Factors that affect the performance of wireless networks
Introduction
The is a wide range of factors which can affect the performance of a wireless network.
The distance from the Wireless Access Point (WAP)
Wireless signals get weaker the further they travel. If you are far away from a WAP, then you may find that the signal you receive is weak and you therefore cannot get a fast or reliable connection.
Barriers to signals
Many WAPs use 2.4 GHz to send and receive the wireless signals. This frequency cannot always pass through solid objects. Some kinds of walls, for example, will prevent signals passing through them, especially if they are very thick or contain metal structures or wire mesh.
The number of users and what they are doing
A WAP allows multiple users to access a network. The more users there are, the more a WAP has to share out its connection. In addition, if some users are downloading files that use a lot of bandwidth, then that will slow down the network for other users as there will typically be a fixed limit to the bandwidth available.
Interference from other WAPs and other wireless devices
If there are other WAPs close by, using the same type of equipment and the same frequency and channel then you may find that the signals interfere with each other. In addition, you may find that the signals used by some types of phones, Bluetooth devices and walkie talkies can interfere with signals.
Poorly installed equipment
WAPs have to be positioned so that the coverage required is achieved. Sometimes, you need multiple WAPs working together to do this, to overcome physical barriers. WAPs also have antennas, which are used to send and receive wireless signals. These are very directional, so if they have not been set up to point in the optimal direction, there may well be a degradation of the signal. Other factors that can impact on wireless signals in a building include where mirrors are, internal fountains and aquariums! A site survey by professional engineers installing a wirelsss network in an office block can help to overcome or avoid altogether these potential problems.
Environmental factors
The weather might have an impact on how good a wireless signal is. For example, lightning can interfere with wireless signals and fog can weaken 
wireless signals.
Other factors
The factors identified here are the main things that could impact on wireless network performance. There are other, less obvious factors which can also cause issues with signals. See if you can find two other factors on the Internet.