二乘(RLS)自适应均衡算法对信道参数迭代估计,从而指导均衡器消除码间窜扰(ISI)。RLS算法利用每次迭代译码器反馈的外信息再次估计信道参数,直接的增加了除训练序列外的可利用数据长度,从而提高估计精度。通过仿真得出在未知信道条件下接收机的性能比已知信道系统接收机的性能降低0.4 d B。