Compiler/CC1350: FEC explanation for implementation Encoder of Long Mode Ranges Packets

Ryan Maroun

Intellectual 920 points

Part Number: CC1350
Other Parts Discussed in Thread: CC1101,

Tool/software: TI C/C++ Compiler

Hi guys!

I have read more deeply about FEC (encoder) for Long Mode Ranges over here:

https://www.ti.com/lit/an/swra642/swra642.pdf

And I didn't understand it and still not obvious , still have confusion of FEC and don't know how it works ... In other words I want to implement software the Convolution encoder(that's found in photo below) in matlab or whatever ..

I need to understand how the Convolution Encoder works in order to implement it, could anyone explain to me in details how does it work to code it? or if there's already coded Convolution Encoder could anyone share it to me(doesn't matter which language) ?? it could be appreciated if the explanation about Convolutional Encoder include examples like (if we input to it "11100111" for instance as what's output ..and how it works)

thanks alot.

over 6 years ago

0 Ryan Maroun over 6 years ago

Intellectual 920 points

Any help guys?!

0 Siri over 6 years ago in reply to Ryan Maroun

TI__Guru* 87911 points

We do not have any examples on how a encoded packet will look like on the air for a given payload (the payload includes optional length, address, crc).

The reason is that both encoding and decoding is implemented for you in the modem and it has not been our intention that customers are going to implement this themselves. However, if you still want to do that, I will recommend that you dig into the reference we have used for the implementation:

Bernard Sklar, Digital Communications – Fundamentals and Applications, 2nd Edition.

Siri

0 Ryan Maroun over 6 years ago in reply to Siri

Intellectual 920 points

I understood, but as what I've seen , the implementation for cc1101 fec decode is the same as cc1350, isn't the same?

because the implementation of cc1101 is already attached in the forum.

0 Ryan Maroun over 6 years ago in reply to Siri

Intellectual 920 points

could you also help me here :

https://e2e.ti.com/support/wireless-connectivity/sub-1-ghz/f/156/t/933945

thanks alot for any assistance !

0 Siri over 6 years ago in reply to Ryan Maroun

TI__Guru* 87911 points

There is a patch for implementing FEC on the CC13x0 that is the same as the FEC implemented for CC1101, but this is not related to what is used in LRM.

Siri

0 Ryan Maroun over 6 years ago in reply to Siri

Intellectual 920 points

FEC is only used just for LRM no?

I didn't get you, I mean if FEC on the cc13x0 the same as cc1101 why cant I use it?

0 Siri over 6 years ago in reply to Ryan Maroun

TI__Guru* 87911 points

No, FEC is not only used for LRM. There is a FEC patch that you can use if you want to do forward error correction that is compliant with the forward error correction implemented on CC1101. The FEC that is part of the LRM PHY for CC13xx has nothing to do with this FEC.

Siri

0 Ryan Maroun over 6 years ago in reply to Siri

Intellectual 920 points

Now all things are missed up! so please bear with me.

Forget from cc1101 !

Im now talking about cc13xx , in LRM PHY they are not using FEC encoder?! I mean Conventional encoder?

I mean by FEC ENCODER is Convolutional Encoder . could you share for me where's the FEC patch found in smartRF studio?!

What Im asking for if 'm the receiver of cc1350 , isnt it having FEC decoder in order to decode data packets if they are correct or not? thanks alot.

0 Siri over 5 years ago in reply to Ryan Maroun

TI__Guru* 87911 points

LRM PHY is using a conv. encoder (FEC) on CC13x0
The FEC is implemented as part of the LRM patches (rf_patch_cpe_lrm/rf_patch_rfe_lrm)
You are saying that you are receiving IQ samples (meaning that you are using the IQ samples patches, not the LRM patches).
Because of this, you need to do the FEC yourself in your application. How the FEC should be implemented is described in Bernard Sklar, Digital Communications – Fundamentals and Applications, 2nd Edition.

Siri

Sub-1 GHz

Sub-1 GHz forum

Compiler/CC1350: FEC explanation for implementation Encoder of Long Mode Ranges Packets