A differential modulation scheme using space-time block codes is put forward. Compared with other schemes, our scheme has lower computational complexity and has a simpler decoder. In the case of three or four transmit...A differential modulation scheme using space-time block codes is put forward. Compared with other schemes, our scheme has lower computational complexity and has a simpler decoder. In the case of three or four transmitter antennas, our scheme has a higher rate a higher coding gain and a lower bit error rate for a given rate. Then we made simulations for space-time block codes as well as group codes in the case of two, three, four and five transmit antennas. The simulations prove that using two transmit antennas, one receive antenna and code rate of 4 bits/s/Hz, the differential STBC method outperform the differential group codes method by 4 dB. Useing three, four and five transmit antennas, one receive antenna, and code rate of 3 bits/s/Hz are adopted, the differential STBC method outperform the differential group codes method by 5 dB, 6. 5 dB and 7 dB, respectively. In other words, the differential modulation scheme based on space-time block code is better than the corresponding differential modulation scheme展开更多
The simplified joint channel estimation and symbol detection based on the EM (expectation-maximization) algorithm for space-time block code (STBC) are proposed. By assuming channel to be invariant within only one STBC...The simplified joint channel estimation and symbol detection based on the EM (expectation-maximization) algorithm for space-time block code (STBC) are proposed. By assuming channel to be invariant within only one STBC word and utilizing the orthogonal structure of STBC, the computational complexity and cost of this algorithm are both very low, so it is very suitable to implementation in real systems.展开更多
Space-time coding is an important technique that can improve transmission performance at fading environments in mobile communication systems. In this paper, we propose a novel diversity scheme using spread spacetime b...Space-time coding is an important technique that can improve transmission performance at fading environments in mobile communication systems. In this paper, we propose a novel diversity scheme using spread spacetime block coding （SSTBC） in multiple antenna systems. At the transmitter, the primitive data are serial to parallel converted to multiple data streams, and each stream is rotated in constellation. Then Walsh codes are used to spread each symbol to all antenna space in a space-time block. The signals received from all receiver antennas are combined with the maximum ratio combining （MRC）, equalized with linear equalizer to eliminate the inter-code interference and finally demodulated to recover to transmit data by using the one-symbol maximum likelihood detector. The proposed scheme does not sacrifice the spectrum efficiency meanwhile maintains the transceiver with low complexity. Owing to the transmission symbols of different transmit antennas passing through all the spatial subchannels between transceiver antenna pairs, the system obtains the partial additional space diversity gain of all spatial paths. It is also shown that the diversity gain is better than the previous space-time block coding （STBC） schemes with full transmission rate.展开更多
