N k d RT A Network-Assisted Inter-RAT Handover Scheme Handover Scheme Sangheon Pack (Korea University) 25 August 2009 25 August 2009
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N k d R T A Network-Assisted Inter-RAT Handover SchemeHandover Scheme
Sangheon Pack (Korea University)25 August 200925 August 2009
Heterogeneous Wireless NetworksHeterogeneous Wireless NetworksBilling VHE
Signalling Gateway
WAP Accounting ISP
SIP Proxy Server
Internet
P
IP backbone
Satellite FES
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이미지를표시할 수없습니다 . 컴퓨…
Broadcast Networks(DVB-T, DMB)
GSM / GPRS
UMTS
G S
IP-based micro-mobility Wireless
LANs
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Case Study: 3G-WLAN VHO (1/2)Case Study: 3G-WLAN VHO (1/2)
NWLANLow cost, high data rate, small coverageDesigned for low terminal velocity (non-contiguous spots)Office, Stations, Department store, Subway etc.
3G Cellular NetworkHigh cost, medium data rate, large coverageEven a fast moving vehicle can use on-line gbrowser
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Case Study: 3G-WLAN VHO (2/2)Case Study: 3G-WLAN VHO (2/2)
3G WLANData rate < 2Mbps < 11MbpsRange 3-5 Km 50-60 mHandover Yes LimitedSecurity High Low (being improved)C Wid H Coverage Wide area
(continuous)Hot spots (non continuous)
Mobility High speed Stationary NomadicMobility High speed Stationary, NomadicService Voice and data Primarily data
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Related Works (1/2)Related Works (1/2)N k k di h d Numerous works on network discovery, handover decision/execution
[1] Wengui Zhang “Handover Decision Using Fuzzy MADM in [1] Wengui Zhang, Handover Decision Using Fuzzy MADM in Heterogeneous Networks,” in Proc. IEEE WCNC 2004.[2] A. Hasswa et al. “Generic Vertical Handoff Decision Function for Heterogeneous Wireless Networks ” in Proc IEEE WOCN 2005Heterogeneous Wireless Networks, in Proc. IEEE WOCN 2005.[3] R. Tawil, O. Salazar and G. Pujolle, “Vertical Handoff Decision Scheme Using MAMD for Wireless Networks,” in Proc. IEEE WCNC 20082008.[4] W. Ying et al., “Vertical Handover Decision in an Enhanced Media Independent Handover Framework,” in Proc. IEEE WCNC 2008.[5] E. Stevens et al., “An MDP-Based Vertical Handoff Decision Algorithm for Heterogeneous Wireless Networks,” IEEE Trans. Vehicular, March 2008.[6] F. Zhu and J. McNair, “Optimizations for Vertical Handoff Decision Algorithms,” in Proc. IEEE WCNC 2004.
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Related Works (2/2)Related Works (2/2)
H d d d d H Handover decision: depending on VHO criteriaChannel condition is a key criteria for VHO
Price Bandwidth Channel condition
Sojourn time
Power Security User preference
[1] O O O O O X X[1] O O O O O X X[2] O O O X O O O
[3,4] O O O X X X X[5,6] X O O X X X X
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MotivationMotivation
h l d bl b Channel scanning is indispensible to obtain channel conditions; However, channel
l d f l !scanning leads to significant latency!In WLANs, scanning latency is about 200-300
!msec!How to reduce channel scanning latency in VHO?
IEEE 802.21 MIH provides useful information via Information Server (IS)Exploit temporal and spatial locality in IS!
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MIH Services (1/3)MIH Services (1/3)
E ( d d d E )MIES (Media Independant Event Service)Link up/down, link parameters change, link going down, link event rollback
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MIH Services (2/3)MIH Services (2/3)
( d d d d )MICS (Media Independant Command Service)MIH Scan, MIH Configure
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MIH Services (3/3)MIH Services (3/3)
( d d d f MIIS (Media Independant Information Service)
Discover and obtain neighboring network information within a geographic region
h h k l- Communicate with neighboring network elements- Query/response mechanism: neighboring network
id d t MAC dd f names, providers and cost, MAC addresses of neighboring network elements, channel information, security QoS security, QoS, ...
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Spatial LocalitySpatial Locality
Information SServer
Collaborative channelchannel scanning
Me!A
11B
Temporal LocalityTemporal Locality
Information SServer
Collaborative channel scanning
Me!A at T B at T-Δ
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System Model (1/2)System Model (1/2)
DB h h d (E )DB Schema in enhanced IS (EIS)Extended channel state information (ECSI)
• ( )( ), , , , id t x y δ
Access point identification,Measurement time,
idt
( )Measurement location,Signal-to-noise ratio (SNR),
( ),x yδ
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System Model (2/2)System Model (2/2)
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Each MN should notify the ECSI to EIS
Estimating the SNR (1/2)Estimating the SNR (1/2)
Temporal LocalityTemporal Locality
Spatial Locality
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Estimating the SNR (2/2)Estimating the SNR (2/2)
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Exising IEEE 802 21 VHOExising IEEE 802.21 VHOMobile node IS
Mobile WiMAX PoAHSDPA PoA
Mobile node
Handover trigger
Neighbor list queryNeighbor list query
Neighbor list response ( HSDPA PoA, Mobile WiMAX PoA )
scanning
scanning late
ncy
Network selection Han
dove
r
Target list query (with the results of scanning)
Target list response ( Mobile WiMAX PoA > HSDPA PoA )
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Vertical handover to Mobile WiMAX PoAHandover to Mobile WiMAX PoA
Proposed IEEE 802 21 VHOProposed IEEE 802.21 VHO
( )( )ECSI id t δ( )( ), , , , ECSI id t x y δ
( )( ), , , , ECSI id t x y δ( )( ), , , , ECSI id t x y δ
( )( )( )0 0 0, , x y t
r lat
ency
Han
dove
Handover to Mobile WiMAX PoA
18Handover to other PoAs for handover failures
Simulation EnvironmentSimulation Environment
l h l d lWireless channel modelCOST-231 Hata model
Mobility modelyRandom way-point mobility model
Heterogeneous network modelHSDPA + Mobile WiMAX + WiFiHSDPA + Mobile WiMAX + WiFi
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Simulation Results (1/4)Simulation Results (1/4)
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Hit: PoA by the proposed scheme = PoA by full scanning procedure
Simulation Results (2/4)Simulation Results (2/4)
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Simulation Results (3/4)Simulation Results (3/4)
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There is optimal for minimizing VHO delayMR
Simulation Results (4/4) ( WiFi P A)Simulation Results (4/4) ( + WiFi PoA)
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Optimal is dependent on the smallest network coverage in heterogeneous networks
MR
ConclusionConclusion
Network assistance and collaboration are important mpin mobile Internet!
To achieve seamless inter-RAT handovermOptimization techniques are needed
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