Hot topic: physical-layer network coding
Proceedings of the 12th annual international conference on Mobile computing and networking
A robust ranging scheme for OFDMA-based networks
IEEE Transactions on Communications
Channel estimation for OFDM modulated two-way relay networks
IEEE Transactions on Signal Processing
Joint frequency offset and channel estimation methods for two-way relay networks
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
ML estimation of time and frequency offset in OFDM systems
IEEE Transactions on Signal Processing
A robust timing and frequency synchronization for OFDM systems
IEEE Transactions on Wireless Communications
Distributed space-time coding for regenerative relay networks
IEEE Transactions on Wireless Communications
Distributed Space-Time Coding in Wireless Relay Networks
IEEE Transactions on Wireless Communications
Cooperative diversity in wireless networks: Efficient protocols and outage behavior
IEEE Transactions on Information Theory
Broadcast Capacity Region of Two-Phase Bidirectional Relaying
IEEE Transactions on Information Theory
Fading relay channels: performance limits and space-time signal design
IEEE Journal on Selected Areas in Communications
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In amplify and forward (AF) two way relay networks (TWRN), two sources are allowed to transmit simultaneously in the multiple access time slot. Signal misalignment at the relay occurs due to the inaccurate time slot synchronization and different propagation delay. In broadband wireless communications, the misalignment could cover several symbol intervals. In orthogonal frequency division multiplexing (OFDM) based TWRN, such signal misalignment raises question on how to choose the fast Fourier transform (FFT) window at the relay node in order to minimize the interference which will be forwarded to the sources. In this paper, the timing issue of the received superimposed signal at the relay for both sources in OFDM based AF---TWRN is investigated. The optimal timing that minimizes the total interference power at the relay is studied. The imperfect timing induced interference power at each timing point is derived. An efficient estimator is proposed for the relay to decide where to establish the FFT window boundary in order to introduce the minimum interference plus noise power based on the superimposed training block from the two source nodes. The estimator is a sliding window estimator measuring the total interference plus noise power at each timing position, and the timing position which minimizes the metric function is the optimal position to establish the FFT window. Finally, the performance of the proposed estimator is evaluated by computer simulation in the presence of different amount of signal misalignment.