Mobile Stations MS

Mobile Stations (A/Gb mode)

 An A/Gb mode MS operates in one of three modes of operation. The mode of operation depends on the network domains that the MS is attached to, i.e. only PS or both PS and CS domain, and upon the MS's capabilities to operate PS and CS domain services simultaneously.

-     Class‑A mode of operation: The MS is attached to both PS and CS domain, and the MS supports simultaneous operation of PS and CS domain services.

-     Class‑B mode of operation: The MS is attached to both PS and CS domain, but the MS can only operate one set of services, PS or CS services, at a time.

-     Class‑C mode of operation: The MS is exclusively attached to the PS domain.

Mobile Stations (Iu mode)

 An Iu mode MS operates in one of three modes of operation. However, these operation modes are different from the ones of an A/Gb mode MS due to the capabilities of an Iu mode RAN to multiplex CS and PS connections, due to paging co-ordination for PS services and CS services that are offered by the CN or the UTRAN/GERAN-Iu, etc. The different Iu mode MS operation modes are defined as follows:

-     CS/PS mode of operation: The MS is attached to both the PS domain and CS domain, and the MS is capable of simultaneously signallingwith the PS and CS core network domains. This mode of operation is comparable to the class‑A mode of operation defined for A/Gb mode. The ability to operate CS and PS services simultaneously depends on the MS capabilities (for example an A/Gb mode MS of class B, which can not operate simultaneously CS and PS services, may have the same limitations when changing to Iu mode and CS/PS mode of operation).

-     PS mode of operation: The MS is attached to the PS domain only and may only operate services of the PS domain. However, this does not prevent CS-like services to be offered over the PS domain (e.g. VoIP). This mode of operation is equivalent to the A/Gb mode GPRS class‑C mode of operation.

-     CS mode of operation: The MS is attached to the CS domain only and may only operate services of the CS domain. However, this does not prevent PS-like service to be offered over the CS domain. The CS mode of operation is outside the scope of this specification.