1. 802.11 Enhancements and Applications 802.11p, 802.11r, 802.11s, 802.11y

2. 802.11p

3. “Dedicated Short Range Communications” (DSRC) –Started in IEEE 1609, spun into 802.11p –Aka (WAVE) Wireless Access for Vehicular Environment Goal –Telematics (collision avoidance a big driver) Roadside-to-vehicle Vehicle-to-vehicle environments –54 Mbps, <50 ms latency Possible competitor to cellular Operates in 5.850 to 5.925GHz band Draft under ballot –Projected for March 2009

4. Broader Context 802.11p part of several standards which will jointly enable widescale telematics Intelligent Transportation Systems doc.: IEEE 802.11-07/2045r0

5. 802.11p Applications Applications –Emergency warning system for vehicles –Cooperative Adaptive Cruise Control –Cooperative Forward Collision Warning –Intersection collision avoidance –Approaching emergency vehicle warning (Blue Waves) –Vehicle safety inspection –Transit or emergency vehicle signal priority –Electronic parking payments –Commercial vehicle clearance and safety inspections –In-vehicle signing –Rollover warning –Probe data collection –Highway-rail intersection warning

6. Example Application IMMINENT FRONT COLLISION Note 1: The OBU in the vehicle recognizing the threat transmits a WARNING and COLLISION PREPARATION MESSAGE with the location address of the threat vehicle. In-Vehicle Displays and Annunciations Traffic Signal OBUs on Control Ch ~ ~ ~ ~ ~ ~ IMMINENT LEFT COLLISION Radar Threat Identification Note 2: Only the OBU in the threatening vehicle processes the message because only it matches the threat address. up to 100 m (328 ft) Note 3: COLLISION PREPARATION includes seat belt tightening, side air bag deployment, side bumper expansion, etc. Car NOT Stopping From: IEEE 802.11- 04/ 0121r0 Available: http://www.npstc.org/meetings/Cash%20WAVE%20Information%20for%205.9%20GHz%20061404.pdfhttp://www.npstc.org/meetings/Cash%20WAVE%20Information%20for%205.9%20GHz%20061404.pdf

7. Operation Spectrum divided into 7 bands –178 is control (safety) –2 edge channels are reserved for future –The rest are service channels (not application specific) IEEE 802.11a adjusted for low overhead operations

8. Safety Messages Control Messaging characteristics –Most messages are single hop –Some broadcasting (e.g., forwarding hazard warnings) –No coordination for channel access –Messages targeted based on vehicle location more so than vehicle identity –Short and mapped to a single frame –Arbitrary distances (100m is a more practical distance) –Vehicles in constant communication –Dedicated channel Messaging Principles –Safety communication is not application-to-application Instead, an intermediate layer is responsible for safety information distribution and aggregation among vehicles and infrastructure. –Applications work by continuously analyzing the aggregated information to look out for potential trigger conditions. –Simply put, the sender of a safety message cannot dictate how the message should be processed –“I-am-braking” vs “You have-to- brake” message. One particular advantage –Simplifies future enhancements

9. Reliability If cars are being controlled wirelessly, dropping packets could cause accidents May need to signal a long ways off Result of studies: –Errors not bursty –Communications up to 1 km feasible Free way conditions Packet error distribution F. Bai, H. Krishnan, “Reliability Analysis of DSRC Wireless Communication for Vehicle Safety Applications,” IEEE ITSC 2006

10. Possible Deployments Good (though dated) schedule at http://www.itsforum.gr.jp/Public/E4Meetings/P03/schnac keTP74.pdf http://www.itsforum.gr.jp/Public/E4Meetings/P03/schnac keTP74.pdf US DoT planning to deploy as Vehicle Infrastructure Integration project (VII) –http://www.networkworld.com/news/2005/111405-vii.htmlhttp://www.networkworld.com/news/2005/111405-vii.html –Widescale deployment decision in 2008 First use in intersections GM possibly going its own route with “Vehicle to Vehicle” which leverages OnStar –http://www.gm.com/company/gmability/safety/news_issues/rele ases/sixthsense_102405.htmlhttp://www.gm.com/company/gmability/safety/news_issues/rele ases/sixthsense_102405.html European Effort – Car-to-Car Communication Consortium –http://www.car-to-car.org/http://www.car-to-car.org/

11. 802.11r Support for Faster Roaming

12. 802.11e overview Fast BSS Roaming/Transition within IEEE WLAN networks –Preserve security with handovers <50ms Fast BSS Roaming is possible only within a certain area called the mobility domain (MD), inter-MD cases are not covered –Mobility Domain (MD): Set of BSS grouped together with the same 48bit MD Identifier –FT functionality seeks to provide handover performance for RT services Key Issues –Resource Reservations –Security Collapsed 5 step process down to 3 –Scanning – active or passive for other APs in the area –Authentication with a (one or more) target AP –Re-association to establish connection at target AP Target 2008 http://www.cs.tut. fi/kurssit/TLT- 6556/Slides/Lect ure4.pdf

