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Small Cell Backhaul Technology

Small Cell Backhaul Technology



This presentation is from the Aviat Networks technology series and is an update on Small Cell backhaul for mobile networks

This presentation is from the Aviat Networks technology series and is an update on Small Cell backhaul for mobile networks



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  • Welcome to ATS, Live from SC, IntroductionsHousekeeping:- Ask questions in Q&A function (mute) – we’ll try and get to themChat function to administratorMarketing@aviatnet.comNot sales pitches – technology overviewsTopic: Small cell backhaulFocus: outdoor mounted pico and micro cells and specifically on backhaul issues regarding wireless BH solutionsFocus: LTE – NA audience
  • There is a ton of talk about small cell now and the one common theme is there’s lots of uncertainty… even for basic questions like is this evolution even going to happen… we’ve heard everything from small cells are the future, to the business case for small cells is not clear. One thing is for sure, small cells are all the rage right now and from a backhaul standpoint, small cells really change the BH paradigmThere are a lot of factors contributing to the confusion – listed on this slideOne thing is for sure is: if this evolution happens, there will beMore sites - higher cost, - more complexityDifferent types of sites - new technologies
  • What’s a myth? Something that is based on passed down via stories and beliefs and is generally not testable. Science on the other hand is based on cumulative, frequently updated knowledge, supported by proven facts and repeatedly testable processes.Like common myths there are perceptions about small cell that are based on misinformation—heresay—even intentional deception. We're here to debunk those myths and provide you with science and facts regarding Small Cell backhaul issuesThe rest of this presentation will be structured as kind of a myth busters – and we have 5 of them
  • Is that sasquatch lives!!! Hardly… because despite a number of claimed sightings all across the US, we at Aviat are pretty certain that based on science, he is a fable.We hear all the time that i’m not going to have LOS to my small cell therefore I will need a NLOS solutionThus, solutions deployed in freq bands of 6GHz and below are best for SC BHWe don’t believe this to be based on science – this needs a reality check with some analysis and dataLets take a look
  • For instance, 3.5G band has 20MHz channel possibilities internationally
  • Spectrum better used for access spectrum
  • the developments in 2.3GHz WCS (ATT wanting to move this to access spectrum) is sign of things to come and supports your point of lack of spectrum <6GHz and every bit of it will be needed for RAN/access
  • Backhaul requirements are more commonly in the range of <16 ppb in terms of clock recover accuracy – many TDD systems are in the range of 50pbb at bestOne way delay is not as much of a factor for 1588v2 as delay variation, so how well their system will perform will more depend on their dejitterizer capabilities than their latency spec.  
  • Because of capacity and synchronization concerns, Large antenna arrays for mimo implementationsLTE based system on chip solutions (need to add 256qam)
  • First mentioned by the ancient greeks, The unicorn is a legendary animal from European folklore that resembles a white horse with a large, spiraling horn projecting from its forehead, and sometimes a goat's beard and cloven hooves. Again… folklore.Similarly, I hear it all the time that PTP (MM Wave) wont work on a pole (primarily b/c of sway and twist and wind, but also because of alignment challenges) – narrow beams
  • Comments: Sway was taken for worst case scenario in Y-Z plane. Maximum distance was calculated using Maximum FCC antenna beam width and minimum antenna gain and typical radio specifications. Outdoor light poles are designed for maximum gust velocities defined in 50 years mean maps like AASHTO (see backup slides) with a minimum wind load of 70 MHP, maximum EPA and weight loading. Sway does not necessarily increase with wind speed as natural turbulence of the air stream at higher speeds. TIA-222-F defines a maximum sway and twist angle based on the antenna beam width calculations in blue show the maximum distance if the link would work continuously at this angle as a point of reference to the pole sway angles. Maximum distance calculations for a fixed availability of 99.99% were performed for San Jose CA and Miami FL based on environmental conditions for these two cities considering rain and multi-path. ITU-530-11 was used with plain terrain. Horizontal antenna polarization was assumed. Pole to Building scenario assumes that the building is static and all sway is due to pole movement. Pole to pole scenario assumes worst case scenario were both poles sway simultaneously resulting in a doubling of sway angle. This scenario is extremely unlikely as both poles would have to sway in synchronization. In the pole to pole deployment with a wind speed of 45 MHP at 70/80 GHz pole sway is above antenna beam width resulting in antenna attenuations above 10dB.
