Wireless Mesh

The Premise

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.

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

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

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)

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

Challenges (cont’d)

• Smart Spectrum Utilization • Analytical Tools• Ease of use (Plug and play,

HCI)• Digital Rights Management (DRM)

Mesh Routing Functionality

Data Channel RadioMiniport Driver

Control Channel Radio

Miniport driver

Mesh Routing Functionality

Mesh Management Module

TCP / IP

Mesh Connectivity Layer(MCL)

Multi-hop Routing/Bridging Radio Selection Metric

Topology Control

Link Monitor Module

Mesh Box Configuration

SECURITY

Diagnostics Kernel Module

Diagnostics Client and Server DLLs

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