A channel may be defined in terms of effects imparted to a signal propagated over the channel, such as inter-symbol interference (ISI), multi-path, Doppler effect, and/or noise.
An adaptive equalizer and/or channel estimator may adapt filter coefficients or weights until an optimum set of coefficients is determined for a channel. A speed or rate of convergence toward the optimum set may depend on increments by which the coefficients are adjusted, or step size. Adaptive equalization and/or channel estimation may be performed with a constant step size (CSS) algorithm or a variable step size (VSS) algorithm.
A receiver may be suitable for some channel conditions may not be as suitable for other channel conditions. For example, an adaptive CSS blind equalizer may be suitable for a relatively static channel (i.e., little or no Doppler effect), which may found in a suburban or rural setting, but may not converge well for a dynamic channel, such as in an urban setting. An adaptive VSS blind equalizer may converge for static and dynamic channels, but may incur greater losses with respect to static channels relative to an adaptive CSS blind equalizer
A receiver may be implemented with additional to operate under a variety of channel conditions, but may incur penalties in terms of added complexity, cost, area consumption, and/or power consumption.
In the drawings, the leftmost digit(s) of a reference number identifies the drawing in which the reference number first appears.