High-speed and long-distance wifi module self-organized network vehicle remote transmission control scheme

1. Project Background

With the advancement of the age of science and technology, the real-time requirements for communication are getting higher and higher. Due to the barriers of communication technology, traditional information collection and control methods cannot be realized in real time. After collection, data analysis is carried out, which greatly reduces the work efficiency and cannot really play the significance of the information collection side. Now we have adopted a new generation of high-speed long-distance wifi module dedicated network Mesh ad hoc network technology to achieve seamless communication and meet real-time needs.

2. Interpretation plan

Within 5 kilometers, there are four wild camper vans, each equipped with a mesh self-assembled network device. A wireless network connection can be achieved between vehicles through mesh devices, and a network communication link can be established. When the vehicle goes out to work, the No. 4 vehicle can park in the work area as a command vehicle, and the No. 1-3 vehicles can move within a range of 5 kilometers around the No. 4 vehicle, and provide high-speed long-distance wifi module mesh self-combined network equipment, The video and vehicle control signals collected by the vehicle are transmitted to vehicle No. 4. Field commanders can receive and watch videos through wireless signals, or control related equipment on cars 1-3 through wireless networks.

3. Technical explanation

1. Ad-hoc network technology mesh

The high-speed long-distance wifi module ad hoc network is a new type of wireless network that is completely different from the traditional wireless network. It has the advantages of self-organizing network, self-healing, multi-hop connection, node self-management, etc., which can greatly reduce the cost and complexity of network deployment, and is a technology for dynamically establishing new links.

2. Technical advantages

The scheme adopts a new wireless network network concept design mobile network group network communication system. The device adopts a non-central distributed network architecture, supports random network topology dynamic network, multi-hop relay, dynamic routing, and is highly resistant to damage. All nodes can move quickly. Real-time network data interaction in a non-line-of-sight blocking environment. Each node in the network architecture, namely MESHPoint (MP), has a self-organized and self-configured dynamic multi-hop network, which is not only a gateway, a router (Client), and a client (Client). Therefore, each node MP can play three roles. Unlike other MESH networks, it is usually divided into three types: MESHGateway, MESHRouter and MESHClient. In the whole network, the roles of nodes are simple and symmetrical, which is especially suitable for the deployment application of mobile grid. When used, any one can realize the self-organizing network function. If any device in the group goes offline, the corresponding device will continue to communicate within the coverage of an active antenna to ensure that the network does not go offline. In practical application, we can use the ring network design without worrying about the blockage of the ring network.

4. Device function

main feature:

1. No central co-frequency group network.

MESH wireless ad hoc network system is a non-central co-frequency system, all nodes have equal status, single frequency point supports two-way communication, frequency management is simple, and spectrum utilization is high. Any node device can act as an end node in the network. Relay node or command node. No matter when and where, no matter other fixed communication network facilities (such as optical fiber, copper cable, etc.), a high-speed long-distance wifi module wireless communication network can be quickly established. All non-centralized co-frequency self-organized network devices, including outdoor fixed stations, emergency layout consoles, vehicle-mounted stations, vehicle-mounted portable stations, etc., can automatically form a wireless network and communicate with each other in real time as long as they are powered on.

2. Fast and flexible multi-node networking

At present, the MESH wireless ad hoc network system can support 32 nodes in the same frequency group network, and can quickly deploy a flexible group network. When each node moves quickly, the system can automatically recalculate the routing relationship between multiple nodes, and quickly generate a new routing table according to the channel quality, data service rate, code error rate and other indicators between multiple nodes. With the information of topology changes, the network topology can be updated in real time. At this time, the voice data and video services will not be affected by the change of the system topology.

3. Quick access to the network

After the node is started and powered on, the group network can be registered in seconds, which is simple and practical. Ensure that system nodes can quickly establish communication when re-entering the network after leaving the network. Vehicle 4 goes offline due to movement. When it gets close to the existing network, it can quickly enter the network again.

