Friday, January 25, 2008

Is Bluetooth On A Collision Course With Wi-Fi?

The recent appearance of some "Wi-Fi" mobile phones on the market has many folks wondering "what could be". With regards to Bluetooth vs WiFi phones are we seeing a potential collision of capabilities? Not so fast...don't be blinded by the light.

OK, you may have seen a couple of mobile phones with Wi-Fi on the market lately... and it appears that the penetration of these mobile "Wi-Fi" phones is only going to increase with time. It also seems that what the current user can achieve with Bluetooth... may also be possible via Wi-Fi at some time in the not too distant future.

Below I've listed the primary use cases for Bluetooth and how Wi-Fi "may" offer a solution.

1. Wireless headset - Wi-Fi headsets take up a lot more current than Bluetooth, this doesn't seem to be insurmountable in due time though.

2. Wireless data transfer - Already possible via Wi-Fi

3. Security - Bluetooth's frequency-hopping transmissions ensure security and less interference, but this again is not an insurmountable hurdle for Wi-Fi

4. Mobile to PC Sync - Possible via Wi-Fi

If a manufacturer is paying $X per chip to put Wi-Fi in... they might as well work towards solving these problems and remove BT from phones.

However, in my honest opinion there's more to the story if you really look under the hood.

So, I believe rather than competing, the two are coming together.

Bluetooth will probably always remain in the handset for two reasons. The first is that it enables low power headsets. Unlike Wi-Fi, Bluetooth enables synchronous voice transmission without the need for VoIP. It was one of the key requirements for the Bluetooth specification and means that headsets can be made that give a good talk time with small batteries. The overhead of VoIP processing for any standard that does not support native voice means that Wi-Fi is unlikely to ever take this market away. And despite the publicity of Wi-Fi in handsets, the only wireless connections that most people ever make is to a headset.

What will reinforce the continuation of Bluetooth in handsets is the new low power variant, also known as Wibree or Ultra Low Power Bluetooth. This is exciting the handset vendors because of its ability to connect the handset to a new range of accessories, such as watches, sports equipment and health sensors. This technology resides inside the same Bluetooth chip, so will add functionality to the handset for no additional cost.

The other important thing to realise about Bluetooth and Wi-Fi is their different topologies. Wi-Fi usually talks to access points, whereas Bluetooth devices talk to other Bluetooth devices in what is know as an ad-hoc connection. 802.11 - the standard behind Wi-Fi can in theory cope with ad-hoc connections, but it's a feature that is poorly implemented and lacks interoperability. Much of the power of Bluetooth has been in building the higher level stacks that provide the ability to find other devices, connect to them securely and perform a range of data transfers. It's taken Bluetooth the best part of ten years to get this aspect right. Wi-Fi hasn't yet started on it.

That's why there is now work going on to combine Bluetooth and Wi-Fi, so that Bluetooth is used for this initial setup of the connection, and then Wi-Fi is switched on, under the control of Bluetooth, to perform a higher speed transfer. There are potential issues to this approach, as both use the same frequencies and if the two are being heavily used at the same time, there may be performance issues that are apparent to the user. To combat that, handset and equipment vendors are also working hard on a combination of UWB and Bluetooth. This provides better immunity to interference, higher data rates at short ranges and a much lower power consumption that can be achieved for a similar data rate using Wi-Fi.

The reality is that we will probably end up with three short range wireless standard in cellphones in the next few years - Bluetooth (including Ultra Low Power), Wi-Fi and UWB. In the near term it's likely that Bluetooth and Wi-Fi will coalesce into a single chip, with UWB as an additional RF chip. If they're all controlled by Bluetooth, the good news is that the user will only have to deal with one application interface.

For a simple online tool to help find the right cell phone for you .... Bluetooth or otherwise .... go to this website: Cell Phones And Accessories

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