Millimeter-Wave Cellular Wireless Networks: Potentials and Challenges
05 Feb 2014-Vol. 102, Iss: 3, pp 366-385
TL;DR: Measurements and capacity studies are surveyed to assess mmW technology with a focus on small cell deployments in urban environments and it is shown that mmW systems can offer more than an order of magnitude increase in capacity over current state-of-the-art 4G cellular networks at current cell densities.
Abstract: Millimeter-wave (mmW) frequencies between 30 and 300 GHz are a new frontier for cellular communication that offers the promise of orders of magnitude greater bandwidths combined with further gains via beamforming and spatial multiplexing from multielement antenna arrays. This paper surveys measurements and capacity studies to assess this technology with a focus on small cell deployments in urban environments. The conclusions are extremely encouraging; measurements in New York City at 28 and 73 GHz demonstrate that, even in an urban canyon environment, significant non-line-of-sight (NLOS) outdoor, street-level coverage is possible up to approximately 200 m from a potential low-power microcell or picocell base station. In addition, based on statistical channel models from these measurements, it is shown that mmW systems can offer more than an order of magnitude increase in capacity over current state-of-the-art 4G cellular networks at current cell densities. Cellular systems, however, will need to be significantly redesigned to fully achieve these gains. Specifically, the requirement of highly directional and adaptive transmissions, directional isolation between links, and significant possibilities of outage have strong implications on multiple access, channel structure, synchronization, and receiver design. To address these challenges, the paper discusses how various technologies including adaptive beamforming, multihop relaying, heterogeneous network architectures, and carrier aggregation can be leveraged in the mmW context.
Citations
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TL;DR: In this article, a millimeter-wave (mm-wave) broadband linearly polarized (LP) substrate integrated magneto-electric dipole (ME-dipole) with a low profile microstrip feeding structure covering the 22-33 GHz band is proposed.
Abstract: A millimeter-wave (mm-Wave) broadband linearly polarized (LP) substrate integrated magneto-electric dipole (ME-dipole) with a low-profile microstrip feeding structure covering the 22–33 GHz band is proposed in this article. It owns a good performance, particularly in terms of bandwidth and gain flatness. Importantly, the proposed substrate integrated LP ME-dipole element can be easily expanded into a full-corporate fed array without bandwidth degradation and requiring additional dielectric substrates. Moreover, its low-profile microstrip feeding structure locating on a hybrid substrate (include a thin dielectric substrate and a bonding film) makes the antennas amenable for direct integration with mm-Wave front-end circuits. Design, fabrication, and measurement of two arrays containing $4 \times 4$ and $8\,\, \times \,\, 8$ ME-dipoles are carried out, respectively. The measured results agree well with the simulated ones, validating the correctness of the proposed designs. The measured results of the $4 \times 4$ and $8\times 8$ array antennas show that both the two prototypes exhibit a wide available bandwidth (considering |S11| < −10 dB and 3 dB gain bandwidth) of more than 44%, a cross-polarization level of lower than −35 dB, a low-profile feeding layer of only 0.227 mm, a peak gain of 19.18 and 25 dBi, respectively, etc. The exhibited performance metrics of the proposed array antennas are promising for a number of applications ranging from 5G communications, satellite communications, to automotive radars, and so on.
25 citations
TL;DR: Artificial noise (AN) aided two-stage secure hybrid beamforming algorithm is proposed in MIMO mm-wave relay system from the perspective of physical layer security and considerably improves the performance and achieves a balance between complexity and performance.
Abstract: Millimeter wave (mm-wave) communications, especially mm-wave relay systems, have been considered as a key technology for next-generation wireless networks due to the rich spectrum resources. However, the problem of information leakage in mm-wave relay systems has not been well investigated. In this paper, artificial noise (AN) aided two-stage secure hybrid beamforming algorithm is proposed in MIMO mm-wave relay system from the perspective of physical layer security. In each time slot of the relay communications, the RF analog beamforming matrices are designed in the first stage, and baseband digital beamforming matrices are designed in the second stage. Through the proposed algorithm, the joint optimization is avoided and the feedback is reduced, which brings low complexity. Moreover, the AN is applied to fight against the eavesdropper by deteriorating the eavesdropping channel. The simulation results show that the proposed hybrid beamforming algorithm considerably improves the performance and achieves a balance between complexity and performance.
