Cell Site Analysis
"Radio, she is a beauty but a mistress to none. Just when you think you have her coralled up she'll jump and kick you right in the backside when you least expect it. She is indeed a worthy challenge."
I said that in 1994, and I haven't changed my mind todate.
The above will be brought home to you only too quickly when you deal with digital radio and the art of cell site analysis. If you want a starting point with GSM, then start with the GSM standards. Having spent many years dealing with GSM and the evidence that can be produced from it, I am still in awe today as I was back in 1993 when I first started to work with GSM. For those not yet having an insight into the GSM, I can only say we really do stand on the shoulders of geniuses. I cannot think of any other technology where the authors produced such an amazing system and went on to fully document what they have done, only asking you respect what they have done by reading the standards and comprehending, and then go on to use it.
For example, when considering GSM, it is worth knowing at least four principles to be understood:
- There are mandatory requirements with mandatory outcomes
- There are mandatory requirements with optional outcomes
- There are optional requirements with mandatory outcomes
- There are optional requirements with optional outcomes
This appears to apply right across the GSM system.
There are some very good radio detection systems around, such as TEMS, Sagem etc, useful for part of the job of cell site analysis radio data acquisition. Each provides different ways to assess the radio system. An expert or examiner cannot get by though relying on devices alone. You need knowledge, skill and experience in order to comprehend the radio assessment and then how to apply it.
If you do come to our branch of forensic science, do make sure you understand the GSM system and not simply knowing how the device works. It does make for better quality of evidence and assist in a higher degree of certainty about the opinion that may be expressed regarding mobile telephone evidence.
Also, if you intend to enter 3G forensic investigation, you will find it much easier having a GSM background understanding and how it impacts; and of course having read the 3G standards.
The caveat in all of this, of course, is both systems (GSM & 3G) are constantly evolving. Even with all the years I have been working with GSM, what I have found is the more I know, the more I need to know. I find exactly the same with 3G.