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RE: [bluetooth-dev] solving a broadcast problem through bluetooth



I believe you have to have a baseband connection to even hear the broadcast.
Otherwise, the slave will not be on the same hopping pattern as the master,
and therefore, cannot hear the broadcast. Additionally, each slave is
assigned a timeslot or timeslots in which to reply to the master in order to
prevent collisions. New piconets will be setup on different hopping patterns
and won't interfere with current baseband connections as every server has a
different hopping pattern based on its BD. I think that the only collisions
which might occur are on the frequency level, handled by the LM, and
potentially if you have mulitple slaves assigned to the same time slot
during an inquiry (one in park, one active).

Please correct me if I'm wrong or anyone has something to add.

Dave.

> -----Original Message-----
> From: ping kidwai [mailto:monuser@xxxxxxx.com]
> Sent: Wednesday, January 31, 2001 1:06 PM
> To: gmcnutt@xxxxxxx.com
> Cc: bluetooth-dev@xxxxxxx.com
> Subject: Re: [bluetooth-dev] solving a broadcast problem through
> bluetooth
> 
> 
> Hi,
> Thanks for your reply, Yes, u r right that a slave cannot 
> broadcast, but a 
> Master can, What happens if they want to form a new piconet 
> and sends the 
> *query* packet, since there is no prior notification in 
> broadcasting to 
> other nodes, if the other node is also sending a *query* 
> packets or two or 
> more nodes reply to that *query* packet at the same time, 
> their packets will 
> collide *at the reciever*. Although the solution given for 
> that, *the Master 
> won't reply and those nodes will wait for random amount of 
> time and resend 
> the packet again.*
> 
> Hope that would clear, What exactly I wanna know, since I am 
> not fully 
> convinced the *random amount of time waitage * stuff before 
> resending the 
> packet. It doesnt give you the gurantee that packet won't 
> collide again.
> I am interested in knowing that, are there any control 
> signals for notifying 
> other nodes that *Hey Iam sending a broadcast *query packet* 
> and nobody 
> dares to send or recieve any packet during this packet time*
> 
> Please let me know
> 
> Thanks in advance
> 
> Hashir Kidwai
> 
> 
> 
> >From: Gordon McNutt <gmcnutt@xxxxxxx.com>
> >To: ping kidwai <monuser@xxxxxxx.com>
> >CC: bluetooth-dev@xxxxxxx.com
> >Subject: Re: [bluetooth-dev] solving a broadcast problem 
> through bluetooth
> >Date: Tue, 30 Jan 2001 03:42:31 -0700
> >
> >ping kidwai wrote:
> >
> > >   Hi, My name is Hashir Kidwai. I am currently focusing 
> on a Topic of
> > > Ad-Networks and would like to know that whether that 
> problem or topic 
> >can be
> > > solved via BlueTooth or not. The Topic is: One node transmits a 
> >broadcast
> > > message and *all* its neighbors receive it successfully. 
> This means that
> > > none of its neighbors should be transmitting or receiving 
> other messages
> > > during this time period. In MACA the receiver is told of 
> an upcoming
> > > transmission by means of the RTS/CTS exchange. However, 
> how would this 
> >work
> > > if there are multiple simultaneous receivers for one transmission?
> > >
> > > _________________________________________________________________
> > > Get your FREE download of MSN Explorer at http://explorer.msn.com
> > >
> > > -
> > > To unsubscribe from this list: send the line "unsubscribe 
> bluetooth-dev" 
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> > > the body of a message to majordomo@xxxxxxx.com
> >
> >Hi Hashir,
> >
> >In Bluetooth, the answer depends on whether or not the node 
> in question is 
> >a
> >master or a slave. If the node is a master, then it can 
> broadcast to all 
> >slaves
> >on its piconet. But if it is a slave, then it cannot 
> broadcast -- it can 
> >only
> >talk to its master.
> >
> >Transmission collision on Bluetooth is avoided with the 
> following scheme. 
> >Legal
> >transmission times on a piconet are divided into slots. Some 
> slots only the
> >master can transmit, and all slaves listen for packets 
> addressed to them. 
> >Other
> >slots only one slave can transmit, and the master listens. A 
> slave knows 
> >that
> >it can transmit, and not collide with another slave, if and 
> only if the 
> >master
> >addressed it in the previous master transmission slot. This 
> scheme is 
> >covered
> >in the baseband protocol portion of the core spec.
> >
> >--gmcnutt
> >
> 
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