Integrating UMTS and Mobile Ad Hoc Networks

1. Integrating UMTS and Mobile Ad Hoc Networks MASc. Student: Jade Wu Computer Networks, Department of Electrical and Computer Engineering, Ryerson University Supervisor: Dr. Muhammad Jaseemuddin Sep 21, 2005

2. Presentation Contents • Background • Design Details • Simulation & Results • Conclusion • Q&A

3. Wireless Communication Systems

4. Motivation UMTS Network Wide area coverage, but low data rate Speed: hundreds kbps Email (PS) Phone call (CS) Local area coverage, high data rate Speed: ~ 54 Mbps Hot Spot Coffee Shop User moves to a hot spot. Can we use this high-speed connection for PS services? Different ISPs? Different interfaces?

5. Objective • Integrating UMTS and ad hoc network • Two interfaces • UMTS interface: always on • 802.11 interface: on when MN detects 802.11 beacons • Integration point is located in UMTS CN. (operated by the same ISP) • Inter-system handover procedures occur when MN moves in or out of 802.11 local area. • 802.11 ad hoc mode enhances flexibility (on-demand routing and multi-hop features) UMTS Connection 802.11 Connection 802.11 Beacon

6. Presentation Contents • Background • Design Details • Simulation & Results • Conclusion • Q&A

7. Key Approaches Integration point: GGSN Apply SGSN signaling for communication between UMTS CN and ad hoc netowrk Inter-SGSN handover GTP tunneling Apply MIP signaling for ad hoc mobility management Gateway discovery Route discovery Overview

8. Signaling between UMTS and Ad hoc networks • Why not IP Signaling? • Full MIP structure: HA (any GSN) FA (Gateway)+ MN • Modifying GSNs is costly and risky. No official standard for implementing MIP on GSNs. • SGSN Signaling • Ad hoc gateway acts as SGSN. • GGSN is the integration point. • Apply inter-SGSN handover signaling between new SGSN, old SGSN and GGSN. (standard by 3GPP) • Use GTP tunneling between GGSN and ad hoc gateway • Maintain 3GPP standard in UMTS CN with some minor modifications • Modifying ad hoc gateways is less expensive.

9. Ad Hoc Mobility Management • MIP signaling is used for ad hoc mobility management. • Gateway acts as a FA. • All the mobile nodes must register with the gateway. • Registration procedure is simplified. No home registration. • Gateway Discovery • Receive ad hoc beacons from neighbours • Send out Gateway Query (Route Request for “All Mobility Agents”) • Receive Gateway Reply from the neighbour who knows gateway or gateway itself • Send Registration Request to the gateway • After Registration Reply is received, Mobile IP installs a default route to the gateway. • Receiving a Router Advertisement directly triggers registration process.

10. Ad Hoc Mobility Management • Ad hoc forwarding is modified. • Route Discovery: • Network ID: Carrying a different network ID means the destination must be located in the Internet. • Routing Table: Host route found means the destination is in ad hoc network. • Destination is unknown: Forward the packet to the gateway. Gateway determines whether or not this destination is in ad hoc network. • If so, gateway sends back error message to inform the sender to perform ad hoc route discovery. • If not , gateway tunnels the packet to GGSN.

11. Inter-System Handovers: UMTS-MANET Handover • When MN moves in an area where it receives ad hoc beacons from other ad hoc nodes • Perform gateway discovery in ad hoc network • Registration message triggers inter-system handover • Inter-SGSN handover between new SGSN (ad hoc gateway) and old SGSN (SGSN) • Buffering is enabled on SGSNs. • Receiving a Router Advertisement directly triggers the registration process.

12. Inter-System Handovers:MANET-UMTS Handover • When MN moves out of ad hoc network • Missing beacons causes registration entry to expire and triggers inter-system handover • Perform inter-SGSN handover procedure between new SGSN(SGSN) and old SGSN (ad hoc gateway)

13. Addressing & Tunneling

14. Presentation Contents • Background • Design Details • Simulation & Results • Conclusion • Q&A

15. Simulation Properties • Simulation tool: OPNET 10.5 • Simulation area: 3km x 3km • Simulation duration: 3,600 secs (1 hour) • Ad hoc node transmission range: 200 meters • No. of ad hoc nodes in MANET: 0, 2, 4, 6, 8, 10 • Traffic: • CBR: • Packet size: 128 bytes • Packet arrival rate: 200, 400, 600, 800 packets/ sec • FTP: • File size: 30000, 85000, 200000 bytes • Inter-request time: 30 secs

16. Simulation Timeline and Trajectory Attach UMTS Power-up MANET-UMTS Handover UMTS-MANET Handover Registration Simulation Timeline (minute) 0 10 11 41 42 60

17. ResultsUMTS-MANET Handover Time where

18. ResultsMANET-UMTS Handover Time where d1 is the transmission delay between SGSN and MN

19. ResultsThroughput (file size = 30,000 bytes) Max: 48,000 Average data rate: 8kbps

20. ResultsThroughput (file size = 85,000 bytes) 2.8 times Average data rate: 22.6kbps

21. ResultsThroughput (file size = 200,000 bytes) Buffer/Retransmission 6.8 times Average data rate: 53.3 kbps > Max. bit rate 48kbps

22. ResultsPacket Loss Packets start to be dropped when buffer is overflow during handovers. Default buffer size = 8172 bytes.

