14-07-2011, 10:15 AM
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Wireless Mesh NetworksChallenges and Opportunities
Overview
Gateways
Multiple interfaces (wired & wireless)
Mobility
Stationary (e.g. rooftop) – most common case
Mobile (e.g., airplane, busses/subway)
Serve as (multi-hop) “access points” to user nodes
Relatively few are needed, (can be expensive)
Wireless Routers
Users
Typically one interface.
Mobility
Stationary
Mobile
Connected to the mesh network through wireless routers (or directly to gateways)
The only sources/destinations for data traffic flows in the network.
User – Wireless Router Links
Wired
Bus (PCI, PCMCIA, USB)
Ethernet, Firewire, etc.
Wireless
802.11x
Bluetooth
Proprietary
Point-to-Point or Point-to-Multipoint
If properly designed is not a bottleneck.
If different from router-to-router links we’ll call them access links
Router to Router Links
Wireless
802.11x
Proprietary
Usually multipoint to multipoint
Sometimes a collection of point to point
Often the bottleneck
If different from router-to-user links we’ll call them backbone links
Gateway to Internet Links
Wired
Ethernet, TV Cable, Power Lines
Wireless
802.16
Proprietary
Point to Point or Point-to-Multipoint
We’ll call them backhaul links
If properly designed, not the bottleneck
How it Works
User-Internet Data Flows
In most applications the main data flows
User-User Data Flows
In most applications a small percentage of data flows
Taxonomy
Mesh vs. Ad-Hoc Networks
Multihop
Nodes are wireless, possibly mobil
May rely on infrastructure
Most traffic is user-to-user
Broadband Internet Access
Extend WLAN Coverage
Mobile Internet Access
Direct competition with G2.5 and G3 cellular systems.
Emergency Response
Layer 2 Connectivity
The entire wireless mesh cloud becomes one (giant) Ethernet switch
Simple, fast installation
Short-term events (e.g., conferences, conventions, shows)
Where wires are not desired (e.g., hotels, airports)
Where wires are impossible (e.g., historic buildings)
Military Communications
Community Networks
Many Other Applications
Remote monitoring and control
Public transportation Internet access
Multimedia home networking