LocationBased Services Henning Schulzrinne Columbia University Overview Time

Location-Based Services Henning Schulzrinne Columbia University

Overview • Time + space • Getting location information • Using location information • Privacy issues

Getting location information • Universal • anywhere in the world • independent of network connectivity • Non-proprietary • Energy efficient • Accurate to 10 m/room level doesn’t exist in one system

Locationdetermination methods Method GPS layer accuracy advantages 10 m • privacy • global • accurate 802. 11 protocols L 2, L 3, L 7 20 -100 m room-level, AP • room-level • simple to implement accuracy • reasonably accurate • no surveying needed • requires survey • only works in urban problems use mostly outdoors Enterprise & home LANs areas • requires Internet connectivity Enterprise & home LANs Some ISPs mapping IP address to switch port? DSL, cable cell tower manual 100 m-2 km room or building AP • no infrastructure cost • client privacy • low accuracy • cell coverage backup for other methods • no infrastructure • privacy • stationary only • doesn’t scale enterprise home PC

Location delivery protocols Method LLDP-MED DHCP HELD L 2 L 3 L 7 (HTTP) room-level, AP • simple to implement • built into switch • direct port/room mapping • simple to implement • network locality • traverses NATs • can be operated by L 2 provider problems may be hard to automate for large enterprises mapping MAC address to location? mapping IP address to switch port? use Enterprise & home LANs Some ISPs DSL, cable ISPs layer accuracy advantages 5

people & vehicle tracking Location-based services indoor routing car park assistance directions traffic management emergency calls Tracking product tracking Emergency Navigation automotive assistance shopping guides travel & tourist guides Information locationbased services mobile yellow pages travel planner Advertising banners & alerts Billing road tolling facility Games Infrastructure geocaching Management Leisure customer relationship mobile games fleet (scheduling) Communications location-aware call handling instant messaging buddy finder security Foundations of Location-based Services (Steinger, Neun, Edwardes), modified) 6 environmental

• • • Location-based services Finding services based on location • • physical services (stores, restaurants, ATMs, . . . ) electronic services (hot spots, printers, . . . ) Using location to improve (network) services • incoming or outgoing communications adapts to location Using location to provide information • • tourist guides advertisements Making others aware of user location • • presence (individual) popularity, movement (group) Security • grant access based on user’s location

Location-based Vo. IP services • • • Location-aware inbound routing • • • do not forward call if time at callee location is [11 pm, 8 am] only forward time-for-lunch if destination is on campus do not ring phone if I’m in a theater outbound call routing • • contact nearest emergency call center send delivery@pizza. com to nearest branch location-based events • • • subscribe to locations, not people Alice has entered the meeting room 8 subscriber may be device in room

• Location-based security Examples: Garmin GPS unlocks at home Only allow person in room to control conference room equipment via web browser Restrict access to bank account based on user’s location IP-address based (Max. Mind, . . . ) Need certified location • • •

Modes of emergency communications emergency call information “I-am-alive” emergency alert (“inverse 911”) civic coordination 10 dispatch

Components of NG 911 system Lo. ST (public) Lo. ST (private) PSAP ESN (county, state, …) PSAP Internet 11

Lo. ST: Location-to-URL Mapping VSP 1 cluster serving VSP 1 replicate root information cluster serves VSP 2 123 Broad Ave Leonia Bergen County NJ US Lo. ST NJ US root nodes NY US search referral Bergen County NJ US sip: psap@leonianj. gov Leonia NJ US 12

Lo. ST Architecture tree guide G G T 1: . us G T 2: . de broadcast (gossip) resolver seeker 313 Westview Leonia, NJ US T 3 T 2 (. de) T 1 (. us) (. dk) Leonia, NJ sip: psap@leonianj. gov 13 (. dk)

Lo. ST: Query example <find. Service xmlns="urn: …: lost 1” recursive="true" service. Boundary="value"> <location profile="basic-civic"> <civic. Address> <country>Germany</country> <A 1>Bavaria</A 1> <A 3>Munich</A 3> <A 6>Neu Perlach</A 6> <HNO>96</HNO> </civic. Address> </location> <service>urn: service: sos. police</service> </find. Service> 14

