Mobile networks fail under strain of historic earthquake and tsunami

Much of the Pacific Rim is on high alert this morning, following a magnitude 8.9 earthquake off the coast of Japan. Within hours, a 23-foot tsunami unleashed its fury on the coast of Japan and began its long journey eastward across the Pacific Ocean. Scores of people have been killed and countless others have been left injured in its wake.

The West Coast woke up this morning to calls for evacuations in the most prone low-lying areas as tsunami warnings and watches were issued by authorities.

As in every major disaster, communications networks quickly showed their inherent weakness in times of greatest need. Japan's NTT Communications reported outages affecting Internet voice data that relies on IP-VPN technology.

In a brief statement, the operator apologized for the "trouble and inconvenience," following the string of earthquakes and significant aftershocks that rattled nerves and buildings throughout much of Japan. Some communication services are no longer available, NTT said, and telephone service, particularly long-distance service, is showing strain as well.

Connectivity is poor across the country, and customers with NTT DoCoMo Inc., KDDI Corp. and Softbank Corp. are all affected. All three carriers are assessing the damage to their network infrastructures. In addition to the brunt impact of the earthquakes and resulting tsunami, network overload is occuring as millions of people attempt to call in and out of the country to contact loved ones. People are lining up at fixed-line phone booths to make calls, The Associated Press reports.

Natural disasters of catastrophic proportion like this also highlight the need for public-safety networks to upgrade away from their legacy systems and address the interoperability that's so badly missing in times of despair like today. Live video monitoring, seamless two-way communication and direct contact with all involved and responsible agencies will undoubtedly serve to make days like today less painful and destructive to the extent possible.

Here are a few approaches for direct communication:

1. Multihop Cellular Networks (MCN) and ODMA. These technologies have their own limitations and problems and not being standardised or adopted.
2. Ad-Hoc Networks that can be formed in case of failure resulting in mobile devices being able to communicate directly without the need for network or base stations. The slight problem is that this approach replies on WiFi being available which may not always be the case.
3. A colleague suggested that in TETRA. I do not know the detail of this technology.

参考：http://www.rcrwireless.com/ARTICLE/20110311/INFRASTRUCTURE/110319990/mobile-networks-fail-under-strain-of-historic-earthquake-and-tsunami