utf-8_wizard-adv (day one).ppt
TRANSCRIPT
March 2006
x-Wizard – Advanced Training
DAY ONE – RF Modeling and Drive Test Data
2
How Does it all Work?
Prediction Tuning
Create IM
Model
Optimize
AFP/ACP
Drive Test
Switch
Channels
Traffic
Exp
ort
AFP/ACP Results
3
Class Agenda
• RSL Predictions – – A general description of how Macro cellular Propagation
Models work
• x-Wizard Predictions – – A description of how x-Wizard has implemented several
propagation models
• Drive Testing – – A discussion on how to collect and import drive test data
for x-Wizard
4
Class Agenda - RSL Predictions
• General Description of RSL Predictions– Basic Propagation Modeling– Accounting for Terrain
Effective Antenna Height Knife Edge Diffraction
– Accounting for Clutter General Concept of Clutter Local vs Pass-Through adjustments
5
Class Agenda - RSL Predictions
• This section of the class is offered . . .– To define basic parts of ANY macrocell Propagation
Model– To illustrate how the predictions account for terrain– To illustrate how the predictions account for clutter
Details of specific models are offered after a general treatment of the material
6
Class Agenda - RSL Predictions
• General Description of RSL Predictions– Basic Propagation Modeling– Accounting for Terrain
Effective Antenna Height Knife Edge Diffraction
– Accounting for Clutter General Concept of Clutter Local vs Pass-Through adjustments
7
RSL Predictions in x-Wizard
Predicted received signal level is composed of three basic parts:– Propagation model prediction (RSLPM)– Terrain Factors
Diffraction loss prediction (DL)
OR Effective Antenna Height (EAH)
– Clutter Adjustments (CA)
CA
EAH
or
DL
RSLRSL PMbin
CA
EAH
or
DL
RSLRSL PMbin
8
Basic Propagation Model
All Macrocell Models share:– The assumption that power decays as Log (Dist) – RSL will form a straight line plot (RSL vs Log (Dist))
The Straight Line Assumption
RSL = N*Log(Dist) + P
log(R/R0)
RSLdBm
n.10.log(R/R0)
P1-mile+10.log(Pt/100)+...
0 1 10
X-Wizard Modelcontrols
9
Basic Propagation Model
There are a couple more factors added:– The prediction depends on the ERP and Tx/Rx height– Some models have explicit frequency dependency
A Basic Propagation Model
)()(*
)(*)(*
FH
HLogQ
P
PLogMDLogNPRSL
ref
act
ref
actoPM
)()(*
)(*)(*
FH
HLogQ
P
PLogMDLogNPRSL
ref
act
ref
actoPM
Straight Line Assumption
ERP
Tx/Rx Height
Frequency
10
Basic Propagation Model
The Propagation Model (RSLPM) only accounts for:– Distance– ERP– Tx/Rx Height– Frequency
But does not account for terrain obstructions
Predictions withEAH turned off,KED set to zero &No Clutter
Note: no shadowing behind a hill
11
Class Agenda - Optimization
• General Description of RSL Predictions– Basic Propagation Modeling– Accounting for Terrain
Effective Antenna Height Knife Edge Diffraction
– Accounting for Clutter General Concept of Clutter Local vs Pass-Through adjustments
12
Accounting for Terrain
The Terrain Effects are calculated as either:– Effective Antenna Height (EAH) Correction
Applies only when there is Line of Sight (LOS) between the Tx & Rx
OR– Knife Edge Diffraction (KED) Correction
Applies only when there is an obstruction in the Fresnel zone or Line of Sight is blocked
Both EAH and KED are independent of the propagation model (i.e. Lee, Hata, COST231)
13
Accounting for Terrain - EAH
• Effective Antenna Height (EAH) Gain/Loss
– It is caused by the reflected waves near the receiver– Reflections are often the result of the local slope
Part of any propagation parameter file in x-Wizard
b
bemEAH h
hEG log
b
bemEAH h
hEG log
Basic Effective Antenna Gain
= Effective antenna height gain (dB),= Effective antenna height multiplier (dB),= Effective antenna height (m or ft),= Physical antenna height (m or ft).
