The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by th...The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by these advantages of OSFBC-OFDM system, this paper considers a secure wireless multicasting scenario through multiple-input multiple-output (MIMO) OFDM system employing OSFBC over frequency selective α-μ fading channels. The authors are interested to protect the desired signals from eavesdropping considering the impact of the number of multicast users and eavesdroppers, and the fading parameters α and μ. A mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multi-casting (SOPM) to ensure the security in the presence of multiple eaves-droppers. The results show that the security in MIMO OSFBC OFDM system over α-μ fading is more sensitive to the magnitude of α and μ and this effect increases in the high signal-to-noise ratio (SNR) region of the main channel.展开更多
As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture, the V-BLAST OFDM system can better meet the demand of next...As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture, the V-BLAST OFDM system can better meet the demand of next-generation (NextG) broadband mobile wireless multimedia communications. The symbols detection problem of the V-BLAST OFDM system is investigated under the frequency-selective fading environment. The joint space-frequency demultiplexing operation is proposed in the V-BLAST OFDM system. Successively, one novel half-rate rotational invariance joint space-frequency coding scheme for the V-BLAST OFDM system is proposed. By elegantly exploiting the above rotational invariance property, we derive one direct symbols detection scheme without knowing channels state information (CSI) for the frequency-selective V-BLAST OFDM system. Extensive simulation results demonstrate the validity of the novel half-rate rotational invariance joint space-frequency coding scheme and the performance of the direct symbols detection scheme.展开更多
As one solution to implement the largecapacity space division multiplexing(SDM)transmission systems,the mode division multiplexing(MDM)has gained much attention recently.The vector mode(VM),which is the eigenmode of t...As one solution to implement the largecapacity space division multiplexing(SDM)transmission systems,the mode division multiplexing(MDM)has gained much attention recently.The vector mode(VM),which is the eigenmode of the optical fiber,has also been adopted to realize the optical communications including the transmission over free-space optical(FSO)and optical fiber links.Considering the concerns on the short-reach optical interconnects,the low cost and high integration technologies should be developed.Direct detection(DD)with higher-order modulation formats in combination of MDM technologies could offer an available trade-off in system performance and complexity.We review demonstrations of FSO and fiber high-speed data transmission based on the VM MDM(VMDM)technologies.The special VMs,cylindrical vector beams(CVB),have been generated by the q-plate(QP)and characterized accordingly.And then they were used to implement the VMDM transmission with direct-detection orthogonal frequency division multiplexing(DD-OFDM).These demonstrations show the potential of VMDM-DD-OFDM technology in the large-capacity short-reach transmission links.展开更多
The emerging ultra-wideband (UWB) system offers a great potential for the design of high-speed short-range communications.Compared with great progress at physical layer,the corresponding medium access control (MAC) la...The emerging ultra-wideband (UWB) system offers a great potential for the design of high-speed short-range communications.Compared with great progress at physical layer,the corresponding medium access control (MAC) layer designs are naturally placed on the schedules.We focus on the optimal power load scheme,which is an integral part of the MAC layer protocol design,for UWB space-time coded (STC) orthogonal frequency-division multiplexing (OFDM) transmissions.Assumed the transmitter has perfect or partial channel stage information (CSI).Based on the optimization criteria of maximizing capacity,three kinds of power load schemes were presented with different tradeoff among performance,complexity and feedback bandwidth overhead.The proposed schemes are verified and compared under the channel prototype proposed by IEEE 802.15.3a Task Group.展开更多
该文研究了基于正交时频空间(orthogonal time frequency space, OTFS)调制的去蜂窝大规模多输入多输出(massive multiple-input multiple-output, mMIMO)系统上行链路通信中的和速率优化问题,提出一种蚁群递归搜索机制。该机制首先采...该文研究了基于正交时频空间(orthogonal time frequency space, OTFS)调制的去蜂窝大规模多输入多输出(massive multiple-input multiple-output, mMIMO)系统上行链路通信中的和速率优化问题,提出一种蚁群递归搜索机制。该机制首先采用最小割分组算法实现用户分组,然后使用蚁群算法进行递归优化求解。仿真结果表明,通过运用该机制进行功率控制,其性能相比于未分组的m MIMO-OTFS系统和m MIMO-正交频分复用(orthogonal frequency division multiplexing, OFDM)系统更好。此外,移动速度对系统用户上行可达速率性能的影响研究结果表明,mMIMO-OTFS系统与mMIMO-OFDM系统的和速率性能差距随移动速度增长呈递增状态。展开更多
多天线OFDM(Orthogonal Frequency Division Multiplexing)系统环境下,针对现有全分集全速率空时编码分集复用交换之间的关系问题,在多天线OFDM系统模型下推导了其分集和复用增益交换曲线,进一步证实了FDFR(Full Diversity Full Rate)...多天线OFDM(Orthogonal Frequency Division Multiplexing)系统环境下,针对现有全分集全速率空时编码分集复用交换之间的关系问题,在多天线OFDM系统模型下推导了其分集和复用增益交换曲线,进一步证实了FDFR(Full Diversity Full Rate)空时编码是一种最优的分集复用交换空时编码。给出了实现全分集全速率空时编码的设计方法。理论分析表明,全分集全速率空时编码具有较好的空间链路适应性。在中国未来通用无线环境研究计划(FuTURE:Future Technologies for a Universal Radio Environment)的系统配置条件下,仿真了全分集全速率空时编码的性能并与其他现有最优空时编码的性能进行对比。结果表明,全分集全速率空时编码具有更好的链路适应性和较好的性能。展开更多
文摘The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by these advantages of OSFBC-OFDM system, this paper considers a secure wireless multicasting scenario through multiple-input multiple-output (MIMO) OFDM system employing OSFBC over frequency selective α-μ fading channels. The authors are interested to protect the desired signals from eavesdropping considering the impact of the number of multicast users and eavesdroppers, and the fading parameters α and μ. A mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multi-casting (SOPM) to ensure the security in the presence of multiple eaves-droppers. The results show that the security in MIMO OSFBC OFDM system over α-μ fading is more sensitive to the magnitude of α and μ and this effect increases in the high signal-to-noise ratio (SNR) region of the main channel.
