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Millimeter Wave Wireless Communications and Networks

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A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Sensor Networks".

Deadline for manuscript submissions: closed (31 May 2016) | Viewed by 84817

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Prof. Dr. Yonghui Lee

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Guest Editor

School of Electrical and Information Engineering, The University of Sydney, Sydney, NSW 2006, Australia
Interests: millimeter-wave wireless communications; machine-to-machine communications; cooperative communications; coding techniques; wireless sensor networks
Special Issues, Collections and Topics in MDPI journals

Dr. Kei Sakaguchi

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Guest Editor

¹ Dept. Wireless Communications and Networks Fraunhofer Heirich-Hertz-Institute, Germany
² Dept. Electrical and Electronic Engineering Tokyo Institute of Technology, Japan
Interests: 5G; millimeter-wave; heterogeneous networks; MIMO; wireless energy transfer

Dr. Yong Li

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Guest Editor

Department of Electronic Engineering, Tsinghua University, Rohm Building 10-202, Beijing 100084, China
Interests: urban sensing and computing; wireless sensor networks; mobile big data; mobile computing; social networks; network science and future internet

Dr. He (Henry) Chen

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Guest Editor

School of Electrical and Information Engineering, The University of Sydney, Sydney, NSW 2006, Australia
Interests: millimeter-wave wireless communications; wireless energy transfer and harvesting; cooperative communications; smart gird; game theory and distributed optimziation theory

Special Issue Information

Dear Colleagues,

Global mobile data traffic is doubling every year, and this trend will continue through the next decade. It is predicted that, within the next ten years, trillions of devices will connect to mobile networks. They will generate a more than 1000-time increase in mobile traffic and result in a spectrum shortage and clogged networks. This spectrum shortage will propel an increase in dropped calls, a rise in mobile data prices, and slowing of data speeds, a nightmare scenario for wireless operators and consumers.

This global spectrum crisis has motivated the exploration of underutilized millimeter wave (mmWave) frequency spectrum from 30 G–300 GHz for future mobile broadband communication networks. Large expanses of a new spectrum in this band could be opened up. Currently, the mmWave unlicensed band at 60 GHz is exploited in the next generation of wireless local area networks to support multi-gigabit data transmissions. Furthermore, mmWave licensed spectrum at other frequencies has been demonstrated to be feasible for 5G cellular systems.

In this Special Issue, we solicit original papers with high quality related to millimeter wave communications and networks. Contributions may include, but are not limited to:

Propagation measurements and channel modeling in mmWave bands
Efficient mmWave channel estimation algorithms
Massive MIMO for mmWave communications (e.g., transceiver desgin)
Wireless back/front haul using mmWave communictions
5G cellular networks utilizing mmWave spectrum
Cooperative and relay techniques for mmWave communictions
Coding techniques for mmWave systems
Wireless energy transfer and harvesting in mmWave bands
New MAC and routing protocols for mmWave communication networks
Novel mobile network architectures supporting mmWave systems
C/U plane seperation in 5G networks involving mmWaves
mmWave communication systems prototyping
New applications of mmWave techniques to other networks

Dr. Yonghui Li
Dr. Kei Sakaguchi
Dr. Yong Li
Dr. He (Henry) Chen
Guest Editors

Manuscript Submission Information

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Published Papers (11 papers)

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Research

689 KiB

Open AccessArticle

An Off-Grid Turbo Channel Estimation Algorithm for Millimeter Wave Communications

