Sunday, April 22, 2012

Mini Course in Cell Site Identification (Pt3.s2)

Mini Course in Cell Site Identification (Pt3.s2)

Links to previous discussions in these Mini Course modules:

Mini Course in Cell Site Identification (Pt3.s1)

Mini Course in Cell Site Identification (Pt2)

Mini Course in Cell Site Identification (Pt1)

In this module the discussion follows on, for section 3.2, identifying further locations where research material maybe obtained to assist cell site identitifcation (CSI). Previously in Pt3 s1 the observations identified where information can be obtained from a local authority or council planning department. The 'reality' of such information being existence and available to any enquiror occurs due to statutory provisions and public employees employed to provide such information and provide such identification that is accessible because of the charges made within national and local taxes. Presumably this might be the same situation in other countries.

In the UK we have the 'communications' (previously known as the 'telecommunications') regulator called OFCOM (Office of Communications). It is the duty, accordng to EU directive, UK statute and regulation that the regulator provides accessible information that is current and up-to-date. One of the tools that an examiner will use is OFCOM's sitefinder service. There is a caveat to the information available from this service, which states (

"Sitefinder was set up as a result of recommendations of the Stewart Report in 2000. It is a voluntary scheme under which mobile network operators make information available on the location and operating characteristics of individual base stations, so that people who wish to inform themselves about this can do so.

"Ofcom hosts the Sitefinder tool on behalf of Government, which can be searched for the location and details of mobile phone base station sites around specific locations. The data within Sitefinder is owned by the mobile network operators, who supply it on a voluntary basis. A request made under the Freedom of Information Act 2000, for Ofcom to make available the information contained within Sitefinder, is subject to an ongoing legal process. Meanwhile, the mobile network operators (except Everything Everywhere) continue to provide voluntary updates which are made every 3 months or so.

The Sitefinder tool therefore remains available and reasonably current (except for Everything Everywhere sites); meanwhile Ofcom will not release the underlying database pending the outcome of the legal process.

Ofcom cannot accept liability for any inaccuracies or omissions in the data provided within Sitefinder, or its currency."

The OFCOM service does provide useful information about cell sites and an examiner would be quite foolish to ignore it, but as equally foolish to believe this is the only source of information, independent from actual enquiries to the mobile network operator and so on.  By way of illustration, I was able to show that information from the local council identified that historcially a base station (cell site) had moved from its original installation (relevant to a particular investigation), which was not revealed by using the OFCOM service. This revelation is further support for an examiner being not only being aware but, equally, being astute.

Examples of the discovery process from the OFCOM sitefinder website is a glimpse at the density of cell sites in a given area:

The relevance of  density of cell site was discussed here -

Moreover, the sitefinder site also provdes details that have been registered by an operator about a particular mast:

Mobile Network Operator
However, the discovery process doesn't stop there but additionally investigation to a particular mobile network operator's website and searching for coverage in a particular geographical area is as equally important to have performed that task. For this reason I have for quite sometime provided links to UK mobile network operators' websites so that examiners can make investigative searches of a particular operator's site regarding coverage relevant for a particular geographical area.

International Marketplace
It is also relevant to be aware that mobile communications also includes 'Roaming' calls and discovery in other countries. The narrative in the aforementioned would largely be wasted without some reference sources and below I have listed a few website in order to bring an international understanding to this discussion:

US cell sites





Sweden PTT

GSMA Roaming and Coverage Maps
And for coverage aspects relevant to roaming an examiner can also visit the GSMA website to see what can be revealed about cell site identification and its coverage before conducting site surveys etc:

In this module it hasn't provided the definitive elements cell site identification (CSI), but it does provide observations for examiners to explore the options about details about a cell site (Mast) and also coverage from it. This may also reveal where the latter can provide important material, such as to define aspects about coverage, which may not have been revealed in documents / information presented by the other side.

As a refresher, readers of this mini course in cell site identification may recall at the very off I set out factors that impact on propagation from a mast and an interpretation of the possible function and responsibility of a mast and thus the natural and obligatory requirement for an exmainer to discover as much about the cell site (mast) as possible. The relevant parts produced thus far have intended to show that even before the examiner peruses call records / mast details obtained for a particular case, the examiner cannot simply take those details on face value and must make strenuous effects to understand that cell site identification is not merely about a cell ID, LAC, postocde, NGR, etc but additionally information about defined coverage that should assist the examiner prepare for site surveys etc. Furthermore, to assess the information provided by the other side to identify or isolate omissions in it/them which, once revealed, may provide an entirely different fact or influence about the evidence the other side had failed to present.

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