4. Fast update routing

7 vehicles form 3 hop topologies. Due to the movement of the vehicle, when the network topology of the high-speed and long-distance wifi module changes, the system can quickly respond to the change of the topology and quickly rebuild the routing system to ensure the smooth flow of information.

5. Choose Smart Routing

If the remaining bandwidth of the optimal path link is insufficient, the high-speed long-distance wifi module MESH wireless ad hoc network can automatically select the suboptimal for information transmission. As shown on the left side of the figure below, when the solid wireless link is full, the vehicle on the far left needs to start a service to the vehicle on the far right, and a transmission path can be established through the uplink shown in the figure on the right.

6. Quickly merge multiple groups.

Due to geographical isolation, the seven vehicle groups were divided into two groups: Group A and Group B. Members of Group A and Group B are temporarily unable to communicate. When the two groups need to coordinate locally and approach again, they can be reintegrated into a 7-car group at 2S~4S. The 7 vehicle members can communicate normally, and the new network topology does not affect the original business transmission.

7. Network topology topology.

MESH wireless ad hoc network system that supports any network topology such as point-to-multipoint, chain relay, mesh network, and hybrid network.

8. Fast mobile high data bandwidth.

The peak data bandwidth of MESH wireless ad hoc network system is 70MBPS (based on 20MHz carrier bandwidth). Under the condition that high data bandwidth services are not affected, nodes have non-fixed mobile transmission capabilities, and fast movement will not affect high data bandwidth services, such as voice.

9. Anti-interference.

Through the external filter, the external harmonic interference can be effectively suppressed, and the anti-interference performance and signal-to-noise ratio of the signal can be improved. At the same time, the ARQ transmission mechanism (automatic retransmission request) is adopted to reduce the loss rate of data transmission and improve the reliability of data transmission. In addition, there is its own frequency sweep function. According to the scanning result of the equipped center frequency, the frequency that is less affected by interference can be manually selected.

Avoid implementing interfering frequencies.

10. Multipath resistance.

The high-speed long-distance wifi module MESH wireless ad hoc network system has strong multipath resistance and supports automatic wireless relay transmission. All nodes in the system support multi-hop relay (relay) communication, which can adapt to various terrains and application scenarios. Especially in mountainous terrain. Dense urban or vegetation cover. Building tall buildings or deep buildings. basement. subway. Tunnels and other conventional radios have difficulty covering or cover weaker scene areas, covering non-visual (NLOS) for the aforementioned obstacles. Surface and underground communications and other demand scenarios can rely on excellent diffraction reflection multipath transmission and penetration capabilities, and then rely on repeaters to effectively cover and expand to achieve multipath relay transmission.

11. Good fault tolerance.

When a single node device fails, the MESH wireless ad hoc network system will not affect the use of the entire network. Wireless MESH network is a network network structure. Therefore, when a node in the network fails, under the guidance of routing protocols, other nodes forward tasks and select the best transmission path for relay transmission, and the entire network can still be used. self-transmission.

The more normal the work is, the more reliable the wireless MESH network is for disaster recovery and the better the fault tolerance.

12. Security and Confidentiality.

The system can effectively prevent illegal users from invading the network by setting multi-lock group encryption, such as operating frequency, carrier bandwidth, disturbance code (ie MESHID), communication distance and network mode. Legal access to the network can only be ensured when the above-mentioned multiple items are completely consistent; the system is a fully self-developed system. The transport protocol is a fully custom protocol. Air interface transmission uses 64 keys, which can dynamically generate perturbation sequences to realize channel encryption and ensure high security of information transmission; in addition, the system also supports AES128/AES256 source encryption.

13. Full IP network interconnection.

At present, the high-speed long-distance wifi module MESH wireless ad hoc network SH wireless ad hoc network system currently supports the undifferentiated transmission of various data, and is easy to interconnect with other heterogeneous communication systems (such as public networks, private networks, microwaves, etc.). Real-time interaction of multimedia services.