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Integrating UMTS and Mobile Ad Hoc Networks

MASc. Student: Jade Wu

Computer Networks,Department of Electrical and Computer Engineering,

Ryerson UniversitySupervisor: Dr. Muhammad Jaseemuddin

Sep 21, 2005

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Presentation Contents

BackgroundDesign DetailsSimulation & ResultsConclusionQ&A

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Wireless Communication Systems

2G – 2.5G 3G 4G

GSM – GPRS UMTS

WLAN

Integrating the existing wireless technologies

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Motivation

Hot Spot Coffee Shop

Email (PS)

Phone call (CS)

ExternalPacket Switched

Network

ExternalCircuit Switched

Network

Packet-Switched

Circuit-Switched

Node B

RNC

SGSN GGSN

MSC/VLR GMSC

Can we use this high-speed connection for PS services?

Different ISPs?

Different interfaces?

User moves to a hot spot.

Wide area coverage, but low data rate

Speed: hundreds kbps

Local area coverage, high data rate

Speed: ~ 54 Mbps

802.11 Router

UMTS Network

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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

UMTS BS Ad hoc Gateway

CN

Internet

UMTS Interface

802.11 InterfaceOFF

ONUMTS Interface

802.11 Interface!!!

ON

802.11 Beacon

UMTS Interface

802.11 Interface

ON

ON

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Presentation Contents

BackgroundDesign DetailsSimulation & ResultsConclusionQ&A

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Overview

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

UMTS Core Network

Ad hoc network

UTRAN

Gateway

GGSNSGSN

RNC

Node B

Internet

SGSN Signaling

MIP Signaling

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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.

UMTS Core Network

Ad hoc network

UTRAN

Gateway/SGSN

GGSNSGSN

RNC

Node B

Internet

SGSN Signaling

UMTS Core Network

Ad hoc network

UTRAN

Gateway/FA

GGSN/HASGSN

RNC

Node B

Internet

MIP Signaling

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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.

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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.

Packet Ready to send. Determine Destination Add.

Same Network ID?

Routing Table Lookup.

Yes

Find Host Route?

Yes

Forward Packet via Next Hop

Forward Packet via Default Route

No

Perform Route Discovery in Ad

hoc Network

No

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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.

MNx MN Gateway GGSNSGSN

Ad hoc Beacon

Gateway Query (unicast RREQ to MNx asking for mutlicast address

"All Mobility Agents")

Gateway Reply (unicast RREP with Gateway info back to MN)

Registration Request

Registration Reply

RARP

RARP Reply with IP@ of MNx

Update PDP Context Request

Update PDP Context Response

SGSN Context Request

Forward Packets

SGSN Context Response

SGSN Context Ack

Gateway Discovery

Inter-SGSN Handover

MIP Signaling

Buffer

Buffer

MN Gateway GGSNSGSN

Router Advertisment

Registration Request

Registration Reply

Update PDP Context Request

Update PDP Context Response

SGSN Context Request

Forward Packets

SGSN Context Response

SGSN Context Ack

Gateway Discovery

Inter-SGSN Handover

MIP Signaling

Buffer

Buffer

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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)

MNx MN Gateway GGSNSGSN

Update PDP Context Request

Update PDP Context Response

SGSN Context Request

Forward Packets

SGSN Context Response

SGSN Context Ack

Inter-SGSN Handover

No Registration Request

No Ad hoc Beacon

Registration Entry Expires

Routing Area Update Request

Routing Area Update Accept

Routing Area Update Complete

Buffer

Buffer

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Addressing & Tunneling

UTRAN

UMTS Core Network

GGSN

RNC

SGSN

GTP Tunneling

GT

P T

unne

ling

MN

Addresses for Links to Internet:Assigned by ISP (public addresses)

Addresses in Core Network:Assigned by ISP

(private or public addresses)

Addresses for MNs in UTRAN: Assigned by GGSN(home addresses)

Packet Switched Network(Internet)

WLAN/Ad hoc

MN

Gateway

Addresses for MNs in Adhoc: Assigned by Mobile Agent

(care-of addresses)

GT

P T

unne

ling

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Presentation Contents

BackgroundDesign DetailsSimulation & ResultsConclusionQ&A

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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

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Simulation Timeline and Trajectory