24 citations
Cites methods from "Millimeter-Wave Cellular Wireless N..."
...beamforming has become a widely accepted beamforming method characterized by its simple hardware structure and low energy consumption [11]–[14]....
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TL;DR: An iterative pilot-aided algorithm based on the expectation conditional maximization for joint estimation of multipath channels, Wiener PHNs, and CFOs in decode-and-forward-based multi-relay orthogonal frequency division multiplexing systems is proposed.
Abstract: Impairments such as time varying phase noise (PHN) and carrier frequency offset (CFO) result in loss of synchronization and poor performance of multi-relay communication systems. Joint estimation of these impairments is necessary in order to correctly decode the received signal at the destination. In this paper, we address spectrally efficient multi-relay transmission scenarios where all the relays simultaneously communicate with the destination. We propose an iterative pilot-aided algorithm based on the expectation conditional maximization for joint estimation of multipath channels, Wiener PHNs, and CFOs in decode-and-forward-based multi-relay orthogonal frequency division multiplexing systems. Next, a new expression of the hybrid Cramer–Rao lower bound (HCRB) for the multi-parameter estimation problem is derived. Finally, an iterative receiver based on an extended Kalman filter for joint data detection and PHN tracking is employed. Numerical results show that the proposed estimator outperforms existing algorithms and its mean square error performance is close to the derived HCRB at different signal-to-noise ratios for different PHN variances. In addition, the combined estimation algorithm and the iterative receiver can significantly improve average bit-error rate (BER) performance compared with existing algorithms. In addition, the BER performance of the proposed system is close to the ideal case of perfect channel impulse responses, PHNs, and CFOs estimation.
24 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...However, this approach maintains higher BER performance at the expense of a loss in the range of network links which could be enhanced by using multi-relay to overcome the blockage issues in some communication systems such as mmWave systems [42]....
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TL;DR: This paper combines the gradient descent (GD) method and the iterative antenna training (IAT) technique, and proposes an iterative local GD (ILGD) algorithm, which can achieve a gain of more than 2 dB at a BER of $10^{-4}$ over the conventional IAT algorithm with the same training overhead.
Abstract: Analog beamforming has been considered an attractive technology for future single carrier millimeter-wave multiple-input multiple-output (MIMO) systems because of the high cost and huge power consumption of mixed-signal devices. Most conventional studies have focused on joint base station and user equipment (BS-UE) analog beamforming with the objective of improving the average signal to noise ratio performance before the baseband equalization. In contrast, this paper aims to optimize the BS-UE analog beamforming vectors in the sense of minimizing the mean square error of the baseband equalized signal. Considering practical implementation requirement, we combine the gradient descent (GD) method and the iterative antenna training (IAT) technique, and propose an iterative local GD (ILGD) algorithm. We analyze the convergence property, bit error rate (BER) performance, training overhead, and computational complexity of the ILGD algorithm. Simulation results show that the proposed ILGD algorithm can achieve a gain of more than 2 dB at a BER of $10^{-4}$ over the conventional IAT algorithm with the same training overhead.
24 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...However, such digital beamforming is not affordable in mmWave systems with large scale antenna arrays because of the high cost and huge power consumption [4], [7], [8]....
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TL;DR: In this article, the authors presented a novel design of a high gain and wideband antenna subarray from 23 GHz to 32 GHz, which covers the frequency bands proposed by the Federal Communications Commission (FCC) for 5G communications.
