The reason of wireless network signal instability 1. Wireless signal coverage and penetration.

In the home environment, the distance is short, and general wireless LAN devices claim that the transmission distance is above 100 meters, so the signal transmission distance is not a problem. However, the family environment has brought a new problem, that is, the family space is crowded and the space is not open enough, among which the wall in the room is the most important obstacle. Because WLAN uses wireless microwave frequency band. The biggest feature of microwave is that it propagates almost in a straight line and its diffraction ability is very weak, so the wireless receiving equipment behind the obstacle will receive weak signals or no signals. What about infiltration?

This is the most concerned issue for many netizens. Everyone hopes that the wireless signal can at least penetrate the partition wall in the house. The effective way to improve the ability of wireless signal to penetrate the partition wall is to increase the antenna gain. When purchasing wireless AP, we'd better choose products with high antenna gain, generally at least 2 dBi is better. According to experience, the gain antenna signal of 2dbi can penetrate two walls. If there are too many rooms and a lot of partitions, it is best to equip the equipment with detachable antennas, so that high-gain antennas can be configured, for example, an omni-directional antenna of 5dBi can be used to enhance it.

Obstacles of metal objects will not only block microwave wireless signals, but also absorb electromagnetic energy, resulting in weak current discharge. Therefore, the biggest obstacle for metal objects without wireless signals in the home environment is the floor with steel mesh, and the signal in this direction is almost impossible to penetrate. To penetrate, the signal is also very weak. For such a large obstacle, microwave diffraction is even more impossible. If the antenna of the antenna device is placed in the center of the room, the wireless signal can only be emitted from the window in a straight line through an open channel.

After we know all the above factors, we must choose the best location for the wireless access point. The requirements for this placement point are as follows:

First, the position should be higher, so as to radiate downward at a higher place, reduce the obstruction of obstacles and minimize the signal blind area;

Second, the selection of anchor points should make the signal pass through the partition wall as little as possible, and it is best that the wireless client in the room can see it with the wireless AP.

Therefore, the best place for wireless AP to be placed at home should be the living room, and it is best to look at it with a computer host in the room.

2. Performance of WLAN

With the rapid development of WLAN, users run more and more key applications on WLAN, so many common high-bandwidth applications, such as video applications, need WLAN to provide higher bandwidth to achieve high-quality performance! We know that the wireless AP device is a? Wireless * * * enjoyment devices ",that is, devices that * * * access wireless clients, are running CSMA/CD (Carrier Sensing Multiple Access/Collision Detection) of Ethernet. What is this? * * * enjoy "network works in the same principle as the previous network hub network, except that the hub cable is abandoned and changed to wireless.

This * * * sharing environment is an inherent disadvantage of wireless LAN, so it is generally recommended that a wireless router or wireless AP can only access 30 wireless clients at most in order to use the current network applications normally and smoothly. If it is exceeded, the transmission performance of the network will be greatly reduced. It seems that home users generally don't have so many wireless clients, so wireless LAN is completely acceptable for families. But try to avoid BT in wireless networks. E donkey and other P2P download software, because it may paralyze the whole wireless network.

BT electric donkey adopts the method of file segmentation and multipoint transmission to improve the file transmission speed. BT software will first divide a file into several parts at the uploader's end and provide it for users to download. When downloading these files, the downloader does not download the divided files in sequence, nor does it need to download the rest from the uploader's computer, but can download them to other downloaders through the distributed cross-download program of BT software. At the same time of downloading, the downloader also undertakes some uploading work, and downloading and uploading are carried out simultaneously, which greatly improves the downloading speed of files, but only if many people download the same file at that downloading point at the same time. When there is only one or two downloaders, the download speed will not be very fast.

BT download is more commonly regarded as a heavyweight killer that devours bandwidth. This is also the biggest reason given by many broadband operators when they announced the ban on BT. In the * * * exclusive network, if you use BT to download, it will take up other online applications to a great extent, making the overall network speed slow down or even increase? Traffic jam. "

Summary: As long as I can correctly understand the wireless characteristics of WLAN and wireless AP, deploying wireless networks at home can be very comfortable. Summarize the factors that affect the wireless network: avoid wireless devices in the same frequency band in the wireless network area and avoid the interference of wireless channels. Wireless AP should be placed in a higher place, visible to wireless clients as much as possible, avoiding blind spots, penetrating too many partitions and being blocked by metal obstacles. Since the wireless network is a * * * exclusive network, BT-type software downloads with large traffic and even network congestion should be avoided.

3. Interference of wireless signals

Because WLAN radio frequency adopts ISM (industrial, scientific and medical) radio frequency band, of which 802+38+0b. 802. 1 19 standard uses 2.4G frequency band, and 802. 1 1a standard uses 5.8G frequency band. Therefore, in the actual operating environment, WLAN will be affected by some sudden RF interference from wireless devices in the same frequency band. Such as a microwave oven. Bluetooth cell phone signals are all in the 2.4G frequency band.

Therefore, when working in WLAN, the microwave oven in the area where it is located suddenly turns on, or the Bluetooth mobile phone uses the Bluetooth headset, or other wireless devices in the same frequency band suddenly work, which will interfere with the wireless signal of WLAN. Changes in the physical environment of the wireless network, such as the sudden appearance of a large obstacle between the wireless AP and the wireless client, will directly lead to a sudden and substantial decline in the network performance of the wireless local area network, which will directly lead to the interruption of wireless signals or the reduction of the rate.

There is the interference of WLAN itself, that is, the interference of different channels in the same frequency band. This interesting situation happens to home users, and it can only be that the wireless APS of adjacent or similar buildings on the same floor interfere with each other. Adjacent wireless AP devices should use different channels without mutual interference. Such as: 802.11b. 802. 1 1g can use channels with a difference of five frequency bands to eliminate interference, and the typical interference-free channels are set to 1 respectively. 6。 1 1 channel.

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Articles about wireless network signals:

1. Wireless network signal setting skills

2. Wireless network signal setting methods and skills

3. What are the main factors that affect the signal coverage of WiFi wireless networks?

4. The wireless network connection can't receive the signal.