Abstract: A wireless local area network allows roaming of a mobile unit to allow it to serially associate with a number of access points of the network fixed backbone. This roaming is supported by an improved measurement of communications link quality, which includes calculating a mean error free length of a test pattern broadcast by each access point and received by a mobile unit. The test pattern is a digital data message. Thus an accurate measurement of link quality is provided which allows a mobile unit to determine whether it should change its association to another access point having improved communications link quality. Further, a load balancing process is provided to balance the communications load amongst a variety of access points, by allowing mobile units also to switch their association with access points in accordance with a current total data rate at any given access point and also considering the number of currently high data rate mobile units associated with a particular access point at any one time.