Digital signal processing (3rd ed.): principles, algorithms, and applications
Digital signal processing (3rd ed.): principles, algorithms, and applications
Iterative detection for pretransformed OFDM by subcarrier reconstruction
IEEE Transactions on Signal Processing - Part I
An overview of peak-to-average power ratio reduction techniques for multicarrier transmission
IEEE Wireless Communications
IEEE Transactions on Wireless Communications
BER of OFDM systems impaired by carrier frequency offset in multipath fading channels
IEEE Transactions on Wireless Communications
Frequency domain equalization for single-carrier broadband wireless systems
IEEE Communications Magazine
Broadband wireless access solutions based on OFDM access in IEEE 802.16
IEEE Communications Magazine
Evolution map from TD-SCDMA to FuTURE B3G TDD
IEEE Communications Magazine
Channel equalization for block transmission systems
IEEE Journal on Selected Areas in Communications
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In current OFDMA systems three major problems arise due to the large number of subcarriers, including high peak to average power ratio (PAPR), sensitivity to carrier frequency offset (CFO), and high complexity in users terminals. In this paper, based on an innovative concept of layered FFT structure, we propose novel Quadrature OFDMA (Q-OFDMA) systems which can overcome these problems. In particular, the proposed systems can achieve the same guard-interval overhead and same bandwidth occupation to conventional OFDMA systems, while with reduced PAPR and improved CFO robustness and frequency diversity. Q-OFDMA systems also promise low complexity in downlink receivers. Parameter configuration is investigated for both predefined and adaptive users' data rates. Theoretical comparison of bit error rate (BER) performance between Q-OFDMA and OFDMA is conducted, and validated by simulation results. It is shown that Q-OFDMA systems could achieve better performance than OFDMA when signal to noise ratio (SNR) is above a threshold depending on the channel condition, and advanced equalizers, such as minimum mean square error equalizer, can significantly decrease this threshold due to the large frequency diversity in Q-OFDMA systems.