Cells may be grouped into specific localised service areas. Each localised service area is identified by a localised service area identity (LSA ID). No restrictions are placed on what cells may be grouped into a given localised service area.
The LSA ID can either be a PLMN significant number or a universal identity. This shall be known both in the networks and in the SIM.
The LSA ID consists of 24 bits, numbered from 0 to 23, with bit 0 being the LSB. Bit 0 indicates whether the LSA is a PLMN significant number or a universal LSA. If the bit is set to 0 the LSA is a PLMN significant number; if it is set to 1 it is a universal LSA.
The LSA ID shall be composed as shown in Figure 19