ARLA/CLUSTER: Fazer chamadas telefônicas sem o uso de redes de provedores de telecomunicações já existentes.

[João Gonçalves Costa]

The Open BTS Project

OpenBTS (Open Base Transceiver Station) is a software-based GSM access point, allowing standard GSM-compatible mobile phones to make telephone calls without using existing telecommunication providers' networks. OpenBTS is notable for being the first free software implementation of the industry-standard GSM protocol stack. It is written in C++ and released as free software under the terms of version 3 of the GNU Affero General Public License (AGPL).

About The Project

What is the Open BTS Project?
The Open BTS Project is an effort to construct an open-source Unix application that uses the Universal Software Radio Peripheral (USRP) to present a GSM air interface ("Um") to standard GSM handset and uses the Asterisk VoIP PBX to connect calls. This is in fact very different from a conventional GSM BTS, which is a dumb device that is managed externally by a base station controller (BSC) and connects calls in a remote mobile switching center (MSC). Because of this important architectural difference, the end product of this project is better referred to as an access point, even though the project is called "Open BTS".

OpenBTS is a Unix application that uses a software radio to present a GSM air interface to standard 2G GSM handset and uses a SIP softswitch or PBX to connect calls. (You might even say that OpenBTS is a simplified form of IMS that works with 2G feature-phone handsets.) The combination of the global-standard GSM air interface with low-cost VoIP backhaul forms the basis of a new type of cellular network that can be deployed and operated at substantially lower cost than existing technologies in many applications, including rural cellular deployments and private cellular networks in remote areas. 

In plain language, we are working on a new kind of cellular network that can be installed and operated at about 1/10 the cost of current technologies, but that will still be compatible with most of the handsets that are already in the market. 

Fonte principal: http://openbts.sourceforge.net/