EU Project BRAIN Handover in the IP-based Radio Access Network Arndt Kadelka Aachen University of Technology, ComNets, Germany

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EU Project BRAINHandover in the IP-based Radio
Access NetworkArndt Kadelka Aachen University
of Technology, ComNets, Germany

• Mobility Concept investigated in European BRAIN
  Project
• Serving Global and Local IP Mobility
• Performance of HiperLAN/2 Handover Procedures
• Integration of HiperLAN/2 Mobility and Local IP
  Mobility

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BRAIN System Concept using HiperLAN/2-based Access
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Serving Local and Global Mobility

• Hierarchical Mobility
• Mobility across Wireless Access Networks served
  by rather slow Mobile IP
• Mobility within Wireless Access Network served by
  fast protocols, e.g., Cellular IP, HAWAII

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Local Handover within Access Network Cellular IP

• Route update by Uplink IP packets sent hop-by-hop
  to Gateway Router

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HiperLAN/2-based Radio Access

• Operates in the license exempt spectrum in5-6
  GHz band
• Radio cells up to 200 m
• 25 Mbit/s typical data rate

• Radio access can be adapted to various
  networksBRAIN IP Conv. Layer

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Actions to Perform a handover

• In H/2 fast handover decision and execution is
  performed by the MTs
• Scanning for alternative channel, i.e., served by
  different APT
• MT indicates absence to serving AP, AP stops data
  transmission
• MT performs measurements on alternative
  channel(s)
• MT may return to serving AP or perform a handover
• Handover decision
• MT decides to perform a handover based on RSSI
  and PER measurements
• Hysteresis to avoid ping-pong-effects
• Handover execution
• MT may indicate handover intention to serving AP
• MT initiates handover by Handover_Request to
  target APT, i.e, forward handover
• Re-establishment of link layer communication

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Scanning Period
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Packet Transmission Delay owing to Scanning

• Downlink Transmission

Uplink Transmission
Amount of data effected by scanning
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Handover within H/2 Radio Access Network

• Radio HO performed within DLC
• IP layer not involved
• Inter-Subnet Network Handover involves also IP
  layer
• Route update of IP routing tables

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Radio Handover Execution
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Serving Local Mobility with H/2

• Changing point of attachment to the network
• Re-establishment of link layer communication via
  the air interface
• Re-registration to the IP network
• Authentication
• Maintaining on-going DLC connections
• Integration with IP mobility via IP CL

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Slow Network Handover Procedure

• Interworking with Cellular IP
• IP CL triggers route update packet
• Loss of IP packets received at APold before route
  update execution

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Analysis of Slow Network Handover
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Packet Loss during Slow Network Handover
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Fast Network Handover with Backbone Signaling

• Information about on-going DLC connections
  retrieved via backbone
• Packets routed to APold are tunneled to APnew
• DLC address of APold is indicated during
  HO_Association
• AP has to maintain address mapping table
• APold DLC ? IP address

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Fast Network Handover Procedure
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Analysis of Fast Network Handover
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Making use of Slow and Fast Network Handover

• To make best use of Fast Network Handover
  procedure IP address of old AP must be known
• Mapping table may be set up
• manually, by operation and maintenance procedures
• administration effort
• not flexible
• dynamically, by following procedure
• AP selects handover procedure to be executed,
  i.e., Slow or Fast Network Handover
• MT performing 1st Handover from APold to Apnew
  carries out Slow Network Handover and provides
  DLC address (during HO_Association) and IP
  address of Apold (via Info_Transfer)
• Stores DLC/IP-address mapping
• Subsequent handovers from this APold are
  performed according Fast Handover procedure

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Conclusion

• H/2 defines handover procedures to serve local
  mobility
• For H/2 mobility integration with IP local
  mobility interworking functions are investigated
  and defined for the new IP CL
• To perform network handover involving the IP
  network almost as fast as radio handover address
  mapping table has to be maintained in IPCL
• Procedure defined to set up the mapping table
  dynamically
• Work will be continued in follow-up project MIND
• Specification of IPCL and contribution to
  ETSI/BRAN
• Mobility integration with UMTS (Vertical Handover)