الرحمن الله الرحمن بسم الله بسمالرحيمالرحيم

Wireless Mesh Network Wireless Mesh Network (WMN)(WMN)

Izzeldin Shibeika – April,25 2005Izzeldin Shibeika – April,25 2005UNCC - ifshibei@uncc.eduUNCC - ifshibei@uncc.edu

I know of no more encouraging fact than the unquestionable ability of man to elevate his life by conscious endeavor .

Henry D. Thoreau

AgendaAgenda1.1. IntroductionIntroduction

2.2. Network ArchitectureNetwork Architecture

3.3. CharacteristicsCharacteristics

4.4. OSI modelOSI model

5.5. ApplicationsApplications

6.6. ChallengesChallenges

7.7. StandardsStandards

8.8. ConclusionConclusion

1.1. IntroductionIntroduction• Starting? Carnegie-melon university,2001Starting? Carnegie-melon university,2001• StandardStandard• AdvantagesAdvantages

– Self organizedSelf organized– Self configuredSelf configured– Easy maintenanceEasy maintenance– Reliability & scalability (no of nodes)Reliability & scalability (no of nodes)

• UsageUsage– Fire fightersFire fighters– Emergency personalEmergency personal– Wearable NTKsWearable NTKs

2. NTK Architecture2. NTK Architecture• Types of arch.Types of arch.

– Backbone WMN Backbone WMN – Client WMNClient WMN– Hybrid WMNHybrid WMN

• HardwareHardware– Mesh router – backbone Mesh router – backbone – Mesh client – stationary, mobileMesh client – stationary, mobile– GatewayGateway

• Routing/repeatingRouting/repeating• Multi-hop communicationMulti-hop communication

– Low powerLow power– Small rangeSmall range

• Other topologies communicationsOther topologies communications– 802.11, 15, 16802.11, 15, 16– Ad hoc, WPAN, EthernetAd hoc, WPAN, Ethernet

3. characteristics3. characteristics

• Mutlihop – LOS, NLOSMutlihop – LOS, NLOS

• Support of ad hoc Support of ad hoc – self forming with more design complexityself forming with more design complexity

• Multiple types of NTK accessMultiple types of NTK access

• Power consumption constraintsPower consumption constraints

WMN vs. Ad hocWMN vs. Ad hoc• IntegrationIntegration

• Wireless backbone/infrastructureWireless backbone/infrastructure

• End-user load decreased – power, costEnd-user load decreased – power, cost

• Multiple radios – configuration, usersMultiple radios – configuration, users

• Mobility of usersMobility of users

4. OSI model4. OSI model

Physical layerPhysical layer• Improve TX rate and physical layer Improve TX rate and physical layer

techniquestechniques– UWB – short distanceUWB – short distance

• Higher layer adaptation (MAC)Higher layer adaptation (MAC)

• Multiple-antenna systemsMultiple-antenna systems

MAC layerMAC layer• Mutlihop communications vs. classicalMutlihop communications vs. classical

– Depends on routing protocolsDepends on routing protocols

• Multipoint-to-multipoint – no Multipoint-to-multipoint – no centralizationcentralization

• Mobility effectMobility effect

• multiple access techniquesmultiple access techniques•TDMA – synchronizationTDMA – synchronization•CDMA - code controlCDMA - code control•CSMA/CACSMA/CA

NTK layerNTK layer

• Performance metricsPerformance metrics– No of hopsNo of hops– Link utilizationLink utilization– RTTRTT

• Load balancing – congestionLoad balancing – congestion

• Scalability – routing pathScalability – routing path

• Adaptive support for routers/clientsAdaptive support for routers/clients– Power consumptionPower consumption

Transport LayerTransport Layer• No protocol specifically for WMN until now No protocol specifically for WMN until now

!!!!• TCPTCP

– Congestion/non-congestion lossesCongestion/non-congestion losses– Acknowledgment.Acknowledgment.

