ETWS (Earthquake and Tsunami Warning System) – Japan – (Cell Broadcast)

ETWS is a kind of public warning system (PWS) to notify all the UEs in a specific area of emergency situation like Earthquake or Tsunami.

Currently one of the best notification solutions is ETWS for mobile users who are receiving pop-up messages on their phones’ screens.

Unique vibration for CB messages, Text-to-speech support Android for CB messages and maximum speed of dissemination (all citizens in 4-9 seconds).

Simultenous reception, will people in disaster area receive the alert message on the same moment.

For Cell Broadcast messages a Government can set up different channels for different types of alerts and a citizen can determine to subscribe to receive these alerts.

The cell broadcast service is mainly used to notify the subscribers about the disasters in GSM, WCDMA, LTE and 5G.

Following radio channels are used for broadcasting:

CBCH: Cell Broadcast Channel in GSM.
CTCH: Common Traffic Channel in WCDMA.

In LTE, the subscribers are notified with system information messages:

1 – Paging : ETWS Indication.

2 – SIB 10 : Primary Notification.

3 – SIB 11 : Second Notification.


SIB Type 12

EU-Alert (Europe);
KPAS (South Korea);

Cellular Technology That Told Japan An Earthquake Was Coming

Cell broadcast’ technology is a largely dormant part of many cell phone network standards.

Imagem Postada

Are cell towers the future of the emergency broadcast system?

Japanese who carry phones serviced by NTT Docomo, Japan’s dominant cell phone carrier, can opt to have alerts about earthquakes pushed directly to their phones. The technology that makes this possible, the Area Mail Disaster Information Service, is designed to deliver detailed alerts as quickly as possible.

This service is uniquely enabled by a little-known technology known as Cell Broadcast, or SMS-CB. It’s totally unlike traditional, point-to-point SMS, in that it can be broadcast directly from cell towers to every phone in range and does not use more bandwidth when sent to more users. In this way it’s just like a over-the-air television or radio, where bandwidth requirements do not increase as more users receive a signal.

This is extremely important in the event of a disaster: According to Israeli SMS-CB company eViglio, cell broadcast has the potential to reach millions of users in seconds in an inherently geo-targeted fashion, whereas trying to reach the same number of users via traditional SMS would swamp the network, slowing the delivery of messages to a crawl.

Tsunami Alerts Not Yet Implemented

It appears that Japan’s Area Mail Disaster Information Service has not yet been equipped to warn of tsunamis. The abstract of an eerily prescient paper from 2009, “A Proposal of Tsunami Warning System Using Area Mail Disaster Information Service on Mobile Phones” opens with the line:

The earthquake with the seismic center around the coast of Miyagi prefecture and the oceanic trench of southern Sanriku is expected to occur with high probability. […] Consequently, a system is required that prefectures, cities, towns and villages collect swiftly and accurately the tsunami monitoring information that is necessary for evacuation behavior, relief and recovery activities, and deliver and share to the local residents.

Sendai, the city most profoundly devastated by last week’s tsunami, is in Miyagi prefecture — the same one mentioned in the abstract. Residents there had only minutes between when they felt the earthquake and the arrival of the first wave of the tsunami. Rohan Samarajiva, an expert on early warning systems for natural disasters, argues that for the people of Sendai, no early warning system would have been sufficient, and only building codes and general disaster preparedness would be of any use.

People more distant from the epicenter of the quake could benefit from cell broadcasting, however, and the technology has also been proposed as a means to coordinate relief efforts without bringing down the network.

Cell Broadcast Warnings for Rocket Attacks, Natural Disasters

The technology is also being tested in a very different part of the world in which disaster may strike with very little warning: Israel. EViglio is working on an SMS-CB system that will warn residents of incoming rockets within seconds after they have been fired. Testing of the system will begin in June 2011.

Cell broadcast systems are also being tested or deployed in a number of other locations around the world. The Maldives, a collection of low-lying islands in the Indian Ocean with nearly 300,000 inhabitants, will be rolling out an SMS-CB system to warn of “tsunamis, earthquakes, flash floods, tidal waves, thunderstorms, tornadoes and waterspouts, strong winds, and drought.” The Netherlands and parts of the U.S. including Florida and other gulf coast states, New York City, and Houston are also working on their own systems, according to U.S. firm CellCast technologies.

This technology does have some obvious disadvantages — for one, not everyone carries their cell phones on them at all times. Compared to other solutions, however, it could prove useful: sirens can’t convey information with anything close to the specificity of a text message, and television and radio can only push messages when they’re in use.

What If Cell Broadcast Were Already Widely Deployed?

CellCast Technologies offers a number of historical examples (pdf) in which the technology could have been useful:

When a freight train derailment near Minot, North Dakota, in 2002 spilled anhydrous ammonia and sent up a cloud of poison gas, a public warning over radio was not broadcast for nearly 90 minutes. The designated emergency announcement station’s single employee on duty could not be reached because phone lines were jammed by residents calling in. Authorities tried activating the radio’s Emergency Alert System, but the EAS failed. What if Minot citizens could have received an emergency message on their cell phones warning them of this toxic danger and appropriate directives to safety?

A similar what-if scenario could be imagined for the events of March 11, 2011. What if citizens further down the coast from Sendai had received an automatic SMS-CB alert, generated by Japan’s elaborate tsunami warning system? Until the issue has been addressed by experts, we won’t know the answer.

Earthquake alerts coming to Japan

While Japan’s mobile phones service is renowned for its sophistication as well as frills, later this year carriers are taking service to a new level with the introduction of early-warning earthquake alerts to mobile handsets. Operators are planning to release handsets supporting the service by the end of the year.

The move will follow the nationwide October 1 launch by the Japan Meteorological Agency (JMA) of its earthquake early warning system, which will give around 10 seconds advance notice of major earthquakes. The JMA believes that with 10 seconds warning people can switch off the gas and move to cover, thus reducing loss of life and injuries.

NTT DoCoMo will use cell broadcasting while KDDI will use the cdma2000 equivalent SMS broadcasting. A Softbank spokesperson said the company has not yet decided which technology to deploy.

Both cell and SMS broadcasting are 3GPP2 standard technologies but neither has been used in Japan, although Softbank is said to have been studying the possibility of working with Qualcomm to offer cell-broadcasting services as part of its quest to offer unique services.

In the first stage, DoCoMo has a target of passing the information to subscribers in the expected earthquake zone within 10 seconds of receiving the warning from JMA. “We expect this system will help reduce the loss of life and injuries in the case of a major earthquake because most people always carry their mobile phones and can get the information instantly,” said NTT DoCoMo spokesperson Shinya Yokota.

TV and radio stations, however, will broadcast warnings within one second of receiving them and sirens in the new digital rural network being rolled out will also go off within one second. “Ten seconds is slow,” insisted a JMA official.

Carriers no doubt face a difficult technological challenge to match the speed of the communication of those media.

Up to now the role of mobile communications and the activities of carriers has focused 100% on swift post-disaster response efforts. The earthquake in Niigata on July 16 was a timely reminder of the importance of mobile communications support at such times and its vulnerability.

DoCoMo lost 16 base stations for two days while KDDI reported 17 of its base stations were put out of action.