1、The basic composition and characteristics of 4G mobile communication technology

(1) 4G communication technology. The address mode used by the 4G LTE communication technology is Orthogonal Frequency Division Multiplexing (Multi-URL). The channel is divided into a plurality of orthogonal sub-channels in a given frequency domain, and each sub-channel is equipped with sub-carriers to complete the required The debugging function, the subcarriers are in a parallel state, and the signals are transmitted such that each subcarrier has a flat channel. This way, the interference between the signal waves can be eliminated or reduced, and the spectrum utilization efficiency is significantly improved. 4G LTE evolution technology can also enable fire communication to be updated more quickly, and technically ensure that fire communication is in a state of rapid development.

(2) Technology evolution of 4G. LTE Advanced enables wireless pop resources of more than two dispersed frequency bands to be integrated to achieve carrier aggregation. This ensures that mobile communication systems in a wide physical frequency band are in normal operation and allow wireless data access. The rate is significantly improved, and the bandwidth of the wireless data enables a wider peak rate, which minimizes the end-to-end delay.

(3) Mobile GIS technology. Based on the mobile computer environment, mobile terminals in limited processing capacity can implement mobile GIS technology. The GIS of information service provides mobility, distribution and randomness. This system integrates GPS, GIS and mobile communication. Achieve the joint application of the three technologies. The use of GIS can also effectively manage and analyze spatial data, and can accurately locate and track under the influence of GPS. The data acquisition function can be successfully completed by PDA. With the support of mobile communication technology, sound, text and image are guaranteed. Wait for information to be transmitted securely. In terms of composition, it includes a mobile terminal device, a wireless communication network, a spatial database, and a geographic application server.

Features of 4G mobile communication technology and its application in emergency communication at fire site

(1) Wireless video transmission technology. Based on the advanced video compression technology, the wireless video transmission technology is developed. Under different coding structures, the video image is more consistent with the texture feature. Under the action of the block structure, the size of the motion compensation block is used as the basis for the change. The size of the block is effectively adjusted to make it more adaptable, ensuring that the capability concentration, image ringing effect and detail retention are in the most balanced state; when the sampling point is adaptively offset, the reconstructed image can be realized. Scientific classification ensures that an image shift occurs in the image pixels, maintaining the authenticity of the image and reducing the distortion of the image. Under the effect of adaptive loop filtering, the reconstructed image can be restored, so that the original image and the reconstructed image have the smallest Mean square error. In addition, wireless video communication technology also uses the most advanced 4G mobile communication technology, which enables image video to be transmitted.

(2) Characteristics of 4G communication technology. 4G communication technology is the most advanced mobile communication technology, and its advantages and features are very significant. 

①  4G communication has a high transmission speed and can achieve 100 Mps. 

② 4G communication technology has good flexibility. It is not limited by time and space in application, and it can make data transmission faster and cope with various problems in the middle. 

③ It can realize high-definition transmission of images and improve the receiving rate of image transmission. 

④ 4G communication technology has good compatibility, it can connect different mobile ports, and can provide various terminal information services. Therefore, the advantages of 4G communication technology make it a good application in mobile communication technology, and it can meet the requirements of “quick, accurate and urgent” in fire rescue.

Application of Main System Functions of 4G Mobile Communication Technology in Emergency Communication at Fire Field

(1) Keep the signal clear. In the event of a fire, the link function of the wireless 4G network can ensure the smooth signal transmission of the fire department, enabling efficient wireless connection between the fire scene and the command center. In the fire rescue process, the command center needs to cooperate closely with the rescue site. With the support of the 4G network, the command release and real-time rescue situation can be quickly transmitted at the command center and the site to ensure that the signal will not be interrupted due to the fire change. The information transmission during the rescue process provides guarantees and improves the continuity and stability of emergency communication.

