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25 February 2017, Volume 15 Issue 1

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The whole issue of ZTE Communications February 2017, Vol. 15 No. 1

2017, 15(1):  0. 

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Special Topic

Channel Measurement and Modeling for Heterogeneous 5G

CUI Shuguang, CHENG Xiang

2017, 15(1):  1-2. 

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An Overview of Non-Stationary Property for Massive MIMO Channel Modeling

ZHANG Ping, CHEN Jianqiao, TANG Tian

2017, 15(1):  3-7.  doi:10.3969/j.issn.1673-5188.2017.01.001

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Massive multiple-input multiple-output (MIMO) emerges as one of the most promising technologies for 5G mobile communication systems. Compared to the conventional MIMO channel models, channel researches and measurements show that significant non-stationary properties rise in massive MIMO channels. Therefore, an accurate channel model is indispensable for the sake of massive MIMO system design and performance evaluation. This article presents an overview of methods of modeling non-stationary properties on both the array and time axes, which are mainly divided into two major categories: birth-death (BD) process and cluster visibility region (VR) method. The main concepts and theories are described, together with useful implementation guidelines. In conclusion, a comparison between these two methods is made.

Measurement-Based Channel Characterization for 5G Wireless Communications on Campus Scenario

YANG Mi, HE Ruisi, AI Bo, XIONG Lei, DONG Honghui, LI Jianzhi, WANG Wei, FAN Wei, QIN Hongfeng

2017, 15(1):  8-13.  doi:10.3969/j.issn.1673-5188.2017.01.002

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The fifth generation (5G) communication has been a hotspot of research in recent years, and both research institutions and industrial enterprises put a lot of interests in 5G communications at some new frequency bands. In this paper, we investigate the radio channels of 5G systems below 6 GHz according to the 5G communication requirements and scenarios. Channel measurements were conducted on the campus of Beijing Jiaotong University, China at two key optional frequency bands below 6 GHz. By using the measured data, we analyzed key channel parameters at 460 MHz and 3.5 GHz, such as power delay profile, path loss exponent, shadow fading, and delay spread. The results are helpful for the 5G communication system design.

A Survey of Massive MIMO Channel Measurements and Models

ZHANG Jianhua, WANG Chao, WU Zhongyuan, ZHANG Weite

2017, 15(1):  14-22.  doi:10.3969/j.issn.1673-5188.2017.01.003

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Compared with conventional multiple-input multiple-output (MIMO), massive MIMO system with tens or even hundreds of antennas is able to give better performance in capacity and spectral efficiency, which is a promising technology for 5G. Considering this, massive MIMO has become a hot research topic all over the world. In this paper, the channel measurements and models of massive MIMO in recent years are summarized. Besides, the related 256 antenna elements with 200 MHz bandwidth at 3.5 GHz proposed by our team, the verification of rationality of the measurement method, and the spatial evolution of clusters in mobile scenario are provided.

Feasibility Study of 60 GHz UWB System for Gigabit M2M Communications

WANG Qi, GENG Suiyan, ZHAO Xiongwen, HONG Wei, Katsuyuki Haneda

2017, 15(1):  23-27.  doi:10.3969/j. issn.1673-5188.2017.01.004

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In this paper, the feasibility and performance of millimeter wave (mmWave) 60 GHz ultra-wide band (UWB) systems for gigabit machine-to-machine (M2M) communications are analyzed. Specifically, based on specifications, channel measurements and models for both line-of-sight (LOS) and non-LOS (NLOS) scenarios, 60 GHz propagation mechanisms are summarized, and 60 GHz UWB link budget and performance are analyzed. Tests are performed for determining ranges and antenna configurations. Results show that gigabit capacity can be achieved with omni-directional antennas configuration at the transceiver, especially in LOS conditions. When the LOS path is blocked by a moving person or by radiowave propagation in the NLOS situation, omni-directional and directional antennas configuration at the transceiver is required, especially for a larger range between machines in office rooms. Therefore, it is essential to keep a clear LOS path in M2M applications like gigabit data transfer. The goal of this work is to provide useful information for standardizations and design of 60 GHz UWB systems.

Measurement-Based Spatial-Consistent Channel Modeling Involving Clusters of Scatterers

YIN Xuefeng, ZHANG Nan, Stephen Wang, CHENG Xiang

2017, 15(1):  28-34.  doi:10.3969/j.issn.1673-5188.2017.01.005

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In this paper, the conventional method of establishing spatial channel models (SCMs) based on measurements is extended by including clusters- of- scatterers (CoSs) that exist along propagation paths. The channel models resulted utilizing this new method are applicable for generating channel realizations of reasonable spatial consistency, which is required for designing techniques and systems of the fifth generation wireless communications. The scatterers’ locations are estimated from channel measurement data obtained using large- scale antenna arrays through the Space- Alternating Generalized Expectation- Maximization (SAGE) algorithm derived under a spherical wavefront assumption. The stochastic properties of CoSs extracted from real measurement data in an indoor environment are presented.

