Wuhan Research Institute of Post and Telecommunication

Wuhan, China

Wuhan Research Institute of Post and Telecommunication

Wuhan, China
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Lu J.,Huazhong University of Science and Technology | Li X.,Wuhan Research Institute of Post and Telecommunication | Fu S.,Huazhong University of Science and Technology | Luo M.,Wuhan Research Institute of Post and Telecommunication | And 4 more authors.
Optics Express | Year: 2017

We present dual-polarization complex-weighted, decision-aided, maximum-likelihood algorithm with superscalar parallelization (SSP-DP-CW-DA-ML) for joint carrier phase and frequency-offset estimation (FOE) in coherent optical receivers. By pre-compensation of the phase offset between signals in dual polarizations, the performance can be substantially improved. Meanwhile, with the help of modified SSP-based parallel implementation, the acquisition time of FO and the required number of training symbols are reduced by transferring the complex weights of the filters between adjacent buffers, where differential coding/decoding is not required. Simulation results show that the laser linewidth tolerance of our proposed algorithm is comparable to traditional blind phase search (BPS), while a complete FOE range of ± symbol rate/2 can be achieved. Finally, performance of our proposed algorithm is experimentally verified under the scenario of back-to-back (B2B) transmission using 10 Gbaud DP-16/32-QAM formats. © 2017 Optical Society of America.


Tao L.,Fudan University | Yu J.,Fudan University | Yang Q.,Wuhan Research Institute of Post and Telecommunication | Luo M.,Wuhan Research Institute of Post and Telecommunication | And 4 more authors.
Optics Express | Year: 2012

We propose a modified localized carrier distribution scheme based on multi-tone generation to generate 60 GHz mm-wave for different wireless users and it improves the carrier utilization efficiency by 33.3%. The principle of multiple-user discrete Fourier transform spread optical orthogonal frequency-division multiplexing (DFT-S OFDM) Radio-overfiber (RoF) system is presented. This multiple-user system is applicable to passive optical network (PON). Then we demonstrate a 8x4.65 Gb/s multiple-user DFT-S OFDM RoF-PON wireless access system over 40 km fiber link and 60 GHz wireless link using two localized carrier distribution scheme with different spectral efficiency. Compared to conventional OFDM, 2.3 dB reduction of receiver power using DFT-S OFDM modulation scheme and the calculated BER performance for 8 wireless users clearly demonstrates the feasibility of this spectrally efficient multiple-user RoF-PON scheme. © 2012 Optical Society of America.


Tao L.,Fudan University | Yu J.,Fudan University | Yang Q.,Wuhan Research Institute of Post and Telecommunication | Shao Y.,Fudan University | And 2 more authors.
Optics Express | Year: 2013

In this paper, a transform domain processing (TDP) based channel estimation method for orthogonal frequency-division multiplexing (OFDM) Radio-over-Fiber (RoF) systems is proposed. Theoretically investigation shows that TDP can greatly reduce the number of required training symbols. An 8 x 4.65 Gb/s multi-user OFDM RoF system over 40 km fiber link and 60 GHz wireless link is experimentally demonstrated utilizing TDP scheme. Compared with conventional time domain averaging (TDA) scheme, the overhead can be reduced from several tens of training symbols to merely one symbol and the receiver sensitivity has been improved by 1.8 dB at BER of 3.8 x 10-3. The calculated BER performance for 8 wireless users clearly validates the feasibility of this TDP-based channel estimation method. © 2013 Optical Society of America.


Zhao Z.,Wuhan Research Institute of Post and Telecommunication
Guangxue Xuebao/Acta Optica Sinica | Year: 2011

The development of optical fiber communications in the world has been briefly introduced, and the current situation of fiber communication on is recalled. The development of optical fiber communications in China is introduced at last.


