4.3.4 Originating side – completion of call setup

23.1723GPPRelease 17Stage 2Technical realization of Circuit Switched (CS) multimedia service UDI/RDI fallback and service modificationTS

The originating MSC receives the Selected Codec and the list of available codecs, and, depending on the active mode, shall do the following:

The call was set up with a multimedia BC-IE first:

– if the Selected Codec is the 3G-324.M codec, no In-Call Modification procedure is necessary (see figure 4.23). If no speech codecs are included in the list of available codecs, all In-Call Modification procedures initiated by the UE using the speech BC-IE shall be rejected with a MODIFY REJECT message;

– if the Selected Codec is a speech codec, an In-Call Modification procedure to change to speech mode shall take place (see figure 4.24). If the 3G-324.M codec is not included in the list of available codecs, all In-Call Modification procedures initiated by the UE using the multimedia BC-IE shall be rejected with a MODIFY REJECT message.

The call was set up with a speech BC-IE first:

– if the Selected Codec is the 3G-324.M codec, an In-Call Modification procedure to change to multimedia mode shall take place (see figure 4.25). If no speech codecs are included in the list of available codecs, all In-Call Modification procedures initiated by the UE using the speech BC-IE shall be rejected with a MODIFY REJECT message;

– if the Selected Codec is a speech codec, no In-Call Modification procedure is necessary (see figure 4.26). If the 3G-324.M codec is not included in the list of available codecs, all In-Call Modification procedures initiated by the UE using the multimedia BC-IE shall be rejected with a MODIFY REJECT message.

NOTE 1: Speech codecs (x, y, z) may or may not be present. If they are not present, subsequent MODIFY requests from the UE are rejected.

NOTE 2: The 3G-324.M2 codec may be included in the list of available codecs after the 3G-324.M codec. This is not depicted in the figure.

Figure 4.23: Multimedia preferred, selected

NOTE 1: The multimedia codec (mm) may or may not be present. If it is not present, subsequent MODIFY requests from the UE are rejected.

NOTE 2: see clause 4.2.3 for the In-Call Modification signalling.

NOTE 3: The 3G-324.M2 codec may be included in the list of available codecs after the 3G-324.M codec. This is not depicted in the figure.

Figure 4.24: Multimedia preferred, speech selected

NOTE 1: Speech codecs (x, y, z) may or may not be present. If they are not present, subsequent MODIFY requests from the UE are rejected.

NOTE 2: see clause 4.2.3 for the In-Call Modification signalling.

NOTE 3: The 3G-324.M2 codec may be included in the list of available codecs after the 3G-324.M codec. This is not depicted in the figure.

Figure 4.25: Speech preferred, multimedia selected

NOTE 1: The multimedia codec (mm) may or may not be present. If it is not present, subsequent MODIFY requests from the UE are rejected.

NOTE 2: The 3G-324.M2 codec may be included in the list of available codecs after the 3G-324.M codec. This is not depicted in the figure.

Figure 4.26: Speech preferred, selected