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本文对TD-LTE和LTE FDD的技术特点进行比较,指出两者在系统设计方面的主要差异,以及这些设计差异对系统性能的影响.在技术比较的基础上,从技术融合和产业融合两方面对TD-LTE和LTE FDD的融合兼容、同步发展进行了探讨. 相似文献
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中继技术能够对原有基站进行覆盖增强,同时OFDMA技术是下一代移动通信的主要多址方式,因而研究设计OFDMA技术约束下的中继方案,具有非常现实的意义.以LTE物理层帧结构为基础,针对OFDMA调制系统的中继实现方式进行了深入分析,结合OFDMA系统灵活的时频资源分配特点,提出针对OFDMA的多跳/单跳资源分配方法,最后,还提出一种针对FDD模式的OFDMA中继实现方案,对认为中继只能用于TDD系统的传统观念进行了前沿性的拓展. 相似文献
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文章首先描述了TD—SCDMA的技术演进路线,然后对TD—LTE的标准进展作了简要的概括,最后介绍了了大唐移动在TD—LTE方面取得的进展。 相似文献
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针对频分双工(Frequency Division Duplexing,FDD)大规模多入多出(Multiple-Input Multiple-Output,MIMO)系统中现有信道状态信息(Channel State Information,CSI)反馈方法复杂度高、反馈精度低的问题,本文提出一种基于深度学习的CSI压缩反馈方法.该方法首先采用卷积神经网络(Convolutional Neural Network,CNN)提取信道特征矢量,然后利用最大池化(Maxpooling)网络压缩CSI,最后考虑到大规模MIMO信道存在空间相关性的特点,分别对单用户和多用户场景使用双向长短期记忆(Bidirectional Long Short-Term Memory,Bi-LSTM)网络和双向卷积长短期记忆(Bidirectional Convolutional Long Short-Term Memory,Bi-ConvLSTM)网络对CSI进行重构.本文利用大规模MIMO信道数据对所提的深度学习网络进行离线训练,该网络学习到的信道信息能充分表征信道的状态.仿真结果表明,与已有的典型CSI反馈方法相比,本文所提方法反馈精度更高,运行时间更短,系统性能提升明显. 相似文献
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第三代移动通信之发展 总被引:3,自引:1,他引:2
本在简述了第三代移动通信标准概况和世界第三代移动通信发展主要现状的基础上,着重介绍了TD-SCDMA技术;比较了FDD和TDD两种模式,指出TDD与FDD两种模式有着相副互无法取代的优点。 相似文献
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The traffic performance of integrated 3G wide-band code division multiple access (WCDMA) and GSM/GPRS network is evaluated.
This type of network links two cellular radio systems which have different set of frequency bands and the same coverage size.
The base station of 3G WCDMA is installed on an existing GSM/GPRS site. Dual-mode mobile terminals use handoff to establish
calls on the better system. The soft handoff or inter-frequency hard handoff occurs when mobile terminals of 3G WCDMA or GSM/GPRS
move between two adjacent cells, respectively. The inter-system hard handoffs are used between 3G WCDMA and GSM/GPRS systems.
The data rate conversions between different systems, soft handoff region size, multiple data rate multimedia services, and
the effect of the mobile terminal mobility on the user mean dwell time in each system are considered in the study. The simulation
results demonstrate that a great traffic performance improvement on the complementary use of 3G WCDMA and GSM/GPRS cellular
radio networks compared with the use of GSM/GPRS cellular radio networks. When high-data rate transmission is chosen for low-mobility
subscribers, both the handoff failure probability, and carried traffic rates increase with the new call generation rate. However,
both rates decrease conversely with the increasing new call generation rate as soon as the new call generation rate exceeds
a critical value. This causes the integrated networks saturation. The higher mean speed for the mobile terminals produces
lower new call blocking probabilities and total carried traffic. The new call blocking probabilities and total carried traffic
increase with the size of the soft handoff region. 相似文献