在基于非正交多址接入技术的多用户下行室内可见光通信(Visible light communication system based on non⁃orthogonal multiple access technology,VLC⁃NOMA)系统中,针对和速率与用户公平性冲突的问题,提出一种基于加权和速率最大化的...在基于非正交多址接入技术的多用户下行室内可见光通信(Visible light communication system based on non⁃orthogonal multiple access technology,VLC⁃NOMA)系统中,针对和速率与用户公平性冲突的问题,提出一种基于加权和速率最大化的迭代功率分配方案。该方案以最大化加权和速率为目标,可通过改变权重因子来调节用户公平性。由于目标问题属于非凸优化问题,通过辅助变量法和凸优化理论将该非凸问题转化为凹问题,再通过拉格朗日对偶法进行求解,并根据问题的解设计了一种迭代功率分配算法。对所提算法的收敛性、系统和速率以及用户公平性进行了仿真。结果表明,所提迭代功率分配算法具有良好的收敛性,相较于VLC⁃OMA系统,VLC⁃NOMA系统能够获得更好的和速率性能。通过调整权重因子,在牺牲较小系统和速率的情况下能够获得比现有功率分配方案更好的系统和速率与用户公平性。展开更多
可见光通信与非正交多址技术结合,是满足室内高速通信和宽带数据接入的重要方法 .由于室内密集设备通信需求增长,小区间干扰和资源紧缺日趋严重,为了降低小区间干扰,进一步增强室内用户设备高速通信的用户体验质量(Quality of Experienc...可见光通信与非正交多址技术结合,是满足室内高速通信和宽带数据接入的重要方法 .由于室内密集设备通信需求增长,小区间干扰和资源紧缺日趋严重,为了降低小区间干扰,进一步增强室内用户设备高速通信的用户体验质量(Quality of Experience,QoE)和提高可见光通信的频谱资源利用率,提出室内基于非正交多址接入的可见光通信(Visible Light Communication-Non-Orthogonal Multiple Access,VLC-NOMA)协作多点用户接入和功率分配算法.在用户接入阶段,设计基于QoE和多接入点协作的用户接入(User Access algorithm based on User Experience Quality and Coordinated Multipoint,UA-UEQCM)算法,根据用户需求的最小速率、推荐速率值和VLC-NOMA提供的可达速率,评估用户的QoE值和等效的用户满意度值;然后,基于VLC-NOMA中用户需求的平均意见评分(Mean Opinion Score,MOS)和VLC接入点协作可用资源,设计NOMA用户组的效用函数优化用户设备与多个接入点协作接入的双向选择,提高VLC-NOMA网络的MOS值;在功率分配阶段,采用改进教与学优化方法优化NOMA组的功率分配,设计VLC-NOMA的总MOS值为适应度函数值,采用自适应更新和学习模式,优化NOMA组的功率分配因子.仿真结果显示,与其他接入算法和功率分配比较,当用户数目为26时,本文提出的接入算法和功率分配分别比VLC-NOMA网络的总MOS值提高18.06%和10.94%.展开更多
One of the major challenges arising in internet of military things(IoMT)is accommodating massive connectivity while providing guaranteed quality of service(QoS)in terms of ultra-high reliability.In this regard,this pa...One of the major challenges arising in internet of military things(IoMT)is accommodating massive connectivity while providing guaranteed quality of service(QoS)in terms of ultra-high reliability.In this regard,this paper presents a class of code-domain nonorthogonal multiple accesses(NOMAs)for uplink ultra reliable networking of massive IoMT based on tactical datalink such as Link-16 and joint tactical information distribution system(JTIDS).In the considered scenario,a satellite equipped with Nr antennas servers K devices including vehicles,drones,ships,sensors,handset radios,etc.Nonorthogonal coded modulation,a special form of multiple input multiple output(MIMO)-NOMA is proposed.The discussion starts with evaluating the output signal to interference-plus-noise(SINR)of receiver filter,leading to the unveiling of a closed-form expression for overloading systems as the number of users is significantly larger than the number of devices admitted such that massive connectivity is rendered.The expression allows for the development of simple yet successful interference suppression based on power allocation and phase shaping techniques that maximizes the sum rate since it is equivalent to fixed-point programming as can be proved.The proposed design is exemplified by nonlinear modulation schemes such as minimum shift keying(MSK)and Gaussian MSK(GMSK),two pivotal modulation formats in IoMT standards such as Link-16 and JITDS.Numerical results show that near capacity performance is offered.Fortunately,the performance is obtained using simple forward error corrections(FECs)of higher coding rate than existing schemes do,while the transmit power is reduced by 6 dB.The proposed design finds wide applications not only in IoMT but also in deep space communications,where ultra reliability and massive connectivity is a keen concern.展开更多
