About WLAN design

WiFi network is an essential part of modern estate, same way as electricity or air conditioning. Very often this part is not getting enough focus on design, deployment and testing. Failure in network purchase can happen like this:

  1. The requirements for WiFi are not initially defined by purchaser
  2. LAN cables are designed, but the needs for WiFi access points are forgotten or only socket reservations to random rooms are being defined
  3. Later on, WiFi gears are being purchased among other IT equipments. The gear vendor is often selected based on price tag, not the quality.
  4. Access points are being deployed. The system is tested just by measuring the coverage of WiFi network.
  5. Once there is a real network traffic from real end users, there is no happiness heard. The throughput and reliability is poor. Problems are attempted to be fixed by moving or adding access points. Without any real improvements..

The deployment of WiFi network is easy. Just buy any access points and locate those to suitable locations within the estate. The coverage requirements can be rather easily met by any person knowing something about WiFi.

Thus, making coverage is easy. Having throughput, enough capacity and a good mobility in WiFi is much more challenging. The capacity of the network is not in the amount of access points, but in the interference-free frequencies. To ensure a sufficient amount of these frequencies to users in needed locations, a frequency planning is needed. Preferably this happens earlier or at the same time with cabling design. In frequency planning, the attenuation characteristics of different construction materials and objects are being taken into account. Also the selection on WiFi gear vendor should be done at this phase. The success in WiFi purchase process can happen like this:

  1. The need for WiFi network is identified
  2. Together with WiFi designer, the requirements for the network are being agreed. For example:
    • The device types and device estimated amounts in deployed network
    • Mobility needs
    • Needs for the voice services
    • The coverage holes (elevators, pathrooms etc.)
    • Guest networks
    • The security level
  3. WiFi designer investigates the attenuation values of the construction materials to be used in the building. WiFi gear vendor is also selected. Based on the CAD floor plans, the access point locations and antenna locations are being designed. As a result, the cabling to access point locations can be defined. As another result, the initial configurations for network are available. (access point power levels etc.)
  4. Access points are being deployed according design. System is being configured by WiFi designer or according design documents.
  5. The network is being validated with measurements and test equipment to ensure the requirements are being met. Preferable testing is performed in real load situations also. The documents about test results are being created for a customer. The maintenance of the network is agreed.

It is good to remember when selecting WiFi network gears, that the user devices are renewed typically with significantly higher rate. (Roughly 2 years renewal rate expected.) To update or change a WiFi network already in production use is at some level always risky. It is really a worth of putting effort to the design phase, to ensure later network changes a kept on minimal level.

Case warehouse: The amount of stuff on the shelves greatly impacts to radio propagation. This needs to be though at the design phase, to ensure wireless devices are working regardless if shelves are full or almost empty.

 

 

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