Abstract: Wideband arrays have recently received considerable attention in 5G applications to cover larger frequency bands. This paper presents a novel design of a high gain and wideband antenna subarray from 23 GHz to 32 GHz, which covers the frequency bands proposed by the Federal Communications Commission (FCC) for 5G communications. The proposed subarray consists of four radiating elements with wideband and high gain characteristics. These elements are composed of two stacked patches, which are fed using the proximity coupling technique. A unit-cell element prototype is first fabricated and tested to validate the gain and bandwidth performances. A 1× 4 subarray prototype is then fabricated and tested, while maintaining an element spacing less than half-wavelength at the center frequency, to avoid grating lobes and to keep the small size of the antenna subarray. The measurement results of the prototypes, i.e., unit cell element and subarray prototypes, show good agreements with the simulations. The subarray measurements demonstrate a high gain of 10–12 dBi, an impedance bandwidth of 33.4%, and a 1-dB gain bandwidth of 10.5%. The proposed antenna subarray is a good candidate for wideband and high gain antenna arrays suitable for 5G mmW applications.
24 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...Extensive propagation measurements presented in [5, 6] demonstrate that mmW systems can offer less interference and more capacity compared to the fourth generation (4G) cellular networks....
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References
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Book•
15 Jan 1996
TL;DR: WireWireless Communications: Principles and Practice, Second Edition is the definitive modern text for wireless communications technology and system design as discussed by the authors, which covers the fundamental issues impacting all wireless networks and reviews virtually every important new wireless standard and technological development, offering especially comprehensive coverage of the 3G systems and wireless local area networks (WLANs).
Abstract: From the Publisher:
The indispensable guide to wireless communicationsnow fully revised and updated!
Wireless Communications: Principles and Practice, Second Edition is the definitive modern text for wireless communications technology and system design. Building on his classic first edition, Theodore S. Rappaport covers the fundamental issues impacting all wireless networks and reviews virtually every important new wireless standard and technological development, offering especially comprehensive coverage of the 3G systems and wireless local area networks (WLANs) that will transform communications in the coming years. Rappaport illustrates each key concept with practical examples, thoroughly explained and solved step by step.
Coverage includes:
An overview of key wireless technologies: voice, data, cordless, paging, fixed and mobile broadband wireless systems, and beyond
Wireless system design fundamentals: channel assignment, handoffs, trunking efficiency, interference, frequency reuse, capacity planning, large-scale fading, and more
Path loss, small-scale fading, multipath, reflection, diffraction, scattering, shadowing, spatial-temporal channel modeling, and microcell/indoor propagation
Modulation, equalization, diversity, channel coding, and speech coding
New wireless LAN technologies: IEEE 802.11a/b, HIPERLAN, BRAN, and other alternatives
New 3G air interface standards, including W-CDMA, cdma2000, GPRS, UMTS, and EDGE
Bluetooth wearable computers, fixed wireless and Local Multipoint Distribution Service (LMDS), and other advanced technologies
Updated glossary of abbreviations and acronyms, and a thorolist of references
Dozens of new examples and end-of-chapter problems
Whether you're a communications/network professional, manager, researcher, or student, Wireless Communications: Principles and Practice, Second Edition gives you an in-depth understanding of the state of the art in wireless technologytoday's and tomorrow's.
17,102 citations
"Millimeter-Wave Cellular Wireless N..." refers background in this paper
...Also, the human body and many outdoor materials being very reflective, allow them to be important scatterers for mmW propagation [28], [30]....
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...However, these measurements were performed in an outdoor campus setting with much lower building density and greater opportunities for LOS connectivity than would be found in a typical urban deployment....
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...Despite the potential of mmW cellular systems, there are a number of key challenges to realizing the vision of cellular networks in these bands: • Range and directional communication: Friis’ transmis- sion law [54] states that the free space omnidirectional path loss grows with the square of the…...
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TL;DR: The motivation for new mm-wave cellular systems, methodology, and hardware for measurements are presented and a variety of measurement results are offered that show 28 and 38 GHz frequencies can be used when employing steerable directional antennas at base stations and mobile devices.
Abstract: The global bandwidth shortage facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks. There is, however, little knowledge about cellular mm-wave propagation in densely populated indoor and outdoor environments. Obtaining this information is vital for the design and operation of future fifth generation cellular networks that use the mm-wave spectrum. In this paper, we present the motivation for new mm-wave cellular systems, methodology, and hardware for measurements and offer a variety of measurement results that show 28 and 38 GHz frequencies can be used when employing steerable directional antennas at base stations and mobile devices.
