Can bluetooth broadcast??

Hanfei Zhao · Joined: 25 Jul 2007 Posts: 5

and how ?

Archived from group: alt>cellular>bluetooth

Mark Williams · Joined: 25 Jul 2007 Posts: 7

"Hanfei Zhao" wrote in message $5au$1@news.yaako.com...
> and how ?

Depends what you mean by broadcast:

1. At the physical level it is a non-directional radio signal and hence
is broadcast - a blueband device can poll all the surrounding devices.
2. At the next level up in the stack it is a point to point protocol and
not a one-to-many protocol. It is not possible as far as (I am aware) to
broadcast a stream (e.g audio data) to multiple receivers over a single
Bluetooth adapter.
3. At the application level it is possible to broadcast objects by
polling all the surrounding devices and sending files to those devices that
support the Object Push Profile or any other Profiles built on the OBEX
protocols.

Hanfei Zhao · Joined: 25 Jul 2007 Posts: 5

Thanks!
But I'm still confused..
1.Though it is non-directional, Bluetooth employ DSSS CDMA as the modulation
and access method.Under such circumstance, the demodulation process would
require the certain pseudo-stochastic series (In my opinion). So I could
imagine only one possible scenario that the transceiver had to send that
series beforehand -- which I could not find a way.

2. At the application level, is the broadcast a "real" one? I need
broadcast because I want a higher speed on the total data ransfer rate.

Maybe I was misleaded by my shallow foundation on theory, and made a
mistaken consideration. Sigh...

"Mark Williams" wrote in message @bt.com...
>
> "Hanfei Zhao" wrote in message
> $5au$1@news.yaako.com...
>> and how ?
>
> Depends what you mean by broadcast:
>
> 1. At the physical level it is a non-directional radio signal and hence
> is broadcast - a blueband device can poll all the surrounding devices.
> 2. At the next level up in the stack it is a point to point protocol
> and not a one-to-many protocol. It is not possible as far as (I am aware)
> to broadcast a stream (e.g audio data) to multiple receivers over a single
> Bluetooth adapter.
> 3. At the application level it is possible to broadcast objects by
> polling all the surrounding devices and sending files to those devices
> that support the Object Push Profile or any other Profiles built on the
> OBEX protocols.
>

Mark Williams · Joined: 25 Jul 2007 Posts: 7

"Hanfei Zhao" wrote in message $21b$1@news.yaako.com...
> Thanks!
> But I'm still confused..
> 1.Though it is non-directional, Bluetooth employ DSSS CDMA as the
> modulation and access method.Under such circumstance, the demodulation
> process would require the certain pseudo-stochastic series (In my
> opinion). So I could imagine only one possible scenario that the
> transceiver had to send that series beforehand -- which I could not find a
> way.

I can't help you there. I don't have details of the Bluetooth radio
protocols.

> 2. At the application level, is the broadcast a "real" one? I need
> broadcast because I want a higher speed on the total data ransfer rate.

No

Hanfei Zhao · Joined: 25 Jul 2007 Posts: 5

Thank you, Mark.
you do help me get out of the confusion.

"Mark Williams" wrote in message @bt.com...
>
> "Hanfei Zhao" wrote in message
> $21b$1@news.yaako.com...
>> Thanks!
>> But I'm still confused..
>> 1.Though it is non-directional, Bluetooth employ DSSS CDMA as the
>> modulation and access method.Under such circumstance, the demodulation
>> process would require the certain pseudo-stochastic series (In my
>> opinion). So I could imagine only one possible scenario that the
>> transceiver had to send that series beforehand -- which I could not find
>> a way.
>
> I can't help you there. I don't have details of the Bluetooth radio
> protocols.
>
>> 2. At the application level, is the broadcast a "real" one? I need
>> broadcast because I want a higher speed on the total data ransfer rate.
>
> No
>

pzboyz · Joined: 25 Jul 2007 Posts: 19

Hanfei Zhao wrote:
> and how ?
>
>

Hi,

Bluetooth has always had support for something called a 'Broadcast
Channel', but it has never worked properly so unless you are designing
all the devices you wish to broadcast from and to, you have no chance of
interoperability. Sad

The biggest problem is the need for retransmissions that you will need
if the device listening to the broadcast recieves a corrupt packet.

pzboyz.

Hanfei Zhao · Joined: 25 Jul 2007 Posts: 5

I found one parameter in one of the HCI commands which is used for indicate
"Broadcast" flag.
But as you said, it might not work well. Because I just designed one side of
the communication, and the other side is people's PPC or Smartphone.
"pzboyz" wrote in message $0$8714$ed2619ec@ptn-nntp-reader02.plus.net...
> Hanfei Zhao wrote:
>> and how ?
>
> Hi,
>
> Bluetooth has always had support for something called a 'Broadcast
> Channel', but it has never worked properly so unless you are designing all
> the devices you wish to broadcast from and to, you have no chance of
> interoperability. Sad

>
> The biggest problem is the need for retransmissions that you will need if
> the device listening to the broadcast recieves a corrupt packet.
>
> pzboyz.