Location based routing protocols for vehicular Ad-hoc network: Project Information Gathering
For the Location-based routing protocols for the vehicular Ad-hoc network, our
1st-week planning is to gather information from the published surveys
or any journals and establishing knowledge about the future works.
So, our 1st-week
plannings are:
1. A position-based routing protocol for vehicular
ad hoc networks in a city environment.
2. Position-based routing in vehicular networks: A
survey
3. A Survey on Position-based Routing Protocol in
Vehicular Ad-Hoc Networks.
A position-based routing in a city environment
Vehicular Ad-hoc Networks is a subclass of Mobile Ad hoc Networks
design to improve traffic safety and
travel comfort of drivers and passengers. VANETs routing has found that position-based
routing for MANETs is a very promising routing strategy for Inter-Vehicular
Communication.
Related Works:
ü Greedy
Perimeter Stateless Routing(GPSR)
ü Geographic
Source Routing (GSR)
ü Anchor-based
Street and Traffic-Aware Routing (A-STAR)
ü Greedy
Perimeter Coordinator Routing (GPCR)
ü Vehicle-Assisted
Data Delivery (VADD)
ü Driving
Path Predication Based Routing (DPPR)
The proposed approach:
Optimal path selection: The optimal path is the shortest path
between the source node and the destination node, which is determined by using
the street-map information of the city and by considering the vehicle density
on this path since nowadays the vehicles can be equipped with digital maps with
detailed locations of streets and intersections.
Data forwarding on the
optimal path: Once the optimal
path to the destination is determined, the sequence of intersections to be
traversed by the data packets is put by the source node in the head of the
packet. Thus, the transmission can be started. Forwarding a packet between two
successive intersections (anchor points) is done on the basis of greedy
forwarding since between two successive intersections no ’obstacles’ should
block the radio transmissions.
Position-based
routing in vehicular networks Strategies
Characteristics of vehicular networks: In
vehicular communication, information can be disseminated or collected through
utilizing existing infrastructure or ad hoc fashion or by combining both
techniques. The vehicular network can be broadly classified into three
categories i.e., cellular, ad hoc, and hybrid.
Forwarding strategies of
vehicular networks:
Greedy forwarding: According to the scenario depicted if
greedy forwarding strategy is used then, source node forwards the packets to a
node closest to the destination ‘D’. In this case ‘S’ sends a packet to ‘A’.
Improved greedy forwarding: In this case, source node first consults its neighbor table and computes the new predicted position of all its neighbors based on direction and velocity and then selects a node which is closest to the destination. ‘S’ computes the new predicted position of its neighbors and suppose at time t2, vehicle ‘B’ overtakes the vehicle ‘A’, then ‘S’ selects ‘B’ as its next hop instead of ‘A’.
Directional greedy forwarding: Directional greedy approach only considers those nodes which are moving towards the destination. It selects a node which is moving towards the destination and is closest to the destination. Thus, it selects vehicle ‘B’ as its next hop.
Predictive directional greedy forwarding: In this strategy, forwarding node maintains the information of its 2-hop neighbors. Before forwarding the packet, forwarding node consults its neighbor table and computes predicted position of all its neighbors (one-hop and 2-hop neighbors) and then selects a node whose one-hop neighbor is moving towards the destination and is closest to the destination.
Position
based routing Protocols
VNET Architecture: VANET.
Communication takes place between vehicle-to-vehicle as well as a vehicle to
roadside unit. An On-Board Unit (OBU) is set up on every vehicle for signal
transmission. Using VANET, vehicles can share music and video files.
Position based routing protocol:
In geographic (position –based) routing, the forwarding by a node is primarily made based on the position of a packets destination and the position of the nodes one-hop neighbors. The position based routing protocol, divided into DTN, Non-DTN, and Hybrid.
Delay Tolerant Network (DTN): Delay Tolerant Network algorithms take some necessary steps to overcome intermittent connectivity in urban areas. Carry and forward strategy are used to cater for frequent disconnections of nodes in the network. In carrying and forward strategy when a node cannot contact with other nodes it stores the packets and forwards them upon connection to a neighboring node.
Non-DTN: The non-DTN types of geographic routing protocols do not consider discontinuous connectivity and are only practical in highly congested VANETs. If there is no neighbor of a node in position based routing then forwarding strategy fails to deliver a packet and the situation is called local maximum. In this situation, the routing protocol of non-DTN routing protocol performs a recovery strategy to deal with such a failure.
Hybrid: Hybrid no DTN is a geographic routing protocol that exploits topology knowledge acquired via 2-hop beaconing to select the best target forwarder and incorporates opportunistic forwarding with the best chance to reach it. A target node is defined to be the node that greedy algorithm or recovery algorithm would normally pick except at the junction where optimization in choosing the target node either beyond the junction or at the junction is based upon whether the routing is in greedy mode or recovery mode. TO-GO is a non-DTN hybrid routing protocol.
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