Wireless Mesh and Multi Hop Relay Networks Raj Jain Washington University in Saint Louis Saint Louis MO 63130 Jain cse wustl edu Audio Video recordings of this lecture are available at http www cse wustl edu jain cse574 10 Washington University in St Louis CSE574s 23 1 2010 Raj Jain Overview Multi Hop Relay Networks 802 16j Mobile Multi hop Relay MMR 802 15 5 WPAN Mesh Networking 802 11s Mesh Networks Applications Wi Fi Mesh Products Washington University in St Louis CSE574s 23 2 2010 Raj Jain Multi Hop Networks Relay Dedicated carrier owned infrastructure Tree based topology One end of the path is the base station Mesh Routing by subscriber equipment Multiple connections mesh topology Ref http en wikipedia org wiki Mesh networking Washington University in St Louis CSE574s 23 3 2010 Raj Jain Multi Hop Relay Networks Next generation networks need very high data rates Data rate 1 distance High density of cell towers High cost Multi hop Networks have fixed infrastructure Do not need complex routing techniques Relays are low cost low transmit power and have no connection to wired infrastructure More capacity due to shorter distances and frequency reuse Goal High capacity and coverage not absence of infrastructure Base Washington University in St Louis Relay CSE574s 23 4 Mobile Host 2010 Raj Jain Coverage Extension Side streets can be covered by relays A series of relays can be used to forward traffic to base Relaying either in time domain or frequency domain Mobile Relay Base Washington University in St Louis CSE574s 23 5 2010 Raj Jain Throughput Enhancement Virtual Antenna Arrays Multiple cooperating relays act as distributed MIMO Challenges Synchronization Sharing of Channel State Information 3 2 MIMO Washington University in St Louis CSE574s 23 6 2010 Raj Jain iCAR Integrated Cellular and Ad Hoc Relaying System Relaying stations are used to divert traffic from congested cells to nearby lightly loaded cells Even existing calls can be moved Secondary relaying Washington University in St Louis CSE574s 23 7 2010 Raj Jain 802 16j Mobile Multi hop Relay MMR Three types of Relays Fixed Nomadic special events Indoor Mobile Relays Trains Washington University in St Louis CSE574s 23 8 2010 Raj Jain 802 16j Technical Issues Centralized vs distributed control Functional division between Base and Relay Scheduling Radio Resource management Power Control Call Admission and Traffic Shaping Policies QoS Network wide load balancing Congestion control Security Management Note Routing is not an issue with fixed relays Washington University in St Louis CSE574s 23 9 2010 Raj Jain Multi Hop Relay Networks Summary Relay concept applies to Cellular Networks and to Wireless Access Relays can help overcome obstacles Relays help improve the capacity by decreasing the distance Relays help decrease the cost since they are much cheaper than base stations Routing with fixed relays is simple Increasing delays Number of hops must be limited to two or three Distributed MIMO Improvement in data rates Washington University in St Louis CSE574s 23 10 2010 Raj Jain Mesh Networks WPAN Mesh 802 15 5 WLAN Mesh 802 11s Washington University in St Louis CSE574s 23 11 2010 Raj Jain 802 15 5 WPAN Mesh Networking Goal Range Extension Routing Redundancy Issues Handle Multiple Master devices Handle multiple super frame coexistence Fair sharing of channel time Minimal changes to 802 15 3 and 802 15 4 Pico nets Washington University in St Louis Mesh Control and Data path CSE574s 23 12 2010 Raj Jain 802 11s Mesh Networks Applications MSOs CLEC Municipal Enterprise Campus 100 1000 Mbps CMTS Internet 10 100 1000 Mbps SS Emergency Response Washington University in St Louis Home Networks CSE574s 23 13 2010 Raj Jain 802 11s Device Classes Stations STA Non mesh capable station Mesh Points MP Mesh capable station Mesh AP MAP MP AP Mesh Portal MPP Entry exit to wired network Support transparent bridging address learning and bridge to bridge communication spanning tree etc Root Portal MPP configured for topology building Elected to become the root of the default forwarding tree MAP MP STA Bridge Router MP MP MPP Ref http en wikipedia org wiki IEEE 802 11s Washington University in St Louis CSE574s 23 14 2010 Raj Jain 802 11s Hybrid Wireless Mesh Protocol Two Configurations With Root Portal and Without Root Portal Route Discovery W O Root Portal On demand Radio Metric AODV RM AODV Cost Amount of air time consumed per packet transmission Radio Aware OLSR Path Selection Protocol Optional Frequency of LS forwarding is reduced with hops Fish eye state routing W Root Portal Most of the traffic is to the root Proactive Tree based distance vector routing Washington University in St Louis CSE574s 23 15 2010 Raj Jain Common Channel Framework All stations use a single control channel Stations dynamically select the data channel They announce it on the common control channel using RTX CTX Not RTS CTS packets Washington University in St Louis CSE574s 23 16 2010 Raj Jain 802 11s Examples X X 1 1 2 2 6 6 5 5 9 9 3 3 7 7 10 4 8 8 4 X 4 sends RREQ No Resp 4 forwards to MPP 1 4 9 4 sends RREQ 9 sends RREP Washington University in St Louis 10 4 CSE574s 23 17 2010 Raj Jain 802 11s Examples X X 1 1 2 2 6 6 5 5 9 9 3 3 7 7 10 4 8 8 4 X 4 forwards to MPP1 MPP1 sends to X Washington University in St Louis 10 4 CSE574s 23 18 4 9 4 forwards to MPP1 MPP1 sends to 9 9 Issues RREQ 4 sends RREP 2010 Raj Jain Wi Fi Mesh Products LocustWorld com MeshAP S W Freeware from locustworld com Allows computers to act as wireless routers Uses AODV protocol Problem of false DVs MeshBox Complete hw sw package MeshBox 2 or MexBox Uses two Wi Fi radio modules Successive routers could share a channel e g 1 2 2 3 3 1 among three routers FireTide Network HotPort 4 9 GHz Public Safety Mesh Nodes HotPort Indoor Mesh Nodes HotPort Outdoor Mesh Nodes Uses MANET Topology Bradcast based on Reverse Path Forwarding TBRPF protocol Washington University in St Louis CSE574s 23 19 2010 Raj Jain Wi Fi Mesh Products Cont Motorola Mesh Networks http www motorola com mesh index htm Tropos Networks www tropos com PacketHop Communications www packethop com MeshDynamics http www meshdynamics com index html SkyPilot Networks http www skypilot com Proxim Wireless http www proxim com can index html Nortel Networks http www2 nortel com go solution content jsp segId 0 catI d 0 parId 0 prod id 47160 locale en US WaveWireless www wavewireless com Washington University in St Louis CSE574s 23 20 2010 Raj Jain
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