EU Project BRAIN
Handover in the IP-based Radio Access Network
Arndt 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
BRAIN System Concept using HiperLAN/2-based Access
BRAIN Radio Cells
BRAIN Radio Cells
HorizontalHandover
RNC
UTRANNode B
Node B
Roaming
VerticalHandover
SGSN
Other Networks
IP Backbone IP WAN
Supports:
- QoS for realtime services- Multicast- Handover
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
Local Handover within Access Network – Cellular IP
Route update by Uplink IP packets sent hop-by-hop to Gateway Router
Titel:CellIPHandover.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.
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
Actions to Perform a handover
In H/2 fast handover decision and execution is performed by the MTs:
1. 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
2. Handover decision• MT decides to perform a handover based on RSSI and PER measurements
• Hysteresis to avoid ping-pong-effects
3. 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
Scanning Period
Packet Transmission Delay owing to Scanning
Downlink Transmission Uplink Transmission
Amount of data effected by scanning:absentpresent
absent
tt
t
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
Titel:HL_2_Subnetze_quer.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.
Radio Handover Execution
Titel:NormalAndRadio_fertig2.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.
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
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
Titel:WorstCase_NW_HO_procd.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.
Analysis of Slow Network Handover
Packet Loss during Slow Network Handover
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
Fast Network Handover ProcedureTitel:BestCase_NW_HO_procd.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.
Analysis of Fast Network Handover
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
1. AP selects handover procedure to be executed, i.e., Slow or Fast Network Handover
2. 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)
3. Stores DLC/IP-address mapping
4. Subsequent handovers from this APold are performed according Fast Handover procedure
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 MINDSpecification of IPCL and contribution to ETSI/BRANMobility integration with UMTS (Vertical Handover)