Kaneda N.,Alcatel - Lucent | Pfau T.,Alcatel - Lucent | Yang Q.,Wuhan Research Institute of Post and Telecommunication | Chen Y.K.,Alcatel - Lucent
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

We review the recent development in real-time coherent optical OFDM (CO-OFDM) transmission for their algorithm and implementation. The unique challenge of real-time implementation of OFDM for high speed optical data transmission including relatively large phase noise, frequency offset and dynamically changing optical channels are discussed. The fundamental digital signal processing (DSP) architectures of transmitter and receiver are presented in the manner achievable in state of the art field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs). Primary DSP components' algorithms and implementations are presented and discussed. The successful demonstration of real-time CO-OFDM receivers includes a receiver with sampling rate of 2.5-Gsamples/s to receive a 3.55-Gb/s single channel and 53.3-Gb/s multi-band CO-OFDM signal. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Liu W.,Wuhan Research Institute of Post and Telecommunication | Li C.,Wuhan Research Institute of Post and Telecommunication
Asia Communications and Photonics Conference, ACP | Year: 2012

A novel blind phase estimation method for general QAM constellations is proposed. The method using constellation link statistics and provides significantly improved performance than the maximum-likelihood (ML) method at medium and high SNRs. © 2012 OSA.


Liu W.,Wuhan Research Institute of Post and Telecommunication | Yang C.,Wuhan Research Institute of Post and Telecommunication
Asia Communications and Photonics Conference, ACP | Year: 2013

A frequency estimation method is presented based on fast Fourier transform of the symbol's phase angle. The method does not require removing modulated data phase and can be used for QAM constellations. The principle of the algorithm is proven and a diagram is proposed to illustrate the algorithm. Numerical simulations are carried out to corroborate the performance analysis. © OSA 2013.


Wang X.-S.,Huazhong University of Science and Technology | Wang X.-S.,Wuhan Research Institute of Post and Telecommunication | Yu S.-H.,Wuhan Research Institute of Post and Telecommunication | Luo T.,Huazhong University of Science and Technology | Dai J.-Y.,Wuhan Research Institute of Post and Telecommunication
Ruan Jian Xue Bao/Journal of Software | Year: 2012

The Ethernet passive optical networks (EPON) are high-speed solutions to the bottleneck problem of the broadband access network. To provide efficient and fair utilization of the EPON upstream bandwidth and support QoS requirements of different traffic classes, a dynamic bandwidth allocation algorithm based on gate threshold is proposed. The algorithm decides the data-receiving rate of the ONU (optical network unit), according to the ONU data-sending response rate and the gate threshold. It then, implements three methods to adapt and adjust the gate threshold, and analyzes these methods' characteristic. Simulation experiments show the algorithm can decrease average packet delay and increase network throughput. © 2012 ISCAS.


Liu W.,Wuhan Research Institute of Post and Telecommunication | Yang Q.,Wuhan Research Institute of Post and Telecommunication
2011 Asia Communications and Photonics Conference and Exhibition, ACP 2011 | Year: 2011

A carrier phase recovery method for optical transmission format of 16-QAM constellations is presented. The method can also be used in coherent optical single carrier or OFDM (CO-OFDM) system to implement blind phase recovery with low computational cost. We apply this method in 112Gb/s 1040 km CO-OFDM transmission, and compare its performance to those using the fourth-power estimator. Experimental results obtained indicate that the proposed method significantly outperform the fourth-power estimator. © 2011 SPIE-OSA-IEEE.


Che D.,University of Melbourne | Che D.,Victoria Research Laboratory | Hu Q.,University of Melbourne | Yuan F.,University of Melbourne | And 2 more authors.
IEEE Photonics Technology Letters | Year: 2015

Directly modulated laser (DML) with direct detection (DD) dominates the commercial optical short reach applications. When upgrading the DML-DD to higher data rate, the frequency chirp is commonly regarded as a performance barrier. On the contrary, in this letter, we take advantage of the chirp to generate phase modulation along with the intensity, namely, realize complex modulation at transmitter using a single DML. Coherent detection (CD) is applied to recover this 2 dimensional (2-D) signal. A modified Viterbi algorithm (VA) conducts maximum likelihood decoding utilizing the signal intensity and differential phase in receiver digital signal processing (DSP). By making decision using 2-D information, VA provides more than 9-dB optical signal to noise ratio (OSNR) sensitivity advantage over the conventional DML-CD with intensity only decision, in a 10-GBaud pulse-amplitude modulation (PAM)-4 system. We demonstrate the first PAM-8 experiment over 160-km standard single mode fiber using the phase diversity DML. © 2014 IEEE.

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