Millimeter Wave Propagation Characterization And Modeling .

2y ago
21 Views
2 Downloads
1.02 MB
14 Pages
Last View : 19d ago
Last Download : 2m ago
Upload by : Troy Oden
Transcription

Millimeter wave propagation characterization and modelingtoward fifth generation systemsArticle (Accepted Version)Salous, Sana, Esposti, Vittorio Degli, Fuschini, Franco, Dupleich, Diego, Müller, Robert, Thomä,Reiner S, Haneda, Katsuyuki, Garcia-Pardo, Jose-Maria Molina, Garcia, Juan Pascual, Gaillot,Davy P, Nekovee, Maziar and Hur, Sooyoung (2016) Millimeter-wave propagationcharacterization and modeling toward fifth-generation systems. IEEE Antennas & PropagationMagazine, 58 (6). pp. 115-127. ISSN 1045-9243This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/66812/This document is made available in accordance with publisher policies and may differ from thepublished version or from the version of record. If you wish to cite this item you are advised toconsult the publisher’s version. Please see the URL above for details on accessing the publishedversion.Copyright and reuse:Sussex Research Online is a digital repository of the research output of the University.Copyright and all moral rights to the version of the paper presented here belong to the individualauthor(s) and/or other copyright owners. To the extent reasonable and practicable, the materialmade available in SRO has been checked for eligibility before being made available.Copies of full text items generally can be reproduced, displayed or performed and given to thirdparties in any format or medium for personal research or study, educational, or not-for-profitpurposes without prior permission or charge, provided that the authors, title and full bibliographicdetails are credited, a hyperlink and/or URL is given for the original metadata page and thecontent is not changed in any way.http://sro.sussex.ac.uk

PAPER IDENTIFICATION NUMBER:1Millimeter-wave Propagation Characterizationand Modelling Towards 5G SystemsS. Salous, V. Degli Esposti, F. Fuschini, D. Dupleich, R. Müller, R. S. Thomä, K. Haneda, J.M. Molina-GarciaPardo, J. Pascual-Garcia, D. P. Gaillot, M. Nekovee, S. HurAbstract— The World Radiocommunications ConferenceWRC15 identified a number of frequency bands between 2486 GHz as candidate frequencies for future cellularnetworks. In this paper an extensive review of propagationcharacteristics and challenges related to the use ofmillimetre wave in future wireless systems is presented.Reference to existing path loss models including atmosphericand material attenuation in recommendations of theInternational Telecommunication Union is given and theneed for new multidimensional models and measurements isidentified. A description of state of the art mm wave channelsounders for single and multiple antenna measurements isfollowed by a discussion of the most recent deterministic,semi-deterministic and stochastic propagation and channelmodels. Finally, standardization issues are outlined withrecommendations for future research.For the above reasons, exploitation of mm-wavefrequencies for 5G standards has started to gainconsiderable traction within the wireless industry, [3]and the European Union’s (EU) Horizon 2020 5G PPPinitiative [4]. Furthermore, following the World RadioConference (WRC’15) where various frequency bandshave been identified for possible allocation for cations Union (ITU) study groups 3 and 5are working towards a suitable channel model.Proprietary wireless technologies operating in indoorenvironments in the 60 GHz ISM frequency band basedon the IEEE 802.11ad and 802.15.3.c standards arealready commercially available [5] [6]. Recently, IEEE802.11 Task Group AY was launched to developenhanced standards for operation in license-exemptbands above 45 GHz. However, the development ofmm-wave technologies for ultra-high capacity mobilecommunication is currently at an early stage. Althoughinitial trials look promising [3], a number of challengesneed to be overcome before the technology movestowards inclusion in 5G standards and extensivecommercial deployment by 2020.The EU Horizon 2020 research program alsoconsiders the extension of wireless communicationssystems to frequencies above 60 GHz to fill the gapbetween the mm-wave and the terahertz spectrum.Furthermore, the first phase of EU’s Horizon 2020 5GPPP initiative is investigating the 6-100 GHzfrequencies, for 5G’s ultra-high data rate mobilebroadband [7].One of the basic highly important challenges in thedevelopment of mm-wave technologies is the lack ofappropriate channel models. The need for new channelmodels to support 5G networks planning has beenrecently reaffirmed during the 3GPP RAN Workshop on5G held in Phoenix [8]. While significant studies of thechannel characteristics are available in the 60 GHz bandfor indoor and short-range scenarios, and more recentlyfor body networks [9] for secure communication, only afew trials have been conducted in other mm-wave bandsand for outdoor, outdoor-indoor, and scenarios withmobility [10]-[15].Under the assumption that antenna dimensions mustbe related to the wavelength, and therefore antenna gainsare nearly constant with frequency, one important issueof mm-wave propagation is the higher path loss, asisotropic free-space attenuation is inversely proportionalto the second power of the wavelength. The use of highgain antenna arrays is therefore mandatory to mitigatethis problem. Other important issues are gaseous andrain attenuation for longer range links, and the higherIndex Terms — Millimeter-wave propagation, 5G,Millimeter-wave Measurements, Channel sounders, MIMO,Beamforming, Diffuse Scattering, Ray Tracing, Standards,FMCW, PRBSI.INTRODUCTIONMobile data traffic is projected to increase 5000 foldby the year 2030 [1]. This increase in traffic can be metthrough increase in link-capacity, spectrum availabilityand massive densification of small cells. Recentadvances in air-interface design provide spectralefficiency performance very close to the Shannon limit.There is, however, room for increase in spectralefficiency through techniques such as CoordinatedMulti-Point (CoMP), Massive Multiple Input MultipleOutput (MIMO), interference management andcancellation [2]. In addition, at millimeter wave (mmwave) bands (30-300 GHz), the availability of largecontiguous blocks of spectrum of 1 GHz or more allowunprecedented link capacities and throughput densities.Moreover at these higher frequencies, smaller antennaelements enable the implementation of large antennaarrays for adaptive beam forming to compensate forpropagation losses to dramatically increase systemperformance and to cope with time variations in thechannel. While a large number of antenna elementscould be implemented on both base stations andterminals, this would also result in increased complexityof the RF frontend of mobile terminals. Thus, the useof the higher range of mm-wave frequencies for mobilecommunications remains challenging.Access to large blocks of spectrum also makes itpossible in early deployments to tradeoff spectralefficiency for bandwidth, i.e. high data rates can beachieved even with low-order modulation schemesrequiring lower power and lower complexity and cost.1

