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TN911; 分析了超宽带室内信号的传播规律,即多径分量成簇到达.在实测数据的基础上,研究了信道模型参数的一般规律:簇的到达率Λ应该远小于径的到达率λ,簇的衰减系数Γ应该大于径的衰减系数γ,并修正了IEEE 802.15.3a信道模型CM2环境下的模型参数.仿真结果表明:修正参数后的CM2信道模型优于原模型,更能体现出多径分量成簇到达特性,与实测数据相比较,能更好地拟合实测数据.

本文回顾了近二十年来物理层安全领域的发展, 着重追踪了基于密钥的物理层安全机制的演变过程. 无线信道密钥生成方法的核心在于合法通信双方通过公共信道和无差错的反馈信道通信共同产生一组安全密钥. 而无线信道的短时互易性为基于密钥的物理层安全机制提供了实际应用的可能. 根据该密钥生成方法的流程, 本文首先从互易性验证、误差补偿、信道特征及去相关四个方面对信道的测量, 结合真实的应用场景作了详细的分析. 而在测量值量化、信息调和以及保密增强环节, 分别讨论了该领域已有文献在这些环节提出的方法的理论依据并对比了基于各种不同方法的密钥的生成算法的优劣. 最后, 本文归纳了在第五代移动通信方式下该领域潜在的研究方向和可能面临的难题.

The emerging fifth generation（5G） wireless communication system raises new requirements on spectral efficiency and energy efficiency. A massive multiple-input multiple-output（MIMO） system, equipped with tens or even hundreds of antennas, is capable of providing significant improvements to spectral efficiency,energy efficiency, and robustness of the system. For the design, performance evaluation, and optimization of massive MIMO wireless communication systems, realistic channel models are indispensable. This article provides an overview of the latest developments in massive MIMO channel measurements and models. Also, we compare channel characteristics of four latest massive MIMO channel models, such as receiver spatial correlation functions and channel capacities. In addition, future challenges and research directions for massive MIMO channel measurements and modeling are identified.

This paper presents 28 GHz path loss model based on cluster obtained from channel measurement campaigns with rotating platforms and directional antennas in the indoor and outdoor environments. The transmitter（TX） and receiver（RX） both sweep a large range of angles in the azimuth and elevation plane on account of covering main propagation paths and measuring burden. As the sequence number of cluster increases, the path loss exponents（PLEs） increase while shadow factors also have a growing tendency. The PLE of all-clusters is the least because of multi propagation paths, and the LOS PLEs of corridor scenario are less compared with that of office scenario because of corridor＇s long and narrow structure. This improved model not only considers cluster characteristics, but also unites directional and omnidirectional models into the same framework, which to some extent improves the 5G mm Wave channel model.

Wireless communication for high-speed railways (HSRs) that provides reliable and high data rate communication between the train and trackside networks is a challenging task. It is estimated that the wireless communication traffic could be as high as 65 Mbps per high-speed train. The development of such HSR communications systems and standards requires, in turn, accurate models for the HSR propagation channel. This article provides an overview of existing HSR channel measurement campaigns in recent years. Particularly, some important measurement and modeling results in various HSR scenarios, such as viaduct and U-shaped groove (USG), are briefly described and analyzed. In addition, we review a novel channel sounding method, which can highly improve the measurement efficiency in HSR environment.