Tuesday, August 25, 2009

Cell Site Analysis (CSA) Images

Cell Site Analysis (CSA) Images
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Cell Site Analysis (CSA) has had a good deal of airing recently here on the forum, so I thought you might like to see images from the work that I get involved.
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Image 1
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Image 1 is one slide from the training course material to introduce students to CSA when starting out discussing radio test measurements. It should be noted that this image represents less than 1% of all data acquired during radio test measurements.
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Image 2
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I thought it would be useful to include this Terrain and Clutter Map (Image 2) as I use this software to assist me in complex cases. Terrain and Clutter are discussed during training and as it was a topic of the discussion about UK Criminal Evidence Delays I thought it would be helpful to let forum members see that I am not referring to theoretical matters, terrain and clutter analysis actually takes place.
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Image 3
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It is essential to understand, when conducting radio test measurements, that just because radio signals can travel some distance from a particular Mast (Image 3) that coverage should not be dismissed or excluded. Operators set threshold limits, hard limits and boundary limits. It does not follow that just because a mobile is in the Green area shown in the Single Cell Prediction Map that the mobile will be excluded from using that coverage.
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Do you remember the discussion that I put up here about fringe coverage?: http://trewmte.blogspot.com/2008/11/mobile-phones-and-fringe-coverage.html
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Image 4
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Best serving coverage is often posed as the deal-clincher to suggest the mobile phone was most likely or consistent with being at a particular location. There can be numerous points that could (and I say 'could' advisedly) point to best server coverage being used but rarely does it come up in evidence because the radio content in evidence rarely gets disclosed these days.
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It is possible with best serving coverage that it can induce a negative outcome that may prevent calls taking place, so it is always important to see the other side of the coin, so to speak:
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http://trewmte.blogspot.com/2007/02/gsm-radio-test-measurements-non.html
- http://trewmte.blogspot.com/2007/01/gsm-radio-test-measurements.html
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I hope the above provides a further illustration of how smart and intelligent a science Cell Site Analysis really is and that by not applying it properly and dumbing down this art of this forensic science:
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- is not only a great loss to the law of evidence
- it reduces the examiner's/expert's knowledge and understanding about the subject with which they are dealing - mobile telephone evidence.

More on Cell Site Analysis: http://cellsiteanalysis.blogspot.com

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