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
More filters
01 Sep 2019
TL;DR: The results reveal that the proposed methods provide means to enhance the robustness of intra-cell UE mobility by decreasing the outage percentage, as well as the signaling overhead associated with the beam management procedures.
Abstract: Carrier frequencies above 6 GHz are adopted for the upcoming fifth generation (5G) mobile networks since they offer higher data rates than today’s legacy networks. High frequencies allow the deployment of multiple antenna elements in single antenna array. Analog, digital, and hybrid beamforming techniques are practiced to generate beams with high beamforming gain compensating for the increased path loss. In 5G, the user equipments (UEs) are not only connected to cells, but also served by specific beams of the cells. This study investigates the beam management procedures specified in the 3rd Generation Partnership Project (3GPP) standard that control the intra-cell UE mobility, which is the mobility of the UEs between beams of single cell. This work defines a comprehensive system model to evaluate the concepts of intra-cell mobility in a representative scenario and network deployment. Moreover, this paper focuses on the implementation of the beam switching algorithm, which is a key element of the beam management procedures. Herein, an additional layer of filtering is introduced at the network side to reduce the fluctuations in the UE measurements that are caused by fast fading and measurement errors. Using the filtered measurements, several methods for beam switching are designed and evaluated. The results reveal that the proposed methods provide means to enhance the robustness of intra-cell UE mobility by decreasing the outage percentage, as well as the signaling overhead associated with the beam management procedures.
4 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...1) Outage Percentage: An outage occurs when received signal is too weak to be correctly detected by the UE [13] or no radio communication is possible at all with the network....
[...]
TL;DR: In this paper, the authors developed a tractable uplink modeling framework for the outage probability of the multi-tier mmWave cellular networks and derived closed-form expressions for the signal-to-interference-plus-noise-ratio (SINR) outage probability for the uplink of the multiuser mmWave networks.
Abstract: In this article, using the stochastic geometry, we develop a tractable uplink modeling framework for the outage probability of the multitier millimeter wave (mmWave) cellular networks. Each tier’s mmWave base stations (BSs) are randomly located and they have particular spatial density, antenna gain, receiver sensitivity, blockage parameter, and pathloss exponents. Our model takes account of the maximum power limitation and the per-user power control. More specifically, each user, which could be in line-of-sight (LOS) or non-LOS to its serving mmWave BS, controls its transmit power such that the received signal power at its serving BS is equal to a predefined threshold. Hence, a truncated channel inversion power control scheme is implemented for the uplink of mmWave cellular networks. We derive closed-form expressions for the signal-to-interference-plus-noise-ratio (SINR) outage probability for the uplink of the multitier mmWave cellular networks, which we later degrade to the single-tier network. Furthermore, we analyze the case with a dense network by utilizing the simplified model, where the LOS region is approximated as a fixed LOS disk. The results show that imposing a maximum power constraint on the user significantly affects the SINR outage probability in the uplink of mmWave cellular networks.
4 citations
TL;DR: In this paper, the authors proposed a method that utilizes the Zadoff-Chu (Z-C) sequence of the Primary Synchronization Signal (PSS) and Sounding Reference Signal (SRS) that are available in every LTE data frame for downlink and uplink respectively, for estimating and compensating the differences in the impulse responses among the RF modules.
Abstract: This paper presents a novel calibration method that equalizes the impulse responses of all the Radio Frequency (RF) modules of an antenna array system operating in Long-Term Evolution (LTE) evolved NodeB (eNB). The proposed technique utilizes the Zadoff-Chu (Z-C) sequence of the Primary Synchronization Signal (PSS) and Sounding Reference Signal (SRS) that are available in every LTE data frame for downlink and uplink, respectively, for estimating and compensating the differences in the impulse responses among the RF modules. The proposed calibration method is suitable for wide bandwidth signal environments of LTE because it equalizes the impulse response of each RF module, which is ultimately equivalent to compensate the phase and amplitude differences among RF modules for the entire frequency band. In addition, the proposed method is applicable while the target eNB is transmitting or receiving a data stream. From various experimental tests obtained from a test-bed implemented with 2 RF modules, it has been verified that the proposed method provides a reliable calibration for Release 10 Time Division Duplex (TDD) LTE signals. Phase errors after the calibration in our test-bed have been found to be about 2.418° and 2.983° for downlink and uplink, respectively.
