Transcript Wireless Mesh - Lyle School of Engineering

Wireless Mesh
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The Premise
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Case for Wireless Mesh
• High-speed wireless packet data access across a wider
coverage area
– Cellular systems don't provide the bandwidth available in
WLANs.
– Isolated hotspot 802.11 deployments don't provide ubiquitous
access or mobility
– Emergence of small-form factor terminals with 802.11
• Minimizes cost of capital, installation and commissioning
– Utilizes low-cost 802.11 technology.
– Uses wireless links for backhaul to eliminate costs associates
with installation of wired interconnect.
– Auto-configuration algorithms in Wireless Access Point
eliminate costs associated with engineering and organization of
the wireless backhaul network.
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Wireless Mesh (Cont’d)
• Minimizes cost of operations
– Uses wireless links for backhaul to eliminate costs
associated with ongoing leasing of facilities.
– Auto-configuration, self-organizing and self-healing are
intrinsic to the Wireless Mesh Network solution
– Centralized OAM&P minimizes staffing requirements.
• Highly flexible in terms of capacity, coverage
and availability
– Increasing capacity, coverage and/or availability simply
means deploying more Wireless Access Points.
– Wireless Access Points maybe deployed indoors or
outdoors
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Community Applications
• Shared Broadband Internet Access
• Ubiquitous Access (roaming solved: one “true”
network)
• Neighborhood Gaming
• Medical & emergency response
• Neighborhood watchdog (e.g. video surveillance)
• Shared Community Resource
– Media repository
– Distributed backup
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Challenges
• Range and Capacity
– Inexpensive electronically targettable directional antenna or
MIMO for range enhancement
– Multiple frequency meshes
– Multi-radio hardware for capacity enhancement via greater
spectrum utilization
– New data channel MAC with Interference management or
higher throughput
• Multi-hop Routing
– L2.5 on-demand source routing with link quality based routes
selection
– Route selection with multiple radios (multiple channels)
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Challenges (cont’d)
• Security, Privacy
– Guard against malicious users (and freeloaders)
– EAP-TLS between MeshBoxes, PEAPv2 or EAP-TLS
between clients and MeshBoxes
– Priority based admission control
‫ ‫‬Self Management & Self Healing
– Minimal human intervention - avoid network operator
– Watchdog mechanism with data cleaning and liar
detection
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Challenges (cont’d)
• Smart Spectrum Utilization
• Analytical Tools
• Ease of use (Plug and play, HCI)
• Digital Rights Management (DRM)
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Mesh Routing Functionality
Mesh Routing Functionality
Mesh Box
Configuration
Mesh Management Module
Diagnostics Client
and Server DLLs
TCP / IP
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Link
Monitor
Module
Mesh Connectivity Layer
(MCL)
Multi-hop Routing/Bridging
Radio Selection Metric
Topology Control
Diagnostics Kernel
Module
Data Channel Radio
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Control Channel
Radio
Miniport driver
Mesh Capacity
• Connectivity Graph
– Models node connectivity
– Incorporates capacity of each link
• Conflict Graph
– Captures interference among links
• Tool
– Solves MAXFLOW problem on the connectivity graph
with constraints drawn from the conflict graph
• “What-if” Analysis
– Scenario based numbers instead of asymptotic bounds
– Allows evaluation of different wireless technologies
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