Handover%20scenarios%20and%20requirements

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Handover scenarios and requirements
Cheng Hong, Tan Pek Yew (Panasonic) IEEE802.21 1
2th May 2004
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Network relationships example from 3GPP
State Description WLAN Coverage 3GPP PLMN Coverage
1 Switch on No coverage No coverage
2 Single network WLAN1 coverage Coverage only available from WLAN1(s) No coverage
3 Overlapping 3GPP WLAN coverage Single network coverage Home network coverage
4 Single network 3GPP-H coverage (HPLMN) No coverage Home network coverage
5 Multiple networks 3GPP coverage No coverage Coverage from home network and other operator(s)
6 Network(s) 3GPP-V coverage (VPLMN) No coverage Coverage from visited network(s) only
7 Overlapping 3GPP WLAN coverage Coverage only available from WLAN2(s) Coverage from visited network only
8 Multiple 3GPP Multiple WLANs WLAN1(s) WLAN2(s) (NOTE 1) Coverage from Home and Visited Networks
9 Multiple WLAN coverage Coverage available from WLAN1(s) WLAN2(s) No coverage
10 Single WLAN2 network coverage Coverage only available from WLAN2(s) No coverage
11 Multiple WLAN coverage Coverage available from WLAN1 WLAN3 No coverage
12 WLAN(s) coverage not interworked Coverage only available from WLAN3(s) No coverage
NOTE 1 May also include WLAN 3 (Not Illustrated) NOTE 1 May also include WLAN 3 (Not Illustrated) NOTE 1 May also include WLAN 3 (Not Illustrated) NOTE 1 May also include WLAN 3 (Not Illustrated)
Assumptions WLAN1(s) interworked with 3GPP-H
(HPLMN) WLAN2(s) interworked with
3GPP-V(VPLMN) WLAN3(s) not interworked.
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Handover scenarios
Handover Case I handover to a directly
connected network
Handover Case II Handover to network indirectly
connected
No point to study cases where the two network
are not connected, since the MT anyway would not
have access to the old session in the new
network
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Relationship to home network
Handover Case I Handover from a foreign network
to another foreign network
Relationship Case III handover from foreign
network to a foreign network Indirectly connected
to the home network
all cases need to be supported The difference
lies in the network discover/handover decision,
and access control, enforcement part
Relationship Case II handover from Home to a
foreign network
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Handover aims at (scope)

• Mainly on Dual/multi-mode terminal
• Single mode is just an extreme case, and should
  be covered by the solution.
• Seamless handover
• Simultaneous connectivity / multi-homing needs to
  be addressed
• Session needs to be continuous, otherwise, no
  different than cases without .21 (not break-
  stop- make)
• Support more than generic IP connectivity
• Where is the limit? How fast is sufficient.
  Requirements come from the services to be
  supported
• Handover should support services provided in a
  specific network, e.g. corporate VPN access, 3G
  services (IMS) access, etc.
• Delay/loss sensitive applications, e.g. VoIP,
  streaming, etc should be supported

6
Handover steps

• Discovery of new network/decision on handover
• Trigger information/network discovery information
  would be used in decision making
• In certain case, the decision making is absent,
  e.g. forced break, lost connection, etc
• .21 triggers, network discovery solutions is
  suitable here.
• Access control of the new network
• Security schemes to be carried out, e.g. 11i, 1x,
  etc
• Depends on individual technology, needs to be
  solved in each WG
• Most work has already been carried
  out/standardized in individual WG.
• Data path establishment over new network
• Requires policy and QoS enforcement, e.g.
  handover from 802.3 to 802.11 may mean QoS change
• Different comes from the network operators and
  technologies
• E.g. layer 2/3 tunnel, VPN, etc needs to be
  carried out
• .21 could work on standard way of enforcement
  control, QoS mapping control, etc
• Detail implementation still needs to be done in
  individual WG, e.g. .11 and .3 has different QoS
  schemes
• Data Session transition (from old interface to
  new interface)
• Actual data being sent over the new path
• .21 could provide trigger for the upper layer
  transition/decision, etc

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Handover requirements

• Security
• It shall not compromise security of a network
  when a terminal handover from a network of lower
  security level
• Security schemes in individual access technology
  should be reused (decided by the PAR)
• Enforcement of policy
• It shall be possible to enforce policy regarding
  the service access by the MT
• It shall be possible to apply consistent policy
  across all networks the MT handover to according
  to its subscription at home network
• QoS
• It shall be possible to provide consistent QoS
  support in the handover
• It shall be possible to map and enforce QoS
  requirements according to individual access
  technology
• The QoS provided shall comply with MTs
  subscription at home network

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Motion

• Move to adapt contents in slide 2 to 4 into a
  handover scenarios section
• Move to incorporate contents in slide 5 into a
  handover scope section of the Technical
  Requirements draft
• Move to incorporate contents in slide 6 into the
  overview section of the Technical Requirements
  draft
• Move to incorporate contents in slide 7 into a
  requirement section of the Technical Requirements
  draft