Planning and implementation
In some sense, the implementation of a wireless mesh network can be deceivingly simple. Today's wireless mesh network equipment allows you to install APs, plug them into an electrical source, and turn them on. The APs automatically identify and connect to other APs in line of sight. However, if the organization involved in setting up the network fails to spend the time to consider and plan for all the operational and environmental factors which impact each installation, the network won't have the necessary coverage and capacity to provide the quality of service expected by users. In many cases, this renders the network useless for many of the intended applications. Below, I'll address the issues to consider when planning a wireless mesh network.

Environment
Many factors impact the performance of wireless signals. In an outdoor environment, the construction and location of buildings, foliage, and natural and man made obstructions can degrade or block wireless signals. Similarly, in an indoor environment, the building composition, contents, and interference sources, such as microwave ovens or electronic equipment, affect service quality.

Use of the network
The number of users accessing the network, and the type of applications they'll employ are important to consider. For example, significantly more users will access the network in a government office than in a parking lot. Also, applications such as public safety communications require high bandwidth, and secure, uninterrupted service.

Coverage and connection
One of the benefits of a mesh network is that all the APs can potentially share information with each other and transport traffic. However, if the traffic has to travel over too many APs before it gets to a wired connection, the user will experience unacceptable delays. At the same time, it's important to make sure there are enough connections available to each AP to ensure redundancy. Therefore, if one or several APs are not operational, the network can still function efficiently. Obviously, this "balancing act" between coverage and connections can be quite difficult to determine.

The traditional way to plan and design wireless networks is through a site survey. This process involves powering up an AP in a part of the area to be covered, taking measurements of signal strength and coverage, and then repeating the exercise until you've covered the entire region. While this may be possible in a small-scale installation, as noted earlier, wireless mesh networks are best suited for large outdoor or indoor installations. In these scenarios, any highly manual and time-consuming process isn't practical for planning the network.

The preferred alternative is a combination of a computer-based design program with a limited site survey. This method allows users to model the coverage area, place APs, designate the proper number of connections between APs, model the usage areas and select the APs that will have wired connections to the network. The network designer can then run simulations of the proposed network's operation and adjust the design to address any identified coverage holes and capacity problems.