Publication: Superimposed training for channel estimation in next-generation wireless multicarrier techniques
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2019-11
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2019-11-08
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Abstract
In this thesis, we propose novel superimposed training (ST) techniques for channel
estimation for future wireless systems for 5G and beyond. ST is a promising technique
that permits to obtain channel state information in a way that it can provide higher
spectral e_ciency compared with dedicated pilot proposals at the cost of increasing
the channel estimation error. In this context, a new proposal called partial-data
superimposed training (PDST) is addressed for orthogonal frequency division multiplexing
(OFDM) systems. The novelty of PDST is that incorporates an additional
power control factor that, unlike previous proposals, allows to improve performance
with an accurate control of data and pilot interference. Based on this proposal the
channel estimation error is derived. The signal-to-interference and noise ratio (SINR)
and average channel capacity are later introduced. The partial superimposition can
overcome classical overlay schemes reducing the number of resources a_ected by the
superimposition.
Secondly, the channel estimation performance of a promising multicarrier technique
known as _lterbank multicarrier o_set quadrature amplitude modulation (FBMCOQAM)
is evaluated. In this contribution, we model the introduction of a superimposed
training sequence in an FBMC-OQAM system. Due to the superimposition
new parameters appear in the formulation known as intrinsic interference and data
interference. An analytical expression for the channel estimation error, which _ts
with the simulation results, is depicted. Then, the SINR and its average channel
capacity expressions are presented. Furthermore, the power allocation factor that
maximizes the spectral e_ciency is found. It is shown that this proposal overcomes
the performance of FBMC-OQAM with pilot symbol assisted modulation (PSAM)
and other multicarrier techniques as OFDM with PSAM and ST.
Finally, the channel estimation in a promising technology known as visible light
communication (VLC) is analyzed. In this proposal, we model a VLC scenario where
ST is used for channel estimation. The multicarrier technique DC-o_set OFDM is
taken into account to adapt the electrical signal to the optical one. Then, multiple input single output (MISO) is considered to be used as the most adequate spatial multiplexing
technique to work with VLC. In this novel technique an extensive analysis
is done for deduction of the channel estimation error, SINR and spectral e_ciency.
Simulation results validate the performance of each proposal in a quasi stationary
environment compared with PSAM-based channel estimation techniques.
High spectral e_ciency and data rate can be expected of implementing these
proposals which successfully could satisfy the new data-rate requirements. All of
these proposals consider multicarrier techniques and novel technologies to be used in
5G and beyond systems thus o_ering new lines of investigation.
Description
Mención Internacional en el título de doctor