WIRELESS COMMUNICATIONS AND MOBILE COMPUTING
Wirel. Commun. Mob. Comput. (2010)
Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/wcm.937
RESEARCH ARTICLE
A novel simplified tone reservation combined with
cross antenna rotation and inversion to reduce PAPR
for MIMO-OFDM system
Xiaofan He
1
, Tao Jiang
2*
and Guangxi Zhu
2
1
Department of Electrical and Computer Engineering, McMaster University, Canada
2
Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
ABSTRACT
In this paper, we first propose a simplified tone reservation (STR) method with low computational complexity which is
based on the Fourier series expansion. Then, we analyze how to combine the STR method with the cross antenna rotation
and inversion method to reduce the peak-to-average power ratio (PAPR) for multi-input multi-output orthogonal frequency
division multiplexing (MIMO-OFDM) system. To validate the analytical results, extensive simulations are conducted and
the numerical results show the efficiency of the proposed schemes including the PAPR reduction and low computational
complexity for MIMO-OFDM system. Copyright © 2010 John Wiley & Sons, Ltd.
KEYWORDS
OFDM; MIMO; peak-to-average power ratio; simplified tone reservation; cross antenna rotation and inversion
*
Correspondence
Tao Jiang, Wuhan National Laboratory for Optoelectronics, Department of Electronic and Information Engineering, Huazhong University
of Science and Technology, Wuhan, 430074, China.
E-mail: Tao.Jiang@ieee.org
1. INTRODUCTION
Orthogonal frequency division multiplexing (OFDM) has
become an amazing technique for wireless communications
due to its high spectral efficiency and capability of high-
data-rate transmission. Multi-input multi-output (MIMO)
is another attractive technique for broadband wireless
communications due to its high spatial diversity. Therefore,
MIMO-OFDM, a combination of MIMO and OFDM
techniques, can exploit the spatial dimension capacity of
OFDM system to improve the wireless link performance
and system capacity by using multiple antennas at both the
transmitter and receiver.
Similar to OFDM system, one of the major challenges
in designing of MIMO-OFDM system is large peak-to-
average power ratio (PAPR) of the transmitted signals,
which results in low efficiency of transmission power
because of the back-off required to maintain the linearity of
high power amplifier (HPA). Otherwise, high PAPR distorts
the transmitted OFDM signals.
Recently, some methods have been proposed to reduce
the PAPR for single-input single-output (SISO) OFDM
system [1--16], among which, conventional tone reservation
(CTR) is a promising method in view of its good
performances of both PAPR reduction and bit-error-ratio
(BER) [1]. However, the high computational complexity
of the CTR method motivates us to find the simplified
TR method. Meanwhile, more attention has been paid to
the PAPR reduction of MIMO-OFDM systems recently.
Some methods have been studied, such as selective mapping
[17], unitary rotations [18], active channel extension [19],
polyphase interleaving and inversion [20] and repeating use
Chu sequences [21]. Cross antenna rotation and inversion
(CARI) [22] is an effective method to reduce the PAPR
of MIMO-OFDM system, which is based on exploiting
the new degree of freedoms in MIMO-OFDM system, i.e.,
spatial degree of freedom among different antennas.
In this paper, we first propose a simplified tone
reservation (STR) method, which is based on Fourier series
expansion (FSE), to reduce the PAPR of OFDM systems.
Compared with the CTR method, the computational
complexity of the proposed STR method is lower.
Moreover, we propose a combination scheme of STR
and CARI methods to reduce the PAPR of MIMO-
OFDM system. Compared with alone CARI method, the
combination scheme of STR and CARI methods can
Copyright © 2010 John Wiley & Sons, Ltd.