4 Network architecture

23.1463GPPRelease 17Technical realization of facsimile Group 3 non-transparentTS

4.1 Service definition

The fixed network facsimile group 3 service is an international telematic service for document transmission between two facsimile group 3 terminals.

The service specifications are comprised of two parts:

– the control procedures described in ITU-T Recommendation T.30;

– the document transmission coding described in ITU-T Recommendation T.4.

The UMTS facsimile group 3 Teleservice allows connections between facsimile group 3 terminals using:

– a UMTS PLMN as stand‑alone facility for mobile‑to‑mobile communication;

– a UMTS PLMN to have access to fixed networks PSTN and/or ISDN for mobile to/from fixed network communication.

For this Teleservice, the coding of the facsimile document is as per ITU-T Recommendation T.4 and the protocol as per ITU-T Recommendation T.30 both modified within the PLMN as detailed in the present document.

The interworking between different networks is based on ITU-T Recommendation X.300.

The particular features of this Teleservice are:

– it uses point‑to‑point communication;

– the information transfer mode is circuit, duplex, asynchronous;

– the information transfer capability is alternate speech/ facsimile group 3 or facsimile group 3 only;

– both mobile originated and mobile terminated calls are supported;

– different end‑to‑end message speeds as per ITU-T Recommendation T.30 may be used within the same connection to match the appropriate quality requirements;

– use of the standard asynchronous terminal adaptation function for non‑transparent network support (as per 3GPP TS 27.002) within the UE is envisaged.

4.2 Network architecture

The network architecture applicable to this Teleservice is shown in figure 1.

: ╔════════╗ :
: ║ ║ :
:─╢ PLMN ╟─:
: ║ ║ :
: ╚════════╝ :
v v : ╔════════╗ :
╔═════╗ ┌──────┐ │ │ ┌───────┐ ┌───────┐ : ║ ║ : ╔═════╗
║ FAX ╟─┤ MT ├─┘ └─┤ RAN ├─┤MSC/IWF├─:─╢ PSTN ╟─:─╢ FAX ║
╚═════╝ └──────┘ └───────┘ └───────┘ : ║ ║ : ╚═════╝
: ╚════════╝ :
: ╔════════╗ :
: ║ ║ :
:─╢ ISDN ╟─:
: ║ ║ :
: ╚════════╝ :

Figure 1: Network architecture

It shows the case of mobile to fixed network interworking. For mobile‑to‑mobile calls, there would effectively be a loop back within the PLMN using two IWFs.