文摘As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture, the V-BLAST OFDM system can better meet the demand of next-generation (NextG) broadband mobile wireless multimedia communications. The symbols detection problem of the V-BLAST OFDM system is investigated under the frequency-selective fading environment. The joint space-frequency demultiplexing operation is proposed in the V-BLAST OFDM system. Successively, one novel half-rate rotational invariance joint space-frequency coding scheme for the V-BLAST OFDM system is proposed. By elegantly exploiting the above rotational invariance property, we derive one direct symbols detection scheme without knowing channels state information (CSI) for the frequency-selective V-BLAST OFDM system. Extensive simulation results demonstrate the validity of the novel half-rate rotational invariance joint space-frequency coding scheme and the performance of the direct symbols detection scheme.
基金the National High Technology 863 Research and Development of China(No.2015AA017102)the National Natural Science Foundation of China(NSFC)(Grant Nos.61575082,61435006,61525502,and 61490715)+2 种基金the Youth Science and Technology Innovation Talents of Guangdong(No.2015TQ01X606)Guangdong Provincial Natural Science Foundation(GDSF)(No.2015A030313328)Pearl River S&T Nova Program of Guangzhou(No.201710010051).
文摘As one solution to implement the largecapacity space division multiplexing(SDM)transmission systems,the mode division multiplexing(MDM)has gained much attention recently.The vector mode(VM),which is the eigenmode of the optical fiber,has also been adopted to realize the optical communications including the transmission over free-space optical(FSO)and optical fiber links.Considering the concerns on the short-reach optical interconnects,the low cost and high integration technologies should be developed.Direct detection(DD)with higher-order modulation formats in combination of MDM technologies could offer an available trade-off in system performance and complexity.We review demonstrations of FSO and fiber high-speed data transmission based on the VM MDM(VMDM)technologies.The special VMs,cylindrical vector beams(CVB),have been generated by the q-plate(QP)and characterized accordingly.And then they were used to implement the VMDM transmission with direct-detection orthogonal frequency division multiplexing(DD-OFDM).These demonstrations show the potential of VMDM-DD-OFDM technology in the large-capacity short-reach transmission links.
基金This work was partially supported by NSF under Grant 60496315 and national "863" projects under Grant2003AA12331005
文摘The emerging ultra-wideband (UWB) system offers a great potential for the design of high-speed short-range communications.Compared with great progress at physical layer,the corresponding medium access control (MAC) layer designs are naturally placed on the schedules.We focus on the optimal power load scheme,which is an integral part of the MAC layer protocol design,for UWB space-time coded (STC) orthogonal frequency-division multiplexing (OFDM) transmissions.Assumed the transmitter has perfect or partial channel stage information (CSI).Based on the optimization criteria of maximizing capacity,three kinds of power load schemes were presented with different tradeoff among performance,complexity and feedback bandwidth overhead.The proposed schemes are verified and compared under the channel prototype proposed by IEEE 802.15.3a Task Group.
文摘该文研究了基于正交时频空间(orthogonal time frequency space, OTFS)调制的去蜂窝大规模多输入多输出(massive multiple-input multiple-output, mMIMO)系统上行链路通信中的和速率优化问题,提出一种蚁群递归搜索机制。该机制首先采用最小割分组算法实现用户分组,然后使用蚁群算法进行递归优化求解。仿真结果表明,通过运用该机制进行功率控制,其性能相比于未分组的m MIMO-OTFS系统和m MIMO-正交频分复用(orthogonal frequency division multiplexing, OFDM)系统更好。此外,移动速度对系统用户上行可达速率性能的影响研究结果表明,mMIMO-OTFS系统与mMIMO-OFDM系统的和速率性能差距随移动速度增长呈递增状态。
文摘多天线OFDM(Orthogonal Frequency Division Multiplexing)系统环境下,针对现有全分集全速率空时编码分集复用交换之间的关系问题,在多天线OFDM系统模型下推导了其分集和复用增益交换曲线,进一步证实了FDFR(Full Diversity Full Rate)空时编码是一种最优的分集复用交换空时编码。给出了实现全分集全速率空时编码的设计方法。理论分析表明,全分集全速率空时编码具有较好的空间链路适应性。在中国未来通用无线环境研究计划(FuTURE:Future Technologies for a Universal Radio Environment)的系统配置条件下,仿真了全分集全速率空时编码的性能并与其他现有最优空时编码的性能进行对比。结果表明,全分集全速率空时编码具有更好的链路适应性和较好的性能。
