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Copyright © Arqiva Limited 2015 1

An Example Drive Test for Coverage

Assurance of Smart Metering in CSP-North


Introduction: The drive test principles


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


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


• 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


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


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.


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


Results


City location: Manchester

Number of sites tested: 9

Frequency Band: 422 – 424 MHz

Results 1 The drive test location


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.


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.


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


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


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)

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