Aalto University School of Electrical Engineering
ELEC-E4750 Radiowave Propagation and Scattering Session 8: Cellular links (1)
ELEC-E4750 10.11.2016
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Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Schedule
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Wk Date Location New topics, lectures and deadlines
43 Tue. 25 Oct. R037/TU3 1194-1195 Thu. 27 Oct.
44 Tue. 01 Nov. Topic 7: wireless and cellular systems Thu. 03 Nov. Clicker lecture 7
45 Tue. 08 Nov. Topic 8: cellular links (1) Thu. 10 Nov. Clicker lecture 8
46Tue. 15 Nov. Topic 9: cellular links (2) Thu. 17 Nov. Clicker lecture 9; threshold deadline of
topics 5-8
47 Tue. 22 Nov. Topic 10: cellular links (3) Thu. 24 Nov. Clicker lecture 10
• Suzan leads on 25 and 27 Oct. • Usman is away for 25.9-01.11. • Usman and Suzan lead on 24 Nov.
Aalto University School of Electrical Engineering
Books, Topics and Exercises § Books
§ Main books § S. Saunders, Antennas and Propagation for Wireless Communication Systems, Chapters 3, 5,
6-8, 10, 12 15, Wiley. § H. L. Bertoni, Radio propagation for modern wireless systems, Chapters 2-6, Prentice Hall. § A. F. Molisch, Wireless Communications, Chapters 1 and 8, Wiley. § John A. Richards, Radio wave propagation, an introduction for the non-specialist, Chapter 3,
Springer. § Hardcover or paperback copies of both books are available in AaltoELEC and main
library. § Supplemental books:
§ D. M. Pozar, Microwave Engineering, Chapter 1, Wiley.
§ Topic 7: Wireless and cellular systems (Ch. 1 of Molisch) § Exercise 1: Wireless systems § Exercise 2: Radio standardization
§ Topic 8: Cellular links (1) (Ch. 8 and 12, Ch. 6) § Exercise 1: Empirical pathloss models § Exercise 2: Physical pathloss models
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Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Contact Sessions for Topic 8• Goals of the present exercise problems are to
– Get acquainted with the cellular concepts of mobile communications and their most relevant propagation mechanisms (problem 1)
– Be able to use physical models and compare their merits with respect to empirical models (problem 2)
• During the contact sessions, you are – solving the exercise problems by referring to relevant parts of the course
books. • A limited number of course books are available in the room.
– encouraged to discuss with other students and teachers. – asked to contact teachers once your solutions are ready.
• If you prepare exercise solutions in an electronic format (recommended), upload the solution to MyCourses first and then contact teachers.
– asked to propose points for your ready solutions to the teachers. – not given exercise points without discussing with teachers.
• The discussions MUST happen in the contact sessions. – reminded that the threshold deadline of Topic 5-8 exercises is November
17th.
Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Cellular Scenarios
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Satellite links (Mega cells)Macrocells Microcells
Pico cells
Aalto University School of Electrical Engineering
Q1a:whichstatementisincorrect?A. Megacellsareusually
communica2onsbetweenasatelliteandground,liketheglobalposi2oningsystems.
B. Macrocellsaremoresuitableforservingdenseusersthanpicocells.
C. Microcellandmacrocellbasesta2onsareusuallyplacedonbuildingwallsandroo?ops,respec2vely.
D. Theneedofmicrocellsandpicocellsemergedmorerecentlythanmacrocells.
Aalto University School of Electrical Engineering
Q1b:whichstatementisincorrect?A. Megacellsareusually
communica2onsbetweenasatelliteandground,liketheglobalposi2oningsystems.
B. Macrocellsaremoresuitableforservingdenseusersthanpicocells.
C. Microcellandmacrocellbasesta2onsareusuallyplacedonbuildingwallsandroo?ops,respec2vely.
D. Theneedofmicrocellsandpicocellsemergedmorerecentlythanmacrocells.
Aalto University School of Electrical Engineering
Q2a:whichstatementisincorrect?A. Megacellcommunica2onsusually
relyonlyonline-of-sight.B. Higherradiofrequenciesaremore
suitableformacrocellsthanformicrocells.
C. Microcellradiopropaga2onisdominatedbyreflec2ons fromwallsina so-calledstreetcanyon.
D. Pathlossofmicrocellsforindoorusersismainlyaffectedbydiffrac2onintobuildingandpenetra2oninsidethebuilding.
Aalto University School of Electrical Engineering
Q2b:whichstatementisincorrect?A. Megacellcommunica2onsusually
relyonlyonline-of-sight.B. Higherradiofrequenciesaremore
suitableformacrocellsthanformicrocells.
C. Microcellradiopropaga2onisdominatedbyreflec2ons fromwallsina so-calledstreetcanyon.
D. Pathlossofmicrocellsforindoorusersismainlyaffectedbydiffrac2onintobuildingandpenetra2oninsidethebuilding.
Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Pathloss Models: Applicability• Can we use the plane-earth pathloss model for studying the
pathloss in macro, micro and picocells?
