Abstract
In underwater direct current-biased optical orthogonal frequency-division multiplexing (DCO-OFDM) system, high peak-to-average power ratio (PAPR) brings in-band distortion and out-of-band power. It also decreases the signal-to-quantization noise ratio of the analog-to-digital converter and the digital-to-analog converter. A time–frequency-domain interleaved subbanding scheme is proposed to reduce the PAPR of underwater DCO-OFDM system with low computation complexity and bit error rate (BER). The system BER is evaluated by the distances of the underwater optical wireless communication (UOWC), as well as by the signal attenuation of the UOWC channel. A least-square channel estimation method is adopted for adaptive power amplification at the receiver side, to further decrease the system BER.
Highlights
With growing interest in the research of ocean exploration, the requirement for high-speed, low link delay, and low implementation cost underwater communication technique has made underwater optical wireless communication (UOWC) an attractive alternative for radio-frequency (RF) and acoustic methods.[1]
When the subcarriers of direct current (DC)-biased O-orthogonal frequency-division multiplexing (OFDM) (DCO-OFDM) signals happened to be in phase, high peak-to-average power ratio (PAPR) will bring serious signal distortion and performance deterioration, and result in nonlinear distortion when the signals passing through the power amplifier or laser diode (LD).[6]
The performances of the proposed time–frequency-domaininterleaved UOWC DCO-OFDM PAPR reduction scheme are evaluated through simulations
Summary
With growing interest in the research of ocean exploration, the requirement for high-speed, low link delay, and low implementation cost underwater communication technique has made underwater optical wireless communication (UOWC) an attractive alternative for radio-frequency (RF) and acoustic methods.[1]. An iterative clipping method in Ref. 8 reduces the PAPR of the VLC-OFDM system without out-of-band interference. In both VLC OFDM and UOWC systems, signal processing is basically the same. A time–frequency-domaininterleaved subbanding technique is proposed to reduce the autocorrelation of the input signal, which according to our theoretical analysis, will lead to further PAPR reduction. Time-domain and frequency-domain signals are interleaved together, which helps to decrease the autocorrelation of the input signal, and brings better PAPR reduction performance compared with the frequencydomain-interleaved method in Ref. 13. A least-square (LS) channel estimation is employed at the receiver side, to adaptively adjust the power amplifier with the estimated underwater channel response, so as to effectively balance the channel attenuation and to obtain a better BER performance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
