Specifications

Interface Protocols
Operating Characteristics
3-22 68P81095E55-E August 08, 2000
Over the Air Parameters
MS Specific Parameters
The Radio Link contains mobile specific information this link operates according to
the RLP and Mobis protocols. Information about the MS that is transmitted includes:
• International Mobile Subscriber Identity (IMSI)
• Authentication Ki
• Temporary Mobile Station Identifier (TMSI)
International
Mobile Subscriber
Identity
The IMSI is a unique ID downloaded by the home system to the MS at initialization
that is specific to the MS The IMSI is commonly used as a billing number.
Authentication Ki The authentication key (Ki) is an identification of the algorithm the MS uses to create
signature numbers from random numbers.
Random Number The Random Number is part of the table used to authenticate the MS. This is
discussed in greater detail in Authentication previously in this chapter.
Signature Number The Signature Number is part of the table used to authenticate the MS. This is
discussed in greater detail in Authentication previously in this chapter.
Temporary Mobile
Station Identifier
The TMSI is a dynamic interconnect call processing, temporary ID that is used to
identify an MS while it is active. This parameter minimizes broadcasting the more
critical IMSI over the air. The IMSI is only transmitted when the MS initially roams
onto a system and registers. The system assigns a TMSI for the MS immediately that
is used to identify the MS until it roams out of the system. A new TMSI is assigned
to the MS each time it changes its location area with the VLR.
Dispatch Identifiers Several parameters are unique to dispatch call processing. The parameters used to
define access and services are:
•Urban ID
•Fleet ID
•Group ID
• Fleet Member ID
Urban ID The Urban Identifier applies to Software Release 8.0 and above. This ID is used to
define the home region (market) of the MS. Motorola assigns Urban ID to markets
and regions. Introduction of this ID allows an MS to roam outside the home region
and maintain a unique identifier that may be used to control service and permit inter-
region and cross-fleet dispatch calling (Horizontal Dispatch).
Fleet ID A Fleet ID is a number that is assigned by the service provider to distinguish major
subscribers (corporate or municipal entities). This defines the largest functional unit
of a dispatch call. Individual users are members of fleets. With SR 8.0 the fleet ID
may be re-used in different Urban ID areas (regions).