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From: | Nemanja Savic |
Subject: | Re: [Discuss-gnuradio] Measuring RSS during packet reception |
Date: | Fri, 19 Jul 2013 00:05:36 +0200 |
I will suggest that donot calculate RSSI for every symbol instead calculate RSSI for complete packetNemanja,Yes, the delay is fix and can be determined by adding delay of all "Filters" in Rx-chain. Moreover IIRC, corrrelate-access-code itself adds 64bits delay that u need to cater for in ur custom block.
>>The problem that I have now is how to ensure that samples from demodulator chain and samples from RSSi calculator come in the same time to the symbol decision block. How can I tune this delay and is it deterministic?
>> On every symbol I read RSSI and send that value forward. As soon as I detect premble i start calculating RSSi for the packet based on number of symbols-AdeelOn Thu, Jul 18, 2013 at 8:05 PM, Nemanja Savic <address@hidden> wrote:Many thanks,The problem that I have now is how to ensure that samples from demodulator chain and samples from RSSi calculator come in the same time to the symbol decision block. How can I tune this delay and is it deterministic?Hi,thank you Adeel for your answer. I implemented almost the same approach yesterday. I bring signal from USRP through rms and log calculator directly to the block for sampling symbol value. On every symbol I read RSSI and send that value forward. As soon as I detect premble i start calculating RSSi for the packet based on number of symbols.
Nemanja--On Thu, Jul 18, 2013 at 2:33 AM, Adeel Anwar <address@hidden> wrote:
2: byte-stream afterNemanja,I built this block sometime back. The ideas is to construct a custom RSSI Measurement block having input
1: complex IQ-samples after USRP-SRC or before "AGC"
"digital_correlate_access_code_bb". Output byte stream has data in LSB (1st bit) while Flag in 2nd bit shows header detection)
3: Calculate system/filters group-delay between the complex-IQ samples stream and output-of-correlate-access-code. This delay will depend on the
a) No. of filters in system e.g. FLL-Filter, PFB-Timing-Synch etc
b) No. of filter Taps3: Delay the complex IQ-samples stream by amount calculated in 3
4: In Custom RSSI-Measurement Block use following logic
if (2-bit of correlate-access-code-stream) is High:
Take average of N-items from IQ-samples stream
where "N" depends on
a) No of symbol in packet
b) Samples-per-Symbol
Hope this helps
-Adeel
On Wed, Jul 17, 2013 at 12:36 AM, Nemanja Savic <address@hidden> wrote:
_______________________________________________This looks a bit silly cause I am speaking with myself. Anyway, maybe I can do something with probe_avg_mag_sqr, but maybe somebody can tell me how can I access that block's values from another block?Best,
Nemanja--On Tue, Jul 16, 2013 at 3:16 PM, Nemanja Savic <address@hidden> wrote:
The only way that is on my mind is to detect burst and store it in a file, and then to send a message to the block that will read that file, and in case of successfull demodulation and decoding to calcualte signal power, but it looks pretty robust and non elegant.Cheers,
Nemanja--On Tue, Jul 16, 2013 at 2:26 PM, Nemanja Savic <address@hidden> wrote:
NemanjaAny suggestions on this topic, opinions?Best--On Tue, Jul 9, 2013 at 4:23 PM, Nemanja Savic <address@hidden> wrote:
Hi again gnuradioers,as always, I would like to ask for your opinion before starting to write my own block.
Basically, I would like to add a feature to my receiver to be able to calculate average signal strength during signal reception. When I receive a valid packet I would like to have a RSS value. My question is what is the best way to accomplish this in GNURADIO? Using tags or messages, ...? IS there anything similar already provided so that I can take a look?
Thank you and best
--
Nemanja Savić
Nemanja Savić
Nemanja Savić
Nemanja Savić
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