WISPr 2.0 boosts roaming between 3G and Wi-Fi

The Wireless Broadband Alliance has released specifications that should make it easier for mobile devices to roam from Wi-Fi hotspots to cellular networks and vice versa.

The alliance, which consists of 32 Wi-Fi operators and vendors, delivered the second version of its Wireless ISP roaming (WISPr) specifications on Monday. WISPr 2.0 defines how communications should be passed between Wi-Fi hotspots and GSM, GPRS, 3G, long-term evolution (LTE) or Wimax networks. A key part covers how roaming users should be authenticated when they join or leave those networks.

Roaming is possible between a limited number of Wi-Fi and cellular networks via a range of services. However, these services use non-standardised software, which, the Wireless Broadband Alliance (WBA) argues, can lead to a bad customer experience.

"Currently, [roaming] is done in a proprietary way," said Shrikant Shenwai, the WBA's chief executive, speaking to ZDNet UK. "What is really required is a common set of specifications. This will provide a convenient way to implement [roaming] across different devices and networks."

Cross-network roaming is helpful for users because it gives users wider connectivity and, when they can find a Wi-Fi network, higher speeds. It also has the potential to cut costs while abroad, because internet access via Wi-Fi is normally cheaper than mobile broadband.

WISPr 2.0 will undergo trials for the next six months with BT, Portugal Telecom and Tata Communications, among others. Shenwai said he hoped commercial implementations of the technology will begin shortly after the end of the trials.

Though BT does not have its own 3G network, nor any sizeable Wimax deployments, it is planning to use WISPr 2.0 to aid the roaming of users between its Wi-Fi hotspots and the Vodafone 3G network, which it offers access to as a virtual operator, according to Chris Bruce, chief of BT's hotspot division Openzone.

Bruce also said that the technology might be useful for mobile carriers O2, Orange and Tesco Mobile, which already offer unlimited access to BT's Wi-Fi hotspots with their tariffs.

However, Bruce warned there were issues to be tackled to ensure users know which network they are using. Without roaming, users always know whether they are on Wi-Fi or a cellular network, he said. But with roaming, a user might not know which network they are on while sitting in a hotel, for example. Some proprietary roaming offerings display a symbol to indicate the network used, Bruce said.

"We want to work with the mobile network operators to signal to users whether they are roaming or not. One of the challenges... is preventing the bill shock," he added.

BT on Monday made a separate announcement aimed at stimulating the use of its Wi-Fi hotspots: the telco said it would lift the usage caps on all its consumer tariffs to give customers unlimited use of its hotspots.

Six members joined the WBA on Monday: AT&T, Cisco, Comcast, Devicescape, KT Corporation and Verizon. The WBA is trying to broaden its membership to include all companies with an interest in promoting Wi-Fi broadband, Shenwai said.