GEAH
Em
hbe
hb
hbe is calculated based on the EAH model you choose (next slide)
14
The Effective Antenna Height (hbe) is the critical factor when calculating EAH correction!
• x-Wizard offers three different ways to calculate EAH– Slope (Shown Below)– Spot or Absolute Spot (Next Slide)
Effective Antenna Height(Gain)
Effect of downward Local Slope Effect of upward Local Slope
BS
MS BS MS
Effective Antenna Height(Loss)
Accounting for Terrain - EAH
15
Effective Antenna Height Spot
• The Spot Method recommended by the (ITU-R). TX
RXhTX-AMSL - hRX-AMSL
hTX-AMSL
hRX-AMSL
hTX-AGL
Sea Level
Line of sight
hTXeff = Effective transmitter antenna height [ft/m]hTX-AGL =Transmitter antenna height above ground level [ft/m]hTX-AMSL =Transmitter antenna height above main sea level [ft/m]hRX-AMSL =Receiver antenna height above main sea level [ft/m]
Absolute Spot MethodEffective antenna height is not limited to hTX-AGL as the mobile height (hRX-AMSL) goes above the base height (H0b).
16
Accounting for Terrain - KED
The affects of Knife Edge Diffraction (KED)– KED is used whenever there is a terrain obstruction
Note: Shadowing behind the obstruction
17
Modeling Knife Edge Diffraction Real obstruction is replaced with a knife edge Replacement allows for an analytical solution for the diffraction
loss
Four different diffraction modelsin x-Wizard:
Picquenard Deygout Epstein-Peterson Japanese Atlas
1d 2d
h
Knife Edge
ActualObstruction
Accounting for Terrain - KED
18
DL Model Comparison
• Always searches for the main obstacle first!– Final set of obstacles
more realistic
• Prioritizing obstacles closer to the transmitter (BTS)– ‘Minimum slope’ obstacle
detection– Tends to omit fairly large
obstacles closer to the receiver
O1 O2 O3
TX RX
O4
"LOS"
1st 2nd
3rd
O1 O2 O3
TX RX
O4
"LOS"
1st 2nd
3rdPicquenardPicquenard
O1 O2 O3
TX RX
O4
"LOS"
PrimaryObstacle
1st2nd3rd
O1 O2 O3
TX RX
O4
"LOS"
PrimaryObstacle
1st2nd3rd Deygout Deygout
19
Epstein-Petersen
• Diffraction Models - Epstein-Petersen– Epstein-Petersen is better for wide separate obstacles– Loss is calculated first at each edge then overall loss is calculated by
summing all three losses caused by the three obstacle edges.– d1, d2, d3, and d4 are distances between edge obstacles– h1, h2, and h3 are respectively the effective heights of edge1, edge2,
and edge3 which are determined by drawing line-of-sight between relevant edge obstacles.
20
Japanese-Atlas– Japanese Atlas is improved for closer obstacles with no dominant
obstruction– Similar to the Epstein-Peterson method – Exception: in calculating loss due to each obstruction the effective source is
not the top of the preceding obstruction, but the projection of the horizon ray through that point onto the plane of the transmitter.
A
B
C
TX
RX
Plane of Transmitter
d1 d2 d3 d4
T’
h’
21
Accounting for Terrain - KED
– Studies Show that KED models are conservative Loss calculated using theoretical KED model is greater than
reality Regardless of the KED model chosen, a correction factor will
‘add-back’ to the signal
– X-Wizard offers two KED Corrections:
Foose Factor – Applies an additive correction per obstruction Polynomial - More robust multiplicative model
CORRRAWTOT KEDKEDKED CORRRAWTOT KEDKEDKED
22
KED Correction … Foose Factor
• Large Foose Factor– KED correction applied for
obstructed cases Should range 0dB < FF < 6dB
– Optimization may lead to FF of very high values (FF > 6dB) High FF results in signal
amplification when FF > DL Signal re-birth effect
• Throw out optimized values of FF >10 dB
• Be careful if 6 < FF < 10 dB
FFnDLCORR FFnDLCORR
][
,
dBfactorFooseFF
nsobstructioofNumbern
Ripple Effect!
