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An Example Drive Test for Coverage
Assurance of Smart Metering in CSP-North
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Introduction: The drive test principles
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Arqiva conducted a drive test campaign for early validation of coverage availability
The test was based on measuring signals transmitted by actual base stations
The base stations were standard-issue type for CSP North, they have been deployed,
tested and commissioned as part of the normal rollout programme
This test made use of a previous campaign of extensive measurements of the
building penetration losses at 420MHz:
• Losses had been measured between a test antenna outside the building and actual locations of
Comms Hubs inside the building
• In total 440 Comms Hub locations had been tested in a range of properties typical for UK
The drive tests confirm the predicted coverage from computer simulations
Introduction 1 The drive test
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The test receiver measured signals transmitted by the base stations
The base stations’ equivalent isotropic radiated power (EiRP) was set to the default
for a standard-bitrate traffic channel
9 separate base station sectors were measured on 9 different channels
A known unused and clear channel was monitored in order to control the levels of man-
made RF noise and interference from other sources
The effects of fast fading were filtered out and slow fading (shadowing) retained in
the presented results by setting the measurement receiver to produce average RMS
values and post-processing of thus recorded data (calculating a median value for each 40λ
of distance travelled)
The results were compared to value of the target planning level derived from the link
budget and based on the previously measured building penetration losses
Introduction 2 The drive test principle
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• Fast scanning receiver:
Rohde & Schwarz, model TSMU™
Very high sensitivity, better than -126 dBm in a 12.5 kHz channel
• Omnidirectional antenna:
Kathrein, model 737003
Gain 2.1 dBi
• Feeder: RG58, 3m, theoretical cable loss 0.9dB, total assembly loss ≈2dB
Introduction 3 The drive test equipment
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Nominal network plan was created using state-of-the-art computer simulation and
prediction product called Mentum Planet™ from InfoVista
All predictions were calculated for the following propagation environment:
Introduction 4 Measurements vs. computer predictions
Base station
antenna is above
the local roof tops
Clutter height
must obstruct
the direct LoS
Measurement
antenna height,
must be well below
the clutter
All propagation paths
to the terminal must
be subjected to
diffraction or reflection
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Target planning level is based on validated link power budget
Validation was carried out during the pilot stage and included extensive campaign for
measuring building-penetration losses
A huge body of similar measurements data already exists and has been published in
technical and scientific literature (e.g. by IEEE, ITU, ETSI), however Arqiva conducted a new
study in order to obtain reliable data typical for UK (other studies quoted results for USA
and continental Europe, where construction methods are different to those used in UK)
The study:
• A wide range of properties typical for UK were selected
• A total of 431 different possible Comms Hub locations were measured
Introduction 5 Building penetration losses
The test receiver compared two signals:
one from a transmitter located inside the
building at the place where a Comms Hub
would potentially be installed, and another
signal from a transmitter immediately
outside the building and at the same
distance as the first transmitter.
The difference between the received
levels of the two signal levels was due to
the losses suffered by the first signal
when penetrating through the internal and
external walls of the building.
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Introduction 6 Building penetration losses (examples of the results)
Summary 360° results for two measured buildings
Examples of possible Comms Hub locations
(external and internal) Example of analysis
50%
60%
70%
80%
90%
100%
0 dB 10 dB 20 dB 30 dB 40 dB 50 dB
CDF of Building Penetration Losses
Pre 2008(161 locations)
2008-present(54 locations)
DECC Property Type Count
Detached/Semi-Detached Houses 259
Terraced Houses 45
Low Rise Apartments 12
High Rise Apartments 18
Locations on an external wall (outdoors) and
other similar (unclassified)97
Total 431
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Results
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City location: Manchester
Number of sites tested: 9
Frequency Band: 422 – 424 MHz
Results 1 The drive test location
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Results 2 The drive test: Computer Prediction against Measured Values
The set of drive test results when compared to the computer prediction of the coverage (area coloured in yellow) showed excellent prediction reliability.
The measured data points are shown with two colours: • green for measured and confirmed coverage; • red for measured lack of coverage.
All data points inside the predicted coverage (inside the yellow area) are green. Some data points outside the predicted coverage are also green, and indicate that there will be coverage overlap with the neighbouring cells. The only red points are at the border of the covered area. These are discussed on the following slides.
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Results 3 The drive test: Google Earth plot
The set of complete drivetest results, showing that almost all data points had signal
level (RSSI) above the planning threshold (those coloured in green)
A few data points to the south and to the east are coloured in red and had RSSI
below the required threshold – these are discussed in the following slides.
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Results 4 The drive test: Google Earth plot (detail)
To the south, two waypoints are coloured in red, however they are on the very edge
of the area targeted for coverage
Detailed analysis shows these point to be less than 1dB below the planning
threshold level, which is considered to be statistically insignificant
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Results 6 The drive test: GoogleEarth plot (detail)
To the east, three waypoints are coloured in red
These are outside of the predicted coverage area of the measured site and actually
located in the coverage area of a neighbouring site that had not been built at the time
this study was conducted
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Conclusions
The results of this initial study provided excellent assurance that the radio network
performance matches the computer models
Drive testing of the CSP-North network is ongoing
• Over 100 base station sectors measured in Q1 2016
• Plan to drive test majority of commissioned sites by Q3 2016 for R1.2 DCC LIVE
(End of the document)