This article introduces in detail the common Wifi channel interference faults (including assisted channel interference and overlapping channel interference) in areas where APs are densely distributed. For different fault types, simulation experiments are conducted under different level environmental conditions to obtain provide valid evidence. At the same time, this article will share troubleshooting tips to help us solve related fault problems more effectively.
The widely popular home-level mid-to-low-end Wi-Fi devices on the market all use the 802.1In protocol and work in 2.4Ghz mode, and use the higher-speed 40Mhz channel bandwidth by default. Wifi technology has been widely used in thousands of households. In areas where APs are densely distributed, interference between channels will inevitably occur.
1. Simulation experiment
1.1 Experiment on simulated Wm signal coverage overlap. I used 2 Wifi routers with different prices and brands. I used 4 computers for testing, of which 2 computers were used as FvI’P servers and 2 computers were used as wireless terminal devices ( does not have MIMO technology). As shown in Figure 1-1, set up 2 APs, named Testap-A (node A) and Testap-C (node C) respectively; set up 2 computers, named PC-B ( terminal B) and PC- D (terminal D). Among them, node A and terminal B are interconnected; node c and terminal D are interconnected. For node A and terminal B, node c is a hidden node. The purpose of this experiment is to test the impact of different channel interference conditions on the actual rate bandwidth when the channel numbers of the two APs are different.
1-2 When the channel bandwidth of the interfering AP and the interfering AP is both 40Mhz:
In the experiment, the channel bandwidth of node A and node c is set to 40Mhz. Node A is fixed at “1 5 channel”, the rate of terminal D is set to 50 Mbps, and the channel of node c is adjusted to gradually move to “1 5 channel”. As shown in Figure 1-2, in the 2.4Ghz frequency band, there is only one condition for two APs to achieve non-interference with each other. Under this condition, terminal B can stabilize at 68Mbps . When node C gradually “translates” to the channel, so that the channels of the two APs begin to cross and overlap with each other, the rate bandwidth of the interfered terminal B decreases rapidly. When the scope of cross-over overlap becomes closer , the degree of deterioration becomes more severe, and the peak value is only 0.5Mbps, this interference situation is “overlapping channel interference” (Overlapping). When the channels of the two APs are completely in “channel 1 5”, the rate of the interfered terminal B is greatly increased to 48Mbps, and the channel deterioration is improved. At this time, it is “assisted channel interference” (Co-channel 1).
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