Digital Signal Processing Reference
In-Depth Information
bits over several dimensions (time/space/frequency), it is prevented that a tem-
porary black-out of the channel corrupts a complete sequence of information
bits. If a sufficient amount of energy is still available in adjacent dimensional
planes, it should be possible to restore the original information sent through
the channel. This is only possible, of course, when some redundant informa-
tion has been made available by the transmitter.
Also, just like in the case of Trellis coded modulation (tcm), the redundant
information should be attached to the data stream without affecting the infor-
mation capacity of the system. At first sight, it may seem that these require-
ments are in direct conflict with the decision to use a single-carrier modulation
method. However, that this is not necessarily always the case will be unveiled
in the subsequent sections. And finally, last but not least, during the develop-
ment of a new transceiver system, one must never forget the high inertia of
bringing new technologies into the market. It must be possible to introduce
the changes gradually and in a non-intrusive way in existing products, without
breaking backward compatibility.