Lo. ST “Find Service” response/warning example <find. Service. Response xmlns="urn: ietf: params: xml: ns: lost 1"> <mapping expires=“ 1990 -12 -31 T 23: 59: 60 Z” last. Updated=“ 2006 -11 -01 T 01: 00 Z”> <display. Name xml: lang="de">München Polizei-Abteilung</display. Name> <service>urn: service: sos. police</service> <service. Boundary profile=”civic”> <civic. Address xmlns="urn: ietf: params: xml: ns: pidf: geopriv 10: civic. Addr"> <country>Germany</country> <A 1>Bavaria</A 1><A 3>Munich</A 3><PC>81675</PC> </civic. Address> </service. Boundary> <uri>sip: munich-police@example. com</uri> <service. Number>110</service. Number> </mapping> <path> <via source=“lost: esgw. uber-110. de. example”/> <via source=“lost: polizei. munchen. de. example”> </path> </find. Service. Response> 15

Citysense. com See the city in true realtime: how busy is the city & where is everyone going, right now? Red: all anonymous destination activity Green: only unusual destination activity Press “ 1” to see the #1 hottest destination, then “ 1” again to see the restaurants and bars there, etc. Now available in San Francisco, more cities rolling out in beta version. GPS Aggregate information

Minimum Volume Embedding Machine learning algorithm that determines behavior and clusters from anonymous aggregate movement from all pairs of corners in the city. Obtains behavioral map of city (vs. geographical map) Restaurants Work Nightlife Residential

Platforms missing network connectivity missing location time zone missing navigation Blue. Tooth? Zig. Bee?

IETF GEOPRIV and SIMPLE architectures DHCP XCAP (rules) target presentity publication interface PUBLISH location server presence agent rule maker notification interface location recipient GEOPRIV watcher SIP presence SUBSCRIBE

Privacy issues • Not all LBS are privacy-sensitive • “where is the M 125 bus? ” • navigation with GPS • Problem: location + personal identity • or derivable (e. g. , via home location)

Privacy threats reveal device anonymously (e. g. , “nearest gas station”) Privacy reveal identity + location to LBS (friend finder service) reveal to individual (friend, other)

Presence and privacy: PIDF-LO • • • All presence data, particularly location, is highly sensitive Basic location object (PIDF-LO) describes distribution (binary) retention duration Policy rules for more detailed access control who can subscribe to my presence who can see what when • • <tuple id="sg 89 ae"> <status> <gp: geopriv> <gp: location-info> <gml: location> <gml: Point gml: id="point 1“ srs. Name="epsg: 4326"> <gml: coordinates>37: 46: 30 N 122: 25: 10 W </gml: coordinates> </gml: Point> </gml: location> </gp: location-info> <gp: usage-rules> <gp: retransmission-allowed>no </gp: retransmission-allowed> <gp: retention-expiry>2003 -06 -23 T 04: 57: 29 Z </gp: retention-expiry> </gp: usage-rules> </gp: geopriv> </status> <timestamp>2003 -06 -22 T 20: 57: 29 Z</timestamp> </tuple> 22

• GEOPRIV privacy rules • User gets maximum of Conditions • • permissions across all matching rules • privacy-safe composition: removal of a rule can only reduce privileges • Extendable to new presence data identity, sphere time of day current location identity as <uri> or <domain> + <except> • Actions • watcher confirmation • Transformations • • – rich presence – biological sensors – mood sensors include information reduced accuracy e. g. , only within 5 mile radius • 23

• • Open technical and standards issues Universal APIs • • As simple as gettimeofday() Not specific to method or vendor Crowd-sourcing Integration between presence and location • presence as universal third party interface? Clear privacy rules • both technical and legal

Deployment issues • • ISPs need to make location available to their customers • • for in-door use location as a chargeable service? LAN-based location for room-level location • • APs and ports enterprise

Conclusion • • • Location as fundamental service building block → time & space Improve user experience • • from navigation and locating services to automatic silent mode Need network protocols for • • • conveying location mapping location to services describing privacy requirements