A new white paper published by ad firm Smaato suggests mobile ad spend within the US could hit more than $5 billion by 2015.

The paper, published in association with MobileSQUARED, claims advertising on mobile platforms in the US is currently enjoying a particularly strong period of growth - one that's set to continue for the foreseeable future.

As a result, overall spending in the US over the next few years will move closer to that of Japan, which is currently the largest mobile ad market globally.

Big in Japan

In total, Japanese firms are expected to spend more than $1 billion on mobile advertising in 2010, with US spending topping $797 million in comparison.

However, in 2011, the US market will surge past the $1 billion marker itself, coming in at $1.24 billion according to Smaato's figures. That total will then more than quadruple by 2015, hitting $5.04 billion.

"Mobile is a conversation that all DDB clients want to have now," said Jeff Swystun, CCO of ad agency DDB Worldwide.

"We believe that mobile can be an integral component of a larger campaign as long as it works to connect people with people, not just people with brands."

International affair

Smaato believes this fondness for mobile advertising won't be restricted to the US.

By 2015, European territories such as the UK, France, Germany, Italy and Spain will also have national mobile ad spend totals of more than $1 billion.

Smaato's figures, which can be viewed in full for free by downloading the whitepaper from the firm's website, are roughly in line with those published by eMarketer at the end of October, albeit a touch more optimistic.

In its own report, the firm predicted US mobile ad spend would total $1.1 billion in 2011, moving on to $2.5 billion by 2014.