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
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
提出了一种基于分布式空时分组编码的译码转发(DSTBC-DF)的新的协同分集方案,设计了适合协同分簇多跳无线传感网的网络协议,并讨论了协同同步情况,分析了协同分集方案的性能和协同分簇无线传感网的能量效率。理论分析与 Mento Carlo 仿...提出了一种基于分布式空时分组编码的译码转发(DSTBC-DF)的新的协同分集方案,设计了适合协同分簇多跳无线传感网的网络协议,并讨论了协同同步情况,分析了协同分集方案的性能和协同分簇无线传感网的能量效率。理论分析与 Mento Carlo 仿真的结果验证了这一新方案的有效性:相比传统的方案,不但实现简单,而且通过合理的协议设计有效地解决了协同同步问题,实现了完全的分集增益,有更高的能量效率,网络系统能耗明显降低。展开更多
协同分集(cooperative diversity)技术通过使网络中各单天线用户共享彼此天线,形成虚拟的多天线阵列来实现发射或接收分集,可以有效地提高系统性能。该文提出无线网络中频率选择性衰落信道环境下的一种基于分布式空时分组码(Distributed...协同分集(cooperative diversity)技术通过使网络中各单天线用户共享彼此天线,形成虚拟的多天线阵列来实现发射或接收分集,可以有效地提高系统性能。该文提出无线网络中频率选择性衰落信道环境下的一种基于分布式空时分组码(Distributed Space Time Block Code,DSTBC)和MC-CDMA的协同发射分集方案,并给出了系统实现。建立了误码模型,探讨了协同用户间的信道状态信息(CSI)对系统误码性能的影响,分析了误码性能的上限,并给出了仿真结果。结果表明,DSTBC-MC-CDMA系统相对于未协同的MC-CDMA系统,获得了明显的性能增益。展开更多
正交频分复用技术可以有效的消除信号符号间干扰并具有较高的频带利用率。空时分组码可以弥补正交频分复用技术对移动造成的多普勒频移比较敏感的缺陷,所以这两种技术的结合在下一代无线通信中的应用引起了越来越多的关注。本文研究了DS...正交频分复用技术可以有效的消除信号符号间干扰并具有较高的频带利用率。空时分组码可以弥补正交频分复用技术对移动造成的多普勒频移比较敏感的缺陷,所以这两种技术的结合在下一代无线通信中的应用引起了越来越多的关注。本文研究了DSTBC(D ifferential Space-Tim e B lockCodes,差分空时分组编码)和OFDM(O rthogonal Frequency D ivisionMu ltip lexing,正交频分复用)技术相结合的系统收发机结构。由于接收端不需要进行信道估计,可大大简化接收机复杂度。通过仿真给出了DSTBC-OFDM系统与STBC-OFDM系统及纯OFDM系统在Rayle igh衰落信道及SUI信道下的比特差错性能。通过比较可看出,在静止情况下或中速移动但信道条件较好的情况下,DST-BC-OFDM系统可作为STBC-OFDM系统的替代。展开更多
在无中心飞行器集群网络中,非直通条件节点间不同的中继路径可能导致较大路径损耗落差,为有限资源前提下网络传输能力的提升带来困难。参考5G移动通信中的终端直通(Device to Device,D2D)技术与中继通信中的虚拟多输入多输出(Multiple-I...在无中心飞行器集群网络中,非直通条件节点间不同的中继路径可能导致较大路径损耗落差,为有限资源前提下网络传输能力的提升带来困难。参考5G移动通信中的终端直通(Device to Device,D2D)技术与中继通信中的虚拟多输入多输出(Multiple-Input Multiple-Output,MIMO)技术,提出一套D2D通信与虚拟MIMO技术结合的无中心飞行器集群网络传输方案。重点研究在正交资源模式下,将不同的协作传输协议与空时编码进行组合,在信噪比、误比特率、接入概率等方面对通信性能的影响。仿真结果表明:D2D通信与虚拟MIMO技术结合的传输方案在不增加资源的前提下,对集群网络的通信性能有明显提升,且引入分布式空时编码可进一步优化误比特率性能,但3种传输协议在不同传输质量评价方向的改善有所不同。展开更多
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.
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.
文摘提出了一种基于分布式空时分组编码的译码转发(DSTBC-DF)的新的协同分集方案,设计了适合协同分簇多跳无线传感网的网络协议,并讨论了协同同步情况,分析了协同分集方案的性能和协同分簇无线传感网的能量效率。理论分析与 Mento Carlo 仿真的结果验证了这一新方案的有效性:相比传统的方案,不但实现简单,而且通过合理的协议设计有效地解决了协同同步问题,实现了完全的分集增益,有更高的能量效率,网络系统能耗明显降低。
文摘协同分集(cooperative diversity)技术通过使网络中各单天线用户共享彼此天线,形成虚拟的多天线阵列来实现发射或接收分集,可以有效地提高系统性能。该文提出无线网络中频率选择性衰落信道环境下的一种基于分布式空时分组码(Distributed Space Time Block Code,DSTBC)和MC-CDMA的协同发射分集方案,并给出了系统实现。建立了误码模型,探讨了协同用户间的信道状态信息(CSI)对系统误码性能的影响,分析了误码性能的上限,并给出了仿真结果。结果表明,DSTBC-MC-CDMA系统相对于未协同的MC-CDMA系统,获得了明显的性能增益。
文摘正交频分复用技术可以有效的消除信号符号间干扰并具有较高的频带利用率。空时分组码可以弥补正交频分复用技术对移动造成的多普勒频移比较敏感的缺陷,所以这两种技术的结合在下一代无线通信中的应用引起了越来越多的关注。本文研究了DSTBC(D ifferential Space-Tim e B lockCodes,差分空时分组编码)和OFDM(O rthogonal Frequency D ivisionMu ltip lexing,正交频分复用)技术相结合的系统收发机结构。由于接收端不需要进行信道估计,可大大简化接收机复杂度。通过仿真给出了DSTBC-OFDM系统与STBC-OFDM系统及纯OFDM系统在Rayle igh衰落信道及SUI信道下的比特差错性能。通过比较可看出,在静止情况下或中速移动但信道条件较好的情况下,DST-BC-OFDM系统可作为STBC-OFDM系统的替代。
文摘在无中心飞行器集群网络中,非直通条件节点间不同的中继路径可能导致较大路径损耗落差,为有限资源前提下网络传输能力的提升带来困难。参考5G移动通信中的终端直通(Device to Device,D2D)技术与中继通信中的虚拟多输入多输出(Multiple-Input Multiple-Output,MIMO)技术,提出一套D2D通信与虚拟MIMO技术结合的无中心飞行器集群网络传输方案。重点研究在正交资源模式下,将不同的协作传输协议与空时编码进行组合,在信噪比、误比特率、接入概率等方面对通信性能的影响。仿真结果表明:D2D通信与虚拟MIMO技术结合的传输方案在不增加资源的前提下,对集群网络的通信性能有明显提升,且引入分布式空时编码可进一步优化误比特率性能,但3种传输协议在不同传输质量评价方向的改善有所不同。
