Motorola Solutions PTP LINK Planning Factors that determine your PTP Solution
Agenda Motorola PTP Solutions Key Questions Propagation Effects Freespace Loss Atmospheric Absorption Rain Fade Clear Air Fading PTP LINKPlanner Motorola PTP Products 2
WIDE RANGE OF MOTOROLA PTP OPTIONS License-Exempt and Defined-Use Licensed Solutions Licensed Solutions PTP 100 and 200 PTP 300, 500, 600 PTP 800 2.4 to 5.9 GHz 6 to 38 GHz 3
How do I decide? What is the range? What is the throughput at that range? What is the availability? The answers to all these questions depend on a number of factors, and change depending where the link is deployed. 4
Key Propagation Effects Atmospheric multipath fading due to abnormal refraction Attenuation due to rain / snow / dust Line-of-sight (LOS), freespace attenuation + atmospheric gas (Oxygen, water vapour) Distortion due to frequency selective fading Fading due to Multipath from surface reflection Diffraction Fading due to obstruction of path by terrain 5 Modelled according to ITU-R P.530
Microwave link planning As in [ITU-R P.530], propagation loss consists of: Freespace loss Lfs Gaseous absorption Lg Rain Lr Clear-air fading (multipath) Lm Loss (db) = Lfs + Lg + Lm + Lr 6
Freespace Pathloss L fs = 32.4 + 20 log( d) + 20 log( f ) d = distance (km) f = frequency (MHz) Perfect Omni antenna High-gain antennas at high freqs 900 MHz 32dB 26 GHz 26 GHz 5 GHz 15dB 0dB 5 GHz 900 MHz 7
Atmospheric Absorption P = 1013 hpa T = 20 o C ρ = 7.5 g/m 3 Atmospheric Attenuation Factor o (db/km) Dry gas Water vapour Total 100.000 60GHz Oxygen absorption peak 10.000 Attenuation factor (db/km) 1.000 0.100 1 10 100 0.303 0.185 0.110 0.010 0.009 0.015 8 0.001 6 11 MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product Frequency or service (GHz) 23 38 80
Key propagation effects above 6 GHz 1. Rain : can be severe 2. Clear-air fading (includes ducting) : can be severe 3. Obstacles and multipath : Unlicensed only for non-los Fresnel zone should be clear for Licensed 9 Licenced Mircrowave (PTP800) is designed for clear LOS operation only!!!
H 2 O is a polar molecule with a separation of charge, so it is affected by microwaves Rain Fade Freq (GHz) ¼ wavelength 5.8 12.9 mm 11 6.8 mm 18 4.2 mm 23 3.3 mm When raindrop size gets close to wavelength you get power absorption Water drop 38 2.0 mm Water drop on a leaf Raindrop falling through air < 2 mm Photo: M.Sellars Surface tension forms pendant shape 10 Photo: M.Sellars Sphere is the shape with smallest surface area Air resistance causes bottom of raindrop to flatten Horizontal dimension is biggest, so Horizontal polarisation interacts more Largest raindrops about 9 mm > 2 mm 5 mm
99.99% Rain fade depth (db) 100.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 Rain fade for V & H Polarisation Horizontal polarisation is more attenuated by rain 18 GHz 23 GHz Large gap between V and H polarisation 5 GHz Rain rate 42 mm/hour Vertical, 5 GHz Horizontal, 5GHz Vertical, 18 GHz Horizontal, 18 GHz Vertical, 23 GHz Horizontal, 23 GHz 11 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Distance (km)
Rain Fading For a 99.99% link need to know max rain rate not exceeded for 99.99% of the time then calculate path loss due to this amount of rain Cambridge U.K. Johannesburg South Africa Kuala Lumpur Malaysia Bombay India Dar es Salaam Tanzania Sydney Australia Lattitude 52.2 N 26.1 S 3.2 N 18.6 N 6.5 S 33.9 S Longitude 0.1 E 28.0 E 101.7 E 74.4 E 39.2 E 151.2 E Rainfall rate R 0.01 = 0.01% 22 mm/hr 51 mm/hr 116 mm/hr 74 mm/hr 95.5 mm/hr 45.9 mm/hr 12
99.99% Rain fade (Morocco 29mm/hour) 5.8 8.0 11.0 18.0 23.0 26.0 38.0 160.0 140.0 120.0 Rain fade (db) 100.0 80.0 60.0 40.0 20.0 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Link length (km) 13
99.99% Rain fade (Malaysia 98mm/hour) 5.8 8.0 11.0 18.0 23.0 26.0 38.0 160.0 140.0 120.0 Rain fade (db) 100.0 80.0 60.0 40.0 20.0 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Link length (km) 14
Clear-air fading Fading NOT due to rain, particles, obstacles (trees, buildings) => CLEAR AIR fading Caused by extremely refractive layers of air in the atmosphere According to ITU-R P.530-12, clear-air fading mechanisms include : Beam spreading (commonly referred to as defocusing) Antenna decoupling Surface multipath Atmospheric multipath These mechanisms can occur by themselves or in combination 15