Signal Re-birth
23
KED Correction … Polynomial
• Polynomial KED correction
– Range 0 ≤ A ≤ 1 -10dB ≤ B ≤ 10dB
• Advantages– 2 levels of freedom (multiply A, additive B)
More accurate optimization results
– More robust, yet not completely foolproof Large A,B values may lead to unreasonable prediction
BDLADL RAWTOT BDLADL RAWTOT ][
],[
dBfactorAdditiveB
unitlessfactortiveMultiplicaA
24
Class Agenda - Optimization
• General Description of RSL Predictions– Basic Propagation Modeling– Accounting for Terrain
Effective Antenna Height Knife Edge Diffraction
– Accounting for Clutter General Concept of Clutter Local vs Pass-Through adjustments
25
Accounting for Clutter
• Recall that RSL is calculated as:where CA = clutter adjustment
Clutter defines areas that contain non-terrain obstructions – trees, buildings, etc.
26
Accounting for Clutter
Clutter consists of 2 files:• Clutter ID file
– Morphological classification of the propagation environment
Typically 7 to 12 classes
• Clutter adjustment file– Defines losses that signal incurs
while propagating through/over each clutter type
27
Accounting for Clutter
• Pass Over– Used for Water only– x-Wizard will attenuate signal as a signal passes over large bodies of
water if Pass Over is checked
• Clutter Height– Defines how high the clutter type is above the terrain– Required if you intent to model pass-through effect
• Receive Height– Used to model bridges and elevated roadways– Defines how high the Rx is above the ground
28
Accounting for Clutter
RX
TX
d3d4
d2
ClutterType 1
ClutterType 3
ClutterType 5
ClutterType 2
ClutterType 4
Clutter attenuates the signal as it passes through and arrives at theLocal Bin.x-Wizard models both types of attenuations:
• Local Adjustment – dB loss due to clutter in the bin being predicted
• Pass Through Adjustment – dB loss due to clutter on the way to bin being predicted
Pass-Through Local
Bin being Predicted
29
Class Agenda – x-Wizard Predictions
• Propagation Predictions in x-Wizard– Propagation Predictions
Prediction Hierarchy Propagation Mode
– Old Standard
– New Standard/ Old Turbo
– New Turbo/ Old Radial
– Specific RF propagation models Lee Model Hata-Okamura Model
30
Class Agenda - x-Wizard Predictions
• This section of the class is offered . . .– To explain x-Wizard prediction hierarchy and prediction
modes– To explain the Lee Model (as implemented in x-Wizard)– To explain the Hata-Okamura Model (as implemented in
x-Wizard)
31
Class Agenda – x-Wizard Predictions
• Propagation Predictions in x-Wizard– Propagation Predictions
Prediction Hierarchy Propagation Mode
– Old Standard
– New Standard/ Old Turbo
– New Turbo/ Old Radial
– Specific RF propagation models Lee Model Hata-Okamura Model Modified Lee Microcell
32
Prediction HierarchyPropMod:
Isotropic Path Loss Predictions
SngServ:Antenna Pattern
Predictions
MLCover:Combo of SngServ
Maps most likely server
InterferencePermissions
MatrixOthers
The number of activesites changes
Antenna, Azimuth,Downtilt changes
Will be re-run if:ERP, Tx Ht., Lat/Lonchanges
33
Class Agenda - x-Wizard Predictions
• Propagation Predictions in x-Wizard– Propagation Predictions
Prediction Hierarchy Propagation Mode
– Old Standard
– New Standard/ Old Turbo
– New Turbo/ Old Radial
– Specific RF propagation models Lee Model Hata-Okamura Model Modified Lee Microcell
34
Propagation Mode: General
