How much do you know about the 3G / 4G / wifi

In the field of vehicle monitoring, the most widely used is still 3G, 4G wireless technology. 4G is undoubtedly an evolved version of 3G. In terms of upstream and downstream speeds, 4G has doubled its base on 3G. It has an absolute advantage in speed and has the ability to transmit higher quality picture quality. In today's 4G era, the pace of its replacement of 3G will be more clear. Operators will continue to increase the construction of 4G base stations, correspondingly stop the construction of 3G base stations, and even replace the original 3G base stations with 4G base stations. However, in the actual wireless transmission process, it is often interfered by factors such as base station coverage, use environment conditions, and busy wireless network, which affect the stable application of the wireless network. In this regard, in order to meet the real-time transmission requirements in any wireless network environment, the manufacturer will use the network adaptation function. In the variable stream mode, the vehicle-mounted system can automatically adjust the stream size according to the strength of the environmental signal and the narrow and wide network channel. , Video quality and transmission strategy, such as: in the case of 3G network, CIF, D1, 960H and other low-resolution video streams; in 4G network, 720P, 1080P and other high-resolution video streams. 4g technology for vehicle monitoring The fatal flaw of WiFi wireless technology is the short transmission distance. The transmission distance of general civilian WiFi is about 10-30 meters, and the industrial-grade stable transmission distance is about 100 meters. However, 3G and 4G wireless transmission technologies can cooperate with multiple base stations to achieve global network signal coverage and achieve traditional wireless transmission that is not limited by distance. However, the use of 3G and 4G will inevitably bring high costs. Therefore, some manufacturers have proposed WiFi LAN high-bandwidth transmission solutions for their vehicle monitoring systems. Under normal circumstances, when 3G and 4G are dormant, the front-end vehicle-mounted equipment stores video and audio data and enters a fixed location covered by WiFi (such as a garage) , Site), the use of high-bandwidth WiFi network to transfer data to the background; when there is mobile monitoring needs, then automatically wake up 3G, 4G for real-time transmission; such a flexible combination can meet the user's low cost, high efficiency, ready to use Use needs.