Specifications

Functions
Dispatch Call Processing
August 08, 2000 68P81095E55-E 4-3
Dispatch Location Area
A Dispatch Location Area (DLA) is logical area that consists of one or more EBTS
sites. Each mobile on the iDEN system has a location area identifier (LAI).
The DLA on a single DAP
The interconnect and dispatch location areas may be different. A Dispatch Location
Area is generally more specific (services fewer cells) than an Interconnect Location
Area.
Cell
A site has a RF propagation pattern that will define the effective size of a cell. An
EBTS may be either omni-directional or sectored. A user MS is located by radio link
integrity between 1 or more cells. How the MS is located between sites is discussed
in greater detail in Appendix D, Handover.
Functions
Dispatch Only Service
Because dispatch calls exist entirely within the iDEN system, the services,
configuration and administration of individual MSs on the system can be tightly
controlled. If desired, a MS on the network may be excluded from using the PSTN
networks. Conversely, a MS may be restricted from making dispatch calls. Both of
these options are defined by service provisioning in the D-HLR and HLR.
General
Figure 4-3 represents a simplified diagram of the iDEN system elements involved in
Dispatch services. The MS sends, receives voice and displays data. The EBTS
converts the radio link to the land network link and discriminates between Dispatch,
Packet Data and Interconnect calls. The MPS routes dispatch call voice packets and
packet data packets. The DAP determines service availability and location
information. The APD duplicates voice packet that need to be sent to multiple MSs
in group calling.
Figure 4-3 Simplified Dispatch Diagram
The control and monitoring steps to complete a dispatch call are internal to the iDEN
system. Aside from dialing, sending and receiving, the steps to complete the call are
user transparent. There three major steps in a typical dispatch call:
MPS
(packet
routing )
DAC
(transport
facilities))
APD
(multi-packet
source)
DAP
(Services &
authentication
)
ETBS
circuit
breakers
iSC
ACG
iMU
Talk
Listen
half-duplex
T. N. French
T. N. French