• PropMod is the single most time-consuming step in any prediction (coverage, interference, permat, etc.)– Few dependencies means we can re-use PropMods– By re-using PropMods, x-Wizard reduces the time for subsequent
analysis runs
• PropMod requires terrain profiles which take a long time to draw– Reduce the number of profiles and you speed up PropMod
35
Propagation Mode: Old Standard
• Profiles are calculated to each bin when using the old Standard Mode– Similar to TV cathode tube beam
scanning
• This mode draws the largest number of radials; therefore the slowest– # of Radials ~ N2 (N is # of ext. bins)– At 100 m terrain and 30 mi Calc Dist
N = 483 bins & # of Rad. = 233,290 radials
– At 30 m terrain and 30 mi Calc Dist N = 1,610 bins & # of Rad. = 2.592 M radials
Tx
c c c c c
c c c c c
c c c c c
c c c c c
ccc c
36
Propagation Mode: New Standard
• Old Turbo Mode is now called ‘Standard’• Profiles are calculated to each exterior bin
when using the new Standard Mode– Profiles are re-used for interior bins– Each bin is calculated using a terrain profile
• Reduces the # of radials (30% to 50% faster than Old Std.)– # of Radials ~ 2 (N+N) (N is # of ext. bins)– At 100 m terrain and 30 mi Calc Dist
N = 483 bins & # of Rad. = 1,932 radials
– At 30 m terrain and 30 mi Calc Dist N = 1,610 bins & # of Rad. = 6,440 radials
Tx
c c c c c
c c c
cc
c c c c c
c
c
c
c
c
cc c c
37
Propagation Mode: New Turbo
The new Turbo Mode (a.k.a. Radial Turbo) allows the User to set the number of radials (i.e. control speed of predictions)
1. This is the most common method in industry (xWizard, Planet, CellPlan, etc)
2. Predictions close to a sector use terrain profiles
3. Predictions farther from the site are interpolated from predictions on either side.
4. Provides a balance between speed and accuracy
interpolation
prediction
38
Propagation Mode: New Turbo
The new Turbo Mode uses the following equation to interpolate between profiles.
RSLBI = RSLB1 + (RSLB1 - RSLB2) * D1-I / D1-2
Where:
D1-I = Straight line distance from B1 to BI
D1-2 = Straight line distance from B1 to B2
39
The number of interpolated bins is a function of the number of radials and terrain bin size.
30 m terrain - # of bins between radials
90 m terrain - # of bins between radials
5km 10km 15km 20km 25km 30km 35km 40km 45km# of radials # of Bins # of Bins # of Bins # of Bins # of Bins # of Bins # of Bins # of Bins # of Bins
360 2 5 8 11 14 17 20 23 26720 1 2 4 5 7 8 10 11 13
1440 0 1 2 2 3 4 5 5 62880 0 0 1 1 1 2 2 2 35760 0 0 0 0 0 1 1 1 1
11520 0 0 0 0 0 0 0 0 0
Propagation Mode: New Turbo
5km 10km 15km 20km 25km 30km 35km 40km 45km# of radials # of Bins # of Bins # of Bins # of Bins # of Bins # of Bins # of Bins # of Bins # of Bins
360 1 2 3 4 5 6 7 8 9720 0 1 1 2 2 3 3 4 4
1440 0 0 1 1 1 1 2 2 22880 0 0 0 0 1 1 1 1 15760 0 0 0 0 0 0 0 0 111520 0 0 0 0 0 0 0 0 0
40
Propagation Mode: ‘Accuracy’
You can say nothing about the accuracy of an un-optimized model, regardless of which mode you choose.
X-Wizard allows you to optimize the model in ANY propagation mode.
Studies have shown that the optimized models have the same accuracy regardless of which mode you choose.
41
Accuracy Comparison Testing
Test Conditions• Terrain and clutter
at 30 meter resolution.
• Drive test data out to 8000 meters. (Drive data doesn’t often get measured much farther from the site.)
