A system-identity structure allows PCS phones to distinguish between public, private, semiprivate, and PBSs. This IS–136 feature facilitates the creation of private systems and allows control of phone behavior around a WOS, PBS, or residential service area. The IS–136 technology includes private-system identifiers for marking specific base stations as part of a private system, HCSs for defining cell preferences, and new registration features to complement private systems.

Operating Principle

• private system identities (PSIDs)—A PSID is assigned to a specific private system by the system operator to identify it to phones in the coverage area of the system. PSIDs are broadcast so that a phone can determine whether it has special services from a particular cell when reselecting a DCCH.

  PSIDs can be assigned on a sector-by-sector basis within a cell, which allows very small service areas to be defined. Alternatively, many cells, as well as systems, could broadcast the same PSID to create a geographically large virtual private system. Phones that recognize PSIDs notify the system and can activate location ID to inform users that they have entered the private system.

  A single DCCH can broadcast up to 16 PSIDs, allowing the support of up to 16 different private systems on one DCCH. This feature is useful in a technology park or campus where it would not be economical to support a DCCH for each small business requiring WOS features.

• residential system identities (RSIDs)—In a manner similar to a PSID, a RSID identifies a residential system within the public cellular and PCS coverage. RSIDs can be used to create residential-service areas or neighborhood residential systems by broadcasting an identifier that is recognized by phones as being at home and therefore receiving special services (for example, billing). A primary use of RSIDs is in the PBS, which allows a cellular or PCS phone to be used like a cordless phone in conjunction with a residential base station.

Location ID

All PCS phones display the name of the wireless carrier providing service. If a phone also has WOS coverage, the location ID feature can display a company name (as shown in Figure 11) or a system banner to inform subscribers that they have entered their private system. This can be particularly important when there is a billing or service difference that should be indicated to the subscriber. The identifying name or banner is removed from the display when the subscriber leaves the WOS coverage. A non-subscriber entering a WOS service area would continue to have only the wireless carrier name displayed.

Figure 11 shows some examples of location ID for private systems and the wireless carrier.

Figure 11. System Identities and Location ID