23. Throughput (file size= 85,000) 2 mobile nodes move randomly.

24. Throughput (file size= 85,000) 5 mobile nodes move randomly.

25. Presentation Contents • Background • Design Details • Simulation & Results • Conclusion • Q&A

26. Conclusion • We assume that a mobile node is equipped with two interfaces – a UMTS interface and a MANET interface. • We consider MANET is connected to UMTS CN and integrated at GGSN. • We developed vertical handover scheme for a mobile node to move from UMTS to MANET and vice versa. • We addressed the issue of signaling and Quality of Service during the intersystem handover.

27. Conclusion • We developed a simulation model of the integrated system in OPNET and evaluated the performance of the integrated system under variety of scenarios. • We analyzed the results and concluded as the following: • Tolerable handover delays • Significant throughput improvement • Low packet loss rate • The purpose of this research relates to the idea of improving data transmission rates and mobility in existing wide area network (UMTS). For mobile hosts in an ad hoc network to enjoy the connectivity from both networks and be able to switch some types of services (i.e. packet data service) which require higher capacity to the 802.11 links.

28. Presentation Contents • Objective • Design Details • Simulation & Results • Conclusion • Q&A

29. Thank you for attending my presentation. Questions?

30. THE END

31. Why release buffer before Update PDP Context? • Distribute the packet load to both side buffers. Both SGSNs are enabled with buffering. • This way keep the packets in order. Packets can be forwarded from the GGSN and old SGSN during handover.

32. Why early expiration? • Missing beacons means mobile node has left the ad hoc network. Therefore should perform handover immediately in order to minimize the packet loss or delay • Why not on gateway side? • Gateway will be informed by new SGSN with the SGSN context request during the handover. • Could be a period of time gateway still sees mobile node is reachable

33. How buffer works? • In SGSN the packets will be assigned N-PDU before being sent. • When SGSN received a SGSN Context Request, the SGSN stop assigning N-PDU for the downlink PDUs toward this mobile node. Unsigned PDU will be put into buffer.

34. How multicast address works for gateway discovery • Multicast address 224.0.0.11 is reserved for all mobility agents. Which mean Foreign Agents or Home agents for Mobile IP. • All the agent join this multicast group when it powers up in the network. • Every router acts as “multicast routers” which in charge of forwarding packets to the modes that related to this multicast address. • Multicast Routing enable • Multicast address list • Default Multicast address IPC_ALL_MOBILITY_AGENT_MULTICAST_ADDR • Interface Multicast enabled

35. What are ad hoc parameters • Hello interval:1 sec • Allow hello loss = 3 • Route Request rate 10 packets/sec • 0.1 sec / request • Retries: 5 • Local repair TTL: • The hop count# to the destination + Local add TTL (default 2)

36. WLAN interface parameters • Beacon interval 0.02sec • 11 Mbps • Max failed polls : 2 • PHY: Direct Sequence Spread Spectrum • Chip Sequence: barker code • XOR • Robustness against interference • MAC: DFWMAC PCF Point Coordination function F , DCF Distributed coordination function. • CTS/RTS CSMA/CA– no hidden node problem • INTER-FRAME SPACING AND BACKOFF TIME DFIS PIFS SIFS

37. Mobile IP parameters • Agent: • IRDP interval: 12-16 • Hold time: 3x 16 = 48 • Mobile nodes: • Registration retries: 4 • Registration interval: 4

38. What if the network partition? • Trick: do not send out ad hoc beacons unless it registers with foreign agent. • Even it received beacons, then the intersystem handover starts. However, the handover will fail due to no way to get to the gateway. Therefore it will still be using UMTS connections.

39. Gateway Discovery Repair

40. RFC or internet draft • RFC 2002 IP Mobility Support

41. How packets being forward by gateway to MNs? • MIP agent deliver packets to MNs through link-layer connectivity; however in ad hoc network, its multihop functionality need to use layer-3 identifier. • On gateway, the ad hoc routing protocol must be used instead of MIP forwarding.

42. Delay – 2 mobile nodes

43. Delay – 5 mobile nodes

44. Why MANET-UMTS Handover doesn’t count Routing Area Update Complete • It’s on SGSN side.!! • We measured on MN side. • Received Accepted and send out Complete is at almost the same time!

45. Ad hoc beacon • Each node maintains its own timer for Beacon interval • Back off random time algorithm • Medium busy • Only one beacon wins • Adjust beacon interval with other nodes when received beacons.