Accuracy Parameters New Standard Mode (1064 radials)
360 Radials
Mean Error 0.1 dB 0.26 dB
Standard Deviation 7.6 dB 7.4 dB
42
Class Agenda - x-Wizard Predictions
• Propagation Predictions in x-Wizard– Propagation Predictions
Prediction Hierarchy Propagation Mode
– Old Standard
– New Standard/ Old Turbo
– New Turbo/ Old Radial
– Specific RF propagation models Lee Model Hata-Okamura Model
43
Lee Model: General
– One of the most popular macroscopic models in the US– Developed by W.C.Y. Lee in eighties as a result of
extensive propagation studies performed in northeast US Considered a US suburban-type model
– Developed for propagation in 800-900MHz frequency band Lee has been validated at 1900 band Lee has no explicit frequency dependence
44
Lee Model: Parts of Model
= Received signal level (dBm),= Reference distance Intercept (dBm),= Output power at the antenna (ERP in W),= Propagation loss factor (n*10 = SLOPE),= Distance between Tx and Rx (miles),= Reference distance (1-mile),= Tx height correction multiplier (dB),= Effective height of the base station antenna (ft),= Actual height of the mobile antenna (ft),= Tx antenna gain relative to the maximal gain (dB).
RSLPM-Lee
P1-mile
Pt
nRR0
Tmhbe
hm
Gt
Straight Line AssumptionERP Tx/Rx Height
tmbe
Mt
mile Gft
h
ft
hT
miR
Rn
W
PP
10
log10150
log][
log10100
log10RSL0
1Lee-PM tmbe
Mt
mile Gft
h
ft
hT
miR
Rn
W
PP
10
log10150
log][
log10100
log10RSL0
1Lee-PM
45
Lee Model: Optimized Parameters
Slope and Intercept Always Optimized
Effective TX Height Can be Optimized
Always Optimized Diffraction Model
46
Lee Model
The Lee Model does not have an explicit frequency dependency, BUT
Note that the Slope is independent of frequency between 150 MHz and roughly 2.2 GHz
Intercept depends on frequency; can convert from one frequency to another using:
2
11121 log20)()(
f
ffPfP milemile
2
11121 log20)()(
f
ffPfP milemile
47
Class Agenda - x-Wizard Predictions
• Propagation Predictions in x-Wizard– Propagation Predictions
Prediction Hierarchy Propagation Mode
– Old Standard
– New Standard/ Old Turbo
– Turbo Radial
– Specific RF propagation models Lee Model Hata-Okamura Model
48
Hata-Okumura Model: General
• Okumura Model– Developed as a summary of large-scale studies in and
around Tokyo during the 1960’s– Designed to work from 200 to 1920 MHz in mostly urban
propagation environment– Presented in forms of path loss curves
• Hata Model– Developed by fitting empirical equations to Okumura
curves– Hata is the most often used version of the Okumura’s
model
49
Original Okumura Model - Equation
• Path loss between TX and RX is given as:
rutumuFS HHALL 50
Where
50L Median path loss in dB
FSL Free space path loss
muA Basic median attenuation
tuH Transmitter antenna height correction
ruH Receiver antenna height correction
Free space loss is given by
]MHz[log20log20log10log10 fdGGXL rtFS
X is 32.45dB if the distance is expressed in km, and X is 36.58dB if the distance is expressed in miles
50
Basic Median Attenuation
• The change of the environmental attenuation due to the change in operating frequency and TX / RX separation
• Given for reference TX height and RX height
• Reference:RX height = 3m TX height = 200m
51
TX Height Correction
• Used to compensate for different TX heights
• Reference TX height is 200m
• The transmitter height used is the effective TX height calculated as Height Above Average Terrain
52
RX Height Correction
• Used to compensate for different heights of the mobile antenna
• Reference mobile antenna height is 3 meters
53
Height Above Average Terrain HAAT
• Calculate the average terrain between 3 and 10 km from the site
• Subtract the height of the average terrain from absolute height of the radiation centerline
Radiation CenterLine
Effective Antenna Height
3 km 15 km
Height of theAverage Terrain
distance0
54
Okumura Model - More Details
• Due to its simplicity Okumura model is widely used• Some Concerns:
– The curves must be implemented in forms of lookup tables for computer-based models
– Empirical nature of model limits its applicability to nonstandard environments
– There are some ambiguities associated with calculation of effective antenna height when the radius of cell is smaller than 3km or when the height of the TX antenna is lower than average terrain. The Effective Antenna Height (EAH) should be modeled as Spot or Absolute Spot
• The above concerns have led to numerous modifications to the model in its practical implementation- Hata, COST-231, Walfish…etc.
