ETSI GSM 03 43-1992 Technical Realization of Videotex《可视图文的技术实现》.pdf

1、m 3404583 0070243 L3T m ETSI/TC SMG Released by : ETSI/PT 12 Release date: February 1992 * RELEASE NOTE Recommendation GSM 03.43 Technical Realization of Videotex Previously distributed version : 3.0.1 (Release 1/90) New Released version February 92 : 3.0.1 (Release 92, Phase 1) * No changes since t

2、he previously distributed version. m 3404583 O070244 076 m GSM 03.43 - version 3.0.1 - page 1 , ETSI GSM Released: ETSI PT12 Date: February 1992 Recommendation: GSM 03.43 Title: TECHNICAL REALIY-.-TC)N OF VIDEOTEX O. Scope 1. Service definition 2. Network architecture 2.1. Videotex centre connected

3、to PSTN/ISDN 2.2. Videotex centre connected to PSPDN via PAD 2.3. Videotex centre connected directly to the IWF 3. Reference configuration of the mobile station (MS) 4. Connection types and signalling aspects 4.1 Transparent asynchronous data 4.2 Non-transparent character oriented 4.3 Non-transparen

4、t with specialized-layer 2 5. Use of Terminal Adaptation Functions (TAF) defined for Asynch. Services 5.1. TAFs for transparent services 5.2. TAFs for non-transparent services 5.3. Call establishment signalling mapping 6. Interworking with PSTN 6.1. Transparent service support 6.2. Non-transparent s

5、ervice support 7. Interworking with ISDN 8. Support of roaming subscribers 8.1. Videotex access to “home“ centre via an international 8.2. Videotex access to “local centre“ call 9. Additional functions 9.1. Direct call 9.2. Charging aspects Annex: BC and HLC elements Qxigiall: English -: 11 W 340458

6、3 00702Y5 TO2 W GSM 03.43 - version 3.0.1 - page 2 o. SCOPE This recommendation describes the technical realization of Videotex service within the GSM-PLMN network, taking into account the Teleservices 41, 42, 43 as specified in the Rec GSM 02.03. It defines: - the service and service elements - the

7、 network architecture - the reference configuration of the MS - the signalling aspects - the use of TAF - the interworking with existing networks - the support of roaming subscribers - the access to foreign Videotex services - the link layer protocol structure 1. The Videotex service is an interacti

8、ve service that by means of proper access points and standardized procedures provide the access to computer-based information stored in data bases, utilizing public transmission networks. The basic elements considered for the Videotex system are: - the user terminal - the telecomunication network -

9、the service access center (Videotex center) - the data bases The specific features that are relevant to the service are: a Videotex call is always a mobile-originated call it is an interactive service - - - the requested information is generally in form of text and/or pictures. 3404583 007024b 949 G

10、SM 03.43 - version 3.0.1 - page 3 - the information access is under the control of the user. - there are three different types of service access profiles, depending on high layer attributes of the teleservice. The teleservice attributes of the different Videotex access profiles are defined in Rec GS

11、M 02.03, in term of: - high layer capabilities - terminal capabilities - low layer capabilities - general attributes 2. The following network schemes are considered to operate the Videotex service in a GSM PLMN : 2.1. Videotex Ceme C-d Tn PSTNIISDN When it is assumed that the Videotex centre is conn

12、ected to the PSTN, the network scheme is shown in Fig 03.43/1a. V.23 MSC centre Fig. 03.43/1a Access to the Videotex Centre directly connected to the ISDN for national matter; a possible network scheme is reportted Fig.03.43/lb V.23 is in Fig. 03.43/1b W 3404583 O070247 885 GSM 03.43 - version 3.0.1

13、 - page 4 MSC IWF - PAD - FHFP L-BS - - PSPDN VTEX 2.2. Videatexed To PSPDN Via PAD Access to the Videotex centre via PSPDN is for national matter; a possible network scheme is reported in Fig. 03.43/2. Fig. 03.43/2 2.3. Yideotexentre. CQnnecZed Directlv To u Direct connection between the IWF and th

