1. 5. 1 Specific mobility model Nodes in the network suffer from a specific mobility model Although roads have speed limitation in both highways and urban scenarios the speed of vehicles is much faster than human activities The vehicles are driven by humans while the movement of vehicles is not purely random but depends on the plans of drivers and the fixed roads nature such as speed limitation signal light, traffic jam and so on
1.5.1 Specific mobility model ◼ Nodes in the network suffer from a specific mobility model ◼ Although roads have speed limitation in both highways and urban scenarios, the speed of vehicles is much faster than human activities ◼ The vehicles are driven by humans, while the movement of vehicles is not purely random but depends on the plans of drivers and the fixed roads nature such as speed limitation, signal light, traffic jam, and so on
1.5.2 Frequently changing topology The topology changes frequently and rapidly due to the fast-mobility of wireless nodes The high speed of mobile nodes directly affects the lifetime of links among wireless nodes, especially the links between two opposite direction nodes Since the roads limit the mobility of nodes, links among vehicles with the same direction on a road usually perform much more stable than that among vehicles with opposite directions
1.5.2 Frequently changing topology ◼ The topology changes frequently and rapidly due to the fast-mobility of wireless nodes ◼ The high speed of mobile nodes directly affects the lifetime of links among wireless nodes, especially the links between two opposite direction nodes ◼ Since the roads limit the mobility of nodes, links among vehicles with the same direction on a road usually perform much more stable than that among vehicles with opposite directions
15. 3 No limitation in computing and energy Vehicles have no limitation in computing capability and energy support With the help of gasoline and engine on vehicles communications in vanets do not need to consider the consumption of energy and the processing capacity, which is one of the key issues in conventional ad hoc networks
1.5.3 No limitation in computing and energy ◼ Vehicles have no limitation in computing capability and energy support ◼ With the help of gasoline and engine on vehicles, communications in VANETs do not need to consider the consumption of energy and the processing capacity, which is one of the key issues in conventional ad hoc networks
1.5.4 Uneven distribution of vehicles a The distribution of vehicles is uneven in the network topology The roads limit the movement of vehicles The behaviors of vehicles depending on the drivers, who usually have hot pots in the cities There exists both sparse and dense vehicles distributions in vanets
1.5.4 Uneven distribution of vehicles ◼ The distribution of vehicles is uneven in the network topology ◼ The roads limit the movement of vehicles ◼ The behaviors of vehicles depending on the drivers, who usually have hot pots in the cities ◼ There exists both sparse and dense vehicles distributions in VANETs
1.5.5 Divided topology The entire topology is divided by roads and intersections into sub-topologies Each sub-topology has its own characteristic, which depends on the actual network environment in the located road which includes road length, number of vehicles etc
1.5.5 Divided topology ◼ The entire topology is divided by roads and intersections into sub-topologies ◼ Each sub-topology has its own characteristic, which depends on the actual network environment in the located road, which includes road length, number of vehicles, etc