1 / 24

State-of-the-Art Research on Wireless Mesh Networks

Learn about the challenges and advancements in Wireless Mesh Networks (WMNs), including nodes, architectures, clients, and applications. Explore the characteristics, factors influencing performance, and issues at each network layer in WMNs compared to conventional wireless networks.

acandida
Download Presentation

State-of-the-Art Research on Wireless Mesh Networks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Xiuzhen Chengcheng@gwu.edu Csci332MAS Networks – Challenges and State-of-the-Art Research – Wireless Mesh Networks

  2. Introduction • In conventional wireless networks eachhost sends it packets to a central router. • In WMN Nodes  Mesh Routers and Clients • Each node operates as a host. In additioneach node also forwards packets on behalfof other nodes. These nodes may not be inthe direct transmission range of theirdestination. Mesh architecture. • Gateway/Bridge functionalities in MeshRouters  Easy integration with other typeof networks.

  3. Mesh Routers • Routing functions • Basic gateway/repeater functions • Supports mesh networking • Also performs bridge functionalities • Equipped with multiple wireless interfaces • Multiple wireless interfaces built on either the same or different wireless technologies • Compared to a conventional wireless router • Built on a similar hardware platform or on different embedded systems (PowerPC or ARM) • A wireless router can achieve the same coverage with much lower transmission power through multihop communications • Enhanced MAC protocol for better scalability

  4. Mesh Clients • Have necessary functions for mesh netorking • Can work as routers without gateway/bridge functions • Have only one wireless interface • Compared to mesh routers • Simpler hardware platform and software • Simpler construction • Have higher variety of devices: laptops PDAs, IP phone, etc.

  5. WMN Architectures • Infrastructure/Backbone WMNs • Mesh routers form an infrastructure for clients that connect to them. • Most commonly used • Community and neighborhood networks • Client WMNs • Client nodes form the actual network and perform routing functionalities. • Peer-to-peer networks among client devices • No mesh routers is needed • One types of radios for all clients • Increased requirements such as routing and self-configuration are placed • Hybrid WMNs • The combination of infrastructure and client meshing • Most applicable

  6. Infrastructure/Backbone WMNs (1/3)

  7. Client WMNs

  8. Hybrid WMNs

  9. Characteristics • Multihop wireless network • Extend coverage, non-LOS connectivity • Support for ad hoc networking, and capability of self-forming, self-healing, and self-organization • Mobility dependence on the type of mesh nodes • Mesh clients can be mobile • Multiple type of network access • Dependence of power-consumption constraints on the type of mesh nodes • Mesh clients may need power efficient protocols • Compatibility and interoperability with existing wireless networks

  10. Compared to Ad Hoc Netoworks • Wireless infrastructure/backbone • More reliable, higher coverage • Integration • For both wireless and wired clients • Dedicated routing and configuration • Load on end-users are decreased • Multiple radios • Better performance • Mobility • Mesh routers usually do not move

  11. Applications • Broadband home networking • Community ad neighborhood networking • Enterprise networking • Metropolitan area networks • Transportation systems • Building automation • Health and medical systems • Security surveillance systems A superset of Ad Hoc Networks

  12. broadband homenetworking • Compared to WiFi • Better coverage • Flexible • Direct communication

  13. Community Networking

  14. Enterprise Networking

  15. Factors Influencing Network Performance • Radio techniques • Scalability • Mesh connectivity • Broadband and QoS • Compatibility andinter-operability • Security • Ease of use

  16. Factors influencing network performance (contd.) • Link level factors/issues: • Links have intermediate loss rates • Node distance is not strongly correlated withloss rate • Links have non-bursty loss patterns • High signal strength Low loss rate • Optimum 802.11 bit-ratesignificant lossrate • Most significant factor  Multi-path fading

  17. Issues at each layer • Physical layer • New wideband transmission schemesrequired to achieve higher transmission ratein a larger area. • Multiple-antenna systems are complex andcostly. • To utilize the advanced features provided byphysical layer, higher layer protocols (esp.MAC layer) need to be carefully designed.

  18. Issues at each layer • MAC layer • Scalability issues in multi-hop ad hocnetworks • MAC protocol for ad hoc network cannot beused in WMN because of several differences • Advance bridging functions required • Multi-channel MAC protocols for multipletransceiver based radio cannot be used asthey are costly • Development of MAC protocol with multipleQoS metrics like delay, packet loss, jitter

  19. Issues at each layer • Network layer • New scalable routing protocols required • Integrating multiple performance metricsinto a routing protocol • Routing protocol for multicast applications • Cross-layer design between MAC androuting protocol • Routing protocol that treats mesh routerand client differently

  20. Issues at each layer • Transport layer • Cross layer optimization is required forincreasing TCP performance • The new enhanced TCP should work with theexisting TCP • Adaptive transport protocols required for anintegrated WMN • Adaptive Rate Control Protocol (RCP) is needfor real time delivery

  21. Issues at each layer • Application layer • Make existing Internet applications workunder architecture of WMNs • Application protocols for distributedinformation sharing • Unique applications that utilize theadvantages of WMNs

  22. Practical Implementations • Various academic test-bed’s exist atuniversities like Carnegie Mellon, MIT,UIUC, Georgia Tech • Various Industrial leaders have alreadyreleased products or are working on WMNs.Companies include Microsoft Research(MSR), MeshNetworks, Intel, Nortel etc. • City wide Wi-Fi WMNs are deployed orplanned at cities like Las Vegas andPhiladelphia.

  23. Practical Implementations (Cont.) • Current implementation at Las Vegas

  24. Conclusions • WMNs reduces complexity of network deploymentand maintenance • WMNs require minimal investment • Allows users to access Internet anywhere, anytime • Existing WMNs prove that performance of WMNs isfar below then expected • All protocols layers need to be improved. Crosslayer design required for optimal performance • WMNs are promising technology for next generationwireless networking but still more research isrequired.

More Related