PAPER IDENTIFICATION NUMBER:2shadowing due to lower diffraction and penetration incase of Line of Sight (LOS) blockage from obstacles.While information relating to gaseous and rainattenuation are well known and available from ITU-Rrecommendations ITU-R P676-10 [16] and ITU-R P530-16 [17], there are no parameters related to path lossexponents apart from a very brief statement and towideband channel parameters such as Root-MeanSquare (RMS) delay spread and angular spread in ITU-R1411-8 [18]. Such models are of great importance inorder to (i) develop and test the required physical andhigher layer components (algorithms and architectures),(ii) perform link and system level feasibility studies, and(iii) investigate spectrum engineering regulatory issuessuch as interference risks and co-existence in the mmwave bands.Only a small number of studies address propagationcharacterization and modelling for very wide-bandwidthchannels with directive arrays, such as those ofbeamforming transmission techniques, which maydrastically influence channel characteristics [13][14][19]-[21]. Fundamental questions on the relationbetween the time dispersion of the channel and thedirectivity of the transmission lobe, or on the spatial,temporal and polarimetric characteristics of thepropagation channel still need to find complete answers.Because of the higher frequencies and widerbandwidths compared to existing standards for 4Gcellular and WLAN below 6 GHz, mm-waveapplications will need specific considerations. Newradio interface technologies such as massive arrays willrender basic assumptions for statistical channel modelsobsolete. Those robust models that performed very wellfor 4G for instance, assume that many propagation pathssuperimpose after OFDM processing. However, themuch higher spatial resolution of high-gainanalogue/hybrid beamforming before digitization and,hence, OFDM, enforce paradigm-shifts towards timedomain concepts and deterministic modellingapproaches [22].The aim of this paper, therefore, is to provide thereader with an insight on recent research in importantaspects of mm-wave propagation characterization andmodelling, for future 5G systems and applications, withparticular focus on research carried out within theEuropean Cooperation Project “COST IC1004”. Therelatively large body of results available for 60 GHz istaken as a starting point, but emphasis is placed on therecent results that are becoming available for outdoorand outdoor-indoor scenarios at other frequencies ofinterest including 28 GHz, 38 GHz and 70 GHz.The rest of this paper is organized as follows: sectionII gives an overview of propagation characteristics basedon available ITU-R recommendations and recent studies;section III describes state of the art channel soundingtechniques available for mm-wave measurements;section IV presents an overview of propagationmodelling including path loss models, shadowingmodels, stochastic channel models and models based onray tracing; section V presents standardization prospectsand finally section VI draws some conclusions andmakes recommendations for further studies.II. PROPAGATION CHARACTERISTICSGiven the link-distance limitations, the foreseenapplication scenarios of mm-wave transmission arelimited to outdoor back-hauling and front-hauling linksand outdoor or indoor access links in LOS or quasi-LOSconditions [2][10].In the case of outdoor small-cell links, it is in principlenecessary to consider the additional attenuation due togases in the lower atmosphere and rain. In the frequencyrange up to 100 GHz, two absorption peaks occur instandard atmosphere. The larger one is due to oxygen at60 GHz and corresponds to 15 dB/km. Therefore gasattenuation should not represent a major concern forfuture mm-wave indoor and small-cell applications [10].Similar considerations hold true for rain effects, with amaximum attenuation of about 30 dB/km for very heavy(100 mm/hr) rainfall.A more important factor to consider is the highpenetration loss of building materials. Typical relativepermittivity and conductivity for different buildingmaterials are reported by [23] and [24] while acomparative study between 5.8 GHz and 62.4 GHz isgiven by [25]. ITU-R recommendation 2040-1 [26]provides an expression for the conductivity σ - whichgives rise to the dB/m specific attenuation factor - as afunction of frequency f in GHz𝜎 𝑐𝑓 𝑑 𝑆/𝑚(1)where values for c and d are tabulated for differentfrequency ranges. For example for a concrete wallc 0.0326 and d 0.8095. This gives 0.0326 [S/m] at 1GHz vs. 0.908 [S/m] at 60 GHz, leading to a much higherpenetration loss. This is in agreement with measurementsin [27] on a brick-wall, showing a permittivity value morethan 10 times greater at 70 GHz than at UHF.Reported penetration losses at 60 GHz are on theorder of some dBs for very thin plastic, wood or plasterpartitions, 4 dB for a 0.7 cm single-panel tempered glassand 25 dB for a 9 cm indoor brick wall when both thetransmit and receive antennas are vertically polarised[28][29]. Penetration losses at 70 GHz are similar to thoseat 60 GHz and are summarized in Table 1 for somecommon materials.Table 1 - Penetration losses at 70 GHz for someconstruction and furniture items (from [27])ObjectIndoor brick wall (9 cm thick,with plaster on both surfaces)LCD PC monitor made ofplastic, metal parts and glass)30 cm deep wooden bookshelfwith a back panel, filled withhard-cover booksPlywood panel (1.3 cm thick)Absorber panel (flat carbonloaded foam, 11 cm 3.84.9