14、e Videotex centre via Videotex Access Point (VAP), as shown in Fig. 03.43/3, is national matter. V.24 a a Fig. 03.43/3 = 3404583 0070248 711 VTEX V.23 - MT2 I GSM 03.43 - version 3.0.1 - page 5 -: The following types of reference configuration of the mobile station are considered: terminal 4 Mobile

15、station w: Conf (a) . modem I I TA . l MT1 VTEX V.23 -: Fig. 03.43/4 terminal modem The definitions of the functional groups shown in the figure are reported in Rec GSM 04.02. I TE2 - MT2 4. N TYPRS AND SS”G -: The relationship between the Videotex profile 1, 2, 3 Teleservices and the connection ele

16、ments are reported in table 6/GSM 03.10. The modem type indication (V.23 ) is given in the BC and LLC information elements of the SET-UP message sent in the call attempt phase (see Annex). The protocol models considered are the Model la, lb, 3a, 3b reporteQ in Fig 6/GSM 03.10. h I I * MT1 TE2 -: 340

17、4583 0070249 658 GSM 03.43 - version 3.0.1 - page 6 * 4.1. -t Data 8 This model can be used for all 3 Videotex profiles; problems of error rate compared to the provision of Videotex service shall be investigated. The reference are the protocol models la and lb of figure 6/GSM 03.10. This model can b

18、e used for the Videotex profile 1, 2 and 3 in order to improve the quality transmission. The protocol reference model relating to the L2R function is reported in fig. 03 . 43/5 End system End system L3 . Transparent higher layer protocol . L3 3 .gNTr: . p. . .LZRCOP q .r:. e . RLP. . . VTEX TE Ms IW

19、F VTEX Centre fig. 03.43/5 The L2R functionality for character oriented non-transparent protocol is described in Rec GSM. 07.02 (Annex 1). Flow control in Videotex is not normally necessary since the host sends data on a screen by screen basis awaiting for a user prompt at the end of each screen ful

20、l before the next screen full is sent. In the non-transparent service, provision must be made for the IWF to buffer the equivalent of a screen full of data in order that ARQs in the Radio link Protocol are able to function. For this pyrpose a 2 Kbyte buffer shall be provided in the interworking func

21、tion for data being sent to the mobile. Buffering in the IWF for data received from the mobile is not necessary. Further study is also needed on the effect of the L2RCOP delays on the high layer protocol. m 3404583 0070250 37T GSM 03.43 - version 3.0.1 - page 7 This model can be used for Videotex pr

22、ofile 1 in order to utilize the improvement of quality service due to the specific layer 2 provided in this profile. A special L2RP shall be defined for this application. The protocol reference model relating to the L2R function is reported in fig. 03.43/6. End System End system . Transparent higher

23、 layer protocol . VTEX TE .NTP . VTEX1 . . RLP. I MS IWF VTEX centre fig 03.43/6 Provision of L2RVTEX1 is for further study: it is needed depending on the quality achieved with the transparent service or on problems detected in mapping Videotex profile 1 protocols in the standard L2RCOP. 5. D FOR AS

24、YNCHRONOUS SERVICES The TAFs to be considered are those defined in section 1.2 of Rec GSM 07.02; they are divided in: 5.1. t Services Regarding to the rate adaption V-series the reference is the section 2.1 of the Rec GSM 07.02. The rate adaption function shall comply with the Rec GSM 04.21 and 08.2

25、0, in particular the 1200/75 .asyncronous rate adaption shall be considered. Regarding to the Interchange circuit signalling mapping the reference is the section 2.2 of the Rec GSM 07.02, and the V.23 interchange circuits mapping shall be considered. m 3404583 0070251 20b W GSM 03.43 - version 3.0.1

26、 - page 8 5.2. ?Fornt - Services The reference for non-transparent character oriented protocol is the GSM 07.02. The application of a specialized layer 2 non-transparent protocol is for further study. 5.3. +,- Regarding to the call establishment signalling mapping (see GSM 07.02 par 2.3), the manual

