Channel Estimation for Two-Way Relay Networks in the Presence of Synchronization Errors

Xie, Xuemei; Peng, Mugen; Li, Yonghui; Wang, Wenbo; Poor, H. Vincent

doi:10.1109/tsp.2014.2360146

Cited by 14 publications

(2 citation statements)

References 18 publications

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“…At the receiver, the frequency offset can be represented by multiplying the received signal in time by a complex exponential with a frequency component equal to the frequency offset value. The relationship between the transmitted S[n] and received signals R[n] under the influence of frequency offset can be expressed as follows [19]:…”

Section: Frequency Offset Error In Ofdmmentioning

confidence: 99%

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Effects of Synchronization Errors on Wavelet-based CR-OFDM Systems in Doubly Selective Fading Channels

RANGASWAMY¹,

Surekha²

2023

Wireless Pers Commun

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The major setback of a Multi-Carrier Modulation (MCM) is Synchronization Errors, which includes time, frequency and phase offset. Especially, Wavelet based MCM catches the eyes of researchers due to its flexibilities which are seen as one of the strong contender for Cognitive Radios. Synchronization errors are mainly due to mobility between nodes and suboptimal local oscillators and it is necessary to learn the behaviour of wavelets under these channel fading conditions. In this paper, we present the joint effects of Wavelet-based Cognitive Radio OFDM (CR-WOFDM) systems under Synchronization Error in terms of based bit error rate (BER). BER Outputs of WOFDM is compared with FFT based OFDM with Cyclic Prefix (CP-OFDM) systems in a doubly-selective channel by designing a communication system for computer simulation. Several well-known wavelets are chosen and analysed, including Daubechies (db), Symlets (sym), Coiflets (coif), Fejér-Korovkin (fk) filters, and biorthogonal (bior) wavelets. First, we show the behaviour of wavelets in terms of BER by considering different doubly selective channel Power Delay Profile (PDP) like, AWGN, FLAT, Pedestrian and Vehicular and channel Doppler models like, Uniform and JAKES. Finally, we calculate and plot Signal-to-Interference Ratio (SIR) of WOFDM with Time and Frequency Offset and compared the results with FFT based CP-OFDM.

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Section: Frequency Offset Error In Ofdmmentioning

confidence: 99%

“…OFDM utilizes low complexity yet effective approach termed as Cyclic Prefix (CP) to overcome synchronization errors. Neglecting the effects of channels w[n] = 0, the timing error at receiver of OFDM after FFT can be represented as [19,12]:…”

Section: Time Offset Error In Ofdmmentioning

confidence: 99%

Effects of Synchronization Errors on Wavelet-based CR-OFDM Systems in Doubly Selective Fading Channels

RANGASWAMY¹,

Surekha²

2023

Wireless Pers Commun

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Spectrum Efficient Joint Frequency Offset and Channel Estimation for Time-Asynchronous Amplify-and Forward Two-Way Relay Networks

2019

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This paper considers the problem of the joint channel and carrier frequency offset (CFO) estimation for asynchronous amplify-and-forward (AF) two-way relay networks (TWRNs). This problem has not been solved to the best of our knowledge, and the presence of timing offsets between the two terminals, in addition to the frequency offsets, makes it necessary to develop signal sampling and joint estimation schemes that explicitly take into account both offsets. As potential solutions, we investigate two estimation strategies. The first strategy is pilot-based estimation, and in this context, we develop the maximum-likelihood joint CFO and channel estimator. Then, we consider the semi-blind estimation strategy, proposing a novel estimator based on expectation maximization (EM). As an alternative to the EM, we also investigate decision-directed (DD) semi-blind estimation. The semi-blind Cramer-Rao bound (CRB) is also obtained as a benchmark. Extensive experiments are used to compare the different estimation methods, showing that the proposed EM algorithm yields significantly lower mean-squared error than both the pilotbased estimator and the DD estimator and converges to the obtained CRB. It also yields much better symbol error rates. This is achieved at a reasonable computational complexity, and only a limited number of EM iterations are sufficient for convergence. The main contribution of our work is the development of the EM estimator, the corresponding CRB, and the use of simulations to demonstrate the superior performance of the proposed EM algorithm compared to other potential solutions.INDEX TERMS Amplify-and-forward, asynchronous, carrier frequency offset, channel estimation, Cramer-Rao bound, decision-directed, expectation maximization, two-way relay network.• We derive the pilot-based ML joint CFO and channel estimator for asynchronous AF TWRNs.

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Recent Advances in Underlay Heterogeneous Networks: Interference Control, Resource Allocation, and Self-Organization

Peng

Wang

et al. 2015

IEEE Commun. Surv. Tutorials

179

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Channel Estimation for Two-Way Relay Networks in the Presence of Synchronization Errors

Cited by 14 publications

References 18 publications

Effects of Synchronization Errors on Wavelet-based CR-OFDM Systems in Doubly Selective Fading Channels

Effects of Synchronization Errors on Wavelet-based CR-OFDM Systems in Doubly Selective Fading Channels

Spectrum Efficient Joint Frequency Offset and Channel Estimation for Time-Asynchronous Amplify-and Forward Two-Way Relay Networks

Recent Advances in Underlay Heterogeneous Networks: Interference Control, Resource Allocation, and Self-Organization

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