5G新空口标准中将引入毫米波通信用来提高数据传输速度和容量。为了确定在使用毫米波通信时对人体辐射影响,利用时域有限差分法(finite difference time domain,FDTD)研究了26 GHz的移动终端对心脏和下肢组织电磁辐射影响。将移动终端26...5G新空口标准中将引入毫米波通信用来提高数据传输速度和容量。为了确定在使用毫米波通信时对人体辐射影响,利用时域有限差分法(finite difference time domain,FDTD)研究了26 GHz的移动终端对心脏和下肢组织电磁辐射影响。将移动终端26GHz毫米波8 8阵列天线分别放置在心脏组织正前方10mm处和右侧下肢离地高800mm、正前方10mm处对组织进行辐射,并以此来计算对应位置的比吸收率。研究结果表明,阵列天线对心脏组织及下肢组织的比吸收率均低于国际安全标准,且下肢部位的比吸收率要低于心脏部位。展开更多
The fifth generation mobile communication（5G） systems can provide Gbit/s data rates from massive multiple-input multiple-output（MIMO） combined with the emerging use of millimeter wavelengths in small heterogeneous...The fifth generation mobile communication（5G） systems can provide Gbit/s data rates from massive multiple-input multiple-output（MIMO） combined with the emerging use of millimeter wavelengths in small heterogeneous cells. This paper develops an energy-efficiency based multi-user hybrid beamforming for downlink millimeter wave（mm Wave） massive MIMO systems. To make better use of directivity gains of the analog beamforming and flexible baseband processing of the digital beamforming, this paper proposes the analog beamforming to select the optimal beam which can maximize the power of the objective user and minimize the interference to all other users. In addition, the digital beamforming maximizes the energy efficiency of the objective user with zero-gradient-based approach. Simulation results show the proposed algorithm provide better bit error rate（BER） performance compared with the traditional hybrid beamforming and obviously improved the sum rate with the increase in the number of users. It is proved that multi-user MIMO（MU-MIMO） can be a perfect candidate for mm Wave massive MIMO communication system. Furthermore, the analog beamforming can mitigate the inter-user interference more effectively with the selection of the optimal beam and the digital beamforming can greatly improve the system performance through flexible baseband processing.展开更多
基金supported by the Hi-Tech Research and Development Program of China(2014AA01A705)
文摘The fifth generation mobile communication（5G） systems can provide Gbit/s data rates from massive multiple-input multiple-output（MIMO） combined with the emerging use of millimeter wavelengths in small heterogeneous cells. This paper develops an energy-efficiency based multi-user hybrid beamforming for downlink millimeter wave（mm Wave） massive MIMO systems. To make better use of directivity gains of the analog beamforming and flexible baseband processing of the digital beamforming, this paper proposes the analog beamforming to select the optimal beam which can maximize the power of the objective user and minimize the interference to all other users. In addition, the digital beamforming maximizes the energy efficiency of the objective user with zero-gradient-based approach. Simulation results show the proposed algorithm provide better bit error rate（BER） performance compared with the traditional hybrid beamforming and obviously improved the sum rate with the increase in the number of users. It is proved that multi-user MIMO（MU-MIMO） can be a perfect candidate for mm Wave massive MIMO communication system. Furthermore, the analog beamforming can mitigate the inter-user interference more effectively with the selection of the optimal beam and the digital beamforming can greatly improve the system performance through flexible baseband processing.
