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.
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TL;DR: This paper introduces a distributed approach that solves the joint association and relaying problem in mmWave networks considering the load balancing at access points as a novel stochastic optimization problem, solved by distributed auction algorithms.
Abstract: Millimeter wave (mmWave) systems are emerging as an essential technology for enabling extremely high data rate wireless communications. The main limiting factors of mmWave systems are blockage (high penetration loss) and deafness (misalignment between the beams of the transmitter and receiver). To alleviate these problems, it is imperative to incorporate efficient association and relaying between terminals and access points. Unfortunately, the existing association techniques are designed for the traditional interference-limited networks, and thus are highly suboptimal for mmWave communications due to narrow-beam operations and the resulting non-negligible interference-free behavior. This paper introduces a distributed approach that solves the joint association and relaying problem in mmWave networks considering the load balancing at access points. The problem is posed as a novel stochastic optimization problem, which is solved by distributed auction algorithms where the clients and relays act asynchronously to achieve optimal client-relay-access point association. It is shown that the algorithms provably converge to a solution that maximizes the aggregate logarithmic utility within a desired bound. Numerical results allow quantification of the performance enhancements introduced by the relays, and the substantial improvements of the network throughput and fairness among the clients by the proposed association method as compared to standard approaches. It is concluded that mmWave communications with proper association and relaying mechanisms can support extremely high data rates, connection reliability, and fairness among the clients.
50 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...Relaying techniques can provide more uniform quality of service by offering robust mmWave connection, load balancing, coverage extension, indoor-outdoor coverage, efficient mobility management, and smooth handover operation [2]–[5], [15], [16]....
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...To have quantitative insights, the human body can attenuate mmWave signals by 35 dB [12], and solid materials such as brick attenuate by as much as 80 dB [2], [13], [14]....
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TL;DR: The wireless-relayed backhaul design has been formulated as a topology-bandwidth-power joint optimization problem, and the influence of path loss, angular spread, array size, and RF power limitation on the user rate has been evaluated.
Abstract: Delivering Gbps high user rate over long distances (~1 km) is challenging, and the abundant spectrum available in millimeter wave band cannot solve the challenge by its own due to the severe path loss and other limitations. Since it is economically challenging to deploy wired backhaul every few hundred meters, relays (e.g., wireless access points) have been proposed to extend the coverage of a base station, which has wired connection to the core network. These relays, deployed every few hundred meters, serve the users in their vicinity and are backhauled to the base station through wireless connections. In this paper, the wireless-relayed backhaul design has been formulated as a topology-bandwidth-power joint optimization problem, and the influence of path loss, angular spread, array size, and RF power limitation on the user rate has been evaluated. It has been shown that for a linear network deployed along the street at 28 GHz, when high joint directional gain (50 dBi) is available, 1 Gb/s user rate within cell range of 1 km can be delivered using 1.5 GHz of bandwidth (using single polarization antennas). The user rates drop precipitously when joint directional gain is reduced, or when the path loss is much more severe. When the number of RF chains is limited, the benefit of larger arrays will eventually be surpassed by the increased channel estimation penalty as the effective beamforming gain saturates owing to the channel angular spread.
50 citations
TL;DR: In this article, the authors studied the asymptotic properties of average area spectral efficiency (ASE) of a downlink cellular network in the limit of very dense base station (BS) and user densities.
Abstract: This paper studies the asymptotic properties of average area spectral efficiency (ASE) of a downlink cellular network in the limit of very dense base station (BS) and user densities. This asymptotic analysis relies on three assumptions: 1) interference is treated as noise; 2) the BS locations are drawn from a Poisson point process; and 3) the path loss function is bounded above satisfying mild regularity conditions. We consider three possible definitions of the average ASE, all of which give units of bits per second per unit bandwidth per unit area. When there is no constraint on the minimum operational signal-to-interference-plus-noise ratio (SINR) and instantaneous full channel state information (CSI) is available at the transmitter, the average ASE is proven to saturate to a constant, which we derive in a closed form. For the other two ASE definitions, wherein either a minimum SINR is enforced or CSI is not available, the average ASE is instead shown to collapse to zero at high BS density. We provide several familiar case studies for the class of considered path loss models, and demonstrate that our results cover most previous models and results on ultradense networks as special cases.
50 citations
01 Dec 2015
TL;DR: By exploiting a large number of antennas at the BSs and properly setting the protection distance between FSS and cellular BS, co-channel deployment of 5G small cells with FSS earth stations is possible, in the sense that adequate user data rates could be provided to the majority of mobile users.
Abstract: In this paper we study coexistence of 5G small cells with fixed satellite systems (FSSs) in a scenario where both systems operate co-channel in the large spectrum bandwidth available around 28 GHz. Such studies are of great importance to inform the research community,industry and regulators which are currently investigating spectrum requirements and technology options for 5G systems. Focusing on the FSS uplink scenario, we use realistic FSS parameters and radiation pattern, combined with very recent channel from the literature, we analyzed the impact of interference resulting from FSS radiation on the achievable capacity and throughput of 5G small cells considering various multiple antenna configurations at the base stations (BSs) and different deployments of the mobile transmitters when no cooperation is allowed between the BSs. Starting from the lower bound, represented by an omnidirectional configuration of the transmitters, we extend our work to the analysis of large antenna arrays that will be used in the new generation of mobile cellular systems. Our results indicate that by exploiting a large number of antennas at the BSs and properly setting the protection distance between FSS and cellular BS, co-channel deployment of 5G small cells with FSS earth stations is possible, in the sense that adequate user data rates could be provided to the majority of mobile users.
50 citations
Cites methods from "Millimeter-Wave Cellular Wireless N..."
...A hybrid analog-digital beamforming scheme that exploits the mmWave channel and an antenna array with a low implementation complexity is presented in [4] and several measurements and capacity studies recently performed in New York City at 28 and 73 GHz are presented in [5]....
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TL;DR: This paper introduces MOSAIC as a new approach for SLAM in indoor environment by exploiting the map-based channel model by performing localization and environment inference through obstacle detection and dimensioning and consists of a first of its kind in mapping an indoor environment based on the RSS, Time-Difference-of-Arrival, and Angle of Arrival measurements.
Abstract: Simultaneous localization and environment mapping (SLAM) is the core to robotic mapping and navigation as it constructs simultaneously the unknown environment and localizes the agent within. However, in millimeter wave (mmWave) research, SLAM is still at its infancy. This paper consists a first of its kind in mapping an indoor environment based on the RSS, Time-Difference-of-Arrival, and Angle-of-Arrival measurements. We introduce MOSAIC as a new approach for SLAM in indoor environment by exploiting the map-based channel model. More precisely, we perform localization and environment inference through obstacle detection and dimensioning. The concept of virtual anchor nodes (VANs), known in literature as the mirrors of the real anchors with respect to the obstacles in the environment, is explored. Then, based on these VANs, the obstacles positions and dimensions are estimated by detecting the zone of paths obstruction, points of reflection, and obstacle vertices. Then, extended Kalman filter is adapted to the studied environment to improve the estimation of the points of reflection hence the mapping accuracy. Cramer–Rao lower bounds are also derived to find the optimal number of anchor nodes. Simulation results have shown high localization accuracy and obstacle detection using mmWave technology.
50 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...INTRODUCTION MilliMeter Wave (mmWave) wireless communication systems have recently gained great research interests due to their benefits in terms of spectrum, propagation characteristics, potential applications and services [1], [2]....
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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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