55
Hata-Okamura: Parts of Model
= Received signal level (dBm),= Output power at the antenna (ERP in W),= Constant loss factor (default = 69.55dB),= Log-frequency multiplier (default = 26.60dB),= Tx height multiplier (default = 13.83dB),= (Mobile) Antenna height correction (dB),= Slope (default = 44.90),= Effective antenna height multiplier (default = 6.55)= Distance between Tx and Rx (miles),= Reference distance (0.62mile),= Area correction factor (dB),= Effective height of the base station antenna (ft),= Reference base station antenna height (3.28ft)= Actual height of the mobile antenna (ft),= Tx antenna gain relative to the maximal gain (dB).
RSLPM-HO
Pt
CL
LM
TM (hm)SEm RR0
Aa
hbe
h0
hm
Gt
tabe
mmbe
McMLt GAR
R
h
hEShα
h
hTfLCP
000HO-PM loglogloglogRSL ta
bemm
beMcMLt GA
R
R
h
hEShα
h
hTfLCP
000HO-PM loglogloglogRSL
Intercept
Freq.
Tx/Rx HeightStraight Line Assumption
Slope
56
Hata-Okamura: Optimized Parameters
Always OptimizedDiffraction Model
Always OptimizedEffective Antenna Height MultiplierArea Correction
57
• (Mobile) Antenna height correction is computed as:
• Medium and Small size city
• Large city
• Change using Calculate . . .
• Dependent on City Size
8.0log56.17.0log1.1 fhfh mm
MHz200 1.154.1log29.8 2 fhh mm
MHz400 97.475.11log2.3 2 fhh mm
Hata-Okumura Corrections
58
• Area correction factor is computed as:• Dense urban areas
• Urban areas
• Suburban areas
• Open areas
• Change using Calculate . . .
• Dependent on Area Type
Hata-Okumura Corrections
dB28
log24.52
fAa
dB94.40log33.18log78.4 2 ffAa
dB3aA
dB0aA
59
Class Agenda - x-Wizard Predictions
• Propagation Predictions in x-Wizard– Propagation Predictions
Prediction Hierarchy Propagation Mode
– Old Standard
– New Standard/ Old Turbo
– Turbo Radial
– Specific RF propagation models Lee Model Hata Model
60
Class Agenda – Drive Testing
• Drive Test Procedures– Test Site Selection– Drive Route Selection
• Measured Data Integration– Importing drive test data– Associating measured data– Filtering measured data
61
Class Agenda – Drive Testing
• This section of the class is offered . . .– To explain how best to pick sites for collecting drive test
data
– To explain some considerations when planning drive routes
– To demonstrate how to import drive test data and then associate it with the site that was driven
– To demonstrate different methods of filtering bad data out of a file once it is in x-Wizard
62
Class Agenda – Drive Testing
• Drive Test Procedures– Test Site Selection– Drive Route Selection
• Measured Data Integration– Importing drive test data– Associating measured data– Filtering measured data
63
Drive Testing – Site Selection
• Divide network into areas that are similar – Typically, the common feature is Morphology
Rural, Suburban, Urban
– Terrain may be used to further sub-divide Morphologies Flat Rural and Hilly Rural Flat Suburban and Hilly Suburban
– Vegetation may also be used to sub-divide Morphologies ‘Treed’ Suburban and ‘Open’ Suburban
The Key: Identify sites that cover only one Area Type
64
• Pick sites that represent an area & do not have mixed coverage
Good Suburban Sitemix of residential, treesand commercial areasthat is consistent over the Coverage area
Bad Suburban Sitesmall pocket of residentialmostly rural in Sectors1 & 3; Mixed Coverage
Drive Testing – Site Selection
65
• Do not pick sites that are special cases– Both examples are limited by water
Sector 3 may be possible; some limits tothe northSectors 1 & 2 cover too much water; youcan not get enough drive test data
This site covers a barrier island; very fewroads to drive plus you will skew resultswith data on causeway over water
Drive Testing – Site Selection
66
Drive Testing – Site Selection
• Site configuration and parameters used in x-Wizard MUST AGREE with the site configuration in the field
ERP Antenna type, orientation, and
downtilt Latitude/longitude, radiation
centerline (height)
– This is of extreme importance…it can invalidate the whole study!!