• UDPUDP– Real time end-to-end delivery not guaranteedReal time end-to-end delivery not guaranteed

• Dependence on other layersDependence on other layers– MAC – asymmetryMAC – asymmetry– NTK - routingNTK - routing

5. Applications5. Applications

– 802.11 AP locations ??802.11 AP locations ??– AP connections – HubAP connections – Hub– Dead zonesDead zones

• Multiple mesh routersMultiple mesh routers

• Power levelPower level

• Mobile Ad hoc NTK, WSNMobile Ad hoc NTK, WSN

a) Home a) Home NetworksNetworks

b) Enterprise Networksb) Enterprise Networks

– Wired ConnectionsWired Connections– Redundancy – costRedundancy – cost– CongestionCongestion

• Public NTKsPublic NTKs

c) Transportation Systemsc) Transportation Systems

• High Speed Mobile Backhaul to High Speed Mobile Backhaul to InternetInternet

• Mobile mesh NTKsMobile mesh NTKs

d) Building Automationd) Building Automation• BAC net (Building automation & BAC net (Building automation &

control)control)– Elec. Devices powerElec. Devices power– LightLight– ElevatorsElevators– A/CA/C

• Connection and Wi Fi Connection and Wi Fi – costcost

6. Challenges6. Challenges• Radio Techniques Radio Techniques

– directional antennasdirectional antennas– Mutli-radio/multi channelMutli-radio/multi channel– MIMO - 802.11n high speed Wi FiMIMO - 802.11n high speed Wi Fi– dynamical control unitsdynamical control units

• QoSQoS– compatibility and inter-operabilitycompatibility and inter-operability– integrationintegration– end-to-end QoS constraintsend-to-end QoS constraints

•delay, throughput, packet loss ratio, ...delay, throughput, packet loss ratio, ...

• ScalabilityScalability– MultihopMultihop– size vs. performance, routing protocolsize vs. performance, routing protocol

• 802.11 share BW802.11 share BW

– multiple access techniquesmultiple access techniques• TDMA – synchronizationTDMA – synchronization

• CDMA - code controlCDMA - code control

• CSMA/CACSMA/CA

• security wirelesssecurity wireless– AAA – centralizationAAA – centralization– WLAN schemesWLAN schemes– speedspeed– Ad hoc schemesAd hoc schemes

• not practical for WMN, ad hoc is like a subsetnot practical for WMN, ad hoc is like a subset

7. Standards7. Standards

802.11802.11• 802.11s802.11s ESS (extended service set)ESS (extended service set)

– define MAC & PHY layersdefine MAC & PHY layers

• 802.11n - 1Gbps802.11n - 1Gbps• two modelstwo models

– Infrastructure, ESSInfrastructure, ESS– Clients, Layer 3 ad hocClients, Layer 3 ad hoc

• IBSS (independent basic SS) IBSS (independent basic SS) •flat IP – no distinction between AP & clientsflat IP – no distinction between AP & clients•Peer-to-peerPeer-to-peer

802.15802.15• 805.15.3a UWB805.15.3a UWB

– DS-UWB - PAN, 1.3 Gbps, 10 m or lessDS-UWB - PAN, 1.3 Gbps, 10 m or less– AdvantagesAdvantages

• low power and costlow power and cost• accurate location informationaccurate location information• high BWhigh BW

• 802.15.4 Zigbee802.15.4 Zigbee– support mesh topologysupport mesh topology– coordinator to start the NTK, NTK parameters, coordinator to start the NTK, NTK parameters,

request-response routing algorithmrequest-response routing algorithm

• 802.15.5 WPAN 802.15.5 WPAN – RecentlyRecently– MAC & PHYMAC & PHY

802.16 802.16 • point-to-multipoint connection-oriented point-to-multipoint connection-oriented

QoSQoS

• freq. 10-66 GHZ with LOSfreq. 10-66 GHZ with LOS

• 802.16a 802.16a – freq. 2-11 GHZ with NLOSfreq. 2-11 GHZ with NLOS

• 802.16 mesh limitation802.16 mesh limitation– 100 subscribers - centralized scheduling 100 subscribers - centralized scheduling

message structuremessage structure– connectionless –QoSconnectionless –QoS– no-interference assumption - 2 hops awayno-interference assumption - 2 hops away

8. Conclusion8. Conclusion

• Promising Promising – self organizingself organizing– reducing the complexity of deployment reducing the complexity of deployment

and maintenanceand maintenance

• variety of applicationvariety of application

• integration with multiple wireless NTKsintegration with multiple wireless NTKs

• hot topic for researchhot topic for research– academic and industrialacademic and industrial

Success is a lousy teacher. It seduces smart people into thinking they can’t lose ,and it’s an unreliable guide to the future .

Bill Gates

The Road Ahead ,1996

Questions Questions ??

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