The use of multiple radio antennas to improve signal integrity. Microwave transmission systems sometimes employ multiple spatial diverse receive antennas, vertically separated on a tower, for example. As the likelihood is that signal will not suffer the same level of attenuation as it disperses slightly and propagates along slightly different paths, the receiver with the strongest signal assumes control of the transmission. Wireless LAN (WLAN) systems based on the 802.11n specification employ multiple transmit and receive antennas in a technique known as multiple-input multiple-output (MIMO). Code division multiple access (CDMA) systems use a similar approach involving rake receivers with multiple fingers. See also 802.11n, antenna, attenuation, CDMA, dispersion, MIMO, propagation, rake receiver, and time diversity.