An improved scheme with cooperative diversity based on distributed space-time block coding （WCD- DSTBC） is proposed, which effectively achieves diversity gains and improves the performance of the system by sharing s...An improved scheme with cooperative diversity based on distributed space-time block coding （WCD- DSTBC） is proposed, which effectively achieves diversity gains and improves the performance of the system by sharing some single-antenna users＇ antennas to form a virtual antenna array and combining with distributed spacetime block coding （DSTBC） mode. Then the relation between the system BER and the interuser BER for WCDDSTBC scheme is theoretically derived and the closed-form expression of BER for WCD-DSTBC system is obtained. The simulation results show that the proposed WCD-DSTBC scheme achieves distinct gains over the non-cooperative multi-carrier CDMA （MC-CDMA） system. When system BER is le-3 and interuser BER is le-3, about 2.5 dB gain can be gotten. When interuser channel state information （CSI） outgoes the users＇ individual CSI, about 3 dB gain is also achieved.展开更多
针对STBC-OFDM信号盲识别中存在着识别所需样本数多、对频偏敏感和不适用于单接收天线等问题,提出一种基于FOLP(Fourth Order Lag Product)的识别方法.根据不同空时分组码元素的相关性,推导了接收信号的FOLP,构造了基于FOLP的峰值检测算...针对STBC-OFDM信号盲识别中存在着识别所需样本数多、对频偏敏感和不适用于单接收天线等问题,提出一种基于FOLP(Fourth Order Lag Product)的识别方法.根据不同空时分组码元素的相关性,推导了接收信号的FOLP,构造了基于FOLP的峰值检测算法.推导和仿真结果表明,该算法能够在单接收天线下运行,且不需要知道信道信息、噪声信息、调制信息以及OFDM块的起始位置;且该算法不受调制方式的影响,对时延、相位噪声和频率偏移鲁棒性能好,能够应用于认知无线电、频谱监控等工程领域中.展开更多
针对具有空时分组码的多载波CDMA(Space Time Block Coding Multi Carrier Code Division Multiple Access,STBC-MC-CDMA)信号扩频码及信息序列的联合估计问题,结合序贯蒙特卡罗(Sequential Monte Carlo,SMC)算法和卡尔曼滤波技术,充分...针对具有空时分组码的多载波CDMA(Space Time Block Coding Multi Carrier Code Division Multiple Access,STBC-MC-CDMA)信号扩频码及信息序列的联合估计问题,结合序贯蒙特卡罗(Sequential Monte Carlo,SMC)算法和卡尔曼滤波技术,充分利用STBC和OFDM(Orthogonal Frequency Division Multiplexing)调制的正交属性,提出了一种快速的盲解扩算法.该算法通过将信号模型按不同符号路数和天线数目进行分段处理,采用卡尔曼滤波方法对均值和协方差进行迭代更新,并用一组带有权值的抽样粒子来近似建立的联合后验概率分布,根据抽样值和重要性权值大小进行参量状态估计,大大提高了算法的计算效率.理论分析和仿真结果验证了本文算法的有效性.展开更多
结合频域均衡(FDE)研究了在频率选择性衰落信道下基于虚拟 MIMO-STBC 的无线传感器网络的功率分配(PA)方案。利用从目标簇反馈回信源簇的信道状态信息,在协同传输节点总发送功率一定的情况下,通过最大化信宿节点接收到数据的信噪比推导...结合频域均衡(FDE)研究了在频率选择性衰落信道下基于虚拟 MIMO-STBC 的无线传感器网络的功率分配(PA)方案。利用从目标簇反馈回信源簇的信道状态信息,在协同传输节点总发送功率一定的情况下,通过最大化信宿节点接收到数据的信噪比推导出了一种基于滤波器组频域加权的 PA 方案。仿真结果表明,在系统一定的误码率要求下,采用这种 PA 方案的无线传感器网络所需要的发射功率要少于等 PA 方案所需要的发射功率,从而减少了无线传感器网络的能耗。展开更多
基金This project was supported by the National Natural Science Foundation of China (60172018) .
文摘A differential modulation scheme using space-time block codes is put forward. Compared with other schemes, our scheme has lower computational complexity and has a simpler decoder. In the case of three or four transmitter antennas, our scheme has a higher rate a higher coding gain and a lower bit error rate for a given rate. Then we made simulations for space-time block codes as well as group codes in the case of two, three, four and five transmit antennas. The simulations prove that using two transmit antennas, one receive antenna and code rate of 4 bits/s/Hz, the differential STBC method outperform the differential group codes method by 4 dB. Useing three, four and five transmit antennas, one receive antenna, and code rate of 3 bits/s/Hz are adopted, the differential STBC method outperform the differential group codes method by 5 dB, 6. 5 dB and 7 dB, respectively. In other words, the differential modulation scheme based on space-time block code is better than the corresponding differential modulation scheme
基金This project was supported by the National Natural Science Foundation of China (60272079).
文摘The simplified joint channel estimation and symbol detection based on the EM (expectation-maximization) algorithm for space-time block code (STBC) are proposed. By assuming channel to be invariant within only one STBC word and utilizing the orthogonal structure of STBC, the computational complexity and cost of this algorithm are both very low, so it is very suitable to implementation in real systems.
