CCS/LAUNCHXL-CC1352R1: Can packets arrive in wrong order?

Tharanga

Tool/software: Code Composer Studio

Hi,

I am working on an application based on rfPacket TX/RX examples. I was just wondering whether is it possible for the sent packets to reach the receiver in wrong order?

i.e. not in an ascending sequence,

For instance, in received order : SeqNumber = 0, SeqNumber = 1, SeqNumber = 2, SeqNumber = 4, SeqNumber = 3, SeqNumber = 6, ...

Technically, I think there is room for this to happen. I just want to verify.

PS: I did some tests, but this scenario never occured to me. Missed packets? Yes. but that is a different story.

over 5 years ago

0 TER over 5 years ago

TI__Guru**** 317180 points

I would say no. Packet n is sent before packet n+1 and will therefore be received before n+1.

Why do you think it could be different?

0 Tharanga over 5 years ago in reply to TER

Intellectual 770 points

TER said:
Why do you think it could be different?

Hi @TER,

True that n is Tx before n+1. But for some reason, what if n+1 comes ahead of n?

(Forget about the Transmitter please. Just assuming there were some weird signal bounces etc.as the Rx was moving... I am just speculating here.)

0 TER over 5 years ago in reply to Tharanga

TI__Guru**** 317180 points

Please consider the physics for a moment. Calculate the time it takes to send a packet with a given length and at a given datarate. If this to happen packet n has to bounce around longer than it takes to send packet n+1. This is RF meaning that the delay of a reflected packet will be very small compared to the time it takes to send a packet over the air (datarate vs speed of light)

0 Tharanga over 5 years ago in reply to TER

Intellectual 770 points

"Calculate the time it takes to send a packet with a given length and at a given datarate."

Can you give me an example to support the above statement.

sizeof(txPacket) = 255

Data Rate = 50kBps, 2GFSK

Distance between Rx and Tx >200m

0 TER over 5 years ago in reply to Tharanga

TI__Guru**** 317180 points

(1/datarate)*(num preamble byte + num sync bytes + num payload bytes + num CRC bytes)*8

0 Tharanga over 5 years ago in reply to TER

Intellectual 770 points

Great. Thanks TER @612009.

Sub-1 GHz

Sub-1 GHz forum

CCS/LAUNCHXL-CC1352R1: Can packets arrive in wrong order?