Specifications

Handover Operation
Handover
August 08, 2000 68P81095E55-E D-9
Handover Operation
Dispatch Calls
During dispatch calling, the reconnect and hosting cell procedures are used to
determine the EBTS the should host (serve) the call. The Host (serving) cell
selection process is used to re-select and re-connect between serving cell. The short
authentication setup time allows the FNE to redirect calls between cells dynamically.
The FNE involved in dispatch is the MPS and the DAP. The basic procedure is:
1) MS determines need and identifies potential neighbors
2) MS sends signal measurements to the FNE
3) DAP/D-VLR finds new host (EBTS) and re-assigns traffic to the EBTS
4) MS re-tunes to the new host (EBTS) channel
5) Channel changed to Traffic channel (TCH) and talk continues
Because Dispatch Calling does not have a lot of signalling and call setup
communication needs, dispatch does not technically handover. The process is a
constant process of selection, authentication, and re-selection.
Interconnect Calls
The Interconnect handover process from Host to candidate is based on an exchange
of information about the radio link quality across the radio link control channel(s).
The FNE involved are the MSC/BSC. The basic procedure (Figure D-5) is:
1) MS determines need and identifies potential neighbors
1) MS signals on associated control channel with measurements
2) FNE - EBTS finds new host and allocates it as Temporary Control Channel
3) FNE - EBTS sends handover and power setting on associated control channel
4) MS changes to assigned channel
5) MS uses the Random Access Procedure (RAP) to get timing information
6) Channel changed to Traffic channel (TCH) and talk continues
Figure D-5 Handover
Radio
Li nk b
Quality
b
host
s
a host
s
EBTS a EBTS b
Mobile or FNE
initiated
Direction of
travel
T. N. French
EBTS b
Frequency
Handover I D
(TCCH)
ID ACK
(TCCH)
Handover ACK (ACCH)
RAP
(TCCH)
timing
(TCCH)
Cell Info
(BCCH)
Traffi c (TCH) b Traffi c (TCH) bUnassigned (UCH) b
EBTS a
Frequency
Measurement
Report (ACCH)
New f r equency
(TCCH)
Handover Cmd
(ACCH)
Traffi c Channel a
(Act i ve voice)
ACCH (Associated Cont r ol Channel)
Unassigned (UCH) a
Radio
Li nk a
Quality