There are no tags for this page.
Dobrica Pavlinušić's random unstructured stuff

voice info

17:42 < dpavlin> stupid question about by first experiment with osmocom-bb 
http://blog.rot13.org/2011/01/osmocom-bb_-_free_software_finally_comes_to_gsm.html - are hex 
                 numbers I see scroll by voice data by any chance or controll stream?
17:42 < steve|m> dpavlin: that's the voice_ind
17:43 < steve|m> http://bb.osmocom.org/trac/changeset/a4e34316c403a49ca57fd907e55a16b721629e35/src
17:43 < steve|m> so maybe revert this commit in your local branch if you don't need that 
                 (transferring voice data to the host)
17:45 < dpavlin> Great. With something like pipe I could go a long way :-)
17:46 < dpavlin> Can I inject it over serial port? For something like text2speech?
17:46 < steve|m> tnt has code for that, but he hasn't committed it yet
17:46 < steve|m> jolly even has written an interface to LCR
17:49 < dpavlin> I would love to help test it, if such help is needed.

19:21 < dpavlin> tnt: do you have any pointers to information about calypso voice format I can read?
19:23 < dw> the code? :)
19:26 < dpavlin> I tried reading code under src/target/firmware/calypso but I'm probably looking in wrong place, 
                 because I'm not closer to understanding voice.raw format than I was few days ago.
19:30 < steve|m> dpavlin: looked at 
http://bb.osmocom.org/trac/browser/src/target_dsp/calypso/dsp_sniff.S?rev=d1cb8ea9b784c7acbafbb2fdcedbdf4655c2f6f5 ?
19:31 < tnt> steve|m: that's not for voice.raw
19:31 < tnt> There is just no written reference anywhere of the buffer format.
19:31 < steve|m> ah, sorry, confused that..
19:44 < tnt> dpavlin: from memory, it's all the class 1 bits, then some bits always at 0 (4 bits IIRC), then all the 
             class 2 bits of a GSM 610 frame.  They're packet in 16 bits works, MSB first

1297284215 <Fatuo!~n0p@> I have a question about burst_ind branch of bb
@1297284218 <mkf00!~mkf00@85-127-108-141.dynamic.xdsl-line.inode.at> hallo
@1297284279 <Fatuo!~n0p@> In l1ctl_burst_ind I understand that the two stealing bits are in bits 58 & 59 (without the training)
@1297284286 <Fatuo!~n0p@> is this correct?
@1297284318 <Fatuo!~n0p@> this is because I think that both must be the same bit 0 for data/voice and 1 for FACCH
@1297284347 <Fatuo!~n0p@> tnt?
@1297284376 <tnt!~tnt@mojito.smartwebsearching.be> no it's not correct
@1297284389 <Fatuo!~n0p@> uhm!
@1297284391 <tnt!~tnt@mojito.smartwebsearching.be> the two stealing bits are at the end, the DSP puts them there.
@1297284439 <Fatuo!~n0p@> both are together?
@1297284440 <tnt!~tnt@mojito.smartwebsearching.be> On the air you are correct they're in the middle but during the packing, the DSP puts the 2*57 bits and then the two stealing bits at the end.
@1297284538 <Fatuo!~n0p@> from my code:
@1297284542 <Fatuo!~n0p@> <0001> layer3.c:418 LEO BURST: 58 93 b5 f6 95 37 9c 83 f7 f1 95 f2 62 fd 10
@1297284605 <Fatuo!~n0p@> we don't need the first 4 bits
@1297284618 <Fatuo!~n0p@> but the next one is 1
@1297284633 <Fatuo!~n0p@> only one stealing bit filled?
@1297284671 <Fatuo!~n0p@> only one stealing bit with 1?
@1297284908 <tnt!~tnt@mojito.smartwebsearching.be> Fatuo: yup. so ?
@1297284945 <Fatuo!~n0p@> I thought that both must be the same....
@1297284983 <Fatuo!~n0p@> Can be FACCH and voice/data in the same frame? I don think so...
@1297285078 <tnt!~tnt@mojito.smartwebsearching.be> well, you think wrong :)
@1297285108 <Fatuo!~n0p@> oh
@1297285111 <Fatuo!~n0p@> tanks :)
@1297285111 <tnt!~tnt@mojito.smartwebsearching.be> you need to re-read GSM 05.03. TCH has diagonal block interleaving.
@1297285148 <Fatuo!~n0p@> ok, i will do right now, thanks a lot
@1297285149 <tnt!~tnt@mojito.smartwebsearching.be> so the 4 * 114 bits are split into 8 half bursts and sent over 8 bursts, half mixing with the next / prev frame.
@1297285247 <Fatuo!~n0p@> I see
@1297285275 <Fatuo!~n0p@> I'll go re-reading that doc
@1297285277 <Fatuo!~n0p@> bye


