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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31 Oct 2022
TL;DR: In this article , a group testing framework is devised, and the associated novel analog and hybrid beam alignment strategies are described to minimize the expected BA duration in uplink mmWave uplink networks.
Abstract: High-frequency bands such as millimeter-wave and terahertz require narrow beams due to path loss and shadowing. Beam alignment (BA) methods allow the transceivers to adjust the directions of these beams efficiently by exploiting the channel sparsity at high frequencies. This paper investigates BA for an uplink scenario, where the channel between the user equipment (UE) and base station (BS) consists of multiple paths. The BS wishes to find the best beams with a given resolution while using the least number of time slots. At each time slot of the BA, the UE transmits a BA packet and the BS uses hybrid beamforming to scan its angular region. To minimize the expected BA duration, a group testing framework is devised, and the associated novel analog and hybrid BA strategies are described. Simulation studies show the performance improvement both in noiseless and realistic 5G mm Wave BA settings.
1 citations
30 Sep 2016
TL;DR: In this article, the authors proposed a reference architecture for virtual mobile small cells, which includes a network and protocol architecture incorporating a so-called "cloud resource optimizer", which aims to mitigate (or coordinate) interference in operator-deployed infrastructures.
Abstract: 5G networks are anticipated to obtain Shannon‐level and beyond throughput, and almost zero latency in future cellular networks. However, there are several challenges to solve if 5G is to outperform legacy mobile platforms; one of these is the design of the communication ‘haul.’ Traditionally, the backhaul segment connects the radio access network (RAN) to the rest of the network where the baseband processing takes place at the cell site. However, in this chapter, we will use the concept of ‘fronthaul access,’ which is recently gaining significant interest since it has the potential to support remote baseband processing based on adopting a cloud radio access network (C‐RAN) architecture that aims to mitigate (or coordinate) interference in operator‐deployed infrastructures; this eases significantly the requirements in interference‐aware transceivers. To do this, we provide a reference architecture which includes a network and protocol architecture incorporating a so‐called ‘cloud resource optimizer.’ The emergence of wireless fronthaul solutions widens the appeal of fronthaul for small‐cell deployments, because a fibre‐only solution – the technology typically used for fronthaul – is too expensive or just not available at many small‐cell sites. Moreover, we will also present the idea of virtual mobile small cells; these small cells are created on demand according to traffic demand.
1 citations
DOI•
01 Jan 2017
TL;DR: A simulation model is proposed that can be used to make simple ray tracing simulations more realistic and to assess the effect of persistence and variations in the angular rate on the capacity, and beam training and tracking process of mm-wave systems.
Abstract: Millimeter-wave (mm-wave) frequency bands are under active consideration for use as short-range mobile broadband links in fifth generation (5G) cellular access networks. Although channel characteristics such as path loss, delay spread and fading distributions have been extensively studied for mm-wave channels, the study of the time-varying nature of the channel is still in its early stages. In this work, we studied the lifetime of multipath components of the mm-wave channel, usually referred to as persistence. An important time-varying characteristic of the mm-wave channel, persistence may affect the capacity, and beam training and beam tracking process of mm-wave systems. We developed a 30-GHz vector-network-analyzer-based channel sounder suitable for characterizing multipath persistence and verified its performance through a three-stage verification procedure; time and frequency domain verifications, two-ray verification, and measurements conducted using the National Institute of Standards and Technology (NIST) mm-wave channel sounder verification artifact. The primary goal of this work was to characterize multipath persistence based on measurements conducted at 30 GHz in indoor and outdoor urban microcell environments. Through analysis of our measurement data, we confirmed that the log-logistic distribution provides an accurate description of persistence and showed how the physical attributes of the channel influence the parameters of the distribution. We also verified that a weak correlation exists between average received power and length of the persistent path. We further showed that the rate of angular change of a multipath component throughout its lifetime follows a Laplace distribution and that the angular rate depends on the distance of reflectors from the transmitter-receiver path. We used these results to propose a simulation model that can be used to make simple ray tracing simulations more realistic and to assess the effect of persistence and variations in the angular rate on the capacity, and beam training and tracking process of mm-wave systems.
1 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...This will make mmwave connections intermittent [49] because directional antenna will have access only to those MPCs of the propagation channel, which are impinging in the beamwidth of the antenna; hence this links will require more adaptation with the movement of the transmitter/receiver....
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01 Nov 2014
TL;DR: This paper develops two iterative hybrid beamforming design algorithms for the MMW channel, using vector quantization of the analog beamformers, and shows that performance of the proposed algorithms can approximate that of the maximum-ratio-beamforming upper bound even if computational complexity may be higher for systems with small number of antennas.
Abstract: Millimeter-wave (MMW) is a probable technology for the future cellular systems Its main challenge is achieving sufficient operating link margin, and directional beamforming with large antenna arrays may be a viable approach With bandwidths on the order of gigahertz, high-resolution analog-to-digital converters are a power consumption bottleneck One solution is to employ an hybrid implementation, digital at baseband and analog at radio frequencies In this paper we develop two iterative hybrid beamforming design algorithms for the MMW channel, using vector quantization of the analog beamformers The proposed algorithms accounts for the RF precoding constraints and assumes the channel matrix is known but not the ray phase vector responses We compare the proposed algorithms with the state-of-art hybrid schemes and the simulation results show that performance of the proposed algorithms can approximate that of the maximum-ratio-beamforming upper bound even if computational complexity may be higher for systems with small number of antennas
1 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...Millimeter-wave (MMW) communication is a promising technology for future outdoor cellular systems [1],[2],[3]....
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TL;DR: A deterministic channel model is introduced for the fifth-generation (5G) of microcellular communication systems based on reflection phenomena, which is a dominated propagation mechanism at mm-W communication systems.
Abstract: In this paper, a millimeter-wave (mm-W)–multiple-input multiple-output (MIMO) channel model is introduced for the fifth-generation (5G) of microcellular communication systems. This determin...
1 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...…signals suffer from high path loss due to smaller antenna aperture, rain and vegetation attenuations and atmospheric absorption at some bands, very high gain, electrically steerable antenna arrays can overcome these problems (Akdeniz et al. 2014; Rangan, Rappaport, and Erkip 2014; Sun et al. 2016)....
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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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