Airspan and Freedom4 make leap in WiMAX roaming
26 November 2008
One of the biggest challenges for operators of new networks is roaming, enabling subscribers to access services in as many places as possible even before wide area roll-outs are practical.
In WiMAX, the presence of roll-outs in multiple bands adds to the complexity, but this is a challenge that equipment vendor Airspan and UK operator Freedom4 claim to be addressing.
The companies have demonstrated the first seamless, uninterrupted handover between the 2.5GHz and the 3.5GHz bands, the two main frequencies in which WiMAX providers are launching, and the key standard profiles within the WiMAX Forum. This should help boost roaming efforts, especially in the US, where Clearwire is planning a major 2.5GHz network, but where there is also significant activity in the lightly licensed 3.65GHz band β not an official Forum profile, but only a skip and a jump from 3.5GHz in radio terms.
There have been a fair number of localized roaming initiatives in the WiMAX community, with regional alliances similar to those in Wi-Fi, but as major carriers start to build out, this will need to take on an international and multiband quality in order to support the most promising early adopter base, business travelers.
The other importance of affordable multiband support will be to give operators the flexibility to build out in two or more frequencies, according to what type of spectrum they can access. Clearwire itself has 3.5GHz licenses in Europe, and Freedom4 holds a 3.6GHz license in the UK, and could consider bidding in the upcoming 2.6GHz auction. The company was formerly known as Pipex Wireless, and was set up as a joint venture between broadband business ISP Pipex, the long time holder of a national 3.6GHz license, and Intel, the most enthusiastic backer of fledgling WiMAX carriers.
Airspan said in its statement: βIn many regions, the availably of 2.5GHz is limited. Now operators can aggregate spectrum to allow significant expansion of coverage and roaming capabilities. A carrier, for example, could begin with a small allocation at 2.3GHz or 2.5GHz and add a larger, often more affordable, allocation at 3.XGHz or even 5GHz.β
The demonstration network used the Airspan HiperMAX base station in the 3.6GHz band and the MacroMAXe base station in the 2.5GHz band communicating with a MiMAX Q-Series quad-band USB device. Also participating in the UK trial was core network vendor Starent Networks, supplier of the ASN gateway for connection and roaming management, and Bridgewater Systems, with its subscriber management and AAA offering. Airspan said its equipment could also support similar handover between all the major WiMAX bands β 2.3GHz, 2.5GHz, 3.3GHz, 3.4-3.6GHz, 3.6-3.8GHz and 5GHz.