Thesis-1986-Zhu.pdf (6.33 MB)
Signal design for satellite links
thesis
posted on 2013-06-10, 13:48 authored by Zhi C. ZhuThe aim of' this investigation is to determine the
combination of signal coding and modulation for satellite
links, that, for a given degree of equipment complexity needed
for the detection of the received signal, achieves the best
tolerance to noise. Computer simulation tests and theoretical
analyses are used
to compare the various proposed signal designs
The trellis coded M-ary phase-shift-keyed (MPSK)
modulation method is introduced as the scheme for which
different codes are to be devised.
A class of known binary convolutional codes for 8 and 16
PSK signals is studied, and new correlative-level codes using
modulo-M arthimetic are designed for MPSK signals.
The soft-decision maximum likelihood Viterbi decoding
algorithm is considered for the two proposed signal designs,
and a more conventional near-maximum likelihood (reduced-state
Viterbi) decoding scheme is also investigated for both types of
coded signals.
Two novel decoding schemes, derived from a more conventional
near-maximum likelihood decoder, are proposed for
coded 8PSK signals. In both decoders the amount of computation
involved in decoding each data-symbol is adjusted to meet the
prevailing noise level in transmission. Results of extensive
computer simulation tests for both decoding schemes are
presented. These results suggest that the new schemes come
very close to achieving the maximum likelihood decoding of the
coded signals without, however, requiring nearly as much
storage and computation per decoded data symbol as does the
Viterbi decoder.
The carrier-phase synchronisation prob1em in a coherent
trellis coded MPSK system is investigated. Eight new
rotationally invariant rate-2/3 and rate-3/U convolutional
codes for 8 and 16 PSK signals are designed. The new coded
MPSK signals, when combined with a simple phase-error
correction system proposed for the receiver, are able to
tolerate the likely carrier-phase changes in the reference
carriers of the coherent demodulation process and therefore
avoid the prolonged error bursts that are otherwise caused in
the decoded data symbols by such phase shifts.
coding gains of the majority of the new codes
The asymptotic
here are either
the same as, or come close to, those of the best known but not
rotationally invariant convolutional codes of the same rates.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Publisher
© Zhi Chun ZhuPublication date
1986Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.383863Language
- en