In a duplex radio link wherein 
digital data information from a 
data interface is transmitted from a local terminal to a remote terminal over 
fading dispersive channels, a method and 
transceiver are described that provide for transmission at an adaptive 
data rate. The transmission is at a constant 
symbol rate so that the 
signal bandwidth can be fixed and at the remote terminal 
receiver the input sampling rate can be fixed. The 
digital data information is transmitted over a constant 
data rate interval in accordance with a selected 
data rate mode that is a function of direct sequence spreading 
gain, error 
correction code rate, and 
signal constellation type. The data rate is adapted by selecting a data rate mode that is a function of the arrival rate of data packets from the 
data interface and a link quality measure fed back from the remote terminal. The data 
packet arrival rate is controlled as a function of the link quality measure and the current data 
packet arrival rate. In systems with multiple 
transmit diversity channels, 
independent data is sent over each of the 
transmit diversity channels. The adaptive data rate technique utilizes both orthogonal transmit diversities such as frequency and troposcatter 
polarization diversity as well as nonorthogonal transmit diversities in a Multiple-input Multiple-Output (
MIMO) configuration. A single antenna troposcatter link using angle diversity and 
adaptation of data rate by feedback communications is described. In an idealized feedback communication example, the single antenna 
system in a Ku-band application is shown to have 15.5 times the data rate capability of a conventional two-antenna 
system at S-band.