Wireless interference problem in the construction of wireless network

In wireless network construction, engineers will consider the problem of wireless signal interference. So, this article will tell you 20 about wireless interference error, so that we have a correct understanding of wireless interference. See below for details, then.

With the popularization of wireless devices and the improvement of mobile application requirements, enterprises must be diligent in managing and planning the entire deployment. And some of the new or emerging wireless technology and common electronic devices have affected the performance of wireless networks. RF interference is the most important factor affecting the operation of the wireless network, it will affect the security and the stability of the wireless network. This article lists 20 of the most common wireless interference errors in the wireless jamming problem.

Wireless jamming error saying #1: "The only interference comes from the other 802.11 networks." ”

802.11 devices are countless, and the other 802.11 networks will certainly interfere with your network. This interference is known to be the same frequency or proximity frequency interference, but since 802.11 devices are followed by the same protocol, so they can cooperate with each other-that is, 2 wireless access points on the same frequency share channel capacity. But in fact, in a band without a license limit, the number of other types of equipment is far more than the number of 802.11 devices. Other devices include microwaves, cordless phones, Bluetooth devices, wireless cameras, outdoor microwave links, wireless game controllers, ZigBee devices, fluorescent lights, WiMAX, and so on, even a bad electrical connection can produce very wide RF spectrum. These non-802.11 types of interference do not work well with 802.11 devices, and they greatly reduce throughput. In addition, they can have two effects, such as reduced rate, interference caused by data retransmission will mislead 802.11 device use low number

According to the rate rather than the appropriate rate.

Summary: Unlicensed frequency bands are an experiment in which the FCC is sharing an irregular spectrum. The experiment has been a great success so far, but RF interference poses a great challenge and needs due attention.

Wireless jamming error saying #2: "My network seems to be working, so jamming is not a problem." ”

The 802.11 protocol is designed to a certain extent to resist interference. 802.11 the device finds interference before the data is transmitted, it pauses the transmission until the disturbance disappears. If the interference occurs during transmission (and the interference causes the packet to not receive properly), then confirm that the packet is not received to retransmit the data.

The final packets will all pass. However, pausing or retransmission of data can severely affect your wireless network capacity and performance.

For example, the microwave oven produces a 50% interference (due to the 60-hz AC cycle) of the duty ratio. This means that the microwave is consistent with your 802.11 wireless access point, reducing the network capacity and performance by 50%. So if your wireless access point rate is designed to be 24Mbps, you may only have 12Mbps around the microwave you are using. If the application on your wireless network is just receiving data (such as surfing the web), then the loss of throughput may not feel obvious. But if you use capacity and latency sensitive applications, such as wireless voice, then controlling interference becomes an important issue.

Summary: Interference is everywhere, it is just a silent killer.

Wireless jamming error saying #3: "I did an RF cleanup before deployment, so I found all the sources of interference." ”

One of the most troubling disturbances is that interruptions are always intermittent. May interfere only at a time of day or week--such as when someone uses a wireless headset. Therefore, unless the continuous cleaning, it is easy to omit some interference sources. Even if you continue to clean up (for example, a 24-hour test in each place), things around you will change over time. Some devices that work in unlicensed bands can easily enter your network environment. No amount of periodic cleanup can guarantee you a completely undisturbed environment.

Summary: It is impossible to eliminate interference problems. Microwave ovens, cordless phones, Bluetooth devices, wireless cameras, outdoor microwave links, wireless game controllers, ZigBee devices, fluorescent lights, WiMAX, and so on, even bad electrical connections-all of which can produce RF spectrum. None of these 802.11 devices can collaborate with 802.11 devices.

Wireless jamming error saying #4: "My infrastructure device automatically detects interference. ”

Some new, switched-based wireless infrastructure products can manage RF interference to a certain extent.

The 802.11 chip detects a non-802.11 signal and then changes the 802.11 channels that interfere with the wireless access point in the zone. But the problem with this function is that he can't solve the problem outside the area. Some jamming devices-such as Bluetooth devices, cordless phones, 802.11 fh devices, and man-made jamming signals-are all broadband, and they are ubiquitous, so changing channels does not avoid them. Even for a device running at a fixed frequency, it can be difficult to manage frequencies in a large, cellular-based network. Therefore, the analysis of the interference source, determine the nature of the device, and then determine how to resolve the interference is the most critical. In many cases, the best solution is to take the device away. Sometimes it is a good choice to move or block the device and avoid interfering with the network.

Summary: Simple, it is useful to interfere with products that can react automatically, but you also need to have a certain understanding of potential problems.