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White Paper M600
58 February 2006
General operational considerations
Mechanisms defined to support service continuity
between different radio systems or radio access
modes should effectively cope with a number of
coverage scenarios:
• Limited coverage in a “sea” of coverage pro-
vided by another radio system or radio access
mode.
• Selective operation at a geographical boundary,
with extensive UMTS Radio Access Network
coverage on one side, and extensive coverage
from another radio system on the other side.
• Geographically colocated areas of UMTS Radio
Access Network coverage and another radio
system.
Performance requirements
Temporary degradation of service caused by
handover
During intra-UMTS Radio Access Network
handover or handover from UMTS Radio Access
Network to GSM/GPRS, degradation of service
should be no greater than during intra-GSM/GPRS
handover. The duration of the discontinuity
experienced by packet switched and circuit
switched real time services should be shorter than
that in the handover of voice calls over GSM/
GPRS.
Requirements on multiple bearer services
handover from UMTS radio access network to
GSM/GPRS
Consideration must be given to services that may
involve multiple bearer services (and simultaneous
sessions). The mapping between UMTS Radio
Access Network bearer services and GSM/GPRS
bearer services depends on many factors such as
data rate, delay constraints, error rate etc. In the
event that certain UMTS Radio Access Network
bearer services cannot be handed over to GSM/
GPRS, the handover of some of the bearers to
maintain the service should not be precluded.
In the case where a user equipped with a dual
mode terminal is in UMTS Radio Access Network
coverage, and has multiple PDP contexts activated
(for instance to support multimedia), then it is
preferable to handover one PDP context, rather
than dropping all of them.
As a first priority only the PDP contexts which have
an associated QoS that can be supported by the
GSM/GPRS should be candidates for handover.
If there are still multiple PDP contexts as “handover
candidates”, then the operator should choose
which PDP is maintained. When roaming, the
serving network should make this decision. The
operator may choose to either:
• Drop all of the PDP contexts.
• Choose one based upon criteria such as dura-
tion, amount of traffic transferred, etc.
Handover in M600
This phone is compliant with the 3GPP R99
December 2002 release.
GSM to UMTS
The product supports circuit switched voice
handover from GSM to UMTS.
UMTS to GSM/GPRS
The product supports packet switched data
handover and circuit switched voice handover from
UMTS to GSM/GPRS.
Positioning
The basic cost efficient positioning method
available in 3G networks relies on measuring
round-trip time. In 3G it is called Cell-ID + TA
(Timing in Advance).
Time difference measurement, involving several
base stations, can be used to obtain a more
accurate position.