UMTS CN

Ad hoc network

UTRAN

Gateway GGSN

SGSNRNCNode B

Internet

Power-up

Attach UMTS

0

Simulation Timeline (minute) 10 11 41 42 60

UMTS-MANET Handover

MANET-UMTS

Handover

Registration

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ResultsUMTS-MANET Handover Time

UMTS-MANET Handover Time

0

20

40

60

80

100

120

140

0 2 4 6 8 10 12

No. of MANET nodes

Han

do

ver

Tim

e (m

secs

)

SGSN Gateway

MN

GGSN

2 SGSN Context Requet

3 SGSN Context Response

4 SGSN Context Ack

5 U

pda

te PD

P

Co

ntext R

esponse

7 R

eqistration

Rep

ly

1 R

egistration

Req

uest

6 U

pda

te PD

P

Co

ntext R

eque

st

d2

d3

d1MN

321 232_ dddtimehandover

esrmedia_nodNo_of_inted1 where

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ResultsMANET-UMTS Handover Time

MANET-UMTS Handover Time

010

2030

4050

6070

8090

0 2 4 6 8 10 12

No. of MANET Nodes

Han

do

ver

Tim

e (m

secs

)

SGSN Gateway

MN

GGSN

2 SGSN Context Requet

3 SGSN Context Response

4 SGSN Context Ack

5 Update P

DP

C

ontext Response

7 Routing A

rea Update

Accepted

1 Routing A

rea Update

Request

6 Update P

DP

C

ontext Request

d2

d3d1

321 232_ dddtimehandover

where d1 is the transmission delay between SGSN and MN

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ResultsThroughput (file size = 30,000 bytes)

Max: 48,000

Average data rate: 8kbps

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ResultsThroughput (file size = 85,000 bytes)

2.8 times

Average data rate: 22.6kbps

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ResultsThroughput (file size = 200,000 bytes)

Buffer/Retransmission

6.8 times

Average data rate: 53.3 kbps > Max. bit rate 48kbps

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ResultsPacket Loss

200400

600800

10000 mobile nodes

2 mobile nodes

4 mobile node

6 mobile nodes

8 mobile nodes

10 mobile nodes

0

10

20

30

40

50

60

70

No

. of P

acket Dro

pp

ed

Packet Arrival Rate(packets/sec)

No. of MANET nodes

Total Packet Dropped During UMTS-MANET Handover

200400

600800

10000 mobile nodes

2 mobile nodes

4 mobile node

6 mobile nodes

8 mobile nodes

10 mobile nodes

0

10

20

30

40

50

60

70

80

No

. of P

acket Dro

pp

ed

Packet Arrival Rate (packets/sec)

No. of MANET nodes

Total Packet Dropped During MANET-UMTS Handover

Packets start to be dropped when buffer is overflow during handovers.

Default buffer size = 8172 bytes.

)(_)(__(sec)

)(___

sec packetbytespackets sizepacketratearrivalpacketmehandoverti

byteshandoverduringbyteoverflow

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

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

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Presentation Contents

BackgroundDesign DetailsSimulation & ResultsConclusionQ&A

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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.

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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.

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Presentation Contents

ObjectiveDesign DetailsSimulation & ResultsConclusionQ&A

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Thank you for attending my presentation.

Questions?

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THE END

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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.

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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

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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.

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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

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What are ad hoc parameters

Hello interval:1 secAllow hello loss = 3Route 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)

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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

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Mobile IP parameters

Agent: IRDP interval: 12-16 Hold time: 3x 16 = 48

Mobile nodes: Registration retries: 4 Registration interval: 4

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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.

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Gateway Discovery Repair3 beacon missing from neighbour A

neighbour A related to FA?

Delete this route from RT

Yes

Receive beacons from other nodes?

Yes

Local RepairPerform gateway discovery.

Send out gateway query

Delete this route from RT and send

out RERRs

No

Mark this registration entry invalid in FA list

Perform MANET-UMTS Handover

No

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RFC or internet draft

RFC 2002 IP Mobility Support

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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.

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Delay – 2 mobile nodes

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Delay – 5 mobile nodes

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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!

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Ad hoc beacon

Each node maintains its own timer for Beacon interval

Back off random time algorithmMedium busyOnly one beacon winsAdjust beacon interval with other nodes

when received beacons.