PAPER IDENTIFICATION NUMBER:3The frequency dependence of penetration loss has alsobeen reported with variations between 18.9 dB at 900MHz, 26 dB at 11.4 GHz to 36.2 dB at 28.8 GHz for athree-wall partition between antennas [30]. Theseadditional losses at the higher frequencies will requirecompensation through higher effective radiated powersand will hinder NLOS applications unless whereobstruction is represented by a few thin partition walls.An important issue of mm-wave propagation is roughsurface scattering. For rough construction materials suchas concrete, bricks, and asphalt, the standard deviation ofsurface-roughness σh, is of the order of 1-2 mm, and thusno longer satisfies the Rayleigh criterion, σh λ/(8 cosθi)as for lower frequencies [31]. This results in a lowerspecular reflectivity of the surface in favour of diffusereflection where each impinging ray is back-scattered intomany low-amplitude rays having random propagationdirections. Although some authors hypothesized for thisreason a stronger Dense Multipath Component (DMC[32]) at mm-wave frequencies compared to lowerfrequencies, recent studies have shown that the actualratio of the DMC to the Specular Component is similar[33][27], or even lower [34]. Probably the higher degreeof rough-surface scattering for some surfaces is overcompensated by the lower level of multipath-richness dueto the suppression of through-wall propagation and bylower diffraction effects. This aspect is important todesign beam forming techniques adopting narrow beams,recently proposed to enhance the Signal to Interferenceand Noise Ratio (SINR) and to implement spatialmultiplexing in multi-Gigabit transmission systems [3].The DMC affects the Spatial-Degrees-of-Freedom(SDoF) of the propagation channel and determines theextent of channel capacity improvement possible througheigenmode transmission. Experiments show [35] that upto 10 spatial eigenmodes are available in indoorpropagation channels for a transmit and receive antennaaperture size of 9λ2 and a 20 dB signal-to-noise ratio.Polarization aspects have long been overlooked inmm-wave propagation as the majority of mm-wave linkswere originally conceived as stationary LOS links withdirective antennas and polarization matching. With theapplication of mm-wave transmission to mobileenvironments, frequent LOS blockage and multipathpropagation, the study of the polarimetric properties ofmm-wave propagation has become important. Recentexperimental investigations at 60 GHz using a channelsounder have shown that most multipath contributions areclearly polarization dependent as they appear or disappearfrom the channel’s power profiles shown in Fig. 1depending on the polarization of the Transmitter (Tx) andReceiver (Rx) antennas [36].Fig- 1 - Power Angle Spectrum at the transmitter for HH polarization (a)and HV channel polarization states (b) [36]These are realised with a sophisticated channelsounder using a wideband signal with a high WaveformRepetition Frequency (WRF). In addition, it is desirableto have an Instantaneous Dynamic Range (IDR) for eachmeasured snapshot that enables the clear detection of themultipath components above the noise floor and a highoverall dynamic range for a deeper understanding of thepropagation channel.The IDR relates to the maximum path power weight(just below the onset of nonlinear distortion) relative tothe noise level in one channel impulse response functionwhereas the system dynamic range describes the dB-rangebetween the highest and the lowest channel attenuationthat can be processed along a recording track. The latter,can be controlled by the transmitter power and automaticgain control (AGC) which can be applied at either side orboth sides of the link. To satisfy all of these requirementsof high dynamic range, time delay resolution and angularresolution, estimation of Doppler shift and polarimetricmeasurements can be costly and even difficult to achieve.To measure the AoA/AoD there are different optionsavailable. The first option is to use a single antennaelement which has to be rotated or physically moved tomultiple positions to form the full array (synthetic array)[37][38]. Measuring the channel in azimuth and inelevation would always require some 2D movement.While some trials with planar positioning ofomnidirectional antennas were reported, using high-gainantennas and rotation positioner allows well resolveddirectional characterisation without any sophisticated terization (azimuth and elevation and double sidedfor AoA and DoD) is time consuming and not applicablefor dynamic scenarios. Fig. 2 (a) shows the DurhamUniversity multi-band sounder with mm wave RF headsset up [39] with a 2.2o beam width lens antenna rotated inazimuth in 5o steps to estimate the power delay profile(PDP) as shown in Fig. 2 (b) in a street canyon.The second measuring philosophy is to use realantennas instead of virtual arrays. A Circular UniformBeam Array (CUBA) [40] might be a good choice for fastdirectional resolution, see Fig. 3 [41]. For double arraysthe transmitted waveforms have to be orthogonal either intime, in frequency or using codes. Fast channel samplingrates can be achieved with simultaneous multiple antennatransmissions using orthogonal codes which is generallycomplex with limited IDR and costly to implement.III. MM-WAVE CHANNEL SOUNDINGFull characterization of the radio channel at mmwaves requires the estimation of a number of parametersof the multipath components and the polarimetriccharacteristics of the channel. Multipath parametersinclude time delay, Doppler shift, angle of departure(AoD), angle of arrival (AoA) and a 2x2 matrix ofpolarimetric path weights.3

