As I understand it, uncoded probably points to the source data that does have have any channel coding associated with it. An example of channel coding is the (7,4) Hamming code, where parity bits are added for channel proofing.
You can look into comm.MIMOChannel to try and understand more about MIMO. There are a few examples to help you get started.
This example tries to study the effects of various antenna arrangements, including MIMO, on BER.
For additional examples, look at the membership functions shipped with the Fuzzy Logic Toolbox. These functions can be found in your $MATLABROOT\toolbox\fuzzy\fuzzy directory
(where $MATLABROOT is the output of the command matlabroot at the command line).
Note that the functions always end with the letters 'mf' (such as 'gaussmf.m', 'trimf.m' etc).
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