As the old adage goes "time and tide wait for no man" it is important to get to grips with GPRS at its easiest stages and when understood move on to track down changes and comprehend them found in the additional layers involved with later transmission technologies.
When I was teaching/training at the Institute the Professor in-charge of educational studies, at that time, wanted me to show where mobile communication research material originated, authenticate sources and compiled the material before student/delegate training could go ahead. Invariably this meant starting out producing hand-drawn sketches that would be converted and re-produced for slide/powerpoint presentations. The information in the sketehes being sourced from standards, books, articles, whitepapers, manufacturer specs etc, and experience (testing), of course. From my GPRS CSA course researched material prepared back in 2002/2003 I have pulled out the folder one hand-drawn sketch (below) from the collection of sketches prepared for GPRS CSA.
The sketch layout is heavily influenced by the existing standards and industry illustrations available at that time. I have added a few personal touches in order to produce this at-a-glance sketch. Perhaps students, investigators and examiners may find it a useful starting point. I shall add more here, at this blog, about GPRS CSA but I do have quite a few other research projects on the go and I want to write about those too.
Just briefly though, GPRS CSA is not possible simply by referring 'only' to CDRs.
Firstly, There are two CDRs to consider. GPRS usage is not soley defined by a Call Detail Record. GPRS has its own record called the Charging Data Record (also referred to by the acronym CDR) defined to confirm data usage, irrespective of the content transmitted in the data, and services used etc.
Secondly, GPRS CSA should not be undertaken lightly and should not be progressed where the investigator/examiner is being given partial information or being denied access to information.
Thirdly, to avoid mishaps associated with the second point mentioned above, examiners/investigators should establish at first instance the MS, (U)SIM/handset, used at the material time. Confirrmation which cells were GPRS enabled and were available for the relevant location/s at the material time; the requirement is also relevant identifing those cells that were not enabled for GPRS for the relevant location/s.
Fourthly, make sure it is clear which GPRS usage is in the home network and which is GPRS usage caused to be transported across donor roaming partner networks but within the same country (cf. Vodafone and Hutchinson 3G (H3G)).
