Obama crowds test mobile networks

Huge crowds can present huge problems for mobile providers

By Mark Ward Technology Correspondent, BBC News website

US mobile phone operators are to boost network capacity and have issued special advice to customers in an effort to avoid a telecoms meltdown at Tuesday's presidential inauguration.

Barack Obama's inauguration is expected to draw unprecedented numbers to Washington, and many will no doubt want to record the moment.

These days, few things say "I was there" like a snap taken on a camera phone, a picture message, a call or a text message.

But all those people taking snaps, making calls and sending messages look set to test mobile networks in Washington to the limit.

Members of CTIA, the industry body for American cellphone operators, have been working hard to help networks cope with the numbers on inauguration day.

In a statement, CTIA said network operators were deploying so-called CoWs (Cells on Wheels) and CoLTS (Cells on Light Trucks) to boost network capacity.

They were also adding more links to the fixed phone network to relay calls and improving so-called "backhaul" services so calls get put through once they are made.

Forward planning

"One of the big challenges that they [mobile networks] have is that they do not know how many people are going to turn up," said Margaret Rice-Jones, head of Aircom, a UK-based mobile network planning firm.

Organisers of the Hajj plan for huge numbers of mobile phone users

Although mobile operators are used to planning for big events such as cup finals or rock concerts, said Ms Rice-Jones, they usually have a rough enough estimate of how many people will be there.

But, she said, that would not be the case in Washington on inauguration day.

It was not impossible to cope with crowds of a million or more, when they were expected, said Ms Rice-Jones.

Mobile phone coverage usually works during the Hajj when millions make the pilgrimage to Mecca, she pointed out.

"It's one of the biggest events in the world but they know how to plan for it," she said.

Unexpected events such as terrorist attacks in crowded Western cities, though, put much more strain on networks as people strive to get in touch with friends and family.

Text not call

Despite the efforts to boost capacity, CTIA said those travelling to Washington should use their phone sparingly to lighten the load on networks.

MOBILE ADVICE Text, don't talk. Snap and save. Send later Have a back-up plan. Arrange a rendezvous before reaching Washington Source: CTIA

"It's really important for the public to understand that unusually large crowds can generate congestion and communications delays," said Steve Largent, head of the CTIA.

"Even though we're building more lanes, if millions of people jump on the road at the same time, there could be a traffic jam," he added.

He urged attendees to text rather than call and delay sending picture messages or videos until after the ceremony was over.

Radio tricks

Ms Rice-Jones from Aircom said operators could employ several different tricks to boost the carrying capacity of their networks.

The 2005 bomb attacks in London tested its mobile phone networks

"You can degrade the quality of the call to let more subscribers on the network," she said. "Though that does have some physical limits."

Also available, she said, were algorithms that govern how a network operates that limit the upper limit of people each cell can handle.

Every mobile device on a network is associated with what is known as "class of service". If the numbers of people trying to use their phones gets too high then the operators can start restricting calls to devices with particular classes of service.

This, she said, meant the networks would always work for the emergency services.

Ricky Watts, Aircom's director of innovation, said the biggest logjam was likely to be in the applications that modern mobiles try to call on.

In particular, he said, the software registers used to support phones roaming outside their home network could be swamped - a major concern given how many people are expected to turn up from outside Washington.

"Many people's phones are just not going to be registered on the network," he said. "They are going to have access problems into the mobile network."

The buffers in messaging systems that relay text and picture messages to recipients are very likely to get overloaded.

"They are not dimensioned for a lot of people," said Mr Watts, "they are expensive and they handle small amount of messages compared to the number of subscribers."

He added that he expected many people to be frustrated by network outages on inauguration day if numbers reach their anticipated peak.