PAPER IDENTIFICATION NUMBER:4phase noise and high stability would be needed to applyhigh resolution estimation algorithms.(a)(a)Azimuth beamwidth45 degrres to 3-dBpoints(b)(b)Fig. 2 (a) Receiver-Sounder with lens antenna, (b) measured power deayprofile versus azimuthal angle [39]Reception can be achieved either using a singleelement or multiple elements. With multiple elements,either a single receiver in conjunction with a switch canbe used or multiple parallel receivers to speed up theacquisition. Antenna elements can be either omnidirectional or directional such as the CUBA array.Directional antenna elements provide a gain advantage inthe mm-wave band due to the higher losses experiencedin the environment and from the additional losses due tothe atmosphere and rain for ranges in excess of a fewhundred meters. This is the reason why mostmeasurements in the mm-wave band are performed usingdirectional antennas. A further advantage of thesemeasurements can be the capability to generate beamformed channel models. Due to the narrow beam width ofthe horn antenna and the high cost of employing parallelchannels usually a single channel with extensivemeasurements are performed with small step incrementsto cover all azimuth directions (sometimes includingelevation) [35][42]. This gives the power delay profiles asa function of angle of arrival and angle of departure whenpositioners are used on both sides of the link.However, the synthetic aperture approach or rotatingboth the transmitter and receiver antennas to cover allcombinations of azimuth and elevation angles takesconsider

