Korean telecoms operator KT Corp has expanded its mobile WiMax network to cover the whole of the country's capital city of Seoul, the company announced yesterday. 

KT Corp uses a Korean variant of the mobile WiMax standard called WiBro. The Korean developers claim that WiBro and WiMax devices and networks are already interoperable, and will be fully compatible by next year given suitable driver software and firmware. 

However, it is unclear whether these claims have been independently tested. Competing WiMax hardware developer Nortel has insisted that mobile WiMax and WiBro are not compatible. 

WiMax is an internet access technology similar to Wi-Fi, but with a much wider range and higher speed. The mobile version also allows users to move between cells with almost no discernible interruption in signal.

Developers in Korea say that WiBro transmitters have a range of about 1km, and can provide internet connections at up to 3Mbps to users travelling in vehicles at up to 120kmph. The Seoul WiBro network also covers subway lines and stations.

KT Corp has been operating a limited WiBro network in busier areas of Seoul since mid-2006. The service has reportedly attracted only a handful of subscribers, in part due to the lack of access devices.

Currently the service is only accessible through a special PC card for notebook PCs. However, hardware makers such as Samsung have already developed WiBro-compatible mobile phones and other handheld devices. 

KT Corp will begin selling these this summer, according to the Korea Herald. 

KT Corp, the former state-run telecoms monopoly, is Korea's largest fixed-line phone and broadband internet access provider, and second largest mobile provider.

Although a WiBro VoIP service would appear to offer a cheaper alternative to mobile phone networks for voice communications, KT Corp's promotions have made no mention of any VoIP applications, which would compete directly with the company's mobile phone division.