by Lingyi Han, Yuexing Peng, Peng Wang and Yonghui Li

Sensors 2016, 16(10), 1562; https://doi.org/10.3390/s16101562 - 22 Sep 2016

Cited by 2 | Viewed by 4609

Abstract

The bandwidth shortage has motivated the exploration of the millimeter wave (mmWave) frequency spectrum for future communication networks. To compensate for the severe propagation attenuation in the mmWave band, massive antenna arrays can be adopted at both the transmitter and receiver to provide large array gains via directional beamforming. To achieve such array gains, channel estimation (CE) with high resolution and low latency is of great importance for mmWave communications. However, classic super-resolution subspace CE methods such as multiple signal classification (MUSIC) and estimation of signal parameters via rotation invariant technique (ESPRIT) cannot be applied here due to RF chain constraints. In this paper, an enhanced CE algorithm is developed for the off-grid problem when quantizing the angles of mmWave channel in the spatial domain where off-grid problem refers to the scenario that angles do not lie on the quantization grids with high probability, and it results in power leakage and severe reduction of the CE performance. A new model is first proposed to formulate the off-grid problem. The new model divides the continuously-distributed angle into a quantized discrete grid part, referred to as the integral grid angle, and an offset part, termed fractional off-grid angle. Accordingly, an iterative off-grid turbo CE (IOTCE) algorithm is proposed to renew and upgrade the CE between the integral grid part and the fractional off-grid part under the Turbo principle. By fully exploiting the sparse structure of mmWave channels, the integral grid part is estimated by a soft-decoding based compressed sensing (CS) method called improved turbo compressed channel sensing (ITCCS). It iteratively updates the soft information between the linear minimum mean square error (LMMSE) estimator and the sparsity combiner. Monte Carlo simulations are presented to evaluate the performance of the proposed method, and the results show that it enhances the angle detection resolution greatly. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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1557 KiB

Open AccessArticle

Performance Evaluation of Analog Beamforming with Hardware Impairments for mmW Massive MIMO Communication in an Urban Scenario

by Sonia Gimenez, Sandra Roger, Paolo Baracca, David Martín-Sacristán, Jose F. Monserrat, Volker Braun and Hardy Halbauer

Sensors 2016, 16(10), 1555; https://doi.org/10.3390/s16101555 - 22 Sep 2016

Cited by 16 | Viewed by 6887

Abstract

The use of massive multiple-input multiple-output (MIMO) techniques for communication at millimeter-Wave (mmW) frequency bands has become a key enabler to meet the data rate demands of the upcoming fifth generation (5G) cellular systems. In particular, analog and hybrid beamforming solutions are receiving increasing attention as less expensive and more power efficient alternatives to fully digital precoding schemes. Despite their proven good performance in simple setups, their suitability for realistic cellular systems with many interfering base stations and users is still unclear. Furthermore, the performance of massive MIMO beamforming and precoding methods are in practice also affected by practical limitations and hardware constraints. In this sense, this paper assesses the performance of digital precoding and analog beamforming in an urban cellular system with an accurate mmW channel model under both ideal and realistic assumptions. The results show that analog beamforming can reach the performance of fully digital maximum ratio transmission under line of sight conditions and with a sufficient number of parallel radio-frequency (RF) chains, especially when the practical limitations of outdated channel information and per antenna power constraints are considered. This work also shows the impact of the phase shifter errors and combiner losses introduced by real phase shifter and combiner implementations over analog beamforming, where the former ones have minor impact on the performance, while the latter ones determine the optimum number of RF chains to be used in practice. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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8739 KiB

Open AccessArticle

Proof-of-Concept of a Millimeter-Wave Integrated Heterogeneous Network for 5G Cellular

by Shozo Okasaka, Richard J. Weiler, Wilhelm Keusgen, Andrey Pudeyev, Alexander Maltsev, Ingolf Karls and Kei Sakaguchi

Sensors 2016, 16(9), 1362; https://doi.org/10.3390/s16091362 - 25 Aug 2016

Cited by 31 | Viewed by 10589

Abstract

The fifth-generation mobile networks (5G) will not only enhance mobile broadband services, but also enable connectivity for a massive number of Internet-of-Things devices, such as wireless sensors, meters or actuators. Thus, 5G is expected to achieve a 1000-fold or more increase in capacity over 4G. The use of the millimeter-wave (mmWave) spectrum is a key enabler to allowing 5G to achieve such enhancement in capacity. To fully utilize the mmWave spectrum, 5G is expected to adopt a heterogeneous network (HetNet) architecture, wherein mmWave small cells are overlaid onto a conventional macro-cellular network. In the mmWave-integrated HetNet, splitting of the control plane (CP) and user plane (UP) will allow continuous connectivity and increase the capacity of the mmWave small cells. mmWave communication can be used not only for access linking, but also for wireless backhaul linking, which will facilitate the installation of mmWave small cells. In this study, a proof-of-concept (PoC) was conducted to demonstrate the practicality of a prototype mmWave-integrated HetNet, using mmWave technologies for both backhaul and access. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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6602 KiB

Open AccessArticle

Channel Measurement and Modeling for 5G Urban Microcellular Scenarios

by Michael Peter, Richard J. Weiler, Barış Göktepe, Wilhelm Keusgen and Kei Sakaguchi