基金This project was supported by the National Science Foundation of China (60496314)
文摘Space-time coding is an important technique that can improve transmission performance at fading environments in mobile communication systems. In this paper, we propose a novel diversity scheme using spread spacetime block coding （SSTBC） in multiple antenna systems. At the transmitter, the primitive data are serial to parallel converted to multiple data streams, and each stream is rotated in constellation. Then Walsh codes are used to spread each symbol to all antenna space in a space-time block. The signals received from all receiver antennas are combined with the maximum ratio combining （MRC）, equalized with linear equalizer to eliminate the inter-code interference and finally demodulated to recover to transmit data by using the one-symbol maximum likelihood detector. The proposed scheme does not sacrifice the spectrum efficiency meanwhile maintains the transceiver with low complexity. Owing to the transmission symbols of different transmit antennas passing through all the spatial subchannels between transceiver antenna pairs, the system obtains the partial additional space diversity gain of all spatial paths. It is also shown that the diversity gain is better than the previous space-time block coding （STBC） schemes with full transmission rate.
基金supported by the State Key Laboratory for Mobile Communication Open Foundation(N200502)the Natural Science Foundation of Jiangsu Province(BK2007192).
文摘An improved scheme with cooperative diversity based on distributed space-time block coding （WCD- DSTBC） is proposed, which effectively achieves diversity gains and improves the performance of the system by sharing some single-antenna users＇ antennas to form a virtual antenna array and combining with distributed spacetime block coding （DSTBC） mode. Then the relation between the system BER and the interuser BER for WCDDSTBC scheme is theoretically derived and the closed-form expression of BER for WCD-DSTBC system is obtained. The simulation results show that the proposed WCD-DSTBC scheme achieves distinct gains over the non-cooperative multi-carrier CDMA （MC-CDMA） system. When system BER is le-3 and interuser BER is le-3, about 2.5 dB gain can be gotten. When interuser channel state information （CSI） outgoes the users＇ individual CSI, about 3 dB gain is also achieved.
文摘针对STBC-OFDM信号盲识别中存在着识别所需样本数多、对频偏敏感和不适用于单接收天线等问题,提出一种基于FOLP(Fourth Order Lag Product)的识别方法.根据不同空时分组码元素的相关性,推导了接收信号的FOLP,构造了基于FOLP的峰值检测算法.推导和仿真结果表明,该算法能够在单接收天线下运行,且不需要知道信道信息、噪声信息、调制信息以及OFDM块的起始位置;且该算法不受调制方式的影响,对时延、相位噪声和频率偏移鲁棒性能好,能够应用于认知无线电、频谱监控等工程领域中.
文摘针对具有空时分组码的多载波CDMA(Space Time Block Coding Multi Carrier Code Division Multiple Access,STBC-MC-CDMA)信号扩频码及信息序列的联合估计问题,结合序贯蒙特卡罗(Sequential Monte Carlo,SMC)算法和卡尔曼滤波技术,充分利用STBC和OFDM(Orthogonal Frequency Division Multiplexing)调制的正交属性,提出了一种快速的盲解扩算法.该算法通过将信号模型按不同符号路数和天线数目进行分段处理,采用卡尔曼滤波方法对均值和协方差进行迭代更新,并用一组带有权值的抽样粒子来近似建立的联合后验概率分布,根据抽样值和重要性权值大小进行参量状态估计,大大提高了算法的计算效率.理论分析和仿真结果验证了本文算法的有效性.
文摘结合频域均衡(FDE)研究了在频率选择性衰落信道下基于虚拟 MIMO-STBC 的无线传感器网络的功率分配(PA)方案。利用从目标簇反馈回信源簇的信道状态信息,在协同传输节点总发送功率一定的情况下,通过最大化信宿节点接收到数据的信噪比推导出了一种基于滤波器组频域加权的 PA 方案。仿真结果表明,在系统一定的误码率要求下,采用这种 PA 方案的无线传感器网络所需要的发射功率要少于等 PA 方案所需要的发射功率,从而减少了无线传感器网络的能耗。