13. Resource Reservation (optional) Resource Reservation (RR) is to setup QoS resources in one or more target AP during FT transition mechanism –RR Setup only follows successful PTK derivation RR is based on one round-trip negotiation – STA requests certain QoS and t-AP provides as much or less QoS Benefits –No delay during re-association for RR (RIC) processing –Better application service quality during FT roaming –Without RR, STA may realize target AP does not have enough resources at the time of reassociation Drawbacks –STA may reserve at multiple AP but use only one => cost –Increased AP complexity –Mechanism –AP advertises the capability in the Beacon frame –STA has the choice to initiate the RR procedure

14. Security New key hierarchy New authentication route http://www.cs.tut.fi/kurssit/TLT-6556/Slides/Lecture4.pdf http://www.networkcomputing.com/gallery/2007/0416/0416t tb.jhtml;jsessionid=0CK4ZKR20HC5QQSNDLPCKHSCJU NN2JVN

15. Reduction in Roaming Time S. Bangolae, C. Bell, E.Qi, “Performance study of fast BSS transition using IEEE 802.11r,” International Conference On Communications And Mobile Computing, 2006

16. 802.11s Mesh Networking in WiFi

17. Modify 802.11 MAC to create dynamic self-configuring network of access points (AP) called and Extended Service Set (ESS) Mesh Automatic topology learning, dynamic path selection Single administrator for 802.11i (authentication) Support up to 32 AP Support higher layer connections Allow alternate path selection metrics Extend network merely by introducing access point and configuring SSID 1. http://standards.ieee.org/board/nes/projects/802-11s.pdfhttp://standards.ieee.org/board/nes/projects/802-11s.pdf IP or Ethernet Objectives 1

18. WLAN Mesh – An IEEE 802.11-based Wireless distribution service consisting of a set of two or more Mesh Points interconnected via IEEE 802.11 links and communicating via the WLAN Mesh Services. Mesh Point - A Mesh Services supporting device (bridge, access point) Mesh AP - Any Mesh Point that is also an Access Point. Mesh Portal - A boundary connection for the Mesh Conceptual Operation http://ieee802.org/802_tutorials/nov06/802.11s_Tutorial_r5.pdf

19. WiMesh http://www.wi-mesh.org/ Major Partners –Nortel –InterDigital –Phillips –Mitre –Naval Research Lab –Thomson SEEMesh Simple, Efficient and Extensible Mesh No group site Major Partners –Intel –Motorola (purchased MeshNetworks) –Nokia –Texas Instruments 1. http://grouper.ieee.org/groups/802/11/Reports/tgs_update.htmhttp://grouper.ieee.org/groups/802/11/Reports/tgs_update.htm Major Participants

20. Key Technologies Topology Formation Internetworking Routing Security

21. Topology Formation Each Mesh Point may have one or more logical radio interface: –Each logical interface on one (infrequently changing) RF channel, belong to one “Unified Channel Graph” –Each Unified Channel Graph shares a channel precedence value Channel precedence indicator – used to coalesce disjoint graphs and support channel switching for DFS http://ieee802.org/802_tutorials/nov06/802.11s_Tutorial_r5.pdf

22. Internetworking 1. Determine if the destination is inside or outside of the Mesh –Leverage layer-2 mesh path discovery 2. For a destination inside the Mesh, –a. Use layer-2 mesh path discovery/forwarding 3. For a destination outside the Mesh, –a. Identify the “right” portal, and deliver packets via unicast –b. If not known, deliver to all mesh portals

23. Default Routing: Hybrid Wireless Mesh Protocol (HWMP) On demand routing is based on Radio Metric AODV (RM-AODV) –Based on basic mandatory features of AODV (RFC 3561) –Extensions to identify best-metric path with arbitrary path metrics –Destinations may be discovered in the mesh on-demand Pro-active routing is based on tree based routing –If a Root portal is present, a distance vector routing tree is built and maintained –Tree based routing is efficient for hierarchical networks –Tree based routing avoids unnecessary discovery flooding during discovery and recovery http://ieee802.org/802_tutorials/nov06/802.11s_Tutorial_r5.pdf

24. RA-OLSR – Key Features (Optional Routing) Multi Point Relays (MPRs) – A set of 1-hop neighbor nodes covering 2-hop neighborhood – Only MPRs emit topology information and retransmit packets Reduces retransmission overhead in flooding process in space. (Optional) message exchange frequency control (fish-eye state routing) – Lower frequency for nodes within larger scope Reduce message exchange overhead in time.

