Tiles, tiles, and more tiles. That’s the best way to describe the look of Microsoft’s new mobile operating system (OS), Windows Phone 7.

While its predecessor, Windows Mobile, was packed with menus and strove to emulate the look of the Windows desktop software, the OS introduced in October 2010 represents a real innovation that sets the system apart from other products on the market, such as Google Android and Apple iOS.

The well-organized, tile-based interface dubbed Metro offers slick navigation elements reminiscent of pictograms used in signs or markers. “This makes it attractive to newcomers,” says Ralf Trautmann from German telecommunication portal Teltarif.de, “because navigation has become more foolproof.” The tiles for the email account, SMS, Facebook, or Twitter actively indicate new messages on the freely customisable start menu page, and the start menu itself can be whisked off to the left to display the installed applications. “The interface of Phone 7 is spartan and highly user friendly,” says Alexander Hengesbach, usability expert at consulting company Sirvaluse.

Navigation takes place via innovative hubs. Tiles such as “Office” or “Music & Video” represent functional areas that are arranged on a single, large canvas. The canvas is too large to be displayed on the entire screen, so it can be browsed by swiping to the left or right.

“A partial view of the neighbouring pages is displayed at the corresponding screen edge to show the user that there are additional applications,” says Hengesbach.

Microsoft is strict when it comes to licensing. Manufacturers who want to sell smartphones with the Phone 7 OS cannot implement their own user interface. Also, every Windows phone only has three buttons: Back, Home, and a search button that activates Bing. The design also does not provide for interchangeable memory cards. Supported cards become an inherent part of the OS.

The technical requirements are demanding. At least a one-gigahertz processor, a graphics accelerator to support the Xbox Live gaming platform, eight gigabytes of memory, a multi-touch display with 800 x 480 pixels, GPS, compass, various sensors, and a camera with a resolution of at least five megapixels. “But the high hardware requirements guarantee smooth scrolling and animations,” says Hengesbach.

So far there are only about ten mobile phones based on Phone 7 — most of them from HTC, LG, and Samsung, with prices ranging from approximately 200 to 500 dollars. But other mobile phones are soon to follow. Nokia is planning to use Phone 7 instead of Symbian for their smartphones starting in 2012.

Microsoft is also on the ball when it comes to apps. All of them are checked before they can be offered on the marketplace. There are already more than 11,500 apps. In comparison, there are 150,000 and 300,000 apps for Android and iOS respectively. One reason for the divide is the time these systems have been in use. In a test published in Connect magazine, the rigid requirements are compared with Apple.

“As a result, the first-generation devices are very similar, but on the other hand, they all have a convincing performance,” says Hengesbach.

Contacts, email messages and calendar entries are synchronised with the PC via the internet and Microsoft Server, while it is not possible to reconcile data via cable or Bluetooth. “People used to other options will consider this a flaw,” says Trautmann. In addition, a Windows Live ID (hotmail account) is mandatory, for example, for synchronising or for accessing the app, game, and music marketplace.

“It’s a rather closed OS that does not offer access to the file system,” says Trautmann. This means that users cannot browse folder structures as they can on a PC. “This limits the user’s options.” Also, Microsoft’s Zune media management software must be installed on the PC to exchange information between the mobile device and the PC. The software accesses the mobile phone’s Zune player via WLAN.

“The fact that the Zune software must be used to transfer videos, photos, or music puts a damper on the overall usability,” says Hengesbach. The Android OS, on the other hand, offers its users full access to the file system. “I find this simpler than using complex software like Zune or iTunes,” he says.

Also, Zune does not support documents such as Word or PDF files.

In order to exchange these with the PC, users have to turn to Microsoft’s Sky-Drive network storage service or attach the document to an email message.

The first update for Phone 7 has already been released. “Copy & Paste was the key feature many users had demanded, so this was provided,” says Trautmann. “But there is still room for improvement.”