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
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
针对低空多径效应和地杂波复合作用导致的低空目标探测性能下降,利用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)-多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达的空间和频率分集特性提高低空目标探测性...针对低空多径效应和地杂波复合作用导致的低空目标探测性能下降,利用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)-多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达的空间和频率分集特性提高低空目标探测性能.在建立正交频分复用-线性调频发射信号模型、多径效应模型和基于对称阿尔法稳定分布的地杂波模型基础上,得出了OFDM-MIMO雷达接收信号模型.采用匹配滤波器恢复发射-接收天线对信号,通过接收信号融合实现参差补偿,减小了接收信号能量的深度衰减和剧烈起伏.仿真算例表明OFDM-MIMO雷达能够有效减小回波信号剧烈起伏和杂波对目标探测的影响,实现多径干扰和杂波背景下对低空目标的稳定探测.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。
文摘针对低空多径效应和地杂波复合作用导致的低空目标探测性能下降,利用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)-多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达的空间和频率分集特性提高低空目标探测性能.在建立正交频分复用-线性调频发射信号模型、多径效应模型和基于对称阿尔法稳定分布的地杂波模型基础上,得出了OFDM-MIMO雷达接收信号模型.采用匹配滤波器恢复发射-接收天线对信号,通过接收信号融合实现参差补偿,减小了接收信号能量的深度衰减和剧烈起伏.仿真算例表明OFDM-MIMO雷达能够有效减小回波信号剧烈起伏和杂波对目标探测的影响,实现多径干扰和杂波背景下对低空目标的稳定探测.
