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WLAN frequency planning needs to take into account the specific conditions of building structure, penetration loss, and cabling system. In principle, only the 2.4 GHz frequency band can be used; the 2.4 GHz frequency band is preferentially used for indoor and outdoor deployment. If the 2.4 GHz frequency band cannot avoid the same frequency interference, or to increase the system capacity, the 5 GHz frequency band can be introduced.
2. Living area signals cover living areas including rooms and dens. There are more internal rooms, more walls, and signal attenuation. According to business needs, APs are deployed independently in specific rooms, and it is advisable that the signals penetrate only one wall.
3. Reception area coverage The reception area includes living room, dining room and banquet hall. Large area, high floor, empty interior. The signal attenuation is small, but the number of access terminals is large. APs need to be deployed in the guest area to ensure multi-user access capacity.
4. Obstructions Radio transmission occurs when radio waves encounter obstacles that cannot be diffracted during propagation. According to the material and thickness of the obstacles penetrated, and the frequency of electromagnetic waves, the transmission losses are also different.
On-Site Investigation of Wireless Networks 1. Geo-survey - the main factors influencing WLAN communications • Direct interference The direct interference is caused by WLAN equipment operating in the same frequency band. For example, 2.4 GHz has three independent channels. If two channels cover the same channel when they are covered, the device will renegotiate and transmit signals when it is interfered with. Therefore, the data will be interrupted and the application will not change.
Unreasonable channel design • Indirect interference is mainly caused by electrical interference, such as generators, telephone systems, microwave ovens, wireless Bluetooth headsets and other household equipment.
2. Preparation tools for land surveys • Survey tools for preparing wireless terminals (laptop, wireless network card, PDA, Wi-F iPhone)
AP and/or AC
Long range distance backup power supply (including PoE power supply)
Signal Test Software: inSSIDerHome
3.AP Installation Suggestion The installation mode of the wireless intelligent AP is flexible, and it does not need to be installed in the wall. It can also be placed in the concealed place such as the air inlet at the air inlet according to actual needs.
Deploying 1 AP per 1-2 rooms, it is generally advisable to penetrate only one wall. Each AP must not penetrate two walls. For rooms with high network requirements (applications for online games), the most It is better to deploy an AP independently; if two adjacent rooms are to be deployed with APs, then in order to prevent interference, APs should be deployed back-to-back on adjacent walls; the signal coverage radius should be around 20-30 meters; in most cases The best choice is to choose 50mW transmit power. In a few cases, consider the signal coverage and radiation problems, and reduce the transmit power appropriately.
The signal coverage of the open zone attenuation table • Signal strength measurement When the signal is greater than -65dBm, then the signal coverage can meet the normal use;
When the signal is less than -70dBm, then the signal coverage here can not meet the normal use;
So the signal strength reaches -70dBm, which is the critical value for signal coverage.
• Due to the complexity of the building structure in the indoor area, planning and design need to strictly test the signal coverage (channel, power) of each room and reduce signal interference;
Consider the access capacity of a specific area;
Consider roaming between APs.
4. Indoor Geological Survey Steps • Determine the location of the first AP Place the reference AP on the corner of the building (reference location), then. Walk diagonally across the opposite side until the received signal strength is -70dBm, at which point the location of the first AP is placed.
Walk outwards where the first AP is placed and find all -70dbm endpoints that are the cellular boundaries of this AP.
• After determining the location of the second AP. After determining the coverage cell and the boundary of the first AP, the next AP is determined from the cell boundary of the first AP and the location of the second AP is determined as before.
After determining the location of the second AP, in order to ensure overlapping signal coverage of different cells, the second AP may be slightly close to the first AP.
Place the second AP and move it outward to find all -70dbm endpoints. These endpoints are the cellular boundaries of the AP.
• Determine the location of other APs Follow the above method to determine the locations of other APs in succession.
The division of the channel pays attention to the same frequency interference. The overlapping area of ​​cells should not be too large to avoid network performance degradation due to frequent roaming. Usually 15%-30% cellular coverage is used.
After determining the location of the AP according to the signal strength, it is possible to walk freely within the building, and at the same time, the address of the public network of the PING or the gateway address of the public network is long to ensure the stability of the communication after determining the location of the AP.
5. Outdoor survey As the outdoor open area is well covered, the planning and design are relatively simple. It is necessary to examine: how long the coverage area is, how many (area) installation positions are wide, and preliminary placement of APs to carry out pilot test of coverage signals.
Outdoor scene AP deployment: For signal coverage of outdoor gardens, in order to avoid the cost and impact of the deployment of moisture-proof, moisture-proof, and damp-proof environments, it is recommended to install it on the first floor or the second floor inner wall near the garden.
Wireless network test and acceptance 1. Signal strength detection After connecting to Wi-Fi, open the inSSIDerHome software to check the signal strength: the signal strength is maintained at -20~-50dBm which is a relatively strong signal.
• When the signal is greater than -65dBm, then the signal coverage here can meet the normal use;
• When the signal is less than -70dBm, the signal coverage here does not satisfy normal use;
• The -70dBm notebook computer can only use the low speed, while the handheld smart terminal, due to its small antenna and low chip sensitivity, will be more difficult to use.
2. Roaming test • Connect to AP1 first, and then roam from AP1 to AP2 to test access to the Internet, data transmission is not interrupted:
• Use the cmd command or terminal command on the PC to continuously ping the public network address to test the roaming loss situation:
• Then go from AP1 to AP2 and roam to see the packet loss situation.
• Test the roaming of other APs as described above.
If the client may be covering the overlapping area with two AP signals and the signal strengths are not much different, there may be situations where roaming cannot be successful.
Smart home integration project wireless network coverage design Raiders
1. Signal coverage and WLAN frequency channel planning When using 2.4GHz frequency points, in order to ensure that the channels do not interfere with each other, up to 3 non-overlapping frequency points can be provided to work simultaneously in a coverage area. Usually, 1 and 6 are used. 11 frequency points. The 5 GHz 24 frequency points do not overlap and can be used in the same coverage area.