Field strength requirements in different WLAN coverage areas

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Depending on signal strength requirements on a WLAN, the field strength requirements are as follows:
- Hotspot field strength: The field strength in major coverage areas ranges from �?0 dBm to �?5 dBm. Field strength higher than �?5 dBm may cause receive overload, and field strength lower than�?0 dBm may reduce the network connection rate.
- Edge field strength: It is determined based on the receive sensitivity and edge bandwidth. Generally, the edge field strength is higher than �?5 dBm. The Internet access requirements can be met even if the network connection rate is reduced.
- Interference field strength: The co-channel interference strength in the same area should not exceed �?0 dBm.
- Leakage field strength: The leakage field strength 10 m away from a building should not exceed �?0 dBm.

Other related questions:
How many types of target coverage areas are there on WLANs? What are field strength requirements in these areas
WLAN networks involve the following target coverage areas: - Major coverage areas: places where many users need to connect to the Internet, such as dormitories, libraries, classrooms, hotel lobbies and guest rooms, meeting rooms, offices, and exhibition halls. - Minor coverage areas: places where few users need to connect to the Internet, such as bathrooms, stairways, lifts, corridors, and kitchens. - Special coverage areas: special areas where users allow or prohibit WLAN access. Depending on WLAN access requirements in the preceding areas, various field strengths must meet the following requirements: - Hotspot field strength: The field strength in major coverage areas ranges from -40 dBm to -65 dBm. A field strength higher than -40 dBm may cause receiver overload, and a field strength lower than -65 dBm may reduce the network connection rate. - Edge field strength: It is determined based on the receiving sensitivity and edge bandwidth. Generally, the edge field strength should be higher than -75 dBm. The network connection rate in minor areas can be lower than that in major areas. - Interference field strength: The co-channel interference strength in an area cannot exceed -80 dBm. - Leakage field strength: The leakage field strength 10 m away from a building cannot exceed -90 dBm.

Types of target coverage areas on WLANs
WLANs can provide wireless coverage in the following target areas: - Major coverage areas: places where many users need to access the Internet, such as dormitories, libraries, classrooms, hotel lobbies and guest rooms, meeting rooms, offices, and exhibition halls - Minor coverage areas: places where few users need to access the Internet, such as washrooms, stairways, lifts, corridors, and kitchens - Special coverage areas: places where WLAN access of users is allowed or prohibited

Coverage distance of the WLAN
In an open environment, the coverage area of an AP is 100 m. When there are interference sources, such as microwave ovens, electromagnetic ovens, or other APs, near the AP, the coverage area decreases and the signal quality of the AP degrades.

What is the WLAN coverage range
Generally, the WLAN coverage range various according to the environment. When no external antenna is used, the WLAN coverage range is about 250 meters. In the semi-open space or the space with a compartment, the WLAN coverage range is about 35 to 50 meters. When external antennas are used, the WLAN coverage range increases with the antenna gain and is determined according to customer requirements. If an outdoor antenna and amplifier are used, the WLAN coverage range can reach up to several tens of kilometers.

Where are interference sources on a WLAN and how is the interference strength
Two frequency bands are available on WLANs: 2.4 GHz and 5 GHz. The 2.4 GHz frequency band is the Industrial, Scientific, and Medical (ISM) open frequency band. Interference sources in the 2.4 GHz frequency band include cordless phones, baby monitors, microwave ovens, wireless cameras, bluetooth devices, infrared sensors, and fluorescent light ballasts. Compared with 2.4 GHz frequency band, 5 GHz frequency band has fewer interference sources and more devices begin to use the 5 GHz frequency band, such as cordless phones, radars, wireless sensors, and digital satellites. In most cases, microwave ovens work at the frequency band ranging from 2.4 to 2.5 GHz, which overlaps the 2.4 GHz frequency band used by WLAN devices. In addition, the power of microwave ovens ranges between 800 W and 2000 W, which is much higher than the transmit power of APs and STAs. Even though interference shielding is performed, microwave ovens still have severe interference on WLAN devices. Microwave ovens greatly reduce the throughput of WLAN devices if they are within a distance shorter than 8 meters around WLAN devices. The power of cordless phones is about 3 W, which is higher than the AP's transmit power. According to the test analysis on the interference caused by cordless phones on WLAN devices, when the distance between cordless phones and APs (or STAs) is within 1 meter, interference increases significantly. When the distance is shorter than 0.5 meter, WLAN devices are even offline and the cordless phone voice is not clear. Therefore, you are advised to deploy cordless phones more than 2 meters away from APs or STAs. The transmit power of wireless cameras ranges from 500 mW to 1000 mW. In indoor scenarios, wireless cameras may affect the WLAN network but have lighter interference than microwave ovens and cordless phones. Therefore, you are advised to deploy wireless cameras far away from WLAN devices during WLAN planning. Bluetooth devices use the frequency hopping spread spectrum (FHSS) technology and 1 MHz channel bandwidth. If a bluetooth device is sending data at the frequency band overlapping with a WLAN channel that is being monitored by a WLAN device, the WLAN device selects a random backoff period. During this period, the bluetooth device changes to work at a non-overlapping channel, allowing the WLAN device to send data. Therefore, bluetooth devices have small interference on WLAN devices. This interference can be ignored during WLAN planning.

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