  • Specificallyconcernherewith the higher bands (again 80GHz) wherebeams are verynarrow and the mostproblematicwhenalignmentisconcerned1990’sCoarsealignmenttoolswere of the Digital voltmeter type (RSSI) and with a fairlywidetolerance; not great for a narrowbeam. 2000’sNowthereis a combination of- much more accurate RSSI readings via laptop and voltmeteraudio signal athighsampling rate to providehighlyaccuratealignment assistance/tracing andoptical alignment tool – example – can be attached to radio for accurate alignment – right angle versions can be used for wall mount much more flexible mounts and smallerlightertransceiversthat are easier to manipulate/alignespecially if they have an integratedantennaFuture- the potential for electromechanical self alignmentutilizinguber-small flat antennas (cost)- thereis scope for innovation whenitcomes to alignment techniques and we’reinvestigating a potentiallyveryfast, user friendly, non opticalalignment technique (currentlyunder patent assessment) 
  • Anyone ever been to disney?Did your dreams come true?Not likely.Similarly I hear this one a lot too – that BH needs to be integrated with the picocell
  • doesn’t make sense for ran vendors to build bh into their solutions since it drives up cost and complexity and number of product variants they would need to support?count possible product variants and estimated costs to add each one…Utilities want something standardized since they want to make sure structure and engineering on the poles are soundThey also are likely going to make sure installers are well trained to work on poles, etcStandardized package will be required
  • FCC is quite flexible in these bands: you can back off the power, no EIRP limitationsHigh volumes of PTP bands – lower costsPTMP shares spectrum – lower capacity70/80: 38dBi gain, 1.2degbeamwidthSmaller hops: equipment can be designed with lower power, thus smaller, etcVerizon (based on Napa trial) – SC distances trialed were between 0.3 to 0.7 KMVerizon (from Exalt preso) – NLOS BH from 1.5-2.0 KM Vodafone UK (Presented at SC World Summit)- Busy areas require 50m radius microcells, Microcell range limited to 150m due to building loss and corner loss.  Busiest 200x200m area requires 6 microcells plus 3 carrier picocells/public femto cells Everything Everywhere (based on customer input): From 50m to  400m    
  • We all know who this is right?What could Dwight Eisenhower possibly have in common with LTE?Well, he is probably best known for commandingour troops in WW2 and it was when the Allies broke through the Western Wall he noticed something that would change the history of this country – he saw Germany's sprawling autobahn network and realizedwhat a modern army could do with an infrastructure capable of accommodating itWhen he eventually became president,IKE initiated the Federal-Aid Highway Act of 1956: Creating the Eisenhower Interstate SystemOne of the biggest construction projects in the history of the country - 41,000 miles of freeway to every nook and cranny of the countryThat’s exactly what LTE is – a massive construction project.  New backhaul (digital highways) will have to be put into 300,000 cellsites in the USWith the IHS, it wasn’t the size of the highways (2 or 3 lanes) that that meant 35 years of work, it was all that goes along with building a road of any size – and the number of them - in a tight timeframe. Similarly, LTE BHis actually lessabout the capacity or the size of the digital highway(both microwave and fiber both exceed the capacity requirement), but more about getting a backhaul solution deployed in the first in place – since its urgent and expensive but also very complicated