(2) Implement image transmission. 4G communication has an efficient image transmission function, which provides strong support for firefighting fire emergency communication of firefighting units. It can provide real-time disasters at different locations within the fire range to the command center in the form of images, and make the disaster relief plan for the command center and the accident handling. Provide information to ensure the effectiveness of the command work. Using the integrated management platform as an effective carrier, the network software and the client can realize the comprehensive scheduling of the software, which can feedback the scene, image and sound information of the disaster rescue, and can also be applied in the network video monitoring system. The digital communication management of video and audio is of great significance for fire command, which makes the command and dispatch clear and visible, and also meets the flattening requirements. The fire command center can get the latest fire dynamics in the first time. 4G communication technology is used to transmit images to ensure its quality and increase the transmission speed. Compared with 3G communication technology, it has a wider application prospect, and it also brings more convenience to fire command work.

(3) Road monitoring. When receiving a fire alarm, the time when the fire rescue team arrived at the scene had a direct impact on the rescue situation. Unsuccessful losses may occur in the next minute. Using the real-time monitoring function of the 4G network, it is possible to reasonably plan the travel route of the fire truck, monitor the entire road section to the fire scene, ensure that the fire truck can reach the scene in the shortest time, carry out rescue work, and control the fire at the fastest speed. To prevent further spread of fire and reduce the damage caused by fire.

(4) Provide a stable broadband channel. 4G technology enables the wireless channel to be at maximum bandwidth while maintaining channel stability. In the process of firefighting personnel, the stability of the wireless broadband channel is ensured, so that the position of each firefighter can be accurately displayed, and the ventilator status information can be fed back in real time to ensure the personal safety of the rescue personnel. The rescue site provides a more complete helpless data transmission channel.

(5) Real-time monitoring and scheduling. When the fire department conducts fire information transmission, it must meet two requirements. The first is that the fire department leader needs to get timely vehicle image monitoring, and the second is to remotely monitor the city's high fire disaster sites. In the event of firefighting, firefighters are very concerned about the driving conditions of the vehicles. Including road smooth conditions, in-vehicle water storage, etc., 4G communication technology enables the command center to timely understand relevant situations, achieve the most efficient vehicle scheduling, and monitor vehicle trajectories and time. Monitoring can be achieved from the time the vehicle exits, to the completion of the rescue, which also allows the fire department to record the rescue situation in detail, so that it can be checked. In addition, today's fire protection work is gradually developing in the direction of prevention and elimination, and real-time monitoring of high-risk units of fire. The use of mobile 4G communication technology can make all-round monitoring become a reality, making monitoring more accurate and reasonable.

Issues that need resolving

(1) Network security and stability. For network communication, the most important thing is security and stability, which is the basic guarantee for the effectiveness of on-site communication. To achieve uninterrupted network communication, stability needs to be improved. In the 4G mobile communication technology, when performing core device processing, hot backup using dual or dual service boards is the best choice. Once the host fails, the backup device can be enabled in time to maintain continuous communication. On the security issue, you can choose to use the open authentication encryption algorithm to complete the communication security work, which can reject the link of unknown devices. In order to ensure that the communication link is in a secure environment, the access layer security function is implemented in LTE, which can separately encrypt the user plane data and the control plane data, and can also ensure the integrity of the control plane data. Therefore, 4G communication technology can provide a stable and safe information channel for fire emergency rescue, ensuring the smooth completion of disaster relief work.

(2) Integration of network and communication equipment. The 4G mobile communication network uses the all-IP network as the core network, enabling uninterrupted links between different networks. The core network can meet end-to-end IP services and has good compatibility with the established core network. Integrating the 4G network with the communication equipment in the coverage area enables deep integration of the satellite system and the 4G mobile communication network. During the emergency rescue process, the fire brigade has diversified forms of on-site emergency communication, and can make the communication channel in an unimpeded state, avoiding the phenomenon of communication, and let the advantages of 4G communication technology be fully utilized. Emergency rescue work provides communication guarantees for efficient completion of emergency tasks....