OpenBSC January 2022

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48 discussions

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Number of symbols in a burst =3D 156.25 symbols, and burst time 156.25 x 3.69... =3D 576,92=ECs Number of symbols in TDMA frame is 8 x 156.25 =3D 1250 symbols, Number of symbols in Multiframe is 26 x 1250 symbols. On Fri, Jan 7, 2011 at 8:51 AM, Nataraju A B <natarajuab.tech(a)gmail.com> wr= ote: > > Hi Andreas, > Thanks for the speedy reply. > The link which sent you is=A0definitely=A0useful. But the very basic ques= tion I wanted to get a clarification was that, what is the drive behind sel= ection of burst time to be 577us. > For example the audio frequency can range upto 4Khz. The sampling frequen= cy should be 8Khz. If each sample is of 8 bit accuracy. This lead to 64K bi= ts of data. ...... =A0If we explore further on these lines we should be abl= e to correlate to the time 577us for each burst. > I wanted some more info these lines. What was/were the drives behind sele= ction of this burst time. Otherwise what are the other end requirements led= to selection of this burst time and in turn TDMA frame hierarchy. > Thanks, > Nataraju A B > On Fri, Jan 7, 2011 at 7:01 PM, Andreas.Eversberg <Andreas.Eversberg@vers= atel.de> wrote: >> >> in addition: >> >> Traffic Multiframe Structures - The 26 traffic multiframe structure is >> used to send information on the traffic channel. The 26 traffic >> multiframe structure is used to combine user data (traffic), slow >> control signaling (SACCH), and idle time period. The idle time period >> allows a mobile device to perform other necessary operations such as >> monitoring the radio signal strength level of a beacon channel from >> other cells. The time interval of a 26 frame traffic multiframe is 6 >> blocks of speech coder data (120 msec). >> (http://www.althos.com/tutorial/GSM-tutorial-frame-structure.html) >> >> one encoded speech block lasts 20ms. >> >> >> =A0 =A0 =A0 =A0576,92307692307692307692307692308us per slot >> =A0 =A0 =A0 =A04615,3846153846153846153846153846 per 8 slots (1 frame) >> =A0 =A0 =A0 =A0120ms per 26 frames (6 speech blocks) >> >> >> > > > > -- > Thanks, > Nataraju A B

3 years, 7 months

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" Raw mode cfmakeraw() sets the terminal to something like the "raw" mode of the old Version 7 terminal driver: input is available character by charac‐ ter, echoing is disabled, and all special processing of terminal input and output characters is disabled. The terminal attributes are set as follows: termios_p->c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON); termios_p->c_oflag &= ~OPOST; termios_p->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN); termios_p->c_cflag &= ~(CSIZE | PARENB); termios_p->c_cflag |= CS8; " If that is set on the socket for the telnet interface it does make a difference.

3 years, 7 months

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by None

GSM handset like the Motorola C123 and talk to GSM-R BTSs. Of course you still need to implement the GSM-R specific features on layer 3 like ASCI. In both cases I think the hardware is there for whoever has a serious interest in experimenting with this technology, and who is not afraid to implement the GSM-R specific bits. -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

3 years, 7 months

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by None

but not the new. But in any case, the OP can fix the sql. The OP seem to have a new/more picky version of sqlite. Before in case of ambiguous column name, it took the one from the first table in the FROM list. (not sql standard but that's why it didn't matter before). > Could you also give us the "old" and "new" git hashes so we can take a > look at what changed? The hash (short) are in the version string, the log is : git log b938..f7a1c Sylvain

3 years, 7 months

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'type' used and the corresponding codec. For GSM FR the RFC specifies PT=3 but for HR/EFR/AMR, they are dynamic and must be chosed in the 96-127 range. AFAIK, we could just use a static mapping in openbsc or load that from the config. Does anyone sees a downside to that ? Sylvain --000325564d6aac09c2047af385f6 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi, I have a nanobts unit 139 with a software that somehow only acce= pts GSM FR (and not EFR), unless I also send the RTP payload type IE ( RSL_= IE_IPAC_RTP_PAYLOAD ) in the CRCX and MDCX messages. (and only the "RT= P payload type" IE, the "RTP payload type 2" has no effect I= can see). From the ip.access dissector, I think it's just a mapping between t= he RTP 'type' used and the corresponding codec. For GSM FR t= he RFC specifies PT=3D3 but for HR/EFR/AMR, they are dynamic and must be ch= osed in the 96-127 range. AFAIK, we could just use a static mapping in openbsc or load that from the = config. Does anyone sees a downside to that ? =C2=A0=C2=A0=C2=A0 Syl= vain --000325564d6aac09c2047af385f6--

