The parameters to be indicated, and negotiated, if applicable, during the call set-up shall include:
GERAN Channel coding(s) acceptable (for the call);
maximum number of GERAN TCH/F (that the mobile user can accept);
wanted AIUR (desired rate that the mobile user wants the network to allocate). The wanted AIUR is applicable to NT services only;
indication if the user initiated modification is required, and if so, the network resource needs;
channel coding asymmetry indication.
Some of the parameters are only utilised by GERAN. When UTRAN radio access bearer is allocated the values are ignored.
The GERAN channel coding(s) acceptable shall be indicated by the mobile at call set-up and is not negotiable. It indicates the GERAN channel coding(s) that may be chosen by the network for the call.
The maximum number of GERAN TCH/F shall be indicated at call set-up. It enables the mobile user to limit the number of GERAN TCH/F used and thus to control an essential parameter for charging. It sets the upper limit of number of TCH/F that the network may allocate to the mobile.
The wanted AIUR (applicable to NT services only) indicates the AIUR that the mobile user wants and which the network shall try to reach but which it is not allowed to exceed. The exception where the network is allowed to exceed the wanted AIUR is when the network can achieve the GERAN AIUR with a lower number of TCH/F, e.g. wanted GERAN AIUR indicated by the mobile is 14,4 kbit/s, GERAN channel codings acceptable are both TCH/F9.6 and TCH/F4.8 and maximum number of TCH/F are 3, then the network shall choose 2 x 9,6 over 3 x 4,8 if a channel coding of TCH/F9.6 is available on two TCH/F.
If the user wishes to make use of the user initiated modification procedure, this shall be indicated at the call set-up.
It shall be possible to reserve a different FNUR than the AIUR.
Channel coding asymmetry indication is only applicable to NT calls where the user has indicated acceptance for channel coding(s) based on enhanced modulation. In this case the user may indicate preference for channel coding symmetry, downlink biased channel coding asymmetry, or uplink biased channel coding asymmetry. The channel coding asymmetry indication is only applicable in direction UE to network.
The ME or the network may propose to modify the FNUR. The calling entity may accept or release the call. Autobauding is not allowed.
The AIUR is always equal to the FNUR.
Fax Group 3 can make use of HSCSD.
The GERAN channel coding selected must be one of the channel coding(s) indicated in the channel coding(s) acceptable parameter, the number of TCH/F selected shall not exceed the maximum number of TCH/F parameter, and the combination of the two shall result in an AIUR that is equal to the FNUR.
The ME or the network may propose to modify the FNUR. The calling entity may accept or release the call. Autobauding is allowed.
The wanted AIUR is indicated by the mobile at call set-up.
For transparent calls the radio resource parameters must remain within limits that allow the transparent call to maintain it is characteristics of fixed end to end throughput and delay. This means that in GERAN the channel coding and the number of TCH/F used may change during the call as long as a channel coding indicated in the channel coding(s) acceptable parameter is used, the maximum number of TCH/F is not exceeded and the AIUR is kept constant.
For NT calls the network may modify the number of TCH/F and the channel coding used at GERAN and thus also the AIUR during the call as long as the maximum number of TCH/F, and the channel coding(s) acceptable are all respected. The network shall try to reach the wanted GERAN AIUR indicated, as long as the resource situation allows it.
The in-call modification feature shall be supported in case of alternate services.