Sensors 2016, 16(8), 1330; https://doi.org/10.3390/s16081330 - 20 Aug 2016

Cited by 14 | Viewed by 6568

Abstract

In order to support the development of channel models for higher frequency bands, multiple urban microcellular measurement campaigns have been carried out in Berlin, Germany, at 60 and 10 GHz. In this paper, the collected data is uniformly analyzed with focus on the path loss (PL) and the delay spread (DS). It reveals that the ground reflection has a dominant impact on the fading behavior. For line-of-sight conditions, the PL exponents are close to free space propagation at 60 GHz, but slightly smaller (1.62) for the street canyon at 10 GHz. The DS shows a clear dependence on the scenario (median values between 16 and 38 ns) and a strong distance dependence for the open square and the wide street canyon. The dependence is less distinct for the narrow street canyon with residential buildings. This behavior is consistent with complementary ray tracing simulations, though the simplified model tends to overestimate the DS. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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948 KiB

Open AccessArticle

Beamforming Based Full-Duplex for Millimeter-Wave Communication

by Xiao Liu, Zhenyu Xiao, Lin Bai, Jinho Choi, Pengfei Xia and Xiang-Gen Xia

Sensors 2016, 16(7), 1130; https://doi.org/10.3390/s16071130 - 21 Jul 2016

Cited by 37 | Viewed by 7458

Abstract

In this paper, we study beamforming based full-duplex (FD) systems in millimeter-wave (mmWave) communications. A joint transmission and reception (Tx/Rx) beamforming problem is formulated to maximize the achievable rate by mitigating self-interference (SI). Since the optimal solution is difficult to find due to the non-convexity of the objective function, suboptimal schemes are proposed in this paper. A low-complexity algorithm, which iteratively maximizes signal power while suppressing SI, is proposed and its convergence is proven. Moreover, two closed-form solutions, which do not require iterations, are also derived under minimum-mean-square-error (MMSE), zero-forcing (ZF), and maximum-ratio transmission (MRT) criteria. Performance evaluations show that the proposed iterative scheme converges fast (within only two iterations on average) and approaches an upper-bound performance, while the two closed-form solutions also achieve appealing performances, although there are noticeable differences from the upper bound depending on channel conditions. Interestingly, these three schemes show different robustness against the geometry of Tx/Rx antenna arrays and channel estimation errors. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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2368 KiB

Open AccessArticle

Efficient Preamble Design Technique for Millimeter-Wave Cellular Systems with Beamforming

by Dae Geun Han, Yeong Jun Kim and Yong Soo Cho

Sensors 2016, 16(7), 1129; https://doi.org/10.3390/s16071129 - 21 Jul 2016

Cited by 2 | Viewed by 5521

Abstract

The processing time for beam training in millimeter-wave (mmWave) cellular systems can be significantly reduced by a code division multiplexing (CDM)-based technique, where multiple beams are transmitted simultaneously with their corresponding Tx beam IDs (BIDs) in the preamble. However, mmWave cellular systems with CDM-based preambles require a large number of cell IDs (CIDs) and BIDs, and a high computational complexity for CID and BID (CBID) searches. In this paper, a new preamble design technique that can increase the number of CBIDs significantly is proposed, using a preamble sequence constructed by a combination of two Zadoff-Chu (ZC) sequences. An efficient technique for the CBID detection is also described for the proposed preamble. It is shown by simulations using a simple model of an mmWave cellular system that the proposed technique can obtain a significant reduction in the complexity of the CBID detection without a noticeable performance degradation, compared to the previous technique. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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4278 KiB

Open AccessArticle

First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands

by Kazuki Maruta, Tatsuhiko Iwakuni, Atsushi Ohta, Takuto Arai, Yushi Shirato, Satoshi Kurosaki and Masataka Iizuka

Sensors 2016, 16(7), 1051; https://doi.org/10.3390/s16071051 - 08 Jul 2016

Cited by 8 | Viewed by 5882

Abstract

Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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932 KiB

Open AccessArticle

Content-Based Multi-Channel Network Coding Algorithm in the Millimeter-Wave Sensor Network

by Kai Lin, Di Wang and Long Hu

Sensors 2016, 16(7), 1023; https://doi.org/10.3390/s16071023 - 01 Jul 2016

Viewed by 4662

Abstract

With the development of wireless technology, the widespread use of 5G is already an irreversible trend, and millimeter-wave sensor networks are becoming more and more common. However, due to the high degree of complexity and bandwidth bottlenecks, the millimeter-wave sensor network still faces numerous problems. In this paper, we propose a novel content-based multi-channel network coding algorithm, which uses the functions of data fusion, multi-channel and network coding to improve the data transmission; the algorithm is referred to as content-based multi-channel network coding (CMNC). The CMNC algorithm provides a fusion-driven model based on the Dempster-Shafer (D-S) evidence theory to classify the sensor nodes into different classes according to the data content. By using the result of the classification, the CMNC algorithm also provides the channel assignment strategy and uses network coding to further improve the quality of data transmission in the millimeter-wave sensor network. Extensive simulations are carried out and compared to other methods. Our simulation results show that the proposed CMNC algorithm can effectively improve the quality of data transmission and has better performance than the compared methods. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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653 KiB