3 years, 7 months

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messages in 12.21 are simply used to communicate state changes ?!? -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

3 years, 7 months

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updating/running the most recent version. > For me now, it's still much easier to debug in windows than in Linux, because > I'm not yet comfortable with gdb in comman-line. There are GUI frontends for gdb, including the old "ddd" as well as modern bloatware like eclipse ;) -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

3 years, 7 months

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"The requirements yielded by the page mode information element are as follows: a) normal paging: no additional requirements; b) extended paging: the mobile station is required in addition to receive and analyse the next but one message on the PCH; c) paging reorganization: The mobile station shall receive all messages on the CCCH regardless of the BS-AG-BLKS-RES setting. It is required to receive all BCCH messages. When the mobile station receives the next message to its (possibly new) paging subgroup the subsequent action is defined in the page mode information element in that message. d) same as before: No change of page mode from the previous page mode." I think the paging reorganization mode is fine. Does anyone know this mode? I don't know if the mobile phone will answer everytimes if i try to do a paging on it for each successive frame. Or if he will answer the first time and ignore the other paging requests after. In addition, this solution enable the cell phone to listen every frames of the CCCH but I don't know if the BTS is abble to do a paging on the same mobile phone on every frames or if it still needs to follow the BS_PA_MFRMS parameter. I saw that the paging group is calculated from the IMSI. And then the paging block is calculated. Is it calculated in the BTS or in OpenBSC? link of the explanation on the paging : http://etutorials.org/Mobile+devices/gprs+mobile+internet/Chapter+5+Radio+I… Thanks Best regards Eric Cathelinaud 2009/7/15 Eric Cathelinaud <e.cathelinaud(a)googlemail.com> > 2009/7/15 Dieter Spaar <spaar(a)mirider.augusta.de> > > Hello Eric, >> >> On Wed, 15 Jul 2009 11:00:14 +0200, "Eric Cathelinaud" < >> e.cathelinaud(a)googlemail.com> wrote: >> > >> > I was just thinking about performing a recursive paging in order to see >> how >> > much time I have until the battery of a mobile phone run out. >> > Does anyone know if the mobile phone answers at every paging or if it >> > doesn't "listen" all the time? I think it listens periodically. If >> anyone >> > can give me a clue, that would be appreciated. >> >> This is an excerpt from a posting to another mainling list, I just >> quote it because I don't want to repeat what I already wrote: >> >> > - The phone is in "idle" mode (no speech/data traffic) >> > and periodically receives the paging channel (PCH) to >> > find out if its being called. Further the phone measures >> > the signal strength of neighbor cells and every now >> > and then (not that frequent as the above actions) >> > receives the cell information in the broadcast common >> > control channel (BCCH) of the serving cell and of >> > at most six neighbor cells with the strongest signal. >> >> .... >> >> > - The time between receiving the PCH is determined by a >> > parameter of the serving cell (BS_PA_MFRMS, range 2 to 9). >> > Its measured in 51-multiframes until the PCH for the phone >> > repeats (if you want to know the details have a look at >> > the GSM specs ;-) . The length of a 51-multiframe is >> > 235.8 ms, this means the time between receiving the PCH >> > is in the range 471.9 ms to 2122.2 ms. In this time the >> > idle phone most of the time sleeps or receives the BCCH >> > of the serving cell or one of the neighbor cells with >> > the strongest signal (at most six). >> >> Best regards, >> Dieter >> -- >> Dieter Spaar, Germany spaar(a)mirider.augusta.de >> > > Thanks a lot for the explanation. It's a pity that the minimum period is 2 > multiframes. I wish I could realize a paging on a mobile phone every frame > but it seems to be impossible finally. > > Best regards, > Eric Cathelinaud > > --001636499281749655046ed2de53 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi, Finally I think I find a solution to make the cell phone listeni= ng to every frames of the CCCH. From gsm04_08: <meta http-equiv= =3D"Content-Type" content=3D"text/html; charset=3Dutf-8"><meta name=3D"Prog= Id" content=3D"Word.Document"><meta name=3D"Generator" content=3D"Microsoft= Word 11"><meta name=3D"Originator" content=3D"Microsoft Word 11"><link rel= =3D"File-List" href=3D"file:///C:%5CTmp%5Cmsohtml1%5C01%5Cclip_filelist.xml= "><style>  </style> "The requirements yielded by the page mode info= rmation element are as follows: a)=A0 normal paging: no additional requirements; b)=A0 extended paging: the mobile station is required in addition to receive and analyse the next but = one message on the PCH; c)=A0 paging reorganization: The mobile station shall receive all messages on the CCCH regardless of the BS-AG-BLKS-RES setting. It is required to receive all BCCH messages. When t= he mobile station receives the next message to its (possibly new) paging subgr= oup the subsequent action is defined in the page mode information element in th= at message. d)=A0 same as before: No change of page mode from the previous page mode." I think the paging reorganization mode is fine. Does anyone know this m= ode? I don't know if the mobile phone will answer everytimes if i try t= o do a paging on it for each successive frame. Or if he will answer the fir= st time and ignore the other paging requests after. In addition, this solution enable the cell phone to listen every frames= of the CCCH but I don't know if the BTS is abble to do a paging on the= same mobile phone on every frames or if it still needs to follow the BS_PA= _MFRMS parameter. I saw that the paging group is calculated from the IMSI. = And then the paging block is calculated. Is it calculated in the BTS or in = OpenBSC? link of the explanation on the paging : <a href=3D"http://etutorials.org= /Mobile+devices/gprs+mobile+internet/Chapter+5+Radio+Interface+RLC+MAC+Laye= r/Listening+to+MS+Paging+Blocks/">http://etutorials.org/Mobile+devices/gprs= +mobile+internet/Chapter+5+Radio+Interface+RLC+MAC+Layer/Listening+to+MS+Pa= ging+Blocks/</a> Thanks Best regards Eric Cathelinaud <div class=3D"gma= il_quote">2009/7/15 Eric Cathelinaud <<a href=3D"mailt= o:e.cathelinaud@googlemail.com">e.cathelinaud(a)googlemail.com</a>>= <blockquote class=3D"gmail_quote" style=3D"border-left: 1px solid rgb(204, = 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class=3D"gma= il_quote">2009/7/15 Dieter Spaar <<a href=3D"mailto:sp= aar(a)mirider.augusta.de" target=3D"_blank">spaar(a)mirider.augusta.de</a>><= /span><div> <div></div><div class=3D"h5"> <blockquote class=3D"gmail_quote" style=3D= "border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padd= ing-left: 1ex;"> Hello Eric, <div> On Wed, 15 Jul 2009 11:00:14 +0200, "Eric Cathelinaud" <<a hre= f=3D"mailto:e.cathelinaud@googlemail.com" target=3D"_blank">e.cathelinaud@g= ooglemail.com</a>> wrote: > > I was just thinking about performing a recursive paging in order to se= e how > much time I have until the battery of a mobile phone run out. > Does anyone know if the mobile phone answers at every paging or if it<= br> > doesn't "listen" all the time? I think it listens period= ically. If anyone > can give me a clue, that would be appreciated. </div>This is an excerpt from a posting to another mainling list, I just<br= > quote it because I don't want to repeat what I already wrote: > =A0- The phone is in "idle" mode (no speech/data traffic)<br= > > =A0 =A0and periodically receives the paging channel (PCH) to > =A0 =A0find out if its being called. Further the phone measures > =A0 =A0the signal strength of neighbor cells and every now > =A0 =A0and then (not that frequent as the above actions) > =A0 =A0receives the cell information in the broadcast common > =A0 =A0control channel (BCCH) of the serving cell and of > =A0 =A0at most six neighbor cells with the strongest signal. .... > =A0- The time between receiving the PCH is determined by a > =A0 =A0parameter of the serving cell (BS_PA_MFRMS, range 2 to 9). > =A0 =A0Its measured in 51-multiframes until the PCH for the phone > =A0 =A0repeats (if you want to know the details have a look at > =A0 =A0the GSM specs =A0;-) . The length of a 51-multiframe is > =A0 =A0235.8 ms, this means the time between receiving the PCH > =A0 =A0is in the range 471.9 ms to 2122.2 ms. In this time the > =A0 =A0idle phone most of the time sleeps or receives the BCCH > =A0 =A0of the serving cell or one of the neighbor cells with > =A0 =A0the strongest signal (at most six). Best regards, =A0Dieter -- Dieter Spaar, Germany =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 <= a href=3D"mailto:spaar@mirider.augusta.de" target=3D"_blank">spaar(a)mirider.= augusta.de</a> </blockquote></div></div></div> Thanks a lot for the explanation.= It's a pity that the minimum period is 2 multiframes. I wish I could r= ealize a paging on a mobile phone every frame but it seems to be impossible= finally. Best regards, Eric Cathelinaud </blockquote></div> --001636499281749655046ed2de53--

3 years, 7 months

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OpenBSC January 2022