git clone git://git.srlabs.de/kraken

13:35 < tomash2> [Thu 13:56] Hi
13:35 < tomash2> [Thu 13:58] When receiving bursts via sylvain/burst_ind, is the frame number for uplink bursts correct?
13:35 < tomash2> [Thu 13:59] Assembled packets appear to be on differrent channel that uplink ones
13:35 < tomash2> [Thu 14:01] It works to do fn=fn-15 for unencrypted packets, but not for encrypted ones
13:35 < tomash2> [Thu 14:01] So how to get correct fn for uplink bursts?
13:35 < tnt> [Thu 14:06] the fn is correct, your code is wrong obviously ...
13:35 < tomash2> [Thu 14:08] Strange, downlink decrypting works, and I do uplink the same way...
13:35 < tomash2> [Thu 14:08] Thakns, I'll go to search for the bug...
13:35 < tnt> [Thu 14:10] ... then that's your problem.
13:35 < tnt> [Thu 14:10] uplink is _not_ same as downlink
13:35 < tnt> [Thu 14:10] the first 116 bits of A5 is for DL, then you need the 116 after that for UL.
13:35 < tomash2> [17:11] tnt: And these second 116 bits are computed from Kc and fn the same way as in uplink?
13:35 < tnt> [17:13] yup
13:35 < tnt> [17:13] 114 not 116 btw
13:35 < tnt> [17:13] stealing bits aren't ciphered
13:35 < tnt> [17:13] (afair)
13:35 < tomash2> [17:14] tnt: That's what I'm doing. But it is not working for uplink
13:35 < tnt> [17:15] well you're doing it wrong :)
13:35 < tomash2> [17:16] tnt: maybe :-)
13:35 < tnt> [17:16] your a5 keystream genreator should generate 228 bits of outpout per frame, the first 114 for DL the next 114 for UL.
13:35 < tomash2> [17:17] tnt: huh
13:35 < tnt> [17:17] That's what I told you above:
13:35 < tnt> [17:17] 14:10 < tnt> the first 116 bits of A5 is for DL, then you need the 116 after that for UL.
13:35 < tomash2> [17:17] so uplink bits are _not_ computed from fn of the uplink burst?
13:35 < tnt> [17:18] ... of course they are
13:35 < xorAxAx> [17:18] frame count!
13:35 < tnt> [17:19] xorAxAx: frame count is just another representation of fn ... (how to feed them in A5). If the DL decryption works, then that part is obviously correct.
13:35 < xorAxAx> [17:19] yeah
13:35 < tnt> [17:20] tomash2: for SDCCH the UL and DL are in different frame, so you would only use one of the pair of 114 bits ... but for TCH you'd use both.
13:35 < tnt> [17:21] but it doesn't matter ... UL is always the second and you _have_ to compute the first 114 bits of DL even if you won't use them.
13:35 < tomash2> [17:22] tnt: I'm talking about SDCCH all the time, I didn't try TCH yet...
13:35 < tnt> [17:22] and as I said : It doesn't matter ...
13:35 <Bassam> Hi.
13:35 <Bassam> What is the relation between the frame numbers in both the UL and DL stages in the SDCCH as you said that both of them are in different frames, is there any equation or something relating the frame numbers




Upload Files

Click "Browse" to find the file you want to upload. When you click "Upload file" your file will be uploaded and added to the list of attachments for this page.

Maximum file size: 50MB

File Name Author Date Uploaded Size

Save Page As

Enter a meaningful and distinctive title for your page.

Page Title:

Tip: You'll be able to find this page later by using the title you choose.

Page Already Exists

There is already a page named XXX. Would you like to:

Save with a different name:

Save the page with the name "XXX"

Append your text to the bottom of the existing page named: "XXX"

Upload Files

Click "Browse" to find the file you want to upload. When you click "Add file" this file will be added to the list of attachments for this page, and uploaded when you save the page.

Add Tags

Enter a tag and click "Add tag". The tag will be saved when you save the page.