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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.

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.

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.

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.

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.

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