Abstract
Considerable effort has been focused on efficienerror correction schemes in digital communications where the
medium of transmission is unfriendly for information.
transmission. Also, some of such channels have certain
frequency characteristics that should be considered during
system designs. Permutation coding (PC) has been reported as
being capable of spectral shaping, by manipulating channel
symbols in such a way that the frequency energy of the
transmitted signal is concentrated towards certain areas of the
frequency spectrum. We, therefore, report an extension
operation that enables the generation of a new PC from a source
PC that is capable of spectrum shaping, while still maintaining
its spectral shaping capability. A mathematical expression that
can predict the low energy sections of the codebook’s spectrum
is also presented, together with their lower and upper bounds.
An added advantage of the proposed scheme is that better error
correction is attainable due to the way the extension is
introduced