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Airspan is also trialling Internet telephony (VoIP) over its network. A multi-protocol iTone Prime gateway (blue and green, top) links the base station into the public switched telephone network via a soft switch (silver, bottom).
A call-controlling software package called VoiceMax is incorporated into both the soft switch and the base station, ensuring quality of service for voice.
Airspan plans to have about two dozen trial subscribers using VoIP and streaming video over the network within the next few weeks.
It has already had success using WiMax to provide the backhaul for Wi-Fi-enabled devices such as Sony’s PSP, Nintendo’s DS and a Sony location-free TV box.
Of course, something has to pick up the signal on the other end, and here are a few of Airspan’s Easy-ST subscriber terminals.
At a cost price of $400 (£217) each, the plug-and-play terminals provide easy connection (via Ethernet cable) and set-up, although they have to be externally powered.
That’s the main reason for calling fixed WiMax "nomadic" rather than "mobile", which will be the next stage in the technology’s evolution.
Lightley told ZDNet UK that the terminals can be moved between base stations, but operators may want to limit this or charge their subscribers for the privilege.
Although many manufacturers will be bringing out PCMCIA cards to implement this, Airspan intends to go for USB connectivity instead as it’s a “much more flexible” solution, not only for laptops but also for handheld consoles, MP3 players and so on.
ZDNet UK then took a laptop and Easy-ST terminal out into the field. Well, a car park rather than a field, but it was around 900 metres away from the base station.
With three FTP processes going (two down, one up), the system managed a fairly impressive download speed of 10Mbps and upload of 600Kbps.
Lightley attributed the speeds to fixed WiMax’s use of FDD, which uses two frequencies to provide an uplink/downlink duplex channel. Mobile WiMax, on the other hand, will use a system called TDD, which uses one frequency and relies on quick swapping between uplink and downlink to provide a seamless connection.
TDD is economical on spectrum, but requires some additional synchronisation of the base stations, perhaps by GPS, to remain in step.