Non-orthogonal multiple access(NOMA) is a new access method to achieve high performance gains in terms of capacity and throughput, so it is currently under consideration as one of the candidates for fifth generation(5...Non-orthogonal multiple access(NOMA) is a new access method to achieve high performance gains in terms of capacity and throughput, so it is currently under consideration as one of the candidates for fifth generation(5 G) technologies. NOMA utilizes power domain in order to superimpose signals of multiple users in a single transmitted signal. This creates a lot of interference at the receive side. Although the use of successive interference cancellation(SIC) technique reduces the interference, but to further improve the receiver performance, in this paper, we have proposed a joint Walsh-Hadamard transform(WHT) and NOMA approach for achieving better performance gains than the conventional NOMA. WHT is a well-known code used in communication systems and is used as an orthogonal variable spreading factor(OVSF) in communication systems. Application of WHT to NOMA results in low bit error rate(BER) and high throughput performance for both low and high channel gain users. Further, it also reduces peak to average power ratio(PAPR) of the user signal. The results are discussed in terms of comparison between the conventionalNOMA and the proposed technique, which shows that it offers high performance gains in terms of low BER at different SNR levels, reduced PAPR, high user throughput performance and better spectral efficiency.展开更多
针对多输入多输出正交时频空间(multiple-input multiple-output orthogonal time frequency space,MIMO-OTFS)系统由最大时延、多普勒扩展、天线数量增加带来信道估计计算开销大、准确率下降的问题,提出了一种基于感知辅助和原子选择...针对多输入多输出正交时频空间(multiple-input multiple-output orthogonal time frequency space,MIMO-OTFS)系统由最大时延、多普勒扩展、天线数量增加带来信道估计计算开销大、准确率下降的问题,提出了一种基于感知辅助和原子选择门限的广义正交匹配追踪(sensing aided generalized orthogonal matching pursuit algorithm based on atomic threshold,SA-TGOMP)信道估计算法。该算法首先将雷达探测的用户和周围环境信息转化为OTFS信道的初始索引集,然后引入以固定值选取相关性原子进行迭代的策略和原子选择门限进行支撑集更新。实验结果表明,本文算法能够有效提高信道估计精度的同时减少导频开销。展开更多
针对基于定向传输的飞行器自组织网络(flying ad-hoc network,FANET)中拓扑变化频繁、链路质量波动以及初始建网困难等问题,提出了一种基于多输入多输出(multiple-input multipleoutput,MIMO)正交时频空(orthogonal time frequency spac...针对基于定向传输的飞行器自组织网络(flying ad-hoc network,FANET)中拓扑变化频繁、链路质量波动以及初始建网困难等问题,提出了一种基于多输入多输出(multiple-input multipleoutput,MIMO)正交时频空(orthogonal time frequency space,OTFS)通感一体化波形的感知辅助快速邻居发现方法,借助感知机制实时获取邻节点信息以加速建网效率,并采用新型的通感一体波形OTFS以对抗快变信道中的多普勒效应,提升链路质量。针对FANET场景研究物理层基于MIMOOTFS通感一体化波形的多目标检测技术;将物理层感知方案映射到上层网络中,设计感知辅助的高效邻居发现算法;最后提出一种多点通感协同机制,通过邻节点间交互感知信息和邻居发现表以间接感知及发现潜在目标,提升FANET初始建网的效率。仿真结果表明,所提方案相比传统通信组网协议可以极大降低FANET的初始建网耗时,增加目标感知精度,提升组网的整体性能。展开更多
针对低空经济通信中导频受限的多输入多输出正交频分复用(Multiple Input and Multiple Output Orthogonal Frequency Division Multiplexing,MIMO-OFDM)存在的信道估计精度低的问题,提出一种适用于低空多径环境的MIMO-OFDM信道估计新...针对低空经济通信中导频受限的多输入多输出正交频分复用(Multiple Input and Multiple Output Orthogonal Frequency Division Multiplexing,MIMO-OFDM)存在的信道估计精度低的问题,提出一种适用于低空多径环境的MIMO-OFDM信道估计新方法。在时频资源平面上,该方法利用信道平滑特征和导频信道系数在子载波和符号维度的关联,根据导频点生成初始的Voronoi图,然后基于插值数据点更新Voronoi图,并将两个Voronoi图叠加。更新Voronoi图中插值数据点所属的Voronoi小区域被初始Voronoi图划分为多块,根据每块面积计算权重,再将多个相邻导频处的信道估计值加权求和,从而得到对应插值数据点的信道估计值。仿真结果表明,与线性插值方法相比,所提方法使得信道估计归一化均方误差降低了50%,误比特率性能提升了1.6 dB。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