Duct = Extremely refractive layer of air Top of duct Earth surface Ducts in atmosphere due to changing refractive index Cause radio waves to bend back towards the earth surface Primarily due to water vapour, worst above coastal areas Gradient of refractive index dn/dh = -39 units/km (linear) Change in temperature -> ducts change -> refractive index changes True Earth 0-39 -157 Equivalent earth Flat Earth (standard atmosphere) 0 0 linear -39-39 -157-157 16 Rays return to earth
Clear air fading ITU combines all types of clear-air fading Not correlated with rain, so fading effects considered independent Based on data of refractive index - Can vary depending on the season eg worst in summer months in UK Use refractivity gradient to estimate probability of ducting as in ITU-R P.453 Cambridge U.K. Johannesburg South Africa Abu-Dhabi UAE Bombay India Dar es Salaam Tanzania Sydney Australia Refractivity index -214-261 -1321-333 -248-468 dn 1 Geoclimatic factor K 2.6e-4 3.6e-4 0.189 5.8e-4 3.3e-4 1.4e-3 17
Clear-air fading depends on: Ducts broken-up Latitude Altitude Surface roughness Inclination angle Frequency worse at equator worse at sea-level worse over flat ground worse on flat path worse at high frequency Transmission path cuts across ducts, => little refraction Transmission path lies inside a duct Ducts form easily and persist Mountains - Low fading 18 Flat coastal - High fading
99.99% Clear-air fade (Ashburton, U.K. vs Abu-Dhabi) 5.8 8.0 11.0 18.0 23.0 26.0 38.0 Abu-Dhabi 5.8 Abu-Dhabi 8.0 Abu-Dhabi 11 Abu-Dhabi 18 Abu-Dhabi 23 Abu-Dhabi 26 Abu-Dhabi 38 100.0 90.0 Abu-Dhabi 80.0 70.0 Fade (db) 60.0 50.0 40.0 30.0 20.0 Ashburton, U.K. 10.0 19 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Link length (km)
RSL U.K. Clear-air fading RSL Abu-Dhabi Clear-air fading mean mean 24dB 0.01% fade 61dB time time 0.01% fade 99.99% Clear-air fade (Ashburton, U.K. vs. Abu-Dhabi) 80.0 70.0 U.K. 8 GHz Abu-Dhabi 8 GHz Abu-Dhabi, at 40km, 8GHz signal will fade by 61dB for 0.01% of time 60.0 Fade (db) 50.0 40.0 30.0 U.K., at 40km, 8GHz signal will fade by 24dB for 0.01% of time 20.0 10.0 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Link length (km) 20 LINKPlanner calculates this automatically
Winnipeg, Canada: 99.99% Fading (Rain and Clear-air) Rain 5.8 Rain 8 Rain 11 Rain 18 Rain 23 Rain 26 Rain 38 CA 5.8 CA 8 CA 11 CA 18 CA 23 CA 26 CA 38 140.0 120.0 100.0 Fade (db) 80.0 60.0 Rain 23GHz 40.0 20.0 Rain 18GHz Clear-air fading 21 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Link length (km)
Geographical variations Sometimes rain dominates (usually at higher frequencies), whereas clear-air fading may dominate near the coast City Rain (mm/hr) Geoclimatic Factor K ( x 0.001 ) Salt Lake City 21 0.055 Seattle San Diego 25 0.190 Phoenix 33 0.130 Boston Dodge City 36 0.170 Boston 41 0.329 Schaumburg 41 0.230 Seattle 41 0.091 Charlottesville 51 0.090 Salt Lake City San Diego Phoenix Dodge City Schaumburg Charlottesville Dallas 55 0.245 Lake Mary 81 0.330 GeorgeTown, Gr. Cayman 84 0.250 Dallas Lake Mary Depends on intensity of heaviest rainstorm NOT frequent drizzle High values above 0.2 mean high ducting GeorgeTown Grand Cayman 22
99.99% Rain fade depth 70.0 60.0 50.0 40.0 30.0 20.0 10.0 Fading calculations for USA - RAIN Rain fade worst in areas of heavy storms (Florida) USA Rain Fade 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Link distance (km) 18GHz 6GHz 11GHz Boston 6GHz Boston 11GHz Boston 18GHz Dallas 6GHz Dallas 11GHz Dallas 18GHz Dodge City 6GHz Dodge City 11GHz Dodge City 18GHz Lake Mary 6GHz Lake Mary 11GHz Lake Mary 18GHz Phoenix 6GHz Phoenix 11GHz Phoenix 18GHz Salt Lake City 6GHz Salt Lake City 11GHz Salt Lake City 18GHz 23 Lower frequencies not affected much by rain
