Abstract:
In this research, we consider the problem of cyclic block construction for
(FDE) of SOQPSK using an intra- x segment in addition to the cyclic pre-
x. We propose a novel procedure to compute the intra- x symbols for both
SOQPSK-MIL and SOQPSK-TG waveforms used in aeronautical telemetry.
The proposed method is employed to generate an exact cyclic signal, which
is a requirement for implementation of FDE at the receiver. The trellis of
SOQPSK-TG signal is very complicated (512 states) because of its partialresponse
characteristic. We identify that the required number of symbols to
generate an exact cyclic signal are unreasonably large for SOQPSK-TG (9
symbols per block). Thus, we also propose an approximate technique that
utilizes only dominant Laurent pulses to help reduce the length of intra-
x upto 2 symbols. A detailed numerical evaluation of this approximate
technique is performed to study the trade-o between the reduction in the
intra- x length and the deviation from constant envelope of the generated
signal. The trellis of SOQPSK-TG signal is very complicated (512 states)
because of its partial-response characteristic. We identify that the required
number of symbols to generate an exact cyclic signal are unreasonably large
for SOQPSK-TG (9 symbols per block). Thus, we also propose an approximate
technique that utilizes only dominant Laurent pulses to help reduce
the length of intra- x upto 2 symbols. A detailed numerical evaluation of
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this approximate technique is performed to study the trade-o between the
reduction in the intra- x length and the deviation from constant envelope of
the generated signal.
