The Serval BatPhone: Making Mesh Mobile Telephony Practical, Anywhere, Any Time.
Conventional mobile telephone networks rely on the availability of significant and expensive infrastructure. While this model makes it possible for the resulting networks to offer strong service guarantees, it is not applicable to all situations. During disaster and unrest, the requisite infrastructure may not be available. In remote and developing areas there may not be sufficient economicy density to support the capital and operating costs of the infrastructure. These scenarios cover perhaps 1/3 of the global population at any point in time, and thus deserve consideration. Recent developments of smart phones running Linux and with the hardware capabilities to support complex software make it possible to consider solutions using commodity mobile telephones. This is what we have pursued with the Serval BatPhone, which includes the first port of Asterisk to Android, and our revolutionary Distributed Numbering Protocol (Serval DNA), which allows mesh users to use their existing phone numbers. We present in this paper what we understand to be the world’s first infrastructure-independent mesh mobile telephony system, which also allows subscribers to retain their existing telephone numbers while on-mesh, and is made freely available under an open-source license, and runs on selected mobile telephone handsets. We summarise our recent successful field-testing of this system in the remote Australian Outback.