About wireless AP coverage knowledge
2019-10-02 14:08:20
AP coverage area: Indoor maximum allowable coverage distance is 35~100 meters Outdoor allowable maximum distance 100~400 meters AP coverage:
The empirical values ​​of penetration loss of 2.4G electromagnetic waves for various building materials are as follows:
A. Cement wall (15~25cm): Decay 10~12dB
B. Wood wall (5~10cm): attenuation 5~6dB
C. Glass Window (3~5cm): Decay 5~7dB
The impact of various building materials on wireless signals is as follows:
When the AP is separated from the terminal by a concrete wall, the AP's transmittable coverage distance is about <5m effective distance.
When the AP and the terminal are separated by a wooden wall, the AP's transmission distance is about <15m effective distance.
When the AP and the terminal are separated by a glass wall, the transmission distance of the AP is approximately <15 m. The effective distance AP is determined:
For an open space with an area of ​​less than 150 square meters, such as public rest areas, small bars, cafes, conference rooms, and western restaurants, if the number of users is expected to be no more than 30, an AP can be placed in each place to meet the demand. When the space is large, multiple APs will be installed to meet the coverage requirement. When the capacity requirement is large, that is, if the number of users in the coverage area of ​​the AP is too large, multiple APs need to be placed in the same space to increase the capacity. AP installation location selection:
Install an AP in a single room and try to place the AP in the center of the hall. The best choice is to place it on the ceiling of the hall. If two APs are installed, they can be placed in two opposite corners of the hall. AP Frequency Planning: Theory Above, the isolation of adjacent frequency points is required to be >= 35db. According to the empirical value, when the adjacent AP sets the same frequency, the interval is required to be more than 25 meters; when the adjacent AP sets the adjacent frequency, the AP needs to be more than 16 meters apart; when the AP sets the frequency, the requirement is: More than 12 meters apart. To maintain a better WLAN, consider the number of users in the coverage area. The number of online terminal users on a single AP should not exceed 30 AP roams: The AP sends a probe every 100 ms. The user can use this to determine the network connection. Quality, then decide which AP to access. When a terminal roams between multiple APs, the new serving AP informs the original service AP in a wired manner and a new connection has been established. Wireless AP roaming protocols are not included in 802.11, and IAP (Interaccess point protocol) is likely to become the standard roaming protocol AP power control: By adjusting the AP output power, the number of users in the coverage area can be controlled to ensure the network quality. When the AP product is shipped, the power is unified. When the user needs to change the power, the corresponding software can be downloaded to adjust the output power.
In the initial stage of the current WLAN construction, the coverage requirements are mainly met, and AP power is less controlled. External interference: type of interference source microwave oven anti-theft device (shopping door inspection) other high-power electronic equipment so AP should be far away from the interference source 1-2 meters Summary: AP planning should follow the following principles: 1. Coverage principle Preferred guarantee signal coverage Users can request; 2, easy installation principle planning site selection should meet the construction requirements
The empirical values ​​of penetration loss of 2.4G electromagnetic waves for various building materials are as follows:
A. Cement wall (15~25cm): Decay 10~12dB
B. Wood wall (5~10cm): attenuation 5~6dB
C. Glass Window (3~5cm): Decay 5~7dB
The impact of various building materials on wireless signals is as follows:
When the AP is separated from the terminal by a concrete wall, the AP's transmittable coverage distance is about <5m effective distance.
When the AP and the terminal are separated by a wooden wall, the AP's transmission distance is about <15m effective distance.
When the AP and the terminal are separated by a glass wall, the transmission distance of the AP is approximately <15 m. The effective distance AP is determined:
For an open space with an area of ​​less than 150 square meters, such as public rest areas, small bars, cafes, conference rooms, and western restaurants, if the number of users is expected to be no more than 30, an AP can be placed in each place to meet the demand. When the space is large, multiple APs will be installed to meet the coverage requirement. When the capacity requirement is large, that is, if the number of users in the coverage area of ​​the AP is too large, multiple APs need to be placed in the same space to increase the capacity. AP installation location selection:
Install an AP in a single room and try to place the AP in the center of the hall. The best choice is to place it on the ceiling of the hall. If two APs are installed, they can be placed in two opposite corners of the hall. AP Frequency Planning: Theory Above, the isolation of adjacent frequency points is required to be >= 35db. According to the empirical value, when the adjacent AP sets the same frequency, the interval is required to be more than 25 meters; when the adjacent AP sets the adjacent frequency, the AP needs to be more than 16 meters apart; when the AP sets the frequency, the requirement is: More than 12 meters apart. To maintain a better WLAN, consider the number of users in the coverage area. The number of online terminal users on a single AP should not exceed 30 AP roams: The AP sends a probe every 100 ms. The user can use this to determine the network connection. Quality, then decide which AP to access. When a terminal roams between multiple APs, the new serving AP informs the original service AP in a wired manner and a new connection has been established. Wireless AP roaming protocols are not included in 802.11, and IAP (Interaccess point protocol) is likely to become the standard roaming protocol AP power control: By adjusting the AP output power, the number of users in the coverage area can be controlled to ensure the network quality. When the AP product is shipped, the power is unified. When the user needs to change the power, the corresponding software can be downloaded to adjust the output power.
In the initial stage of the current WLAN construction, the coverage requirements are mainly met, and AP power is less controlled. External interference: type of interference source microwave oven anti-theft device (shopping door inspection) other high-power electronic equipment so AP should be far away from the interference source 1-2 meters Summary: AP planning should follow the following principles: 1. Coverage principle Preferred guarantee signal coverage Users can request; 2, easy installation principle planning site selection should meet the construction requirements
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