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1.3.4    Validation phase

The validation was conducted by comparing the results of multiple tries of adding subscribers to the HLR, with the different backends. The results are detailed sections 5 and 6

1.4    3gpp and standards

3gpp is an organization which develops standards for telecommunication Systems, much like IETF for Internet. 3gpp were created late 1998 by a group of separate telecommunications organizations, which earlier developed their own standards. The purpose of the organization is to develop and maintain technical specifications and reports for telecommunication Systems, which everyone can use freely.

Because of the changing naturę of telecommunication, with new standards and services created and old ones discarded, 3gpp “freezes” specifications in “releases”. Therefore one has to decide for a specific release for which the HLR has to comply. The goal is to implement for a reasonably new, and in all stages frozen release and there was two options, release 7 and release 8. Release 7 was frozen in stage 3 during the year 2007 (stage 1 and 2 before that) and has had some time to be implemented fairly widespread. Release 8 was frozen in all stages during 2008 and has not had as much time to be tested as release 7. Therefore we chose release 7.

The main 3gpp specifications used in this thesis are [3], [4], [5], [6], [7] and [8].

1.5    Related Works

Home Location Registers are a basie part of the GSM network and there are many implementations in daily use today¹.

Cardell [9] compares the performance of CouchDB and Tokyo Cabinet with Mnesia. In his thesis he exchanges the backend at a different level using MnesiaEx. MnesiaEx is an extended version of Mnesia that enables users to use modules (other than ets or dets) that implement a database backend.

There is extensive number of papers on Erlang, for example [10]. And discussing testing using Erlang and telecom availability problems [12]

1.6    Thesis Outline

This thesis will add to the earlier work, with taking an alternate route to extend the Mnesia backend by carefully customizing it.

Section 2 gives the reader an insight into the telecom network and the Erlang programming language.

^xAt http://www.openss7.org there is a (stalled) project to develop a MAP-compliant HLR with GPRS support.

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