Fading calculations for USA Clear-air USA Clear-air fade 99.99% Fade depth 60.0 50.0 40.0 30.0 20.0 10.0 24 Clear-air fading worst on coast (Boston, Cayman Isl) Best in Salt Lake City (high altitude, mountains, inland) 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Link distance (km) Boston 6GHz Boston 11GHz Boston 18GHz GT Cayman Is. 6GHz GT Cayman Is. 11GHz GT Cayman Is. 18GHz Seattle 6GHz Seattle 11GHz Seattle 18GHz Phoenix 6GHz Phoenix 11GHz Phoenix 18GHz Salt Lake City 6GHz Salt Lake City 11GHz Salt Lake City 18GHz
Fading calculations for USA Rain and Ducting combined Link Distances for 99.99% Availability, 256-QAM, 6-foot dish Frequency (GHz) 18GHz Salt Lake City Phoenix GeorgeTown, G.Cayman Boston Lake Mary Dominated by rain fading, worst in stormy areas (GeorgeTown) Salt Lake City has lowest rainfall so high frequencies travel quite far 18 GHz in Salt Lake City travels further than 6 or 11 GHz in most other places! 11GHz FCC Rules for 11 GHz: Smallest antenna = 2.6ft Shortest path = 5 km 6 GHz Dominated by clear-air fading, worst on coast (Lake Mary) FCC Rules for 6 GHz: Smallest antenna = 6ft Shortest path = 17 km 25 0 10 20 30 40 50 60 70 80 Distance (km) Salt Lake City is in the mountains so clear-air fading is low
Simple Questions? What is the range? What is the throughput at that range? What is the availability? There is no quick answer to these questions, a lot depends on your location and a number of factors for your link Calculating these factors manually would be very time consuming! 26
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MOTOROLA LINKPlanner software Link planning should be carried out BEFORE equipment purchase / install Download the FREE tool from http://www.motorola.com/ptp/software Start the PTP LINKPlanner tool 28 Create sites Create links Request path data from Motorola Free 3 metre Terrain Data (US Only, 10 metre world wide) Aerial Photography (free from Google Earth) Load obstruction data into link tools Obstructions estimated from aerial photography and local knowledge Estimate antenna heights Estimate appropriate antenna sizes Estimate environmental noise Configure link for customer needs
Long link, 112km 29
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Fresnel zone clear if possible PTP 800 is designed for clear LOS operation only!!! Width of First Fresnel zone (n=1) 28GHz, d=10km, F n 5m d 1 F n d 2 Fn = nλd 1d d + d 1 2 2 Curvature of Earth Radius of Earth 6371km Effective Earth Radius factor typically 4/3 bulge 1.5m for d=10km ITU-R P.526 model for irregular terrain 31
Guidance for PTP 800 link distances Distances calculated for various frequencies assuming: 128QAM, 99.99%, 4-foot dishes, medium fading (rain = 58 mm/hr, refractive index dn1 = -219) Frequency (GHz) 38 Short, high-capacity links Minimum link dist ~ 0.5km 26 Short, high-capacity links 23 Short, high-capacity links 18 Medium links 15 Medium links 11 6 Regulator may not license < 5km or 17km (FCC) Long trunks Long trunks 4.9-5.8 Unlicensed 32 0 0.5 5 10 15 20 25 30 35 40 45 50 55 Distance (km)
PRODUCTS AND KEY FEATURES PTP Feature PTP 100 PTP 200 PTP 300 PTP 500 PTP 600 PTP 800 33 RF bands (GHz) Max. Throughput Max. LOS Range Max. NLOS Range Security Wind Speed Survival Operating Temperature 2.4, 5.2, 5.4, 5.8 14 Mbps 21 Mbps 35 mi (56 km) with reflector 4.9, 5.4 5.4, 5.8 5.4, 5.8 5 mi (8 km) Integrated antenna 25 Mbps 50 Mbps LOS option 155 mi (250 km) 2.5, 4.5, 4.8, 4.9, 5.4, 5.8, 5.9 105 Mbps 300 Mbps 155 mi (250 km) 124 mi (200 km) 6 38 368 Mbps (full duplex) NA NA 6 mi (10 km) 6 mi (10 km) 5 mi (8 km) NA 56-bit DES 128-bit AES 118 mph (190 kph) -40º~131º F (-40º~55º C) 56-bit DES 128-bit AES 118 mph (190 kph) -40º ~131º F (-40º~55º C) 128/256-bit AES 202 mph (325 kph) -40º~140º F (-40º~60º C) 128/256-bit AES 202 mph (325 kph) -40º~140º F (-40º~60º C) 128/256-bit AES; FIPS 140-2 202 mph (325 kph) -40º~140º F (-40º~60º C) NA 128/256-bit AES 150 mph (242 kph) -27º~131º F (-33º~55º C)
Summery Why use Lower frequencies?? Unlicensed No Licence Fees Unlicensed Quick and Easy to deploy No Frequency Co-ordination Long Distance Non Line of Site possible 34
Summery Why use higher frequencies?? Bandwidth much more available > 10GHz Easier to make Narrow-beam antennas (e.g. point-to-point links) Better frequency re-use (e.g. 38GHz, 60GHz) Always use LINKPlanner!! 35
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