Millimeter wave propagation characterization and modeling . advances in air-interface design provide spectral efficiency performance very close to the Shannon limit. There is, however, room for increase in spectral . comparative study between 5.8 GHz and 62.4 GHz is given by [25]. ITU-R recommendation 1 [26] 2040- .

Related Documents:

oped millimeter wave coax contacts with the same millimeter wave electrical connector performance from DC to greater than 65 GHz as standard Super SMA, 2.92mm, 2.40mm and 1.85mm millimeter wave connectors. They are fully interchangeable with the standard, miniature, MIL-C-39029 (non-coax)

i IEEE INTERNATIONAL NETWORK GENERATIONS ROADMAP - 2021 EDITION MILLIMETER WAVE AND SIGNAL PROCESSING ABSTRACT The "Millimeter-Waves and Signal-Processing" Working Group (MMW-SP WG) will examine improvements in current millimeter-wave architectures, hardware capabilities, and signal processing

wave propagation, including ground wave and ionospheric propagation, goes on to make this text a useful and self-contained reference on antennas and radio wave propagation. While a rigorous analysis of an antenna is highly mathematical, often a simplified analysis is sufficient for understanding the basic principles of operation of an antenna.

Ground Wave Ground wave propagation occurs at low frequencies. Typically 4 MHz and below. In ground wave propagation, the magnetic field ofIn ground wave propagation, the magnetic field of the RF signal couples with the earth. A vertically polarized antenna works well for this type of propagation.

Ground-Wave Propagation Ground-wave propagation involves the transmission of a radio signal along or near the surface of the earth. The ground-wave signal is divided into three parts: the direct wave, the reflected wave, and the surface wave. The direct wave travels through the atmosphere from one

Motive Wave. It is a five wave trend but unlike a five wave impulse trend, the Wave 4 overlaps with the Wave 1. Ending Diagonals are the last section ("ending") of a trend or counter trend. The most common is a Wave 5 Ending Diagonal. It is a higher time frame Wave 5 trend wave that reaches new extremes and the Wave 3:5 is beyond the .

Millimeter Wave Promise 3 60 GHz, 183 GHz, 325 GHz, and 380 GHz for short-range apps. Other frequencies have little air loss compared to 6 GHz Worldwide agreement on 60 T. S. Rappaport, et. al., Millimeter Wave Wireless Communications, Prentice-Hall c. 2015. GHz!

American Revolution in Europe working to negotiate assistance from France, Spain, and the Netherlands. Foreign Assistance French ultimately provided critical military and financial assistance Spain and the Netherlands provided primarily financial assistance to the American cause. A comparison of the resources held by the British and by the colonies: The population of the thirteen colonies .