Friday, February 09, 2007

Squeezing the spectrum

A more technical post today: let’s talk about ultra-wideband (UWB). The frequency spectrum for wireless communications is becoming quite scarce, and expensive for some operators… So it’s like a ‘natural resource’ with some slight differences: its amount is fixed and we know it (well, theoretically frequencies are infinitely extended, but other thing is that they are feasible), and their extensive use is not exhausting the resource nor polluting the environment…

UWB uses a very large bandwidth (more than 500 Mhz, imagine commercial UMTS mobile communications use carriers of 5Mhz…). And the more bandwidth tat is used, the more is the throughput. Although this is some kind of tricky because they have to use very high frequencies, and the range is very low Taking into account Shannon limit for the wireless channel, that states that the highest the bandwidth, the lower the signal to noise ratio required for a certain throughput. Also the emission levels permitted are relatively small. Therefore its main use will be for personal area networks.

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