  • So we see the real LTE challenge is not being only about capacity, but mostly construction or perhaps more accurately implementation.It’s the site surveys, frequency coordination, the engineering, planning, and installation, troubleshooting when something goes wrong, etc, etc. No two sites are the same, and 2/3G not going away, and there’s no more people to do all this withWhat we’re focused on as a company is making sure MW meets the capacity needs of LTE, and more importantly figuring out ways we can ease the implementation pain.Today's presentation: 2 things:Capacity: and features that exist to meet the LTE capacity need – our recommendations for which ones make senseConstruction:and some of the ways we can help ease the pain and simplify your life (both from features on the radio standpoint, and services standpoint)Business Case cannothold water if installation is longer than 45mm (presented by the NGMN @ the Packet MW conf in London)
  • Often called “The seventies answer to George Jetson's mode of transportation” – the AMC pacer is one of the most interesting cars… Anyone ever own one?"The Flying Fishbowl”- Great wheels, snazzy paint scheme, white leather seats, rear roof spoiler, lots of windows, cupholders…..a lot of stuff, but one of the worst cars of all time – it didn’t work(didn’t work, wasn’t reliable and wasn’t practical)FOCUS ON WHAT”S IMPORTANTWhat’s important?Easing construction Pain – especially with small cells !!!Delivering new innovations to reduce costs, make microwave easier to deploy, and integrated into the rest of the networkStand-alone LOS-based solutions emerging as most viable SC BH optionMaking them easier to deploy will be key

Small Cell Backhaul Technology Small Cell Backhaul Technology Presentation Transcript

  • AVIAT TECHNOLOGY SERIES SMALL CELL BACKHAUL: UPDATE Gary Croke, Eduardo Sanchez - Aviat Networks
  • Small Cell Backhaul = FEAR street level mounting? line of sight? spectrum availability capacity costs vendor hype LTE requirements? traffic growth security, reliability, n etwork planning confusing and complicated….
  • NLOS CAPACITY DEGRADES VERY QUICKLY WITH OBSTRUCTIONS 1 mile 5.8 GHz LOS 40 MHz, San Jose CA 130 Mbps LTE small cell capacity requirement 1 mile 5.8 GHz nLOS 40 MHz, San Jose CA <10 Mbps LTE small cell capacity requirement
  • AND UNLICENSED HAS NOISE….. -74 dBm ISM Source: NTIA Report 00-373 Measured Occupancy of 5850-5925 MHz and Adjacent 5-GHz Spectrum in the United States, 1999.
  • AND CAPACITY DEGRADES EVEN FURTHER WITH INTERFERENCE 1 mile 5.8 GHz LOS 40 MHz, San Jose CA 130 Mbps 1 mile 5.8 GHz nLOS 40 MHz, San Jose CA <10 Mbps No Interference 70 Mbps -74 dBm interferer signal LTE small cell capacity requirement No Interference N/A LTE small cell capacity requirement -74 dBm interferer signal
  • 0Mbps 50Mbps 100Mbps 150Mbps 200Mbps LOS PTP 40MHz Less spectrum, les s capacity More obstruction, l ess capacity More links, less capacity LOS PTP 20MHz Datasheet NLOS PTP 20MHz Bandwidth is shared!!! NLOS PTMP (n links) 20MHz In Licensed < 6GHz Bands, NLOS Capacity Realities are Much Worse