Open AccessArticle

Mobility-Aware Caching and Computation Offloading in 5G Ultra-Dense Cellular Networks

by Min Chen, Yixue Hao, Meikang Qiu, Jeungeun Song, Di Wu and Iztok Humar

Sensors 2016, 16(7), 974; https://doi.org/10.3390/s16070974 - 25 Jun 2016

Cited by 148 | Viewed by 12554

Abstract

Recent trends show that Internet traffic is increasingly dominated by content, which is accompanied by the exponential growth of traffic. To cope with this phenomena, network caching is introduced to utilize the storage capacity of diverse network devices. In this paper, we first summarize four basic caching placement strategies, i.e., local caching, Device-to-Device (D2D) caching, Small cell Base Station (SBS) caching and Macrocell Base Station (MBS) caching. However, studies show that so far, much of the research has ignored the impact of user mobility. Therefore, taking the effect of the user mobility into consideration, we proposes a joint mobility-aware caching and SBS density placement scheme (MS caching). In addition, differences and relationships between caching and computation offloading are discussed. We present a design of a hybrid computation offloading and support it with experimental results, which demonstrate improved performance in terms of energy cost. Finally, we discuss the design of an incentive mechanism by considering network dynamics, differentiated user’s quality of experience (QoE) and the heterogeneity of mobile terminals in terms of caching and computing capabilities. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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574 KiB

Open AccessArticle

Millimetre-Wave Backhaul for 5G Networks: Challenges and Solutions

by Wei Feng, Yong Li, Depeng Jin, Li Su and Sheng Chen

Sensors 2016, 16(6), 892; https://doi.org/10.3390/s16060892 - 16 Jun 2016

Cited by 86 | Viewed by 13346

Abstract

The trend for dense deployment in future 5G mobile communication networks makes current wired backhaul infeasible owing to the high cost. Millimetre-wave (mm-wave) communication, a promising technique with the capability of providing a multi-gigabit transmission rate, offers a flexible and cost-effective candidate for 5G backhauling. By exploiting highly directional antennas, it becomes practical to cope with explosive traffic demands and to deal with interference problems. Several advancements in physical layer technology, such as hybrid beamforming and full duplexing, bring new challenges and opportunities for mm-wave backhaul. This article introduces a design framework for 5G mm-wave backhaul, including routing, spatial reuse scheduling and physical layer techniques. The associated optimization model, open problems and potential solutions are discussed to fully exploit the throughput gain of the backhaul network. Extensive simulations are conducted to verify the potential benefits of the proposed method for the 5G mm-wave backhaul design. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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3772 KiB

Open AccessArticle

Asymmetric Directional Multicast for Capillary Machine-to-Machine Using mmWave Communications

by Jung-Hyok Kwon and Eui-Jik Kim

Sensors 2016, 16(4), 515; https://doi.org/10.3390/s16040515 - 11 Apr 2016

Cited by 8 | Viewed by 4443

Abstract

The huge demand for high data rate machine-to-machine (M2M) services has led to the use of millimeter Wave (mmWave) band communications with support for a multi-Gbps data rate through the use of directional antennas. However, unnecessary sector switching in multicast transmissions with directional antennas results in a long delay, and consequently a low throughput. We propose asymmetric directional multicast (ADM) for capillary M2M to address this problem in mmWave communications. ADM provides asymmetric sectorization that is optimized for the irregular deployment pattern of mulicast group members. In ADM, an M2M gateway builds up asymmetric sectors with a beamwidth of a different size to cover all multicast group members with the minimum number of directional transmissions. The performance of ADM under various simulation environments is evaluated through a comparison with legacy mmWave multicast. The results of the simulation indicate that ADM achieves a better performance in terms of the transmission sectors, the transmission time, and the aggregate throughput when compared with the legacy multicast method. Full article

(This article belongs to the Special Issue Millimeter Wave Wireless Communications and Networks)

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