针对频分双工大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)通信系统中信道状态信息(Channel State Information,CSI)反馈方法复杂度高、精度低和开销大的问题,本文提出了一种基于深度学习的低复杂度CSI反馈方法.该方法通...针对频分双工大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)通信系统中信道状态信息(Channel State Information,CSI)反馈方法复杂度高、精度低和开销大的问题,本文提出了一种基于深度学习的低复杂度CSI反馈方法.该方法通过端到端的方式构建了一种从用户设备编码器到基站解码器相结合的网络结构.编解码器利用连续的平均池化层和上采样层完成特征图的降维和升维,同时引入深度可分离卷积神经网络减少网络参数量.在解码器部分,本文利用残差网络构建连续的拥有大卷积核的残差块逼近原始CSI矩阵.仿真结果表明,和已有的代表性方法相比,本文所提方法在归一化均方误差上有2 dB~5 dB的性能提升,在余弦相似度上也有2%~5%的提升,并且在时间复杂度和空间复杂度上均有更好的表现.展开更多
This paper presented a scheme of two-hop cellular network with fixed relay nodes (FRN). Based on this scheme, co-channel interference and signal interference ratio(SIR) received by base station(BS) and FRN were analyz...This paper presented a scheme of two-hop cellular network with fixed relay nodes (FRN). Based on this scheme, co-channel interference and signal interference ratio(SIR) received by base station(BS) and FRN were analyzed. Both the theoretical analysis and simulation results show that the SIR can be improved significantly when relays are employed in the network. The higher spectral efficiency can be obtained due to the improved two-hop link quality through the use of adaptive modulation and coding (AMC). The antenna height of FRN and the cell radius of BS and that of FRN influence SIR received by BS and FRN and the system spectral efficiency greatly. The proper antenna height of FRN and cell radius of BS and that of FRN were also given to get the highest spectral efficiency.展开更多
In the context of next-generation optical access networks beyond 10 G, for high SE and flexible dynamic bandwidth allocation (DBA), the scheme of hybrid 64/16/4QAM-OFDM signal for downlink transmission and hybrid 16/8...In the context of next-generation optical access networks beyond 10 G, for high SE and flexible dynamic bandwidth allocation (DBA), the scheme of hybrid 64/16/4QAM-OFDM signal for downlink transmission and hybrid 16/8/QPSK-OFDM signal for uplink transmission is successfully proposed and experimentally presented in a full-duplex PON based on OFDM system. Here, for the uplink, in order to unit management of the optical line terminal (OLT) and reduce cost, the optical source functioned as the optical subcarrier at optical network units (ONUs) is from OLT in the central station. Moreover, there is an external cavity laser (ECL) with center frequency of 193.2 THz not only employed as optical modulated signal but also acted as LO signal. Our simulation results show that bit error ratio (BER) under hardware detection forward error correction has been successfully gained after 20 km of SSMF transmission. It is observed that the receiver sensitivity of multilevel PSK (M-PSK) is obviously larger than that of the M-QAM in this measurement scheme.展开更多
提出了自适应双工的思想,基于该思想设计了一种新型的自适应非对称频分双工(AFDD,asymmetric frequency division duplex)传输方案。该方案综合考虑了未来移动通信中上下行链路业务非对称的特点以及电磁辐射对移动通信可能造成的影响,...提出了自适应双工的思想,基于该思想设计了一种新型的自适应非对称频分双工(AFDD,asymmetric frequency division duplex)传输方案。该方案综合考虑了未来移动通信中上下行链路业务非对称的特点以及电磁辐射对移动通信可能造成的影响,提出了一种自适应非对称双工以及频带分配方案。该方案具备传统FDD系统的优点,同时又具备了一定的TDD系统资源动态自适应调配的能力,可以提高频谱利用率。将AFDD与CDMA结合,证明了其相对于传统上下行等带宽系统可以获得性能上的提升。展开更多
基金National Science Fund for Creative ResearchGroups (No. 60521002) Chinese NationalKey Technology R&D Program(No. 2005-BA908B02)Science Foundation of ShanghaiMunicipal Commission of Science and Tech-nology(No.05dz05802)
文摘This paper presented a scheme of two-hop cellular network with fixed relay nodes (FRN). Based on this scheme, co-channel interference and signal interference ratio(SIR) received by base station(BS) and FRN were analyzed. Both the theoretical analysis and simulation results show that the SIR can be improved significantly when relays are employed in the network. The higher spectral efficiency can be obtained due to the improved two-hop link quality through the use of adaptive modulation and coding (AMC). The antenna height of FRN and the cell radius of BS and that of FRN influence SIR received by BS and FRN and the system spectral efficiency greatly. The proper antenna height of FRN and cell radius of BS and that of FRN were also given to get the highest spectral efficiency.
文摘In the context of next-generation optical access networks beyond 10 G, for high SE and flexible dynamic bandwidth allocation (DBA), the scheme of hybrid 64/16/4QAM-OFDM signal for downlink transmission and hybrid 16/8/QPSK-OFDM signal for uplink transmission is successfully proposed and experimentally presented in a full-duplex PON based on OFDM system. Here, for the uplink, in order to unit management of the optical line terminal (OLT) and reduce cost, the optical source functioned as the optical subcarrier at optical network units (ONUs) is from OLT in the central station. Moreover, there is an external cavity laser (ECL) with center frequency of 193.2 THz not only employed as optical modulated signal but also acted as LO signal. Our simulation results show that bit error ratio (BER) under hardware detection forward error correction has been successfully gained after 20 km of SSMF transmission. It is observed that the receiver sensitivity of multilevel PSK (M-PSK) is obviously larger than that of the M-QAM in this measurement scheme.
文摘提出了自适应双工的思想,基于该思想设计了一种新型的自适应非对称频分双工(AFDD,asymmetric frequency division duplex)传输方案。该方案综合考虑了未来移动通信中上下行链路业务非对称的特点以及电磁辐射对移动通信可能造成的影响,提出了一种自适应非对称双工以及频带分配方案。该方案具备传统FDD系统的优点,同时又具备了一定的TDD系统资源动态自适应调配的能力,可以提高频谱利用率。将AFDD与CDMA结合,证明了其相对于传统上下行等带宽系统可以获得性能上的提升。
