Photos: WiMax in action

Photos: WiMax in action

Summary: Mobile broadband is on the move. ZDNet UK paid a visit to a trial network where one of the prime contenders is being tested

TOPICS: Networking

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  • 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.

  • Airspan then took us to a house in Stratford-upon-Avon where a couple of its Pro-ST terminals have been installed, about 1.3km from the base station.

    The terminals convert WiMax to Wi-Fi, and tests within the house using a Wi-Fi-enabled laptop worked very well.

    Switching between two Wi-Fi access points involved a handover of 0.2s (although this would be longer with encryption) and no packet loss.

Topic: Networking

David Meyer

About David Meyer

David Meyer is a freelance technology journalist. He fell into journalism when he realised his musical career wouldn't pay the bills. David's main focus is on communications, as well as internet technologies, regulation and mobile devices.

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  • Given that glass doesn't impede electromagnetic radiation at 3.5Ghz, why would the people rolling this out be surprised that two sheets of glass, er, don't impede electromagnetic radiation at 3.5Ghz?