TY - JOUR
T1 - Joint adaptive code rate technique and bit interleaver for direct-detection optical OFDM system
AU - Tang, Qi
AU - Yu, Jianjun
AU - Cao, Zizheng
AU - Xiao, Jiangnan
AU - Li, Xinying
AU - Fall, Mango
AU - Chen, Lin
PY - 2013/1
Y1 - 2013/1
N2 - In this paper, we have theoretically analyzed that the existence of inter-subcarrier mixing interferences (ISMI) and frequency selective fading (FF) in the directed-detection optical orthogonal-frequency-division-multiplexing (DDO-OFDM) system will cause an unbalanced error distribution and degrade the system performance. Then we propose to employ the adaptive code rate technique (ACT) and bit interleaver in the DDO-OFDM system to combat ISMI and FF. The experimental results show that the receiver sensitivity of 5.9-Gb/s 64-ary quadrature-amplitude-modulation (64QAM) OFDM signal employing ACT(9.43 Gb/s after encoding) is improved more than 2 dB compared with the 5.9-Gb/s OFDM signal with 0.66 turbo coding rate (8.85 Gb/s after encoding) at the bit-error ratio (BER) of 1e-4. When the coding rate is all 0.625, the OFDM signal employing ACT has more than 1-dB gain improvement compared with the OFDM signal encoded with fixed-rate turbo coding. And additional ∼1-dB receiver sensitivity improvement is enabled when the OFDM signal employ ACT and bit-interleaver simultaneously.
AB - In this paper, we have theoretically analyzed that the existence of inter-subcarrier mixing interferences (ISMI) and frequency selective fading (FF) in the directed-detection optical orthogonal-frequency-division-multiplexing (DDO-OFDM) system will cause an unbalanced error distribution and degrade the system performance. Then we propose to employ the adaptive code rate technique (ACT) and bit interleaver in the DDO-OFDM system to combat ISMI and FF. The experimental results show that the receiver sensitivity of 5.9-Gb/s 64-ary quadrature-amplitude-modulation (64QAM) OFDM signal employing ACT(9.43 Gb/s after encoding) is improved more than 2 dB compared with the 5.9-Gb/s OFDM signal with 0.66 turbo coding rate (8.85 Gb/s after encoding) at the bit-error ratio (BER) of 1e-4. When the coding rate is all 0.625, the OFDM signal employing ACT has more than 1-dB gain improvement compared with the OFDM signal encoded with fixed-rate turbo coding. And additional ∼1-dB receiver sensitivity improvement is enabled when the OFDM signal employ ACT and bit-interleaver simultaneously.
KW - Adaptive code rate technique (ACT)
KW - Bit interleaver
KW - Direct detection (DD)
KW - Optical fiber communication
KW - Orthogonal frequency division multiplexing (OFDM)
UR - http://www.scopus.com/inward/record.url?scp=84871457528&partnerID=8YFLogxK
U2 - 10.1016/j.yofte.2012.10.001
DO - 10.1016/j.yofte.2012.10.001
M3 - Article
AN - SCOPUS:84871457528
SN - 1068-5200
VL - 19
SP - 35
EP - 39
JO - Optical Fiber Technology
JF - Optical Fiber Technology
IS - 1
ER -