Review

A Survey of System Software Techniques for Emerging NVMs

BAI Tongxin, DONG Zhenjiang, CAI Manyi, FAN Xiaopeng, XU Chengzhong, LIU Lixia

2017, 15(1):  35-42.  doi:10.3969/j.issn.1673-5188.2017.01.006

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The challenges of power consumption and memory capacity of computers have driven rapid development on non-volatile memories (NVM). NVMs are generally faster than traditional secondary storage devices, write persistently and many offer byte addressing capability. Despite these appealing features, NVMs are difficult to manage and program, which makes it hard to use them as a drop-in replacement for dynamic random-access memory (DRAM). Instead, a majority of modern systems use NVMs through the IO and the file system abstractions. Hiding NVMs under these interfaces poses challenges on how to exploit the new hardware’s performance potential in the existing system software framework. In this article, we survey the key technical issues arisen in this area and introduce several recently developed systems each of which offers novel solutions around these issues.

Research Paper

An Indoor Positioning Scheme for Visible Light Using Fingerprint Database with Multi-Parameters

CHEN Xiaohong, QIAN Chen, WEI Wei

2017, 15(1):  43-48.  doi:10.3969/j.issn.1673-5188.2017.01.007

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This paper proposes a novel indoor positioning scheme based on visible light communication (VLC). A new indoor VLC positioning scheme using fingerprint database with multi-parameters have been raised. We conduct simulation and experimental research on the illumination intensity distribution of several direction parameters. In the experiment, four LED matrixes are identified by LED-ID with room dimensions of 3.75×4.00×2.7 m³. The results show that the mean of the location error is 0.22 m in the receiving plane, verifying the correctness and feasibility of the positioning scheme.

A Method for Constructing Open-Domain Chinese Entity Hypernym Hierarchical Structure

CAI Hongbo, CHEN Hong, LIU Shen

2017, 15(1):  49-54.  doi:10.3969/j. issn.1673-5188.2017.01.008

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Entity relation is an essential component of some famous knowledge bases, such as Freebase, Yago and Knowledge Graph, while the hyponymy plays an important role in entity relations that show the relationship between the more general terms (hypernyms) and the more specific instances of the terms (hyponyms). In this paper, we present a comprehensive scheme of open-domain Chinese entity hypernym hierarchical construction. Some of the most important unsupervised and heuristic approaches for building hierarchical structure are covered in sufficient detail along with reasonable analyses. We experimentally evaluate the proposed methods and compare them with other baselines. The result shows high precision of our method and the proposed scheme will be further improved with larger scale corpora.

Moving Target Detection and Tracking for Smartphone Automatic Focusing

HU Rongchun, WANG Xiaoyang, ZHENG Yunchang, PENG Zhenming

2017, 15(1):  55-60.  doi:10.3969/j.issn.1673-5188.2017.01.009

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In this paper, a non-contact auto-focusing method is proposed for the essential function of auto-focusing in mobile devices. Firstly, we introduce an effective target detection method combining the 3-frame difference algorithm and Gauss mixture model, which is robust for complex and changing background. Secondly, a stable tracking method is proposed using the local binary patter feature and camshift tracker. Auto-focusing is achieved by using the coordinate obtained during the detection and tracking procedure. Experiments show that the proposed method can deal with complex and changing background. When there exist multiple moving objects, the proposed method also has good detection and tracking performance. The proposed method implements high efficiency, which means it can be easily used in real mobile device systems.

Nonbinary LDPC BICM for Next-Generation High-Speed Optical Transmission Systems

LIN Changyu, Ivan B. Djordjevic, WANG Weiming, CAI Yi

2017, 15(1):  61-66.  doi:10.3969/j. issn.1673-5188.2017.01.010

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We propose a nonbinary byte-interleaved coded-modulation scheme with inner and outer turbo-like iterative decoder. The net coding gain is 0.6 dB higher than the state-of-the-art binary single parity check (SPC) low-density parity-check (LDPC) based turbo-product counterpart, with adjustable iterations and lower error-floor. We provide the details of Bahl-Cocke-Jelinek-Raviv (BCJR) based inner code decoder and optimum signal constellation design (OSCD) method in this paper. The single-mode fiber (SMF) channel simulation is also discussed.