In this paper, the problem of computing the free distance of Trellis Coded Modulation (TCM) signal sequence has been discussed; a new algorithm-the matrix algorithm is proposed; and the step-number estimation problem ...In this paper, the problem of computing the free distance of Trellis Coded Modulation (TCM) signal sequence has been discussed; a new algorithm-the matrix algorithm is proposed; and the step-number estimation problem for state transmission to compute the free distance of TCM signal sequence has been theoretically solved. The matrix algorithm is derived from the Viterbi algorithm, and is an implementation of Viterbi algorithm in the form of matrix. Compared with other algorithms, the matrix algorithm gains two advantages: (1) The explicit solution, and its relatively less complexity. (2) More reflexible ability to the signal space distance variation. As examples, the results of some TCM signal sequence on AWGN channel and fading channels have been presented.展开更多
当信道变化较慢时,无法利用无线信道的时变冗余特性实现密钥协商。针对上述问题,给出了一种基于网格编码调制(TCM)的慢衰落信道密钥协商方法。对随机生成的密钥序列进行TCM编码得到带有冗余的密钥信息,并利用两端的保密序列分别对密钥...当信道变化较慢时,无法利用无线信道的时变冗余特性实现密钥协商。针对上述问题,给出了一种基于网格编码调制(TCM)的慢衰落信道密钥协商方法。对随机生成的密钥序列进行TCM编码得到带有冗余的密钥信息,并利用两端的保密序列分别对密钥信息进行隐藏与恢复,同时利用密钥信息中的冗余纠正两端的保密序列不一致引起的恢复误差,最终获得一致的密钥序列。仿真结果表明,在比特率为10-4时,该方法比现有方法有将近5 d B的增益。展开更多
信道带宽窄、强多途、强噪声干扰一直是水下信息高速、可靠传输的主要障碍,提出用网格编码调制技术(Trellis-CodedModulation,TCM)与正交频分复用技术(Orthogonal Frequency Division Multiplexing,OFDM)相结合的传输体制可有效解决水...信道带宽窄、强多途、强噪声干扰一直是水下信息高速、可靠传输的主要障碍,提出用网格编码调制技术(Trellis-CodedModulation,TCM)与正交频分复用技术(Orthogonal Frequency Division Multiplexing,OFDM)相结合的传输体制可有效解决水下高速数据传输的带宽效率和可靠性问题;并详细介绍了TCM、TCM-8PSK的原理及在基于OFDM的水声通信系统中的应用;理论分析和计算机仿真结果表明使用该传输体制的水声通信系统能在不损失数据速率也不增加带宽的情况下编码增益能提高3dB左右,水声通信系统的性能得到明显改善。展开更多
文摘In this paper, the problem of computing the free distance of Trellis Coded Modulation (TCM) signal sequence has been discussed; a new algorithm-the matrix algorithm is proposed; and the step-number estimation problem for state transmission to compute the free distance of TCM signal sequence has been theoretically solved. The matrix algorithm is derived from the Viterbi algorithm, and is an implementation of Viterbi algorithm in the form of matrix. Compared with other algorithms, the matrix algorithm gains two advantages: (1) The explicit solution, and its relatively less complexity. (2) More reflexible ability to the signal space distance variation. As examples, the results of some TCM signal sequence on AWGN channel and fading channels have been presented.
文摘当信道变化较慢时,无法利用无线信道的时变冗余特性实现密钥协商。针对上述问题,给出了一种基于网格编码调制(TCM)的慢衰落信道密钥协商方法。对随机生成的密钥序列进行TCM编码得到带有冗余的密钥信息,并利用两端的保密序列分别对密钥信息进行隐藏与恢复,同时利用密钥信息中的冗余纠正两端的保密序列不一致引起的恢复误差,最终获得一致的密钥序列。仿真结果表明,在比特率为10-4时,该方法比现有方法有将近5 d B的增益。
文摘信道带宽窄、强多途、强噪声干扰一直是水下信息高速、可靠传输的主要障碍,提出用网格编码调制技术(Trellis-CodedModulation,TCM)与正交频分复用技术(Orthogonal Frequency Division Multiplexing,OFDM)相结合的传输体制可有效解决水下高速数据传输的带宽效率和可靠性问题;并详细介绍了TCM、TCM-8PSK的原理及在基于OFDM的水声通信系统中的应用;理论分析和计算机仿真结果表明使用该传输体制的水声通信系统能在不损失数据速率也不增加带宽的情况下编码增益能提高3dB左右,水声通信系统的性能得到明显改善。
