Monday, January 16, 2012

Mini Course in Cell Site Identification (Pt3.s1)

Mini Course in Cell Site Identification (Pt3.s1)

Mini Course in Cell Site Identification (Pt1)

Mini Course in Cell Site Identification (Pt2)

In Part 1 and Part 2 of this mini course on cell site identification certain themes have been illustrated. For Part 1 four images were presented with the intention to provide the reader with a starting point. That starting point related to identifying various ways in which the Mast, a.k.a. BTS etc provided ‘the’ pivotal link that enabled a mobile station (MS) to communicate with the mobile network in order to send and receive communications(voice/text) and obtain other services. Identification of various factors that are needed was also illustrated; nothing in-depth, of course, just bullet points hinting at matters to be considered. Behind each of the bullet points there hides a huge range of material such that each bullet point deserves its own chapter in a book, e.g. purely on cell site identification issues alone.

I do not have the luxury to produce all the material I have because this is only a free mini course with an intention to prompt the examiner, investigator and/or expert into appreciating the importance of a mast. That is to say, merely going to site, taking a photo of a mast and performing a selection of ‘motionless’ or ‘drive tests’ doesn’t even begin to cover the important science and art of cell site identification, let alone cell site analysis, let alone cell site identification.     

In Part 2 the discussion moved on to demonstrating a selection of images of masts defined by the effect of the propagation they produce and how environmental condition impacts against propagation due to the siting of the mast. But as the course is about cell site identification and not radio propagation, I set out to challenge the reader with examples of whether the reader’s understanding of the images could be altered. Why did I do that? For exactly the point I made above in the last paragraph. Taking a photo of a mast said to have produced ‘the’ coverage used by a particular MS, but omitting definition and technical detail about a mast, is certainly not cell site identification.  Moreover, failing to comprehend the arrangements of the way in which a mast is installed, position and setup in order to deliver radio coverage can impact down the line.

One example, if one looks at the image Fig. D. The mast has been sited in the centre of the roof. A depiction of radio coverage has been enunciated by the use of blue-scale colour and an explanation of a probable outcome of coverage forecast from that particular install. Additional commentary was given to challenge the reader to consider that minimal acquisition of information about a mast may not be satisfactory for cell site identification when analysis is made following radio test measurement and the results may raise questions about coverage because of a lack of understanding, at first instance, about the mast install.

For Part 3 the theme continues with further consideration about masts, but from the viewpoint of ways to identify and investigate the technical install of and at the mast. In order to give this part of the topic some airing Part 3 will be separated in to three sections (3.1, 3.2 and 3.3) so illustrate places where discovery can be made.

The earlier images shown in Part 2 illustrated various types of masts regarding their location/positioning but no detail of the technical install was given, so the examiner, investigator and/or expert has to look to options available to obtain details of a mast’s technical install. A word of caution about cell site identification details received about a mast, especially in criminal proceedings, the discovery of information (data etc) served can be very limited.   There can be numerous reasons for this and rather than e.g. an investigating police officer accepting information presented under the camouflage caveat of information s/he is entitled to receive or entitled to request under “proportionality”, a good copper with a nose for policing wont allow his/her horizons to be limited by that.

Section 3.1 - The Council Planning Department
This line of enquiry may be a shock that it is mentioned at all and for consideration first, but it is being given promenance precisely for those reasons. The amount of times I recall being informed by one party or another that the limited information provided to me by them is all I can have as that is all that is available I found quite astounding. Put simply, it is mendacious (whether intentional or not) to claim 'limitation' about the avalability of the details about a mast, particularly where the operator, depending upon which country is relevant, has obligations to main details about a particular mast in some cases upto six months after a mast has been decommissioned. Moreover, archives of mast installs can go back much longer than that. Any proposed install (mast) that has the intention to be used to provide radio coverage to a geographical location requires proper scrutiny regarding the operator's mission statement, environmental impact, interference with or to other services and health and safety etc prior to its approval to install. There are some exceptions where planning may not be required for external operator masts, but that doesn't mean that the planning department is unaware about a mast's detail. 

Submitted plans for a proposed install or an existing install are available locally. There is a large range of information available, and to whet your appetite below is a selection of technical detail I have choosen that you can find out from your local planning office:

A photo of the Mast (this one is b/w because that is how it was submitted to the planning department)

Because some masts are occupied by more than one operator's equipment the elevation and detail of a mast's height and the height of each operator's equipment on it is important to know.

Additionally, for the antenna array it is important to comprehend the mechanical arrangement of the antenna and the delivery of intended coverage to the e.g. azimuth

In preparation for comprehending site survey and radio test measurements you may also think it important to understand the detail of True North/Magnetic North and other bearings given for the arrangements at the mast's core.

So the range of information provided from this source should be treated as important in the fact finding process and form a natural and integral part of the cell site identification (CSI) investigation.

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