7 Identities

03.563GPPCTS Architecture DescriptionGSM Cordless Telephony System (CTS), Phase 1Stage 2TS

7.1 Identification of the CTS-FP

7.1.1 IFPSI

A CTS specific identity is assigned to a CTS FP subscriber of a CTS service.

7.1.2 IFPEI

Each CTS-FP is assigned by the manufacturer a unique IFPEI number see GSM 03.03 [3].

The coding rules of the IFPEI and the rules for changing the IFPEI shall be equal to the rules defined for the IMEI in GSM 03.03 [3].

7.1.3 FPBI

The CTS-FP broadcasts (after CTS-FP initialisation has been performed) a beacon which carries information conveying the Fixed Part Beacon Identity which identifies the CTS-FP. The FPBI need not be unique due to the capacity of signalling on the beacon. The FPBI is defined in GSM 03.03 [3]. The use of the beacon and the FPBI related procedures are defined in [5].

7.2 Addressing parameters

7.2.1 Addressing the CTS-FP CTS-FP Fixed Network dialling number

This is the fixed network dialling number (PSTN/ISDN) to which the CTS-FP is connected. A single CTS-FP may have several fixed network dialling numbers. CTS FP name

It shall be possible to assign a subscriber-defined identifier to each CTS FP. The CTS FP name can e.g. be an icon or an alphanumeric text up to 10 characters.

7.2.2 Addressing the CTS-MS subscriber MSISDN

The MSISDN is the dialling number at which the CTS-MS can be reached in the cellular network. It may also be used for CTS applications.

In order to address a CTS-MS by its MSISDN, this number has to be known by the CTS-FP and the CTS-MS. The MSISDN may be submitted to the CTS-FP either:

  • from the CTS-HLR at CTS-MS enrolment; or
  • by means of user input; or
  • by the CTS-MS CTS-MS Subscriber Identity(CTS-MSI)

The CTS-MSI is an CTS-MS identity which has only local significance between a CTS-MS and CTS-FP pair, its purpose is to maintain the anonymity of the users of the CTS service as specified in [4].

The CTS-MSI is assigned and maintained by the CTS-FP during CTS-MS enrolment, and is reallocated by the CTS-FP during CTS attachment and as part of each Mobile originated and Mobile terminated signalling exchange. It is unique for each CTS-MS enrolled at the CTS-FP. The CTS-MSI allocation procedure and CTS-MSI reallocation procedure data flows are specified in [4].

In order to maintain anonymity of the subscriber the CTS-MSI shall be used in all signalling procedures by both CTS-MS and CTS-FP.

The protocols shall ensure that the CTS-FP can detect any CTS-MSI conflicts (e.g. duplicated CTS-MSI). In case of CTS-MSI conflicts, it is up to the CTS-FP to resolve the situation by the appropriate security checks (i.e. by obtaining the IMSI of the CTS-MS, performing local security procedures (see [4]) and verifying the enrolment rights).