4 citations
Cites methods from "Millimeter-Wave Cellular Wireless N..."
...Particularly for mmWave application that is one of the key technologies in 5th Generation (5G) mobile communications, since the bandwidth could be up to a few GHz [9], it is practically impossible to adopt the calibration techniques given in [5–8]....
[...]
TL;DR: In this article, the authors compared the upper bound performance of multicarrier-division duplex (MDD) and half-duplex (HD) by applying unfair greedy resource allocation.
Abstract: In-band full-duplex (IBFD) systems require promising resource allocation (RA) strategies to fully exploit the available time-frequency resources. Furthermore, the acquisition of channel state information and signal reception in IBFD systems are significantly impacted by insufficient self-interference cancellation (SIC), impeding the applications of IBFD in practical wireless systems. Multicarrier-division duplex (MDD), which benefits low-budget SI mitigation in digital domain and flexible subcarrier assignment, is expected to be a promising transitional technique from half-duplex (HD) to IBFD. To demonstrate the advantages of MDD over HD, this paper first compares the upper-bound performance of MDD and HD by applying unfair greedy RA. Then, considering the millimeter-wave (mmWave) with hybrid beamforming, we propose the RA optimization with the quality-of-service constraints on both downlink (DL) and uplink (UL) mobile-stations (MSs). To solve this non-convex RA problem, we divide it into a suboptimal subcarrier allocation problem solved by the proposed improved fair greedy (IFG) algorithm, and a convex power allocation problem. Furthermore, we design two general hybrid precoder based on matrix factorization and direct approach, and a combiner having high SIC capability. Our results show that the proposed RA algorithm can achieve the performance near the upper-bound achieved by the unfair greedy algorithm, while guaranteeing the proportional fairness among all DL/UL MSs. The performance of the two precoding schemes is depended on the number of radio frequency chains supported. Finally, the proposed SIC algorithm is able to provide sufficient SI mitigation, which can be implemented without impacting the RA operation.
4 citations
01 Oct 2017
TL;DR: This paper proposes a two-stage alternative method with nearly optimal sum rate performance and much lower computation complexity, which firstly calculates the optimal number of opened RF chains, and then the nearly optimal precoder and combiner are directly obtained within only one round calculation.
Abstract: It is necessary to optimize the energy-efficient (EE) performance for millimeter-wave (mmWave) wireless systems, since the power consumption problem becomes increasingly crucial at high frequency bands. In hybrid precoding mmWave systems, the EE-oriented optimized elements include the analog and digital precoders at the transmitter, the analog and digital combiners at the receiver, as well as the corresponding number of opened radio frequency (RF) chains. In contrary to calculate the optimal precoding/combining matrices exhaustively for all possible numbers of RF chains as in the existing works, this paper proposes a two-stage alternative method with nearly optimal sum rate performance and much lower computation complexity. It firstly calculates the optimal number of opened RF chains, and then the nearly optimal precoder and combiner are directly obtained within only one round calculation. The complicated calculations of all the elements in optimization are decoupled by exploring the asymptotical property of the mmWave system with large antenna arrays, as well as the sparsity characteristic of the mmWave fading channel. Simulation results are further provided to verify the validation of the proposed method.
4 citations
Cites background from "Millimeter-Wave Cellular Wireless N..."
...Millimeter-wave (mmWave) communication has great potential to increase the system capacity due to the widely unused spectrum at high frequency bands [1-3]....
[...]
References
More filters
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]....
[...]
...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....
[...]
...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…...
[...]
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]....
[...]
...• 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]....
[...]
...Details of the measurements can be found in [26], [28]– [33], [81]....
[...]
...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]....
[...]
...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]....
[...]
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]....
[...]
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....
[...]