Friday, June 18, 2010

Checking Masts - CSA 2

Checking Masts - CSA 2
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In response to the discussion at Checking Masts - CSA, a couple of questions that I have been asked:
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- Do you, yourself perform Cell Site Analysis/Surveys for cases?
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- If so what equipment do you use for this very interesting task??
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Answer:
Yes I do and have been doing so since the early 90s for GSM and since 2006 for 3G.
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I use Nokia network monitor for 2G and have used, but do not particularly like, some of these newer independent flash files that enable some smartphones to obtain 3G network control data. I do continue to use them as one tool but for fairness reasons in dealing with the radio evidence.
The reason for that is there are no:
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1) forensic standards for the calibration of test equipment generating evidence
2) forensic standards for the content or quantity of radio data captured for evidence
3) forensic requirements for user mobile phones to be calibrated
4) standards that requires a mobile phone after it has left the manufacturing production line to maintain its radio mask calibration longer than 12-months.
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For example, dealing with point 4) most mobiles in use do not precisely meet calibration standards, but largely their radio mask is towards the upper or lower limits due to the way in which mobile phones are treated by their users: dropped, fall in water, exposed to fag ash, drink splatter, overcharging, over heating, running the battery flat during calls etc etc. All these things and more take there toll on mobile phone operation over time and it is not surprising to find that calibrated radio engineer test equipment often produce a better RxLv sensitivity. For instance, if one puts a used mobile phone side by side with a radio engineers test rig they both record 'absolute' measurments, obviously, but the disparity between 'relative' measurements can be surprising.
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For radio engineer test rig I use Anite's Nemo Handy. Also I have secured in evidence the requirement for the readings and the electronic files that contain the readings and the screen prints to be served in evidence because:
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a) they are original evidence
b) it exposes not just preservation of evidence but the processes which brought the evidence about
c) it means the prosecution can meet the Golden Rule without being fed spurious argument of why things can't be done
d) it stops outsourcer firms holding back on evidence or unilaterally deciding that they control what our courts and criminal justice system can or cannot see
e) whilst I used Anite's Nemo Handy .dt1 file for the criminal case in which I was advising, the requirement is not limited to simply radio test measurements from Nemo Handy but all other radio test equipment etc and equally applies to handset and U/SIM card evidence.
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The additional benefit this offers is that where the police want to save money extracting and harvesting data that is subsequently produced in reports and want to cut down on unessential data, this means they can still produce reports with only the content they want to show. The full copy of data are still obtained by the examiner and this means the defence, having a copy of the full data in electronic format, can examine all the other data to see whether any vital evidence for the defendant's case has been overlooked or not.
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Moreover, the defence can still examine the exhibit as the prosecution will have already produced their evidence. This will allow for variations in evidential standard or interpretation to be checked and exposed, if any, in order to maintain the principle 'nothing lost in translation.'
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This can also work on other levels as well. Such as, we know the Forensic Regulator is due to launch soon and the public sector are rushing around to create and approve their own standards. However, the independent sector has not had the opportunity to qualify whether the public sector standards are better than the standards in the independent sector. The work I have been doing is to highlight issues and attitudes to mobile phone evidence and to let the courts know there is evidence the courts can have. If the Regulator accepts procedures created by the public sector it should not bar the independent sector procedures being accepted also.
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If the independent sector were automatically disbarred from having their own procedures accepted it could potentially lead to following public sector standards containing systemic failure being promulgated throughout the country. Not only that but the knock-on can directly affect small business by placing heavy regulation and financial demands upon small business, causing collapse and unemployment in MPs constituencies. Apart from which there may be the issues associated with breach of human rights under the Human Rights Act and the European Convention on Human Rights.
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Apologies for the length of commentary. It was necessary to go along this discussion path because it is important to promote standards and to highlight choices available to people interested in mobile telephone evidence and identify what is possible by knocking over artificially generated psychological boundaries. I would hope to get the message into evidence in the London area, but my instructions come from outside of London these days and London appears to be a bit of a no-go zone.
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If you want to start a new topic, ask a question or join the discussion on ny previous postings then please join in a Forensic Focus Mobile Forensic Discussion Forum.

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