1、W 2326434 0008349 7 Page 1 TS43-1 E Recommendation T/S 43-11 (Edinburgh 1988) SIGNALLING REQUIREMENT ON INTERWORKING BETWEEN THE ISDN OR PSTN AND THE PLMN Recommendation proposed by Working Group T/WG I 1 “Signalling, Protocols and Switching” (SPS) Text of the Recommendation adopted by the “Telecomm
2、unications” Commission: “The European Conference of Post and Telecommunications Administrations, considei*ing - that it is intended to open a pan European mobile service, - that signalling information is required to be passed between PLMNs and ISDN/PSTN, recommends that European Administration who w
3、ish to introduce this mobile service apply the following Recommendation. Note. This Recommendation is also referenced as T/GSM 09-03. 1. INTRODUCTION The purpose of this Recommendation is to present the general requirements for the PSTN and the ISDN as well as for the mobile network to be met in ord
4、er to ensure a correct integration of the mobile service in the fixed network. This Recommendation covers only the signalling aspects of the interworking. The service requirements have to be covered in a specific Recommendation: only the signalling impacts have to be dealt with here. 2. GENERAL SIGN
5、ALLING REQUIREMENTS 2.1, Requirements for the mobile network In order to be integrated in the fixed network the PLMN must comply with the following requirements: a) The MAP which supports information exchanges between the nodes of the mobile service uses the facilities of transactions Capabilities o
6、f Signalling System No. 7. Therefore the equipments of the mobile network must comply with the specifications of the interface between TCAP and the application user. If TCAP functions are integrated in the mobile network equipments, the latter must comply with the relevant specifications (CCITT Reco
7、mmendations 4.771 to 4.774). b) For MAP messages routing purpose, the mobile nodes must provide the SCCP via TCAP with an address complying with the relevant specifications (CCIT Recommendations 4.71 1 to 4.714). c) For call Set-up, the MSCs must interface with the fixed exchanges. In the detailed i
8、nterworking recom- mendations, the fixed network signalling considered are the Signalling System No. 7 and its User Parts (TUP or ISUP). The MSCs must comply with the same signalling interface specifications as the fxed exchanges. d) The PLMN and the signalling on the radio path must provide the inf
9、ormation needed to ensure a correct interworking with the fixed network. The interworking in the MSCs must occur with a minimum loss of information. e) The PLMN nodes must interface with the No. 7 signalling network. For that, they must comply with the MTP specifications (CCITT Recommendations Q.701
10、 and 4.707). Edition of January 15. 1989 4- -. = 2326414 0008150 3 = TIS 43-11 E Page 2 2.2. Requirements for the fixed nework The adaptations of the fixed network needed for the integration of the mobile service have to be minimized. The minimum requirements in the case of a fixed network completel
11、y seperate from the PLMN is for the provision of suitable facilities to carry Signalling System No. 7 messages between PLMNs. In other cases where the PLMN is integrated to a greater or lesser extent with the fixed network, some facilities could be provided to facilitate access to the mobile service
12、 or the operation of the PLMN. a) The implementation of the No. 7 signalling network could be useful for the mobile service. Before No. 7 Signalling System is implemented, a dedicated signalling network using a subset of No. 7 could be used as an interim solution for transfer of the data between fun
13、ctional units of PLMNs. b) It will be useful that, in addition to the signalling network, the SCCP facilities be available in order to avoid a specific implementation of such a service in the PLMN equipments. c) The interrogation procedure based on TCAP prior to connection set up to a mobile would s
14、ave circuits resources in the network and would increase the service quality provided to the fixed calling subscriber by e.g. reducing the post dialling delay in such kinds of calls. The best way is to introduce this procedure as near as possible to the local originating exchanges. 3. INTERWORKING W
15、ITH THE PSTN FOR CALL SET-UP The interworking with the Telephone User Part of the Signalling System No. 7 is the only case considered here. Particular aspects: a) The fixed telephone network provides an end-to-end transparent link at least for speech use. It is then possible to have a data transmiss
16、ion communication on a telephone call. This would not be the case with a mobile subscriber: the radio path would not be transparent. Therefore, if a calling subscriber wishes to have a data transmission call with a mobile it would be necessary to inform the network and precise the characteristics of
