Title :
A Multistage CPE Scheme Based on Crossed Constellation Transformation for M-QAM
Author :
Xiaofei Su ; Lixia Xi ; Xianfeng Tang ; Zhaomin Zhang ; Shunchang Bai ; Wenbo Zhang ; Xiaoguang Zhang
Author_Institution :
State Key Lab. of Inf. Photonics & Opt. Commun., Beijing Univ. of Posts & Telecommun., Beijing, China
Abstract :
A multistage carrier phase estimation (CPE) scheme for any m-ary quadrature amplitude modulation (QAM) formats is proposed and analyzed in coherent optical communication systems. The scheme is based on the crossed constellation transformation algorithm that is transparent to all modulation formats whose constellations are on the square grid. Simulation results show that the hardware complexity of the proposed CPE scheme can be significantly reduced by the group factors of 6.1/8.6, 4.7/6, and 2.6/3.3 (in the form of multipliers/adders) for 32-QAM, 64-QAM, and 128-QAM compared with the singlestage blind phase search algorithm. In 32-QAM, 64-QAM, and 128-QAM, coherent optical communication systems with 1-dB SNR penalty at bit error rate is 1 × 10-2, the comparable linewidth symbol duration can be reached with the values of 6 × 10-5, 4 × 10-5, and 8 × 10-6, respectively.
Keywords :
error statistics; optical communication; optical modulation; optical noise; phase estimation; quadrature amplitude modulation; 128-QAM; 32-QAM; 64-QAM; M-QAM; SNR penalty; bit error rate; coherent optical communication systems; crossed constellation transformation algorithm; group factors; hardware complexity; linewidth symbol duration; m-ary quadrature amplitude modulation formats; modulation formats; multiplier-adders; multistage CPE scheme; multistage carrier phase estimation scheme; square grid; Complexity theory; Constellation diagram; Partitioning algorithms; Phase estimation; Phase noise; Phase shift keying; Signal to noise ratio; Optical communications; carrier phase estimation; coherent detection; phase noise; quadrature amplitude modulation;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2014.2361952