6,708 citations
"Millimeter-Wave Cellular Wireless N..." refers background or methods in this paper
...In both 28- and 73-GHz measurements, each point was classified as either being in a NLOS or LOS situation, based on a manual classification made at the time of the measurements; see [26] and [28]–[33]....
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...• Empirical NYC: These curves are based on the omnidirectional path loss predicted by our linear model (1) for the mmW channel with the parameters from Table 1, as derived from the directional measurements in [26]....
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...Details of the measurements can be found in [26], [28]– [33], [81]....
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...This tremendous potential has led to considerable recent interest in mmW cellular both in industry [7]–[9], [18], [19] and academia [20]–[26], with a growing belief that mmW bands will play a significant role in beyond 4G and 5G cellular systems [27]....
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...In particular, we survey our own measurements [26], [28]–[33] made in New York City (NYC) in both 28- and 73-GHz bands and the statistical models for the channels developed in [34]....
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TL;DR: The gains in multiuser systems are even more impressive, because such systems offer the possibility to transmit simultaneously to several users and the flexibility to select what users to schedule for reception at any given point in time.
Abstract: Multiple-input multiple-output (MIMO) technology is maturing and is being incorporated into emerging wireless broadband standards like long-term evolution (LTE) [1]. For example, the LTE standard allows for up to eight antenna ports at the base station. Basically, the more antennas the transmitter/receiver is equipped with, and the more degrees of freedom that the propagation channel can provide, the better the performance in terms of data rate or link reliability. More precisely, on a quasi static channel where a code word spans across only one time and frequency coherence interval, the reliability of a point-to-point MIMO link scales according to Prob(link outage) ` SNR-ntnr where nt and nr are the numbers of transmit and receive antennas, respectively, and signal-to-noise ratio is denoted by SNR. On a channel that varies rapidly as a function of time and frequency, and where circumstances permit coding across many channel coherence intervals, the achievable rate scales as min(nt, nr) log(1 + SNR). The gains in multiuser systems are even more impressive, because such systems offer the possibility to transmit simultaneously to several users and the flexibility to select what users to schedule for reception at any given point in time [2].
5,158 citations
"Millimeter-Wave Cellular Wireless N..." refers background in this paper
...These multiple antenna systems can be used to form very high gain, electrically steerable arrays, fabricated at the base station (BS), in the skin of a cellphone, or even within a chip [6], [10]–[17]....
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TL;DR: In this article, the authors describe five technologies that could lead to both architectural and component disruptive design changes: device-centric architectures, millimeter wave, massive MIMO, smarter devices, and native support for machine-to-machine communications.
Abstract: New research directions will lead to fundamental changes in the design of future fifth generation (5G) cellular networks. This article describes five technologies that could lead to both architectural and component disruptive design changes: device-centric architectures, millimeter wave, massive MIMO, smarter devices, and native support for machine-to-machine communications. The key ideas for each technology are described, along with their potential impact on 5G and the research challenges that remain.
3,711 citations
TL;DR: The technical and business arguments for femtocells are overview and the state of the art on each front is described and the technical challenges facing femtocell networks are described and some preliminary ideas for how to overcome them are given.
Abstract: The surest way to increase the system capacity of a wireless link is by getting the transmitter and receiver closer to each other, which creates the dual benefits of higher-quality links and more spatial reuse. In a network with nomadic users, this inevitably involves deploying more infrastructure, typically in the form of microcells, hot spots, distributed antennas, or relays. A less expensive alternative is the recent concept of femtocells - also called home base stations - which are data access points installed by home users to get better indoor voice and data coverage. In this article we overview the technical and business arguments for femtocells and describe the state of the art on each front. We also describe the technical challenges facing femtocell networks and give some preliminary ideas for how to overcome them.
3,298 citations
"Millimeter-Wave Cellular Wireless N..." refers background in this paper
...Heterogeneous networks, or HetNets, have been one of the most active research areas in cellular standards bodies in the last five years [45], [48], [67], [68], with the main focus being intercell interference coordination and load balancing....
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