17、 this transmission: the mobile PLMN will then be able to replace the speech coder by a data coder adapted to the type of transmission modem used. One solution could be that the mobile has one telephone number per type of data transmission service he can use. b) The usual routing of a call to a mobil
18、e includes a rerouting according to the roaming number allocated to this mobile. This number is temporary allocated and difficulties could appear in some cases such as a failure of a register. c) To remove the need for multiple Roaming Numbers (e.g. in the case of data transmission from the PSTN) it
19、 may be possible, if the implementation allows, to include the called party address in the Initial Address Message sent to the MSC. Alternatively, an indicator specifying the service required could be employed. 4. INTERWORKING WITH THE: ISDN FOR CALL SET-UP Since the radio path could not economicall
20、y provide a transparent 64 kbit/s channel to mobile subscriber all the time, all the ISDN services foreseen in the fixed network will not be available to the mobile subscribers. The quality of service in land mobile networks may also in some cases not meet the quality of service requirements for cer
21、tain ISDN services. Therefore, some service limitations need to be introduced in the access to mobile stations. Different methods may be foreseen to implement this limitation: a) The interrogation is used also to check the service capabilities of the mobile access. This procedure can also be used to
22、 perform a compatibility check between the parties. But this test is only possible if the HLR knows the relevant characteristics of the mobile station and cannot be used with card-operated stations; in that case a mobile subscriber can use different stations. b) The simplest solution is that normal
23、mobile call set-up be processed and controlled by the incoming MSC. As such the incoming MSC can also provide a compatibility check for card-operated stations. c) The call is set up in the normal way up to the mobile. The IAM contains the characteristics of the service requested and on the terminal
24、needed by the call. The network, MSC included, is transparent in the compatibility check. This method is the same as this defined in the ISDN. Edition of January 15, I- TIS 43-11 E Page 3 5. IMPACT OF THE OFF-AIR CfiL SET-UP ON THE INTERWORZ(ING The use of the off-air call set-up.in the PLMN has an
25、impact on the interworking with the fixed network. Both outgoing and incoming calls have to be considered: the consequences are not the same. As it was stated before, the use of the Off-Air Call Set-up procedure is optional and must be limited to national telephone calls only (see Recommendation T/G
26、SM 03-01). Definition of the off-air call set-up To save the radio resources, the radio traffic channel may be allocated to the communication only when both calling and called parties are present i.e. at the answer instant. This method called “Off-Air Call Set-up” (OACSU) has some implication on the
27、 interworking with the fxed network. But the consequences are not the same whether the mobile subscriber is the calling or the called party. Outgoing Cali from a mobile station Upon initiation of an outgoing call, a traffic channel is allocated to the communication when the ealled subscribes answer
28、is received in the MSC. In some cases, no idle traffic channel may be available when necessary. Therefore, an appropriate announcement must be given to the called party when no idle traffic channel is available within a certain interval upon receipt of the called partys answer. Whenever the announce
29、ment is used, it must always be played through in its entirety, even ifa trafic channel becomes available before it is completed, except if the called party clears, in which case the call should be cleared forward. If the ADDRESS COMPLETE message indicates that there will possibly be no ANSWER messa
30、ge upon the connection of the called party (e.g. ADC without any information), the radio path must be established immediately upon receipt of the ADC. Due to interworking constraints coming from the characteristics of the different signalling systems used in the countries, the OACSU technique should
31、 only be used for national calls. Incoming call to a mobile station For incoming calls, the impact is not so important, but some rules must be applied in order to limit the influence on the service quality. Concerning the sending instant of the answer message, the nosmal operating rules apply. If th
32、e call is successfully set up to the mobile station, the answer message must be sent to the originating exchange only when the traffic channel is established upon recognition of the called party connection. 5.1. 5.2. 5.3. 6. SPECIAL ARRANGEMENTS 6. I. Control of speech processing and echo control devices For further study. Edition of January 15, 1989 e- -
