| Communications Toolbox | |
After you have created a channel object as described in Specifying Fading Channels, you can use the filter function to pass a signal through the channel. The arguments to filter are the channel object and the signal. At the end of the filtering operation, the channel object retains its state so that you can find out the final path gains or the total number of samples that the channel has processed since it was created or reset. If you configured the channel to avoid resetting its state before each new filtering operation (that is, ResetBeforeFiltering is 0), then the retention of state information is important for maintaining continuity between successive filtering operations.
For an example that illustrates the basic syntax and state retention, see Power of a Faded Signal.
If you want to use the channel visualization tool to plot the characteristics of a channel object, you need to set the StateHistory property of the channel object to 1, so that it will get populated with plot information. See for details.
A communication system involving a fading channel usually requires component(s) that compensate for the fading. Here are some typical approaches:
Differential modulation or a one-tap equalizer can help compensate for a frequency-flat fading channel.
An equalizer with multiple taps can help compensate for a frequency-selective fading channel.
See Equalizers to learn how to implement equalizers in this toolbox. See the dpskmod reference page or the example in Comparing Empirical with Theoretical Results to learn how to implement differential modulation.
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