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Cell Site Survey Case Study

Hardware and software for Law Enforcement, Government & State Security Organisations

• BTS and cell survey equipment

• BTS and cell survey services

• Consultancy

• Legal and evidential support

Case Study: A UK Police Force deployed Delma’s Cell Seeker technology in a criminal case in order

to verify that two mobile phones belonging to the accused had been used in a series of

voice calls and SMS transmissions for which the date, time and cell information were

available.

The data connected with the voice calls and text messages had been obtained from the

mobile service provider. The data also contained Cell ID information relating to the voice calls and text messages.

Verification that the mobile phones belonged to the accused was carried out by

confirmation that the mobile phone network cells providing the mobile phone service at

the home address of the accused, a public house frequented by the accused, the

workplace of the accused and on a section of motorway used by the accused were

exactly as those which appeared in the mobile phone records.

The cell verification was carried out using Delma Cell Seeker PDA based cell detection

systems at each of the desired locations. The Cell ID data obtained was collated and

mapped using Delma Cell Seeker Back Office software. The finished results were

compared to the Cell data obtained from the mobile service provider for each mobile

phone and found to be an exact match.

The mobile usage evidence was so compelling as to encourage the accused to plead

guilty to the charges thus saving the Police considerable further effort and avoiding

potentially lengthy and expensive court proceedings.

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Survey processes:

Cell Site Surveys

The process of surveying the mobile phone

infrastructure is designed to produce an accurate

mapping of the reception footprint of a particular

BTS (Base Transceiver Station). All BTS have one

or more cells associated with them and cells can be of a variety of shapes.

Although intended to be of a regular geometric shape the reception footprint of cells may be

modified by the presence of buildings, structures and topographical features.

The antenna utilised for the transmission and reception of the RF based mobile phone service can give rise to anomalies. It is vital to know

how these anomalies influence the reception footprint of a given cell.

The accurate mapping of a single BTS and its associated cells is often referred to as a Cell Site

Survey.

The mapping process involves the following

• Measurement of RF transmission levels at

various points within the area of interest.

The higher the number of points the more

accurate the cell footprint will be known

• GPS readings taken simultaneously with

each set of transmission level readings. • Off air identification of the MNC (Mobile

Network Code i.e the service provider), LAC (Location Area Code) and Cell ID (Cell

identity) of the cell being mapped.

• Off air identification of the frequency of transmissions (e.g. 900, 1800 or

2100MHz) • Processing of the data into a database

and digital mapping system to provide a

graphical representation of the cell and its supporting data.

• Comparison with historical data to

determine changes.

Cell coverage footprints can be of different shapes and sizes depending on the type and location of BTS antennae:

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Survey equipment and systems:

Cell Seekertm System I & II

Delma provides two levels of Cell Survey

equipment.

In Cell Seeker System I the hardware comprises a portable PDA loaded with software which handles the taking of RF transmission readings,

cell data and GPS coordinates. The second part of the system is a laptop based mapping

application which is responsible for download,

storage, mapping and reporting of the collected data.

The features of this system are:

• The PDA is highly portable and can be

taken into the most inaccessible of areas

for the taking of readings.

• The PDA has an in-built camera for the capture of possible additional

photographic data • The PDA can act as a mobile phone

allowing data to be sent by SMS to the

laptop system. • The PDA can access any 2G, 2.5G or 3G

network globally • The PDA has in-built GPS (System II)

• The laptop may be vehicle based or office

based depending on tactical requirement

• The laptop is Windows based providing the user with a variety of mapping options

(e.g. Mapinfo, Google Maps etc) • The laptop has extensive storage

capabilities but can also be networked to the organisation’s server network.

• The PDA and laptop can connect to each

other via BlueTooth or WiFi or direct cable

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Cell Seekertm Laptop System

In Cell Seeker System II the emphasis is on high speed gathering of cell data from large numbers

of cells from a moving vehicle. The hardware comprises a vehicle based laptop

fitted with multiple mobile network reception units, a GPS receiver and roof mounted

antennae.

The laptop is loaded with software capable of

rapid multi-network sampling for RF transmission

readings, cell data and GPS coordinates for each set of readings.

The features of this system are:

• All networks are handled simultaneously

• Large geographical areas can be covered

quickly. • The PDA described in System I above can

be used by surveyors on foot to cover

areas inaccessible to the vehicle. SMS, • The laptop combines the data capture and

mapping processes • Data can be gathered at high speed (e,g

for Motorway cell mapping)

•

Cell Seeker back office system

Data collected from Cell Seeker systems, GSM

interceptors and other devices may be securely

and efficiently uploaded to the Cell Seeker back office system. A full suite of storage and analysis

programs provide access to then following

functions

• Storage of Base Transceiver Station (BTS)

data Storage of Cell information and BTS

cross referencing

• Auto upload of survey data with creation of cell and BTS records as appropriate

• Screening and analysis of survey data • Mapping of specific survey or mission data

to provide cell footprints for law

• enforcement evidencial purposes or

security mission purposes • Reporting

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Example Cell footprint map (O2 cell 30720)

Cell Survey Services

Delma employs experienced consultants who can be deployed with the required equipment to

perform training, independent cell mapping services in support of Law Enforcement and other

qualifying organisations. Professionally prepared training material, reports, presentations and other

supporting material are provided as part of the service. The same consultants are available for

advice and legal work.

For information contact: Email: info@delmamss.co.uk

Telephone: +44 1962 735859 Fax: +44 1962 735890

In writing to: Delma MSS Ltd., Newhouse Farm, Northington, Alresford, Hampshire SO24 9UB