Wireless technology in video surveillance systems. Part 1: The original Wi-Fi technology was used where there was no possibility of laying the cable. However, over time, wireless is becoming more spread not only in order to bring computers, but in video surveillance systems. Currently, the video surveillance market growing share IP video cameras, among which are a large number wireless solutions. That makes it easier to use the latest installation of video surveillance systems. However, the wireless solution has some nuances that leave their mark on this system.
First, it is worth noting that there are several standards of wireless networks. This so-called standards a, b, g, n. Each of them is supported by the maximum allowable speed of the connection: 11 Mbit / s, 54 Mbit / s and 300 Mbit / s, respectively. It is fair to say that the connection speed and actual speed are very different, and this difference is about 2 times. Thus, with increasing distance between Wi-Fi client and access point (or router) is reduced and the connection speed. These points should be considered at the design stage wireless video surveillance system. Based on the foregoing, we should also expect the configuration of your wireless network: the number of wireless devices and their configuration, the need to connect more with different antenna pattern and power. However, this will be a separate article later.
As for the standard Wi-Fi, then each new standard supports the previous ones. At the design stage it is important to choose and arrange equipment for wireless video surveillance as well as selected access point 802.11g standard is not allows you to take advantage of speed, which can give you a wireless IP camera standard 802.11n. Above I mentioned that depending on the speed wireless connection from a distance. Now bring some figures that will be useful. Standard 802.11b: indoors: 30m distance: 11 Mbit / s connection speed, 5 Mbit / s transmission speed, distance 91m: 1 Mb / s connection speed, 0.5 Mbit / s transfer rate, open space in the line of sight: 120m distance: 11 Mbit / s connection speed, 5 Mbit / s transmission speed, distance 460m: 1 Mb / s connection speed, 0.5 Mbit / s transfer rate. Standard 802.11g: indoors: 30m distance: 54 Mbit / s connection speed, 25 Mbit / s transmission speed, distance 91m: 1 Mb / s connection speed, 0.5 Mbit / s transfer rate, the open space in the line of sight: length 120 m: 54 Mbit / s connection speed, 25 Mbit / s speed, distance 460m: 1 Mb / s connection speed, 0.5 Mbit / s transfer rate.