CODEWITHSUNDEEP
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Won Hee Lee
Won Hee Lee

Reputation: 65

802.15.4 MAC Ack frame related problems

I am making 802.15.4 protocol on CC2538 board.

In 802.15.4 document, Ack frame doesn't have any address information.

How can get an Ack frame on device or coordinator ?

For example

data frame sending each other, they have to synchronize with ack frame.

but when device or coordinator send ack frame to other side,

there was no information about destination address.

How Ack frame is received on device/coordinator ?

enter image description here

Upvotes: 0

Views: 960

Answers (2)

larzhang
larzhang

Reputation: 26

I think you could use an enhanced ACK frame format.

'Enhanced Acknowledgment Frame Format' Table

Upvotes: 1

Ciaran Woodward
Ciaran Woodward

Reputation: 176

In IEEE 802.15.4, the Ack frame is sent very quickly (192uS) in response of a non-ack frame that has requested acknowledgement. The CC2538 conforms to IEEE 802.15.4-2006. In IEEE 802.15.4-2006, every frame must have a sequence number, and the corresponding Ack will match that sequence number.

The transmitter will wait to see an ack with the same sequence number as the frame it just transmitted. If it does not see an Ack within the wait time, it will retransmit the frame.

Iarzhang is correct in that later versions of the standard allow suppression of the sequence number in certain situations, and the Ack can contain full addressing information (and more). This does lead to larger ack frames, however.

Upvotes: 1

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