mac80211: TDMA approach feasible?

mac80211: TDMA approach feasible?

[ffileppo]

Hi all,

I was wondering if with mac80211 is now possible (and what effort is needed) to implement a TDMA approach. In particular I would like to: override 802.11 MPDU frame format, eliminate RTS/CTS exchange, eliminate automatic ACK and retransmission, eliminate virtual carrier sense (NAV), control PHY clear channel assessment and control transmission backoff.

I've read that mac80211 allows arbitrary packets to be injected down any Monitor Mode interface from userland but it is still not clear to me if it is possible to override some of the 802.11 MAC features.

Thank you,

Francesco

Re: mac80211: TDMA approach feasible?

[Kalle Valo]

"ffileppo" <ffileppo@libero.it> writes:

> Hi all,

Hello,

> I was wondering if with mac80211 is now possible (and what effort is
> needed) to implement a TDMA approach. In particular I would like to:
> override 802.11 MPDU frame format, eliminate RTS/CTS exchange,
> eliminate automatic ACK and retransmission, eliminate virtual carrier
> sense (NAV), control PHY clear channel assessment and control
> transmission backoff.

Most of this is usually implemented in firmware, so you need access to
firmware sources.

-- 
Kalle Valo

Re: mac80211: TDMA approach feasible?

[ffileppo]

 
> > I was wondering if with mac80211 is now possible (and what effort is
> > needed) to implement a TDMA approach. In particular I would like to:
> > override 802.11 MPDU frame format, eliminate RTS/CTS exchange,
> > eliminate automatic ACK and retransmission, eliminate virtual carrier
> > sense (NAV), control PHY clear channel assessment and control
> > transmission backoff.
> 
> Most of this is usually implemented in firmware, so you need access to
> firmware sources.
> 

Hi,
thanks for your answer.

If these features are implemented in firmware, it should be possible to modify them if using for example Ath5k (which is a completely FOSS Linux driver) Right? Could you give me any directions?

Talking about the TDMA implementation I was wondering if it is possible to achieve a time granularity of 1?s using commercial-of-the-shelf wifi cards (e.g. atheros ones).

I would appreciate any ideas or thoughts on this matter.

Thank you,

Francesco

Re: mac80211: TDMA approach feasible?

[Kalle Valo]

"ffileppo" <ffileppo@libero.it> writes:

>  
>> > I was wondering if with mac80211 is now possible (and what effort
>> > is needed) to implement a TDMA approach. In particular I would
>> > like to: override 802.11 MPDU frame format, eliminate RTS/CTS
>> > exchange, eliminate automatic ACK and retransmission, eliminate
>> > virtual carrier sense (NAV), control PHY clear channel assessment
>> > and control transmission backoff.
>>  Most of this is usually implemented in firmware, so you need access
>> to firmware sources.
>
> If these features are implemented in firmware, it should be possible
> to modify them if using for example Ath5k (which is a completely FOSS
> Linux driver) Right? Could you give me any directions?

Sorry, I'm not familiar with ath5k.

-- 
Kalle Valo

Re: mac80211: TDMA approach feasible?

[Nick Kossifidis]

2009/5/22 ffileppo <ffileppo@libero.it>:
>
>> > I was wondering if with mac80211 is now possible (and what effort is
>> > needed) to implement a TDMA approach. In particular I would like to:
>> > override 802.11 MPDU frame format, eliminate RTS/CTS exchange,
>> > eliminate automatic ACK and retransmission, eliminate virtual carrier
>> > sense (NAV), control PHY clear channel assessment and control
>> > transmission backoff.
>>
>> Most of this is usually implemented in firmware, so you need access to
>> firmware sources.
>>
>
> Hi,
> thanks for your answer.
>
> If these features are implemented in firmware, it should be possible to modify them if using for example Ath5k (which is a completely FOSS Linux driver) Right? Could you give me any directions?
>
> Talking about the TDMA implementation I was wondering if it is possible to achieve a time granularity of 1?s using commercial-of-the-shelf wifi cards (e.g. atheros ones).
>
> I would appreciate any ideas or thoughts on this matter.
>
> Thank you,
>
> Francesco
>

Check out freebsd they have TDMA support for the ath driver as far as
i know. It would be cool if we could port it on linux ;-)


-- 
GPG ID: 0xD21DB2DB
As you read this post global entropy rises. Have Fun ;-)
Nick

Re: mac80211: TDMA approach feasible?

[Luis R. Rodriguez]

On Fri, May 22, 2009 at 6:46 AM, Nick Kossifidis <mickflemm@gmail.com> wrote:
> 2009/5/22 ffileppo <ffileppo@libero.it>:
>>
>>> > I was wondering if with mac80211 is now possible (and what effort is
>>> > needed) to implement a TDMA approach. In particular I would like to:
>>> > override 802.11 MPDU frame format, eliminate RTS/CTS exchange,
>>> > eliminate automatic ACK and retransmission, eliminate virtual carrier
>>> > sense (NAV), control PHY clear channel assessment and control
>>> > transmission backoff.
>>>
>>> Most of this is usually implemented in firmware, so you need access to
>>> firmware sources.
>>>
>>
>> Hi,
>> thanks for your answer.
>>
>> If these features are implemented in firmware, it should be possible to modify them if using for example Ath5k (which is a completely FOSS Linux driver) Right? Could you give me any directions?
>>
>> Talking about the TDMA implementation I was wondering if it is possible to achieve a time granularity of 1?s using commercial-of-the-shelf wifi cards (e.g. atheros ones).
>>
>> I would appreciate any ideas or thoughts on this matter.
>>
>> Thank you,
>>
>> Francesco
>>
>
> Check out freebsd they have TDMA support for the ath driver as far as
> i know. It would be cool if we could port it on linux ;-)

And if such support comes around, it would make sense as a separate
driver. You would need also need a way to ensure proper regulatory
compliance.

http://wireless.kernel.org/en/developers/Regulatory

CRDA was designed to be flexible for any wireless technology.

  Luis