针对传统室内定位方法在准确性及稳定性上的不足,本文提出了一种基于信道状态信息(channel state information,CSI)的无源室内定位方法。该方法采用普通设备搭建了实验平台,离线阶段采集CSI数据建立位置指纹库,在线阶段则利用机器学习...针对传统室内定位方法在准确性及稳定性上的不足,本文提出了一种基于信道状态信息(channel state information,CSI)的无源室内定位方法。该方法采用普通设备搭建了实验平台,离线阶段采集CSI数据建立位置指纹库,在线阶段则利用机器学习的朴素贝叶斯算法进行位置分类。为进一步提高分类准确度,本文还提出了置信度方法,通过综合多条天线对的结果来减少位置误判。实验结果表明,本文所提出方法能有效实现对室内人员的无源定位,可以达到90%以上的准确度。展开更多
基金supported by Priority Research Centers Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education, Science and Technology (2018R1A6A1A03024003)
文摘Non-orthogonal multiple access(NOMA) is a new access method to achieve high performance gains in terms of capacity and throughput, so it is currently under consideration as one of the candidates for fifth generation(5 G) technologies. NOMA utilizes power domain in order to superimpose signals of multiple users in a single transmitted signal. This creates a lot of interference at the receive side. Although the use of successive interference cancellation(SIC) technique reduces the interference, but to further improve the receiver performance, in this paper, we have proposed a joint Walsh-Hadamard transform(WHT) and NOMA approach for achieving better performance gains than the conventional NOMA. WHT is a well-known code used in communication systems and is used as an orthogonal variable spreading factor(OVSF) in communication systems. Application of WHT to NOMA results in low bit error rate(BER) and high throughput performance for both low and high channel gain users. Further, it also reduces peak to average power ratio(PAPR) of the user signal. The results are discussed in terms of comparison between the conventionalNOMA and the proposed technique, which shows that it offers high performance gains in terms of low BER at different SNR levels, reduced PAPR, high user throughput performance and better spectral efficiency.
文摘针对多输入多输出正交时频空间(multiple-input multiple-output orthogonal time frequency space,MIMO-OTFS)系统由最大时延、多普勒扩展、天线数量增加带来信道估计计算开销大、准确率下降的问题,提出了一种基于感知辅助和原子选择门限的广义正交匹配追踪(sensing aided generalized orthogonal matching pursuit algorithm based on atomic threshold,SA-TGOMP)信道估计算法。该算法首先将雷达探测的用户和周围环境信息转化为OTFS信道的初始索引集,然后引入以固定值选取相关性原子进行迭代的策略和原子选择门限进行支撑集更新。实验结果表明,本文算法能够有效提高信道估计精度的同时减少导频开销。
文摘针对基于定向传输的飞行器自组织网络(flying ad-hoc network,FANET)中拓扑变化频繁、链路质量波动以及初始建网困难等问题,提出了一种基于多输入多输出(multiple-input multipleoutput,MIMO)正交时频空(orthogonal time frequency space,OTFS)通感一体化波形的感知辅助快速邻居发现方法,借助感知机制实时获取邻节点信息以加速建网效率,并采用新型的通感一体波形OTFS以对抗快变信道中的多普勒效应,提升链路质量。针对FANET场景研究物理层基于MIMOOTFS通感一体化波形的多目标检测技术;将物理层感知方案映射到上层网络中,设计感知辅助的高效邻居发现算法;最后提出一种多点通感协同机制,通过邻节点间交互感知信息和邻居发现表以间接感知及发现潜在目标,提升FANET初始建网的效率。仿真结果表明,所提方案相比传统通信组网协议可以极大降低FANET的初始建网耗时,增加目标感知精度,提升组网的整体性能。
文摘针对低空经济通信中导频受限的多输入多输出正交频分复用(Multiple Input and Multiple Output Orthogonal Frequency Division Multiplexing,MIMO-OFDM)存在的信道估计精度低的问题,提出一种适用于低空多径环境的MIMO-OFDM信道估计新方法。在时频资源平面上,该方法利用信道平滑特征和导频信道系数在子载波和符号维度的关联,根据导频点生成初始的Voronoi图,然后基于插值数据点更新Voronoi图,并将两个Voronoi图叠加。更新Voronoi图中插值数据点所属的Voronoi小区域被初始Voronoi图划分为多块,根据每块面积计算权重,再将多个相邻导频处的信道估计值加权求和,从而得到对应插值数据点的信道估计值。仿真结果表明,与线性插值方法相比,所提方法使得信道估计归一化均方误差降低了50%,误比特率性能提升了1.6 dB。
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。
文摘针对传统室内定位方法在准确性及稳定性上的不足,本文提出了一种基于信道状态信息(channel state information,CSI)的无源室内定位方法。该方法采用普通设备搭建了实验平台,离线阶段采集CSI数据建立位置指纹库,在线阶段则利用机器学习的朴素贝叶斯算法进行位置分类。为进一步提高分类准确度,本文还提出了置信度方法,通过综合多条天线对的结果来减少位置误判。实验结果表明,本文所提出方法能有效实现对室内人员的无源定位,可以达到90%以上的准确度。
