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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.