Unicast routing and forwarding method, chip and communication system for vehicle ad hoc network

Abstract

The invention relates to the field of vehicle networking in intelligent transportation, and specifically discloses a unicast routing and forwarding method, chip and communication system for a vehicle-mounted self-organizing network. The method includes a VSM unicast message forwarding process, and the VSM unicast message forwarding process includes: query MRT step: After the first vehicle node generates or receives the first VSM unicast message that DstIP is the second vehicle node, it uses DstIP as the index item to query the stored MRT, and obtains the corresponding NextHopMAC from the MRT entry; send the VSM step : According to the obtained NextHopMAC, send the first VSM unicast message to the corresponding next-hop vehicle node. Unicast packet forwarding is based on the next-hop technology. It only needs to obtain the NextHopMAC from the MRT table entry without obtaining the complete routing information. The forwarding process is simple and does not need to consider the problem of convergence. It is efficient and flexible, and the system overhead is small.

Description

technical field [0001] The invention relates to the field of intelligent transportation, in particular to a unicast routing and forwarding method, chip and communication system for a vehicle-mounted ad hoc network. Background technique [0002] First introduce the commonly used technical terms in this field: [0003] VANET: Vehicle Ad-hoc NET work, vehicle self-organizing network; [0004] VSM: Vehicle Safety Message, vehicle safety information; [0005] MANET: Mobile Ad-hoc NET work, mobile ad hoc network; [0006] Geocast: location-assisted multicast; [0007] MRT: Message Relation Table, communication relationship table; [0008] DstIP: destination IP address; [0009] NextHopMAC: next hop MAC address; [0010] SrcMAC: source MAC address; [0011] SrcIP: source IP address; [0012] DstMAC: destination MAC address; [0013] DM: Directly Messaging, direct communication; [0014] MOPR: Movement Prediction based Routing, motion prediction algorithm; [0015] GPSR: ...

AI Technical Summary

Problems solved by technology

[0024] Different from the traditional Ad-hoc, most of VANET is composed of vehicle-mounted nodes, and the rest is composed of roadside nodes. The vehicle-mounted nodes are installed on the vehicle and move with the vehicle, so that each vehicle-mounted node maintains a relatively fast relative displacement speed Therefore, the problem of inter-symbol interference caused by Doppler frequency shift in the communication between vehicle nodes is highlighted. The greater the relative speed between vehicle nodes, the greater the inter-code interference. The speed of the two sides is low, and their relatively large relative displacement speeds will also lead to significant intersymbol interference. This problem will be more serious in the communication between vehicles traveling in the opposite direction in the highway environment, mainly reflected in: On the one hand, due to Due to the limitations of the road, especially when there are dense buildings on both sides of the urban road, the VANET topology mostly presents a strip structure, and the radio waves emitted by the vehicle cannot effectively propagate in the two directions perpendicular to the vehicle. Although, the roads on both sides of the road Buildings or other objects can reflect radio waves, but multipath propagation delays can also cause intersymbol interference; on the other hand, the strip structure of VANET is more sensitive to network topology and network environment than circular or cellular networks. When the road environment is complex (especially in urban environments), the wireless communication channel of VANET will be extremely bad and unstable. These problems combine to make the communication window time between different vehicle nodes in VANET short and unstable.

From the perspective of network topology, the rapid movement of vehicle nodes leads to an extremely unstable network topology. The topology changes in real time and rapidly. When the communication between two vehicle nodes needs to be forwarded by other intermediate vehicle nodes, the intermediate vehicle nodes change rapidly. The network topology of the network will make it difficult for the communication between the two vehicle nodes, the communication efficiency will be low and the network bandwidth will be large, and the available communication capabilities of the intermediate vehicle nodes will be greatly reduced. Be applicable

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