prbt in monolithic architecture
DESCRIPTION
This document is about a short description of the Personalized Ring Back Tone feature that provides huge revenue or increased ARPU to the mobile operator. This specifically deals with the feature in monolithic switches. The readers can comment on the content. Finally, the implementation is correlated with implementation in Ericsson nodes.regards,ramTRANSCRIPT
PRBT in Monolithic architecture – Rev 1.0.0
A Ring-back Tone (RBT) or Audible Ringing Tone is the audible ringing that is heard on the telephone line by the calling party after dialing and prior to the call being answered at the receiving end. This tone assures the calling party that a ringing signal is being sent on the called party's line, although the ring-back tone may be out of sync with the ringing signal.
The ring-back tone is different in various countries depending on the requirements for the ring-back specification in those countries. The ring-back signal may be generated by the called-party servicing switch(S-MSC) or by the calling-party switch (O-MSC), but it is not generated by the called telephone instrument. It is generally started and stopped at the same rate as the ringing signal itself but perhaps out of phase.
For most countries, it consists of a 0.4-second pulse, a 0.2-second pause, a 0.4-second pulse, and a 2-second pause. In some countries the pulse is made by mixing a 400 Hz and 450 Hz sine wave.
The first functional prototype for RBT replacement as we know them today was created by PromoTel, a US company using Karl Seelig's RBT technology in August 2001
http://en.wikipedia.org/wiki/Ringback_tone
PRBT or Personalized Ring Back Tone is a Supplementary service (SS) in telecommunication. This service enables the calling party to hear a personalized music whenever he makes call to particular number subscribed to this service.
Concept:
The underlying concept is very simple. The tone that is sent by the terminating MSC towards the calling party after the alerting of the called party is suppressed. Instead of that, a personalized music is played till the called party answers the call. Immediately after the answering, the music is disconnected and the call is connected. In calls with normal tone around 400Hz and 450Hz sine wave utilizes less bandwidth whereas in PRBT systems, 3.1KHz music is played thus requiring more bandwidth.
Nodes Involved:In a normal call, the mandatory nodes that are required in a normal call flow are MSC/VLR, HLR, BSC, and STP (optional). In networks equipped with PRBT, one additional node is available meant for playing the music. Hereafter this node shall be denoted as PMS (Prbt Music Server). The PMS must be supportive to ISUP transaction with network nodes like MSC/GMSC. It should have both signaling and traffic connectivity with MSC/GMSC.
We will go for a comparative analysis on normal MT call with network equipped with PRBT and not equipped.
In networks without PRBT, the normal call flow would be,1. The GMSC receives IAM for a MT from the originating MSC.2. It interrogates with the HLR for routing information.3. HLR, knowing the current VLR of the subscriber requests the roaming
number for the subscriber for optimal routing.4. Received roaming number is sent towards GMSC for call termination.5. The GMSC based on available data, routes the call with the roaming number
to the terminating MSC.6. Terminating MSC upon the availability of the subscriber acknowledges the
originating MSC of the call by sending the alerting tone towards the calling party.
7. Upon the answer from called party, the call is connected through and the conversation begins.
8. After conversation either of the party release call and the same is acknowledged.
9. The ISUP messages IAM, ACM, REL and RLC are have the appearance only once in the call.
PRBT Systems:There is one main difference when compared to normal or non PRBT systems.
1. The HLR while returning the roaming number provided by the visitor VLR to the GMSC notifies that the subscriber is attached with the PRBT profile.
2. The returned message in the MAP will carry the SS list number towards the GMSC.
3. The GMSC will then route the call towards the terminating MSC/VLR. Upon reception of the ACM and alert signal from the terminating MSC the GMSC reacts.
4. At this stage, the GMSC initiates an IAM towards the PMS with certain combination of A-number, B-number and the service key for PRBT. Both the party numbers are required to facilitate the replay of music personalized between these two subscribers.
5. The PMS will reply with ACM and play the music in this intermediate stage.6. On the reception of ANM from called party, the PRBT path is disconnected and
the actual voice path is connected.
In case of PSTN originated or other operator originated calls, the GMSC can be used to interact with the PMS.
Ericsson implementation:
In Ericsson AXE nodes, the following key points are important.
Following are the Database tables. Check them by,DBTSP:TAB=AXEPARS,SETNAME=GSMMSSC,NAME=” “;(underlined titles below)
PRBTACT -The AXE parameter controls the activation status of the function personalized ring back tone.
The value 0 indicates that the PRBT function is deactivated. The value 1 indicates that the PRBT function is activated.
PRBTNOTIFCONT
The AXE parameter indicates if the PRBT function will be provided in case that a call waiting indication is received from the called subscriber or in case that the indication for 'inband information available' is received after the reception of the alerting indication, which triggered the PRBT function.
The value 0 indicates that the PRBT function will not be provided. The value 1 indicates that the PRBT function will be provided.
PRBTPREF1TO4
The AXE parameter defines the first four digits of the prefix which is added to the MSISDN in order to interrogate the PRBT server.
PRBTPREF5
The AXE parameter defines the fifth digit of the prefix which is added to the MSISDN in order to interrogate the PRBT server.
PRBTPREFLEN
The AXE parameter defines the length of the prefix which is added to the MSISDN in order to interrogate the PRBT server.
TIMEPRBTRNG
The AXE parameter defines the time to wait for the reception of the inband information indication from the PRBT server before the PRBT server is released.
The block that is responsible is GORR and print the data asEXROP:DETY=GORR;
The output BO from the printout will be routed towards the PMS. This is a traffic route. The value of the prefix is normally 254 and it can vary with operators.
Call flow in PRBT environment:
Compiled by,
Ramanathan [email protected]
For suggestions and comments contact [email protected]
