Training Sequence Design for Channel Estimation with Nonlinear OQPSK-Type Modulations
Cercas, Cercas, F.
Training Sequence Design for Channel Estimation with Nonlinear OQPSK-Type Modulations, Proc Conf. on Telecommunications - ConfTele, Castelo Branco, Portugal, Vol. CS.2, pp. 1 - 5, May, 2013.
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Nonlinear OQPSK-type (Offset Quadrature Phase
Shift Keying) can be designed to have almost constant envelope,
making them suitable for systems requiring highly-efficient and
low-cost grossly nonlinear power amplifiers.
In this paper we consider the use of pseudo-random spreading
sequences for channel estimation purposes in systems employing
nonlinear OQPSK-type modulations. We consider Maximum-
Length sequences, Kasami sequences, Gold sequences and Tomlinson,
Cercas, Hughes sequences, all known to have good autocorrelation
properties, making them appropriate for channel
estimation purposes. The cross-correlation between different
OQPSK components that constitute nonlinear OQPSK-type signals
is obtained and its impact on the channel estimation
performance is evaluated. It is shown that Tomlinson, Cercas,
Hughes sequences outperform the other sequences in the channel