Section: Annex M (normative): Additional Requirements for backward compatibility with PCS 1900 for NA revision 0 ME
Content: This annex provides additional requirements to support network mechanisms for backward compatibility with PCS 1900 for NA revision 0 mobile equipments (applicable until July 1, 1998). PCS 1900 for NA revision 0 mobile equipments are defined to understand Mobile Network Codes made of up to 2 digits. However federal regulation mandates that a 3-digit MNC shall be allocated by each administration to network operators. Therefore each network operator is identified by a 3-digit Mobile Country Code and a 3-digit Mobile Network Code. An operator whose network code complies to the allocation principle specified for PCS 1900 for NA and wants to achieve for a transition period of time the backward compatibility with PCS 1900 for NA revision 0 mobile equipments shall apply the following: - The network shall send over the air interface the 3-digit Mobile Country Code and only the two most significant digits of the Mobile Network Code (the value of the "digit" sent instead of the 3rd digit is specified in 3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ] , subclause 10.5.1.3) (see note). When a PCS 1900 for NA (revision greater than 0) mobile equipment recognizes over the air the Mobile Country Code and the two most significant digits of the Mobile Network Code as being the HPLMN codes of the current IMSI, the mobile equipment shall take into account the value of the sixth IMSI digit read from the SIM/USIM. If this value matches to a value contained in the limited set of values for the least significant MNC digit assigned by the number administration bodies for PCS 1900 for NA then the following applies for the mobile equipment: - The value sent over the air instead of the 3rd MNC digit in the Location Area Identification (for coding see 3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ] , subclause 10.5.1.3) shall be interpreted as the value of the sixth IMSI digit read from the SIM/USIM. NOTE: It is still a network operator option to apply this requirement after July 1, 1998. However, in this case the following shall be considered: 1. Network selection considerations for overlapping networks: - Networks overlapping to the HPLMN, identified over the radio interface by an identical combination MCC1 MCC2 MCC3 MNC1 MNC2 (possible after July 1, 1998) may be selectable by PCS 1900 for NA mobile equipments revision 0 with the same priority as the HPLMN or presented to the user as the HPLMN. 2 Roaming considerations: - Roamers (SIM/USIM) from networks identified by an identical combination MCC1 MCC2 MCC3 MNC1 MNC2 (possible after July 1, 1998) when roaming into the operator network with PCS 1900 for NA mobile equipments revision 0, may cause these equipments to exhibit an unpredictable behaviour (e.g. looping in the HPLMN selection and registration procedures). - Home subscribers (SIM/USIM) roaming with PCS 1900 for NA mobile equipments revision 0 into networks identified by an identical combination MCC1 MCC2 MCC3 MNC1 MNC2 (possible after July 1, 1998), may consider being attached to the HPLMN.