Full duplex infinity loop

GNU Radio
1

Hello,
can anyone suggest how to prevent infinity loop in case of full duplex
RX/TX on same frequency ?
Any ideas?

GRC example:
UHD source -> GMSK DEMOD -> packet decoder -> packet encoder -> GMSK MOD
-> UHD SINK

but in this case of course its gonna be infinity loop,
any suggestion how to avoid this?

Thx.

2

Do you mean the fact that you’ll be receiving your own packets? There’s
several ways to do this, e.g. You can catch your own packets in the mac
layer.

M
On 5 Sep 2014 17:27, “TSAREGORODTSEV, Yury”
[email protected]

3

Dear Martin,
yes, absolutely, idea is to do signal repeater.
Whats the best solution can be ?

----- Original Message -----

From: “Martin B.” [email protected]
To: “Yury TSAREGORODTSEV” [email protected]
Cc: [email protected]
Sent: Friday, September 5, 2014 5:31:05 PM
Subject: Re: [Discuss-gnuradio] full duplex infinity loop

Do you mean the fact that you’ll be receiving your own packets? There’s
several ways to do this, e.g. You can catch your own packets in the mac
layer.

M
On 5 Sep 2014 17:27, “TSAREGORODTSEV, Yury” <
[email protected] > wrote:

Hello,
can anyone suggest how to prevent infinity loop in case of full duplex
RX/TX on same frequency ?
Any ideas?

GRC example:
UHD source → GMSK DEMOD → packet decoder → packet encoder → GMSK MOD
→ UHD SINK

but in this case of course its gonna be infinity loop,
any suggestion how to avoid this?

Thx.

Discuss-gnuradio mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

4

Well, as Martin said, if you want to avoid resending your own packets
you will need to be able to keep track of which packet you already sent;
you can also “numb” the receiver for the duration of your TX. None of
this hasn’t, to my knowledge, been with the GNU Radio examples, and
since it involves logic that cannot be well represented by graphical
flowgraphs, you’ll most likely have to get your hands dirty writing some
MAC intelligence. Packet en/decoder is only that – Phy layer packet
decoders; you will need some MAC on top of that to have control medium
access.

Generally, doing it on the same frequency will effectively half your
available time-bandwidth product, ie your transmission capacity, and it
will lead to receivers seeing both the original and your repeated packet
receiving things twice. In many cases, this is ok or even desirable, but
for simpler set ups, where spectrum is not overly hard to obtain, you
might want to go for a frequency translating repeater.

Greetings,
Marcus