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TX
RXhb
d
hmPlane earth
From exercise problem 5.1
101 102 103 104 105Distance [m]
-150
-100
-50
0
Path
loss
[dB]
PELFSL1d4
Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Empirical Models: Based on Measurements (called Channel Sounding)
• Okumura-Hata model (1968) – The most popular empirical model in cellular wireless design – Based on measurements made in and around Tokyo – Validity range of the model:
• Frequency f between 150 MHz and 1500 MHz • Transmit antenna height hb between 30 and 200 m • Receive antenna height hm between 1 and 10 m • Transmit-receive antenna distance r between 1 and 10 km
• COST 231-Hata model (1999) – Extension of the Okumura-Hata model for medium to small
cities to cover 1500 MHz to 2000 MHz
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Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Okumura-Hata Model
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Urban areas : LdB = A + B log10 R – E Suburban areas : LdB = A + B log10 R – C Open areas : LdB = A + B log10 R – D A = 69.55 + 26.16 log10 fc – 13.82 log10 hb
B = 44.9 – 6.55 log10 hb
C = 2 ( log10 ( fc / 28 ))2 + 5.4
D = 4.78 ( log10 fc )2 + 18.33 log10 fc + 40.94
E = 3.2 ( log10 ( 11.7554 hm ))2 – 4.97 for large cities, fc ≥ 300MHz
E = 8.29 ( log10 ( 1.54 hm ))2 – 1.1 for large cities, fc < 300MHz
E = ( 1.1 log10 fc – 0.7 ) hm – ( 1.56 log10 fc – 0.8 ) for medium to small cities
Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Empirical Pathloss Estimation
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Example of macrocellular measurement data from suburban area, and its pathloss model
Aalto University School of Electrical Engineering
Q3a:whichstatementisincorrect?A. Thepathlossmodelhasmuchgreater
errorsatTx-Rxdistanceof6000mthanat1000m.
B. Thegreatuncertaintyofthepathlossmodelisduetomobileloca2onvariability,whichwewouldneedothermodelstodescribethem.
C. Thispathlossmodelmaybeusedreliablyevenwhenwemovethebasesta2onantennafromroo?optobuildingwall.
D. ThepathlossexponentofthefiNedlineisgreaterthan2.
Aalto University School of Electrical Engineering
Q3a:whichstatementisincorrect?A. Thepathlossmodelhasmuchgreater
errorsatTx-Rxdistanceof6000mthanat1000m.
B. Thegreatuncertaintyofthepathlossmodelisduetomobileloca2onvariability,whichwewouldneedothermodelstodescribethem.
C. Thispathlossmodelmaybeusedreliablyevenwhenwemovethebasesta2onantennafromroo?optobuildingwall.
D. ThepathlossexponentofthefiNedlineisgreaterthan2.
Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Ikegami Model
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LE =10 log10 fc +10 log10 (sinϕ )+ 20 log10 (h0 − hm )−10 log10 w −10 log10 1+3Lr2
"
#$
%
&' − 5.8
Φ = angle between the street and the direct line from base to mobile Lr = reflection loss = 0.25
Defines excess losses due to rooftop-to-street coupling, on top of free space pathloss (r-2 dependence)
Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
COST231 Walfish-Ikegami Model
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Restrictions :
• Frequency f between 800 MHz and 2000 MHz • TX height hBase between 4 and 50 m • RX height hMobile between 1 and 3 m • TX - RX distance d between 0.02 and 5 km
Aalto University School of Electrical Engineering
Q4a:whichstatementisincorrect?A. Empiricalmodelsaresimplein
theirforms,butarepronetomeasurementuncertain2esandhencearelessaccuratethanphysicalmodels.
B. Physicalmodelscancalculatepathlossatspecificsitesmoreaccuratelythanempiricalmodels,attheexpenseofgreatermodelcomplexity.
C. TheOkumura-Hatamodelworksfordifferentenvironmentswithvariableterrainprofiles.
D. TheIkegamimodelassumesthatenergyfromabasesta2oncomesmainlythroughdiffrac2onoverroo?opsnearthemobilesta2on.
Aalto University School of Electrical Engineering
Q4b:whichstatementisincorrect?A. Empiricalmodelsaresimplein
theirforms,butarepronetomeasurementuncertain2esandhencearelessaccuratethanphysicalmodels.
B. Physicalmodelscancalculatepathlossatspecificsitesmoreaccuratelythanempiricalmodels,attheexpenseofgreatermodelcomplexity.
C. TheOkumura-Hatamodelworksfordifferentenvironmentswithvariableterrainprofiles.
D. TheIkegamimodelassumesthatenergyfromabasesta2oncomesmainlythroughdiffrac2onoverroo?opsnearthemobilesta2on.
Aalto University School of Electrical Engineering
Q5a:wehavefourpropaga4>3.B. 4>1>2>3.C. 3>2>4>1.D. 2>4>1>3.E. Noidea.
Base station
Mobile10 m
1000 mPlane earth 10 m
8 m1 m
321 4
1 23 4
Aalto University School of Electrical Engineering
Q5b:wehavefourpropaga4>3.B. 4>1>2>3.C. 3>2>4>1.D. 2>4>1>3.
Base station
Mobile10 m
1000 mPlane earth 10 m
8 m1 m
321 4
1 23 4
Aalto University School of Electrical Engineering
Aalto University School of Electrical Engineering
Contact Sessions for Topic 8• Goals of the present exercise problems are to
– Get acquainted with the cellular concepts of mobile communications and their most relevant propagation mechanisms (problem 1)
– Be able to use physical models and compare their merits with respect to empirical models (problem 2)
• During the contact sessions, you are – solving the exercise problems by referring to relevant parts of the course
books. • A limited number of course books are available in the room.
– encouraged to discuss with other students and teachers. – asked to contact teachers once your solutions are ready.
• If you prepare exercise solutions in an electronic format (recommended), upload the solution to MyCourses first and then contact teachers.
– asked to propose points for your ready solutions to the teachers. – not given exercise points without discussing with teachers.
• The discussions MUST happen in the contact sessions. – reminded that the threshold deadline of Topic 5-8 exercises is November
17th.