67
Class Agenda – Drive Testing
• Drive Test Procedures– Test Site Selection– Drive Route Selection
• Measured Data Integration– Importing drive test data– Associating measured data– Filtering measured data
68
Local Area Mean(LAM)
Geographical Bin
Drive Route
0 10 20 30 40-82.5
-82
-81.5
-81
-80.5
-80
-79.5
-79
-78.5
-78
Distance in w avelengths
Inst
anta
neo
us
RS
L [
dB
m]
DiscreteMeasurements
Prop. model calculates RSL over small geographical areas called bins
Drive test equipment should average 50 samples every 40 into a LM
After import, the LMs inside a bin are averaged to obtain a LAM
Local Mean (LM)
Drive Testing – Route Selection
69
fc
hhhhd rtrt
c
44
f
c
hhhhd rtrt
c
44
• Drive routes should concentrate on data past ~200 m from site:
RF propagates in a predictable manner
Sets min. dist. for collecting data
• Inside ~200 m, propagation experiences Rayleigh fading
• Min dist. depends on: Frequency Transmitter height Receiver height Local clutter
10-2
10-1
100-100
-80
-60
-40
-20
0
20
distance [km]R
SL [
dB
m] Slope of 20
dB/dec
Slope of 40 dB/dec
Check distance dc
Drive Testing – Route Selection
70
• Noise floor Minimum signal level that a receiver can filter out from the
noise Determines MAXIMUM DISTANCE to drive from the test site
– Ways to determine noise floor: Calculation
Equipment manufacturer specifications Measurements
F(kTB) 10log10NF F(kTB) 10log10NF
k=Boltzman’s constant 1.38·10-23 J/KT = environmental temperature, KB = collection bandwidth, HzF = equipment noise figure, dB
Test signal
Noise floor
Drive Testing – Route Selection
71
• You need at least 300 data points per TX to perform a statistically valid optimization– This typically requires data out to 3 or 4 miles from site
• Collect data along radial routes and crossing routes– Radials capture Rn relationship– Crossing routes capture general effects of clutter shadowing
• Collect data near and far from the site
• Watch for interfering signals – Should drive only clear channels since co-channel introduction will change the tuned slope
Drive Testing – Route Selection
72
Good Example• Good Density provides
>300 data points• Nice mix of radial routes• And crossing routes• Data extends from 200m
to ~4 miles
Good routes
Drive Testing – Route Selection
73
Bad Example• Not enough data
– Most data is within 2 mile of site
• Not much ‘crossing’ data– Most data is along Hwy 30
Not enough data
Drive Testing – Route Selection
74
Class Agenda – Drive Testing
• Drive Test Procedures– Test Site Selection– Drive Route Selection
• Measured Data Integration– Importing drive test data– Associating measured data– Filtering measured data
75
• File > Import > Measured Data ...
Supported Data TypesAgilent SD5 (Nitro)Berkley Varitronics CHAMPCharacter Delimited ASCIICOMARCODTI ScannerGeneric Measured Data ASCII Grayson CellScopeGrayson PageTrackerGrayson SpectrumTrackerLCC Cellumate and RSATLCC DeskCatMLJ PathViewSAFCO OIFZK Celtest ZK SAM
Drive Testing – Importing Data
76
• File > Import > Measured Data ...
Give same ‘Source Datum’ as project or the drive test data will not match roads in the project.
