5.2.4 User initiated service level up- and downgrading (A/Gb mode)

23.0343GPPHigh Speed Circuit Switched Data (HSCSD)Release 17Stage 2TS

Figure 9 depicts the procedures for a successful user initiated service level up- and downgrading for on‑going HSCSD call in A/Gb mode.

During a HSCSD call the user may request, if so indicated in the call setup, the network to change the current maximum number of traffic channels and air interface user rate parameters and/or channel coding asymmetry preference. This is done by using the CC User initiated service level up- and downgrading procedure.

If network allows the modification, the resulting new parameters are forwarded to BSC and the radio interface resources may be adjusted accordingly. The resource upgrading or downgrading is done separately from the change in HSCSD parameters. However, if a contradiction between the new parameters and the used air interface resources exists, the resource downgrading may be needed before the network acknowledges the new parameters.

The user initiated service level up- and downgrading is applicable in non-transparent mode connections, only.

Figure 9: User initiated service level up- and downgrading in A/Gb mode