  • SPECTRUM CONSIDERATIONS 90 MHz 81-86 GHz 71-76 GHz 57-64 GHz 38.6-40.0 GHz 21.2-23.632 GHz 29.1-29.25 GHz 27.5-28.35 GHz 21.2 - 23.632 GHz 17.7-19.7 GHz 12.75-13.25 GHz 10.7-11.7 GHz 10.5-10.68 GHz 7.125-8.5 GHz 5.925-7.125 GHz ISM 5.785-5.815 GHz ISM 5.725 - 5.25 GHz 4.4-5.0 GHz ISM-2.435-2.465 WCS-2.3-2.7 GHz BRS/EBS 2.3-2.7 GHz AWS 1.71-2.180 GHz Broadband PCS 1.7-2.2 GHz 1.670-1.675 GHz 700 MHz SMR-0.698-0.940 GHz Cellular 698-940 MHz 3000 5000 5000 7000 TOTAL 20GHZ millimeter wave licensed and unlicensed 14 2432 150 850 2432 2000 TOTAL 12GHZ 500 licensed microwave 1000 30 1375 1200 30 159 600 30 42.5 TOTAL 1.71GHZ sub- 194 230 6ghz unlicensed fixed and mobile 120 5 84 24 188 1 10 100 1000 10000 Sources: FCC 11-103 , FCC Part 101, FCC Part 15
  • LATENCY CONSIDERATIONS Radio Type Sub 6GHz PTmP TDD 4-15ms Sub 6GHz PtP TDD 3ms PTP Microwave FDD 11 Typical Latency (one way) 0.3 - 0.6ms LTE Latency Requirement: 20ms one way, multihop/total IEEE 1588v2 SyncE No Depends on number hops No No No No Yes Yes Yes
  • Sub 6GHz solutions should be seen as last resort option for LTE small cell backhaul today New innovations talked about (largely still long ways off)
  • REPRESENTATIVE POLE FOR ANALYSIS Pole Characteristics Structure: monotubular aluminum tower with x cantilever arm z Dimensions: – Pole height:10.67 m – Diameters: bottom 25 cm, top 15 cm – Cantilever arm: 3.66 m spread, 1.52 m rise Accelerometer positions
  • MAXIMUM DISTANCE (99.99%) AND WIND SWAY Max Max Distance Distance Pole to Pole Deployment San Jose Miami Wind is just another factor that needs to be incorporated into the path planning (rain, capacity, re liability, etc) Frequency Band (GHz) Frequency Range (GHz) Antenna Gain (dBi) Antenna 3dB beamwidth (°) Antenna Size (m) Max Radio Power (dbm) Channel Size (MHz) Maximum FCC 3dB Beamwidth (°) Minimum FCC Antenna Gain (dBm) FCC Max EIRP (dBm) Target Availability (%) QPSK Max Distance / Throughput 16QAM Max Distance / Throughput 64QAM Max Distance / Throughput QPSK Max Distance / Throughput 16QAM Max Distance / Throughput 64QAM Max Distance / Throughput Maximum wind speed: 11 MPH Maximum wind speed: 22 MPH Maximum wind speed: 34 MPH Maximum wind speed: 45 MPH 18 17.700–19.700 33.5 2.2 <0.3 51.5 80 MHz 3.3 33.5 85 99.99 4.3 Mi / 90 Mbps 3.1 Mi / 182 Mbps 2.6 Mi / 269 Mbps 11 Mi / 90 Mbps 7.5 Mi / 182 Mbps 6 Mi / 269 Mbps 0.2° 0.44° 0.52° 1.28° 23 21.2-23.6 30.5 3.3 <0.3 34.5 50 MHz 4.5 30.5 65 99.99 2.3 Mi / 74 Mbps 1.7 Mi / 148 Mbps 1.3 Mi / 233 Mbps 5.5 Mi / 74 Mbps 4 Mi / 148 Mbps 2.9 Mi / 233 Mbps 0.2° 0.44° 0.52° 1.28° 70/80 71-80 43 1.2 <0.3 42 1000 MHz 1.2 43 85 99.99 0.9 Mi / 360 Mbps 0.8 Mi / 720 Mbps 0.6 Mi / 980 Mbps 1.8 Mi / 360 Mbps 1.5 Mi / 720 Mbps 1.1 Mi / 980 Mbps 0.2° 0.44° 0.52° 1.28° Utility and standard compliant short light poles are less likely to sway and should be preferred for SC Pole to pole for gusts > 45mph on Eband links is the only scenario where wind-related outages might occur (above 10dB)
  • 80GHZ: THE DIMINISHING ALIGNMENT/INSTALLATION CHALLENGE 1990’s poor training skills large transceiver/enclosure heavy separate antenna inflexible difficult to manipulate slow coarse alignment tools ½ day to install 2012 high quality training/skills small transceiver/enclosure light integrated antenna flexible user friendly fast highly accurate alignment tools ½ hour to install
  • ?
  • Construction is Key LTE Challenge Today… will be much worse w/ small cells so, its not all about technology widgets…
  • TO ACHIEVE SMALL CELL VISION, we need to pay attention to what’s important…