930 likes | 1.19k Views
Emergency Communication. DUMBO: Digital Ubiquitous Mobile Broadband OLSR. Outline. Disaster Emergency Network Vehicular Communication Available Technologies DUMBO DUMBO 2. Disaster. Natural Tsunami, Nargis, Manmade Terrorist attack, Fire. Disaster (cont…). Consequences:
E N D
Emergency Communication DUMBO: Digital Ubiquitous Mobile Broadband OLSR
Outline • Disaster • Emergency Network • Vehicular Communication • Available Technologies • DUMBO • DUMBO2
Disaster • Natural • Tsunami, Nargis, • Manmade • Terrorist attack, Fire
Disaster (cont…) • Consequences: • Huge death • Huge wounded • Destroy surrounding (roads, buildings) • Traditional communication infrastructure becomes inoperable • Requirements: • Rescue operation • Co-ordination between the field worker and command center • Emergency medical assistance
Emergency Network • An emergency network: • Fast deployable • Without relying on the fixed infrastructure • Provide multimedia communication (voice, video, text) • Wide network coverage • Available network devices (home appliances) • Real-time monitoring systems • Capable to move the network nodes independently within the network coverage
Emergency Network (cont…) Traditional Process: Usually the rescue worker uses walkie talkie while in rescue operation. But it has many demerits: • Short range • Collisions in communication (everybody uses the same channel) • No video support • No central monitoring systems to monitor the relative movement of the field worker
Vehicular Communication • Vehicle to Vehicle Communication (V2V) • Send and receive information between vehicles to vehicle • Vehicle to Infrastructure Communication (V2I) • Share information among the vehicles and the fixed infrastructure
Available Technologies (cont…) • TETRA : Terrestrial Trunked Radio • Special type of Mobile • Walkie Talkie like service • Low Throughput • Fixed Infrastructure • Expensive
DUMBO Use Mobile Ad Hoc Networks (MANET) in an environment where fixed network infrastructure is not available, such as in the case of natural disaster
IP Star Satellite Field Satellite Access IP Star Uplink MANET OLSR IP Star Gateway Field Satellite Access Terrestrial Internet MANET OLSR PDA PDA sensor Simulated Head Command Center (AIT) Simulated Disaster Area 1 DUMBO’06 Simulated Disaster Area 2
DUMBO 2 • Interconnectivity between Mobile Ad-hoc Network and Fixed infrastructure • Vehicle-to-Vehicle (V2V) communications with mixed vehicle types • Vehicle-to-Infrastructure (V2I) Internet-like Gateway • A newly revised Emergency Response Multimedia Communication Applications (P2P SIP) • Real-time monitoring system for rescue worker’s movement.
Outline • Mobile Ad Hoc Network (MANET) • Optimized Link State Routing (OLSR) • Easy Disaster Communication (EasyDC)
IEEE 802.11 Infrastructured network Ad hoc network A B C
Mobile Ad-Hoc Network (MANET) • Fast deployable • Self configuring • No need for network infrastructure • Moving nodes • Multi-hop network
MANET example • B and D as intermediate nodes forward a packet to E • Multi-hop network
MANET applications • Military operations • Sensor networks • Rescue operations • University • Conferences
MANET characteristics • Dynamic topology • Limited bandwidth • Energy constrained operation • Limited physical security
MANET routing protocol • Reactive routing • Finding routes when needed (on demand) • Proactive routing • Maintaining all routes to reachable destinations (table-driven routing) • Using continues control messages to set up routes • Reactive • Low routing overhead • High delay of setting up a connection • Proactive • High routing overhead • Low delay of setting up a connection
RREQ RREQ RREQ RREQ RREQ Ad-hoc On-Demand Distance Vector (AODV), RFC 3561 • Finding routes when needed (on demand) • Flooding a route request (RREQ)
RREP RREP RREP Ad-hoc On-Demand Distance Vector (AODV), RFC 3561 • Finding routes when needed (on demand) • A route reply is unicasted back
Optimized Link State Routing (OLSR), RFC 3626 • A table-driven routing protocol • Using MultiPoint Relays (MPRs) to efficiently relay broadcast messages • Three main modules • Neighbor detection • Topology discovery (via MPRs) • Route calculation
1. Neighbor detection HELLO HELLO HELLO
Neighbor sensing HELLO HELLO Neighbor nodes of B A C D HELLO
Multipoint relay • Reducing the number of duplicate retransmissions while forwarding a broadcast packet • Limit the set of MPRs retransmitting a packet • The number of MPRs should be small
Multipoint relay selection • Each node selects and maintains its own MPRs • “At A, For all two-hop neighbors n there must exist a MPR m so that n can be contacted via m”
Multipoint relay selection • Each node selects and maintains its own MPRs • “At A, For all two-hop neighbors n there must exist a MPR m so that n can be contacted via m”
2. Flooding topology information without MPRs Neighbor nodes of B A C D
Flooding topology information with MPRs Neighbor nodes of B A C D
Route calculation Routing of E Dest. Next hop A D B D C C D D B {A, C, D} Routing of D Dest. Next hop A B B B C B E E Routing of A Dest. Next hop B B C B D B E B D {B, E}
OLSR implementation • olsr.org • An ad hoc wireless mesh routing daemon • Many OS platforms are supported • Nokia, iPhone, Mac OS, Linux, Wins
Configured olsrd parameters • HELLO interval • HELLO hold • TC interval • TC hold • MID interval • MID hold • More details no olsrd parameters • http://www.olsr.org/docs/olsrd.conf.5.html
Reasonable HELLO interval • In RFC 3626 • HELLO interval = 2s • TC interval = 5s • The larger HELLO interval, the longer delay of neighbor detection • OLSR on a vehicle • HELLO interval should be small
Communication applications • Existing communication applications, VoIP, require centralized servers • The centralized architecture is not suitable for MANETs due to mobility
Using P2P on MANETs Operated Operated
Easy Disaster Communication (EasyDC) • Providing multimedia communications for an emergency operation • Peer-to-peer (P2P) application where no a centralized server is needed • Running on OLSR protocol