Select more than one file for import and you have the option to combine all the files into one *.WMD file
Drive Testing – Importing Data
*.WMD format preserves each drive test point.Routine aggregates points whendata is displayed.
77
Notes on Format• Samples of all supported formats can be found in the Help >
Index . . . drop down menu– Search for “Generic ASCII”; Display “Preparing Measured Data for
Import” Topic
Drive Testing – Importing Data
78
Data Types requiring *.frq table
Berkley Varitronics CHAMPGrayson PageTrackerGrayson SpectrumTracker
Generic Measured Data ASCII
Notes on Format• Some formats require a frequency table that
maps frequency to channel number– Edit “pagetrc.frq” to add frequencies– File is found in the Common directory
Drive Testing – Importing Data
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Class Agenda – Drive Testing
• Drive Test Procedures– Test Site Selection– Drive Route Selection
• Measured Data Integration– Importing drive test data– Associating measured data– Filtering measured data
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x-Wizard allows you to assign data files to the site(s) that were driven. This enables:– Batch Mode Model Optimization– Clutter Optimization– Quick display of drive data– Aggregation of multiple drive test files when running
optimizations– Good “book-keeping”
Keeps track of what sites have been driven
Drive Testing – Association
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You can Associate Measured Data:– From the menu, Tools > Associate Measured Data– From the WEX, rt. mouse click the sector you want to
associate data.
Then it is a Four Step Process
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• Associating Measured data is a step-by-step process
Step One – select the transmitter to which data will be associatedStep Two – select the data file that will be associated
– Note: data must already be imported to x-Wizard– The routine is looking for the *.wmd files found in Project’s
MEASURED directoryStep Three – select the channel to associate (if more than one)
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Step Four: Filter the Data
Drive Testing – Association
Filter based on distance• Set the distance manually• Use ‘Get’ button to have distance
calculated based on the signal threshold
• ‘Draw Boundary’ will display the maximalBoundary for data that will be includedat the site
Use ‘Associate More’ to cycle backto Step 1 and associate data at another site
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Once data is associated . . .– A new entity displays in the WEX
Measured Data icon is placed under the transmitter
– Right Mouse menu allows you to display the data quickly
Drive Testing – Association
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Class Agenda – Drive Testing
• Drive Test Procedures– Test Site Selection– Drive Route Selection
• Measured Data Integration– Importing drive test data– Associating measured data– Filtering measured data
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• Bad data can be filtered within x-Wizard using one of three methods:
Model or Clutter Optimization Analysis Dialog
Associated Measured Data Process
Filter Measured Data Utility
Drive Testing – Filtering Data
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• The Propagation Model and Clutter Optimization dialog allows you to filter data based on:
Distance – set a min/max distance for comparison Accuracy – exclude points where Delta > 30 dB Signal Level – exclude points below a certain
threshold Angle – exclude points based on azimuth, antenna
beamwidth
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• Some Precautions:– Start with 0.25 mi for min distance; increase if data is bad– Reduce max distance if data strays into a different morphology or
there is interference from a different site– Do not use data from behind a sectorized antenna; use horizontal
beamwidth
• The Propagation Model and Clutter Optimization dialog is useful because:– It can accommodate most situations– It does not delete data points
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• Associate Measured Data
The last step filters by Max. distance and RSL Optimizations that use Associated Data only have Min.
distance settings in the dialog
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• Tools > Filter Measured Data This tool allows you to DELETE data from drive test
files– You must re-import the data file to recover the original points
Drive Testing – Filtering Data
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• Tools > Filter Measured Data
– Measured Data files are listed along the left pane
– The operation can delete points or modify selected points Add, Subtract, Divide, Multiply or
assign a constant value
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• Tools > Filter Measured Data
– Filter on defined coordinates
– Filter on a drawn object– Filter on a range of RSL
– Filter by distance
Note: These changes are permanent!! To recover original data, you must re-import data.
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• Tools > Filter Measured Data
– In order to delete data using a drawn object, you must have a pre-existing object prior to entering the dialog.
– All objects are used so be careful! Don’t forget other objects
that may be off screen
Drive Testing – Filtering Data
Questions???