27、 call operation utilizing both unrestricted digital capability and alternate Speech/Data or Speech followed by Data is utilized for the configurations “b“ and “c“ reported in Fig. 03.43/4. For the other configurations also the “autocalling“ call operation can be utilized (see GSM 07.02 par 2.3). The

28、 “autoanswering“ call operation is not used for Videotex service . 6. PSW The key characteristics of the networks concerned are definited in section 6 of GSM 09.07. In the case of Videotex service only mobile originated network interworking shall be considered (section 9.2.1 of GSM 09.07). The selec

29、tion of the interworking function based on V.23 type modem is provided on the basis of the information contained in the SET-UP message sent by the mobile terminal (see Annex). 6.1. -t Smxifie SupgnrfL The reference for this item is the section 9.2.3 of GSM 09.07. 6.2. e - The reference for non-trans

30、parent character oriented protocol is the GSM 07.02. The application of a specialized layer 2 non-transparent protocol for profile 1 is for further study. 7. * In this case it is assumed that the Videotex service is transported by means of the 3.lkHz audio bearer service: the reference is the sectio

31、n 10.2 of GSM 09.07 3404583 0070252 142 GSM 03.43 - version 3.0.1 - page 9 8. Some practical solutions are considered according to different scenarios: *I 8.1. No additional functions are required by terminals and Videotex centre, if the access is provided on the basis of dialling information; this

32、implies the use of an international PSTN call when the user is in a “foreign“ PLMN. The roaming subscriber must be aware of the compatibility between the protocol characteristics of his terminal and those of the Videotex access centre that he has addressed. The roaming user needs to be registered in

33、 the public Videotex service of any country in which he intends to have Videotex access; in order to overcome the protocol problems of different Videotex services, the roaming user may have a multi-profile terminal or the “local“ center may provide a multi standard access . More complex scenarios ca

34、n be investigated when an integration among the various national Videotex centres will be possible. 9. Some additional functions can be provided such as: The GSM PLMN network, on the basis of the HLC information element included in the Set-up message or of the terminal characteristics, can provide a

35、 direct call to the local videotex centre. 9.2. wects This service is mobile originated and therefore only charging aspects related to the outgoing service will be covered. The usage charges are time dependent both for PLMN and for PSTN/ISDN connection to the Videotex center. The particular charging

36、 aspects related to the Videotex information are outside the scope of this recommendation. For PSPDN access to a VTEX Centre additional charges may be levied (see GSM 09.05). Special charging method could be defined for access to local VTEX centre via a direct call. = 3YOY583 0070253 089 GSM 03.43 -

37、 version 3.0.1 - page 10 - Configuration User Rate Modem Type Synch/Asynch ANNEX The Bearer Capability information element is structured as shown in Fig. 10,53/GSM 04.08; the coding of the BC elements requested by the VTEX service is reported in the following table 1. Intermediate Rate Information T

38、ransfer Capability Structure Radio Channel requirements I Connection Element Number of Data Bits Parity Duplex Mode User information Layer 2 protocol Rate Adaption Signalling access protocol Circuit 4 kbit/s Unrestricted digital, Speech followed by unrestricted digital inform.,3.1 kHz Ex PLMN Unstru

39、ctured Demand Point to point 1200/75 (The 75 is in the direction MS to Network) V.23 Asynchronous Full rate, Half rate, Dual rate/half, Dual rate/full Transparent, non-transparent 1, 2 7 Odd, Even Full duplex Videotex profile 1, IA5, videotex profile 3 I Table 1: Bearer Capability Elements = 3404583

40、 00702.54 TI5 GSM 03.43 - version 3.0.1 - page 11 High layer characteristics identification The High Layer Compatibility (HLC) information element is structured as shown in fig 10.16/GSM 04.08. The following Table 2 contains the coding of the HLC elements requested by VTEX service. Document application profile for videotex interworking between gateways (T.504) Table 2: HLC Elements