Thursday, August 11, 2011

WLAN version DECT?

Isn’t DECT a dead-end technology? With WiFi and WLAN practically everywhere today, it seems there is no reason to have a different technology for handsets any more.

Well, that’s what we thought before we started the DECT adventure. However, in Europe DECT was very popular already, practically everyone at home was already using DECT for many years and it felt natural that DECT and VoIP had to go together. I think the biggest advantage about DECT is that it takes only very little power. DECT was designed for low power! A handset can sit there, not sending a single signal out for a whole day and just (from time to time) listen if there is a call coming in. That is extremely power efficient, and this explains why DECT devices usually have a standby time for a week or so. BTW it also has the side effect that there is only very little radiation sent out by the mobile devices, some people get crazy thinking about brain cancer from using the cell phone too much and the whole electro smog story.

Apart from being able to build devices with cheap batteries, the other big benefit for DECT is that it runs not in a free spectrum. That means it is very well with the interference. Because nobody else is allowed to disturb the signals, the quality of service in DECT is much better. After all, it is the good old TDM world! If you have successfully allocated a channel, you can use it exclusively for your voice stream. It is old-fashioned, but in the wild world of wireless that is an advantage IMHO.

Of course DECT is digital. It is no comparison to the analog cordless devices that were popular in residential devices not too long ago. Digital has also the advantage that things like Caller-ID are a no-brainer, dialing can be very fast, and you can even have such features like picture Caller-ID or use your address book from the base station.

Oh and another thing that DECT has which I believe is very difficult in WiFi, is the handover. DECT allows that you walk from one base station to another and keep the call alive. This is something the m9 does not support yet, but it is so cool that we are working on it.

And I think last not least, the number of DECT base stations that you need to cover and office if far less than the number of WiFi access points (think two or three dimensional!), so even if companies have to roll out multiple infrastructure elements, from a number perspective the problem is not too big.

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