Subject: Re: [manet] Selective Acknowledgement

From: [email-masked]
Date: Tue, 27 Jan 2004 11:28:55 +0100

For my purpose I don't expect everybody to receive the broadcast. 
Therefore this solution doesn't match it. Morever, IEEE 802.11 doesn't 
allow RTS/CTS mechanism prior a brodcast transmission. As a consequence of 
this, modifications on the standard must be done and that's what I would 
like to avoid.

Thanks anyway.

Joan

"Philippe Jacquet" <[email-masked]>
01/27/04 10:59 AM

        To:     Joan Martin/ACN/RESEARCH/PHILIPS@EMEA1
<[email-masked]>
        cc: 
        Subject:        Re: [manet] Selective Acknowledgement
        Classification: 

The problem differs if you want to check that all neighbor receives the 
broadcast or check that at least one neighbor receives it. 
 
For the first problem, in HIPERLAN 1, long time ago, we proposed a 
collision signal after each transmission. When a node receives a corrupted 
packet it emits a collision signal burst just after the packet. The signal 
is just energy and can aggregate with other signals. When the broadcaster 
senses signal after its packet transmission, it inferes collision and 
retransmits. 
 
In IEEE 802.11 you can use the RTS CTS mechanism with broadcast. Of course 
there are no CTS. Therefore if the broadcaster senses signal after its 
RTS, then it just backoff transmission. 
 
Philippe
----- Original Message ----- 
From: [email-masked] 
To: [email-masked] 
Sent: Tuesday, January 27, 2004 9:19 AM
Subject: [manet] Selective Acknowledgement

Hi, 

Does anybody know any literature about selective acknowledgement applied 
to manet (802.11). Concretely, selective acknowledge in response to a 
broadcast transmission. 

The IEEE 802.11 MAC specification does not allow acknowledging on 
receiving a broadcast transmission. Therefore how could I design a 
mechanism which ensures me that at least one neighboring node has received 
the broadcast message (imagine a critical application, e.g. car accident 
warning, in which you cannot permit a broadcast message "to be lost on the 
air") 

Best regards, 
Joan

---

From: "Emmanuel Baccelli" <[email-masked]>
Date: Wed, 28 Jan 2004 12:19:21 +0100

Hi,

Actually, maybe you could use OLSR and MPR flooding for this: in this context, when a given node transmits a broadcast message, at least one neighbor (MPR for the node) should retransmit it, and the node should be able to overhear this retransmission since this MPR is a neighbor (by definition). This overhearing could be taken as implicit selective acknowledgement. To make sure the broadcast message is not lost in the air, the node could just keep transmitting again until it overhears such a retransmission.

Emmanuel

  ----- Original Message ----- 
  From: [email-masked] 
  To: [email-masked] 
  Sent: Monday, January 26, 2004 6:10 PM
  Subject: [manet] Selective Acknowledgement

  Hi, 

  Does anybody know any literature about selective acknowledgement applied to manet (802.11). Concretely, selective acknowledge in response to a broadcast transmission. 

  The IEEE 802.11 MAC specification does not allow acknowledging on receiving a broadcast transmission. Therefore how could I design a mechanism which ensures me that at least one neighboring node has received the broadcast message (imagine a critical application, e.g. car accident warning, in which you cannot permit a broadcast message "to be lost on the air") 

  Best regards, 
  Joan