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    Pilot-Assisted Channel Estimation for SFBC MIMO-OFDM with Index Modulation in Higher Time-Varying Fading Channel
    (2024-01-01)
    Mata, Tanairat
    ;
    Boonsrimuang, Pisit
    Orthogonal frequency division multiplexing (OFDM) with Index modulation can provide higher spectral and energy efficiencies. For multiple-input, multiple-output OFDM with space-frequency block coding (SFBC MIMO-OFDM), the transmitter can send the information signal with high transmit diversity gain to the receiver, improving system performance. In this paper, we propose a pilot-assisted channel estimation by using SFBC MIMO-OFDM with index modulation. The proposed system can perform a better bit-error-rate (BER) performance and higher transmission data rate than the conventional system in a higher time-varying fading channel.
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    Proposal of channel estimation method for wireless two-way relay system of using SFBC MIMO-OFDM technique
    (2016-12-01)
    Mata, Tanairat
    ;
    Boonsrimuang, Pisit
    ;
    Mori, Kazuo
    ;
    Kobayashi, Hideo
    In a two-way relay communication system, two user terminals (UTs) can communicate and exchange their information data through a relay station by using two timeslots. To realize the two-way relay communication system, each UT is required to estimate channel frequency responses (CFRs) both for up and down links in two timeslots efficiently which be employed in the demodulation of the other user’s information data with frequency domain equalization. To satisfy this requirement, this paper proposes a novel CFR estimation method for the wireless two-way relay communication system of using SFBC MIMO-OFDM technique. The salient feature of proposed CFR estimation method is to employ the maximum likelihood estimation method for the proposed scattered pilot subcarriers assignment which can achieve higher CFR estimation accuracy even in higher time-varying fading channel and when the transmission OFDM signal is sampled by the non-Nyquist rate. In the proposed system, the SFBC technique is also employed for the data subcarriers both for the pilot symbols including data subcarriers and data symbols consisting of all data subcarriers in the frequency axis to improve the bit error rate (BER) performance in the two-way relay system. From the computer simulation results, this paper demonstrates the effectiveness of proposed two-way relay communication system of using SFBC MIMO-OFDM technique. To demonstrate the effectiveness of proposed two-way relay communication system of using SFBC MIMO-OFDM technique, this paper conducts various computer simulations as comparing with the conventional methods in higher time-varying fading channel. From the computer simulation results, this paper confirms that the proposed method even at the non-Nyquist rate can achieve higher channel estimation accuracy evaluated by the normalized mean square error (NMSE) and better BER performances by 5 and 22 times, respectively as comparing with the conventional methods when the normalized Doppler frequency (f<inf>d</inf>T<inf>S</inf>) is 10 <sup>- 2</sup> and the carrier to noise power ratio (C/N) is 25 dB.
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    Channel estimation method for SFBC MIMO-OFDM based wireless two-way relay system in time-varying fading channel
    (2014-10-03)
    Mata, Tanairat
    ;
    Mori, Kazuo
    ;
    Kobayashi, Hideo
    ;
    Boonsrimuang, Pisit
    This paper proposes SFBC MIMO-OFDM based two-way relay system to improve signal quality with keeping higher transmission efficiency. In the two-way relay system, each user terminal (UT) is required to estimate channel frequency responses (CFRs) for up and down links between both UTs and RS (Relay Station) precisely which are used in the demodulation of the other user's information data with frequency domain equalization. To satisfy the above requirement, this paper proposes a novel CFR estimation method for the SFBC MIMO-OFDM based two-way relay system which can achieve better CFR estimation accuracy and better BER performance even in the higher time-varying fading channel. The salient features of proposed system are to employ the SFBC technique both for data subcarriers in the pilot symbols and data symbols and to apply the Maximum Likelihood (ML) and Cubic Spline Interpolation methods to the estimated CFR at pilot subcarriers with Walsh codes in the estimation of CFR for the frequency axis and time axis, respectively. From the computer simulation results, this paper demonstrates the effectiveness of proposed system which can achieve higher signal quality with keeping higher transmission efficiency even in the higher time-varying fading channel.
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    Proposal of improved PTS method for STBC MIMO-OFDM systems
    (2010-01-01)
    Mata, Tanairat
    ;
    Boonsrimuang, Pornpawit
    ;
    Boonsrimuang, Pisit
    ;
    Kobayashi, Hideo
    This paper proposes a new Partial Transmit Sequence (PTS) method in conjunction with the concurrent algorithm for Space Time Block Code Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (STBC MIMO-OFDM) systems. The feature of proposed PTS method is that each cluster is divided into two parts and these two parts employ the different weighting factors to achieve the better Peak to Average Power Ratio (PAPR) with keeping the same size of side information and almost the same size of computational complexity as that for the conventional concurrent PTS method. Copyright © 2010 The Institute of Electronics, Information and Communication Engineers.