2007-12-28 20:03:37

by Olivier Le Pogam

[permalink] [raw]
Subject: Re: [Bluez-devel] Add 3 HCI commands / concurrent connection setup question

Hi Marcel,

> the design of AFH is to help _other_ 2.4 GHz radios to survive while
> Bluetooth is active in the same area. It is not meant to protect it
> against its own technology. The basics behind AFH is too play nice with
> WiFi networks in the same area. That's it.

I have found an interesting article about this (for people who find this
interesting as well !) :

http://www.us.design-reuse.com/articles/5715/adaptive-frequency-hopping-for-reduced-interference-between-bluetooth-and-wireless-lan.html

Sorry to carry on theorically speaking, but in my opinion it's always good
to understand the underlying techniques ... do you know how AFH is
implemented by chips ? Is the channel blacklisting "manually" up to the
developper (software), or is there a built-in blacklisting algorithm
(hardware) ?

Regards,
Oli


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2007-12-28 22:35:02

by Marcel Holtmann

[permalink] [raw]
Subject: Re: [Bluez-devel] Add 3 HCI commands / concurrent connection setup question

Hi Olivier,

> > the design of AFH is to help _other_ 2.4 GHz radios to survive while
> > Bluetooth is active in the same area. It is not meant to protect it
> > against its own technology. The basics behind AFH is too play nice with
> > WiFi networks in the same area. That's it.
>
> I have found an interesting article about this (for people who find this
> interesting as well !) :
>
> http://www.us.design-reuse.com/articles/5715/adaptive-frequency-hopping-for-reduced-interference-between-bluetooth-and-wireless-lan.html
>
> Sorry to carry on theorically speaking, but in my opinion it's always good
> to understand the underlying techniques ... do you know how AFH is
> implemented by chips ? Is the channel blacklisting "manually" up to the
> developper (software), or is there a built-in blacklisting algorithm
> (hardware) ?

it is fully up to the firmware running on the Bluetooth chip. The only
chance a host stack has it to modify the channel map and even that one
can be ignored by the chip.

Regards

Marcel



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