Pilot Design of OFDM/OQAM System Based
on Interference Cancellation
Zhiguo Sun
College of information and Communication
Engineering, Harbin Engineering University
Harbin, China
e-mail:sunzhiguo@hrbeu.edu.
Xiaoyan Ning *
College of information and Communication
Engineering, Harbin Engineering University
Harbin, China
e-mail:ningxiaoyan@hrbeu.edu.
Zhanfang Sun
College of Information and Communication
Engineering,
Harbin Engineering University
Harbin, China
e-mail:474092905@qq.com
Zengmao Chen
College of Information and Communication
Engineering,
Harbin Engineering University
Harbin, China
e-mail:chenzengmao@hotmail.com
Abstract—In order to suppress the imaginary intrinsic part
interference of OFDM/OQAM system in radio channel, a
new pilot design approach is proposed. The new design
approach can suppress the intrinsic imaginary interference
in quasi-stationary channel and reduce the pilot peak power
due to sparse data forms. This paper analyzes the reason
why the imaginary intrinsic interference produces in the
PLC (power line communication) channel and the new pilot
eliminates the imaginary intrinsic interference. Compared
with the pilot design of OFDM/CP,OFDM/OQAM system, it
is verified that the new pilot design approach is better than
OFDM/CP ,IAM-R,IAM-I and almost the same as IAM-new
under MATLAB simulation platform in the PLC channel
with the same channel estimation and equalization mode.
Keywords- OFDM/OQAM; pilot design; PLC; IOTA;
interference cancellation
I. INTRODUCTION
As suggested in [1-3], OFDM/OQAM(Orthogonal
frequency division multiplexing offset quadrature
amplitude mapping, OFDM/OQAM) has, different from
OFDM/CP, the advantage of resisting ISI (inter symbol
interference, ISI)and ICI (inter carrier interference, ICI),
having no cyclic prefix ,having low out of band radiation
in comparison with OFDM/CP [4]. In multipath
transmission channel, however, OFDM/OQAM signal is
easily susceptible to the imaginary intrinsic interference,
which leads to the fact that OFDM/CP pilot design cannot
be directly applied to the OFDM/OQAM. So the basic of
the block pilot and the discrete pilot can be found in[5-
6],it is more recently seen that the pilot based on the
equivalent power maximization, such as the IAM-
R[7],IAM-I[8],IAM-new[9], the pilot design based on
interference cancellation[10,11]has also received more and
more attentions. The new pilot design based on the
interference cancellation is not required a priori knowledge
of the pulse function and can avoid complicated
calculations. In addition, the peak power of the pilot can be
reduced by sparse data form.
In the Section Ⅱ , the mathematical model of
OFDM/OQAM systems is established in the multipath
channel, the imaginary intrinsic interference how to
produce is also discussed. In the Section Ⅲ, a new design
approach of pilot is presented. In the Section Ⅳ, the new
pilot is simulated in the PLC channel[12] in comparison
with the OFDM-CP and OFDM/OQAM methods.
II. OFDM/OQAM IN MULITPATH FADING CHANNEL
A. The basic principle of OFDM/OQAM
Complete orthogonal basis does not exist in the
complex domain of the OFDM/OQAM, while orthogonal
basis exists in the real domain, which suggests that the
transmitted symbols must be real [13-14]. OFDM/OQAM
structure diagram is shown as Fig .1.
Data
interleaving
upsampling
M/2
()gt
2
mc
j
f k
T
e
A
W
G
N
Data
interleaving
Data
interleaving
upsampling
M/2
upsampling
M/2
downsampling
M/2
upsamplingM/
2
upsamplingM/
2
Data
interleaving
Data
interleaving
Data
interleaving
Figure 1. OFDM/OQAM system structure diagram
International Conference on Mechatronics, Electronic, Industrial and Control Engineering (MEIC 2014)
© 2014. The authors - Published by Atlantis Press