History and Importance of Cell Broadcast

By nature, all radio systems are multi point to multi point systems, unless you force them not to be so, by adding elaborate protocols. Cellular phone networks are radio networks and are therefore naturally suited to Broadcasting.

Back in 1897 Guglielmo Marconi called his invention the “Wireless Telegraph”, because he wanted his customers to visualize the use to which the system would be put. In order to make radio behave like a telegraph network, Marconi had to introduce a regime of call signs and traffic procedures to control the flow of traffic. As far as any sender of a telegram was concerned, the telegram was delivered from point to point, so the illusion was complete.

Nevertheless the fact remains that signals are broadcast from a base station, but reception is intentionally limited by means of protocols resident in the terminal (the phone). A simple change in those protocols would enable any terminal to pick up Broadcasts from any base station.

This point was not lost on the ETSI’s GSM committee, (who, 100 years after the invention of radio) added a feature called ‘Cell Broadcast’ to the GSM standard. This is contained in standards GSM 03.49 and others. Technologically this was successful and had been demonstrated in Paris by 1997. By now all GSM phones and base stations have the feature latent within them, though sometimes it is not enabled in the network.

There are four important points to recall about the use of Cell Broadcasting for emergency purposes.
1: It is already resident in most network infrastructure and in the phones, so there is no need to build any towers, lay any cable, or write any software or replace terminals.
2: It is not affected by traffic load; therefore it will be of use during a disaster, when load spikes tend to crash networks, as the London bombings 7/7 showed. Also it does not cause any significant load of its own, so would not add to the problem.
3: It is geo scalable, so a message can reach hundreds of millions of people across continents within a minute.
4 It is geo specific, so that government disaster managers can avoid panic and road jamming, by telling each neighborhood specifically, if they should evacuate or stay put.

In short, it is such a powerful national security asset, that it would be inexcusable not to seize the chance to put an existing technology, to the benefit of the safety of citizen.

Abstract from: Mark Wood, Hon. CTA CEASa.