September 2017 - baseband-devel

Re: SDR_PHY question
by Vadim Yanitskiy 07 Sep '17

07 Sep '17

Hi, > I believe I need to keep focusing on osmo-trx support > as the gr-gsm app does not seem to support TX (please > correct me if I'm wrong though). You are right, currently it doesn't. But we together with Piotr Krysik are working on TX support for GR-GSM... > I will keep investigating this and I will provide you > some patches for osmo-trx which enable power > measurement and synchronization. Great! Having both OsmoTRX and GR-GSM TRX support would be good. I am currently busy with TCH implementation for trxcon, so as soon as I finish, I'll put my development power on this too. With best regards, Vadim Yanitskiy.

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Re: SDR_PHY question
by Vadim Yanitskiy 06 Sep '17

06 Sep '17

Hi Adrian, > I am interested in the sdr_phy work being done currently Great to hear that. > I built osmo-trx from the ms branch and implemented a crude > power measurement command. When running trxcon everything works > fine, I get power indications for channels, and then when the > mobile app is trying to sync to an ARFCN I start having issues. I have never developed / tested trxcon with OsmoTRX so far. Currently I am using GR-GSM as a L1 back-end, and the virtual connection between OsmocomBB and OsmoBTS during development. In general, trxcon should be able to 'speak' with OsmoTRX, because one do use classical transceiver UDP interfaces. But there are some CTRL commands, which aren't implemented in OsmoTRX yet (such as ECHO and MEASURE). > I had to change the code of trxcon in order for SCH to work, > because the bit values were inverted (0 was 1 and viceversa). > I am attaching the changes at the end of the message. Sounds strange. In case of virtual Um-interface (FakeTRX) and GR-GSM TRX all SCH messages are decoded correctly. I will look closer to this issue, thanks anyway! > It appears as if the deinterleaving in gsm0503_xcch_decode > does not work... could be the order of bursts? The order of bursts should be consistent, I mean frame-by-frame. You need to make sure that a frame number from SCH burst is being decoded correctly by OsmoTRX. Every burst coming from OsmoTRX has a header with frame number, which is used by trxcon to determine a current frame position within a multiframe. Probably, the problem is due to incorrect / consistent frame number values. The internal clock counter (sched_clck.c) is only used to schedule the UL bursts transmission. > I'd appreciate any help here. I'm also ready to share the > changes I've made to osmo-trx/ms and trxcon. For now, have a look at: - GR-GSM based transceiver: https://github.com/axilirator/gr-gsm/tree/fixeria/trx - Virtual Um-interface (brief description): http://git.osmocom.org/osmocom-bb/tree/src/target/fake_trx/README?h=fixeria… - The latest version of trxcon (use fixeria/fake_trx branch): http://git.osmocom.org/osmocom-bb/log/?h=fixeria/fake_trx You can also join the development process, feel free to mail me. I will create the wiki page as soon as possible. With best regards, Vadim Yanitskiy.

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SDR_PHY question
by Adrian Musceac 06 Sep '17

06 Sep '17

Hello, I am interested in the sdr_phy work being done currently, and I'm trying to get it set up on my computer. I built osmo-trx from the ms branch and implemented a crude power measurement command. When running trxcon everything works fine, I get power indications for channels, and then when the mobile app is trying to sync to an ARFCN I start having issues. The FCCH bursts are decoded fine, and so are the SCH bursts (which I can also see in the osmo-trx terminal). I had to change the code of trxcon in order for SCH to work, because the bit values were inverted (0 was 1 and viceversa). I am attaching the changes at the end of the message. Unfortunately, the BCCH and CCCH bursts are not decoded: <0006> sched_lchan_sch.c:98 Received SCH: bsic=30, fn=1116799, sched_fn=1116798 <0006> sched_lchan_xcch.c:69 Data received on BCCH: fn=1116800 ts=0 bid=0 <0006> sched_lchan_xcch.c:69 Data received on BCCH: fn=1116801 ts=0 bid=1 <0006> sched_lchan_xcch.c:69 Data received on BCCH: fn=1116802 ts=0 bid=2 <0006> sched_lchan_xcch.c:69 Data received on BCCH: fn=1116803 ts=0 bid=3 <0006> sched_lchan_xcch.c:117 Received bad data frame at fn=1116800 (2/51) for BCCH with 66 errors It appears as if the deinterleaving in gsm0503_xcch_decode does not work... could be the order of bursts? I'd appreciate any help here. I'm also ready to share the changes I've made to osmo-trx/ms and trxcon. Best regards, Adrian diff --git a/src/host/trxcon/trx_if.c b/src/host/trxcon/trx_if.c index 6a84af6..def571c 100644 --- a/src/host/trxcon/trx_if.c +++ b/src/host/trxcon/trx_if.c @@ -325,6 +325,11 @@ int trx_if_cmd_setslot(struct trx_instance *trx, uint8_t tn, uint8_t type) return trx_ctrl_cmd(trx, 1, "SETSLOT", "%d %d", tn, type); } +int trx_if_cmd_sync(struct trx_instance *trx, uint8_t type) +{ + return trx_ctrl_cmd(trx, 1, "SYNC", "%d", type); +} + /* * Tuning Control * @@ -392,7 +397,7 @@ int trx_if_cmd_measure(struct trx_instance *trx, LOGP(DTRX, LOGL_ERROR, "ARFCN %d not defined\n", arfcn_start); return -ENOTSUP; } - + trx_ctrl_cmd(trx, 1, "RXTUNE", "%d", freq10 * 100); return trx_ctrl_cmd(trx, 1, "MEASURE", "%d", freq10 * 100); } @@ -421,6 +426,7 @@ static void trx_if_measure_rsp_cb(struct trx_instance *trx, char *resp) arfcn == trx->pm_arfcn_stop); /* Schedule a next measurement */ + usleep(50000); if (arfcn != trx->pm_arfcn_stop) trx_if_cmd_measure(trx, ++arfcn, trx->pm_arfcn_stop); } @@ -558,9 +564,9 @@ static int trx_data_rx_cb(struct osmo_fd *ofd, unsigned int what) /* Copy and convert bits {254..0} to sbits {-127..127} */ for (i = 0; i < 148; i++) { if (buf[8 + i] == 255) - bits[i] = -127; + bits[i] = 127; else - bits[i] = 127 - buf[8 + i]; + bits[i] = -127 + buf[8 + i]; }

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help me
by Олег Суворов 04 Sep '17

04 Sep '17

Hello, I am from Russia, can you help me with Filter Replacement! I have to mobile, Motorolla C115 and C118. I was bye all elements to make filter replacement. Motorolla C115 look like your instruction and I was done filter replacement. Motorolla C115 nice work after it. But Motorolla C118 don`t look like in your instruction (no network signal or network signal is 1 level from 5). I read: "Different circuit Sometimes the input (at the bottom of the balun) is not with caps in series and a resistor in parallel. Instead it might be without the resistors in parallel and resistors in series. Remove the resistors and place 2x the appropriate cap in series (22 pF for GSM90, 15 pF for DCS1800". But I don`t understand what I must do. I do like my picture (your network email network filter doesn`t allow me to download my photo, but I can send it if you allow this), but after it Motorolla don`t work: No signal from Network (or network signal is 1 level from 5). Can you help me? With Best Regards, Oleg Syvorov

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