文摘在基于非正交多址接入技术的多用户下行室内可见光通信(Visible light communication system based on non⁃orthogonal multiple access technology,VLC⁃NOMA)系统中,针对和速率与用户公平性冲突的问题,提出一种基于加权和速率最大化的迭代功率分配方案。该方案以最大化加权和速率为目标,可通过改变权重因子来调节用户公平性。由于目标问题属于非凸优化问题,通过辅助变量法和凸优化理论将该非凸问题转化为凹问题,再通过拉格朗日对偶法进行求解,并根据问题的解设计了一种迭代功率分配算法。对所提算法的收敛性、系统和速率以及用户公平性进行了仿真。结果表明,所提迭代功率分配算法具有良好的收敛性,相较于VLC⁃OMA系统,VLC⁃NOMA系统能够获得更好的和速率性能。通过调整权重因子,在牺牲较小系统和速率的情况下能够获得比现有功率分配方案更好的系统和速率与用户公平性。
文摘可见光通信与非正交多址技术结合,是满足室内高速通信和宽带数据接入的重要方法 .由于室内密集设备通信需求增长,小区间干扰和资源紧缺日趋严重,为了降低小区间干扰,进一步增强室内用户设备高速通信的用户体验质量(Quality of Experience,QoE)和提高可见光通信的频谱资源利用率,提出室内基于非正交多址接入的可见光通信(Visible Light Communication-Non-Orthogonal Multiple Access,VLC-NOMA)协作多点用户接入和功率分配算法.在用户接入阶段,设计基于QoE和多接入点协作的用户接入(User Access algorithm based on User Experience Quality and Coordinated Multipoint,UA-UEQCM)算法,根据用户需求的最小速率、推荐速率值和VLC-NOMA提供的可达速率,评估用户的QoE值和等效的用户满意度值;然后,基于VLC-NOMA中用户需求的平均意见评分(Mean Opinion Score,MOS)和VLC接入点协作可用资源,设计NOMA用户组的效用函数优化用户设备与多个接入点协作接入的双向选择,提高VLC-NOMA网络的MOS值;在功率分配阶段,采用改进教与学优化方法优化NOMA组的功率分配,设计VLC-NOMA的总MOS值为适应度函数值,采用自适应更新和学习模式,优化NOMA组的功率分配因子.仿真结果显示,与其他接入算法和功率分配比较,当用户数目为26时,本文提出的接入算法和功率分配分别比VLC-NOMA网络的总MOS值提高18.06%和10.94%.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.61601346 and 62377039)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2018JQ6044)+2 种基金the Ministry of Industry and Information Technology of the People's Republic of China(Grant No.2023-276-1-1)the Fundamental Research Funds for the Central Universities,Northwestern Polytechnical University(Grant No.31020180QD089)the Aeronautical Science Foundation of China(Grant Nos.20200043053004 and 20200043053005)。
文摘One of the major challenges arising in internet of military things(IoMT)is accommodating massive connectivity while providing guaranteed quality of service(QoS)in terms of ultra-high reliability.In this regard,this paper presents a class of code-domain nonorthogonal multiple accesses(NOMAs)for uplink ultra reliable networking of massive IoMT based on tactical datalink such as Link-16 and joint tactical information distribution system(JTIDS).In the considered scenario,a satellite equipped with Nr antennas servers K devices including vehicles,drones,ships,sensors,handset radios,etc.Nonorthogonal coded modulation,a special form of multiple input multiple output(MIMO)-NOMA is proposed.The discussion starts with evaluating the output signal to interference-plus-noise(SINR)of receiver filter,leading to the unveiling of a closed-form expression for overloading systems as the number of users is significantly larger than the number of devices admitted such that massive connectivity is rendered.The expression allows for the development of simple yet successful interference suppression based on power allocation and phase shaping techniques that maximizes the sum rate since it is equivalent to fixed-point programming as can be proved.The proposed design is exemplified by nonlinear modulation schemes such as minimum shift keying(MSK)and Gaussian MSK(GMSK),two pivotal modulation formats in IoMT standards such as Link-16 and JITDS.Numerical results show that near capacity performance is offered.Fortunately,the performance is obtained using simple forward error corrections(FECs)of higher coding rate than existing schemes do,while the transmit power is reduced by 6 dB.The proposed design finds wide applications not only in IoMT but also in deep space communications,where ultra reliability and massive connectivity is a keen concern.
