Today, Communication has increasing influence on our Daily life. Wireless data Communication services allow people to access the data Network without a physical Connection. This work Studying Wireless Local Area Network WLAN features and describing all technologies and standard necessary to operate this network. This work aims also at comprehensive investigation of wireless network including wireless Local Area Networks implementation and performance analysis. Testing WLAN performance through some practical measurement such as site surveying in different locations, finally measuring the strength of the signals different locations in the coverage area, test results can be used in order to enhance the network performance.