25. Security The MPs are no longer wired to one another There is no intrinsic node hierarchy MPs need to maintain secure links with many other MPs Transport security –Mutually authenticate neighbor MPs –Generate and manage session keys and broadcast keys –Data confidentiality over a link –Detect message forgeries and replays received on a link Authentication and Initial Key Management –Basic approach is to re-use 802.11i/802.1X –Re-use of 802.11i facilitates implementation

26. Usage Models

27. Vehicular mounted APs interconnected via WDS (wide area data services) Dismounted troops carry client STAs APs & client STAs are communication endpoints Occasionally a STA may need to switch roles and become an AP in order to heal a bifurcated mesh Predominance of multicast applications, e.g., situational awareness, conference mode VoIP, … Type 1 encryption, e.g., Harris SecNet 11 Auto configuration –plug and play, or nearly so Multiple 802.11 ESS Meshes interconnected via JTRS ELOS links –Some JTRS ELOS links may belong to the WDS while others are external to the WDS, i.e., are terminated via IP routers rather than by 802.11 APs. Picture from: IEEE 802.11-04/1006r0 802.11 ESS Mesh Mesh AP Links 802.11 MAC/PHY (4-addr data frames) Client-to-AP Links 802.11 MAC/PHY (3-addr data frames) JTRS ELOS Links (Joint Tactical Radio System) (Extended Line-of-Site) Logica l View Slide from: J. Hauser, D. Shyy, M. Green, MCTSSA 802.11s Military Usage Case Combat Usage Case

28. WiFi Mesh Products Motorola Mesh Networks –www.motorola.com/meshwww.motorola.com/mesh Tropos –www.tropos.comwww.tropos.com PacketHop Communications –www.packethop.comwww.packethop.com MeshDynamics –www.meshdynamics.comwww.meshdynamics.com SkyPilot Networks –www.skypiilot.comwww.skypiilot.com Proxim Networks –www.proxim.com/can/www.proxim.com/can/ Nortel Networks Wave Wireless –www.wavewireless.comwww.wavewireless.com LocustWorld.com FireTide Network List from: http://www.cs.wustl.edu/~jain/cse574-06/ftp/j_jmesh/sld019.htm

29. 802.11y Dynamic Spectrum Access

30. Background FCC issued rules for novel “lite licensing” scheme for 3650-3700 MHz band –Licensees pay small fee for nation-wide non-exclusive license Pay additional fee for each high-powered base station (up to 20 W) –No need for license for clients nor operators, but devices must be “enabled” –Devices must be identifiable (to find the culprit) –Support contention based protocol to give opportunity to transmit to multiple licensees –Interference disputes between licensees must be resolved between themselves Applications –Back haul for Municipal Wi-Fi networks –Industrial automation and controls –Campus and enterprise networking –Last Mile Wireless Broadband Access –Fixed Point to point links –Fixed point to mobile links –Public safety and security networks

31. Ports 802.11a to 3.65 GHz – 3.7 GHz (US Only) –FCC opened up band in July 2005 –Conditionally approved Summer 2007, to sponsor ballot, ready 2008 Intended to provide rural broadband access (distances up to 5 km) Incumbents –Band previously reserved for fixed satellite service (FSS) and radar installations – including offshore –Must protect 3650 MHz (radar) –Not permitted within 80km of inband government radar –Specialized requirements near Mexico/Canada and other incumbent users Leverages other amendments –Adds 5,10 MHz channelization (802.11j) –DFS for signaling for radar avoidance (802.11h) Database of existing devices –Access nodes register at http://wireless.fcc.gov/uls –Must check for existing devices at same site Source: IEEE 802.11-06/0YYYr0 802.11y

32. Key 802.11y technologies DFS (802.11h) Channelization (802.11j) Contention based protocol (CBP) –geographic protection of the grandfathered satellite stations –database for users to research other users in their area –Location information Extended channel switch announcement (ECSA) –Dependent notification of DFS –Continuous adaptation Dependant station enablement (DSE)

33. Dependant station enablement DSE controls when a dependant is allowed to transmit in licensed spectrum –enabling station need not be an access point, may be elsewhere –Need not be completed via a direct link https://edge.arubanetworks.com/article/ standards-corner-august-2007-ieee- 802-11y-3650-3700-mhz-operation-usa DSE Enabling Process

34. Summary 802.11 is expanding into lots of applications –VOIP roaming (802.11r) –Cellular like ranges with dynamic spectrum access (802.11y) –Telematics (802.11p) –Mesh networks (802.11s) Leverage and enhance previous amendments Expect to see cross-pollination of technologies later.