abstract = "Ultra wideband (UWB) technology is characterised by
transmitting extremely short duration radio pulses. To
improve its multiple access (MA) capability, UWB
technology can be combined with traditional spread
spectrum (SS) techniques. Existing spreading codes are
only optimal in additive white Gaussian noise (AWGN)
and their performance degrades in multipath fading and
narrow band interference. In this paper, we propose the
use of spreading codes obtained using a novel design
methodology based on genetic programming (GP) and DNA
computation for DS-UWB communications. The spreading
codes obtained by this novel design methodology
performs better than traditional spreading codes in
both AWGN and multipath fading. In addition, spreading
codes with desired spectral characteristics could be
designed to minimise the mutual interference between
the DS-UWB and co-existing narrowband systems. The
proposed design methodology is attractive for spreading
code in terms of performance and flexibility to design
spreading codes for a specific design criteria",