scholarly journals Spectrum-Efficient Triple-Layer Hybrid Optical OFDM for IM/DD-Based Optical Wireless Communications

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 10352-10362 ◽  
Author(s):  
Tian Zhang ◽  
Han Ji ◽  
Zabih Ghassemlooy ◽  
Xuan Tang ◽  
Bangjiang Lin ◽  
...  
Keyword(s):  
Wireless Communications ◽  
Optical Wireless ◽  
Optical Wireless Communications ◽  
Triple Layer ◽  
Optical Ofdm

scholarly journals BER Performance of Stratified ACO-OFDM for Optical Wireless Communications over Multipath Channel

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zelalem Hailu Gebeyehu ◽  
Philip Kibet Langat ◽  
Ciira Wa Maina
Keyword(s):  
Wireless Communications ◽  
Spectral Efficiency ◽  
High Speed ◽  
Multipath Fading ◽  
Ofdm Systems ◽  
Optical Wireless ◽  
Optical Wireless Communications ◽  
Efficiency Loss ◽  
Optical Ofdm ◽  
Ber Performance

In intensity modulation/direct detection- (IM/DD-) based optical OFDM systems, the requirement of the input signal to be real and positive unipolar imposes a reduction of system performances. Among previously proposed unipolar optical OFDM schemes for optical wireless communications (OWC), asymmetrically clipped optical OFDM (ACO-OFDM) and direct current biased optical OFDM (DCO-OFDM) are the most accepted ones. But those proposed schemes experience either spectral efficiency loss or energy efficiency loss which is a big challenge to realize high speed OWC. To improve the spectral and energy efficiencies, we previously proposed a multistratum-based stratified asymmetrically clipped optical OFDM (STACO-OFDM), and its performance was analyzed for AWGN channel. STACO-OFDM utilizes even subcarriers on the first stratum and odd subcarriers on the rest of strata to transmit multiple ACO-OFDM frames simultaneously. STACO-OFDM provides equal spectral efficiency as DCO-OFDM and better spectral efficiency compared to ACO-OFDM. In this paper, we analyze the BER performance of STACO-OFDM under the effect of multipath fading. The theoretical bit error rate (BER) bound is derived and compared with the simulation results, and good agreement is achieved. Moreover, STACO-OFDM shows better BER performance compared to ACO-OFDM and DCO-OFDM.

scholarly journals Investigation of the Scattering Noise in Underwater Optical Wireless Communications

Sci ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 27
Author(s):  
Behnaz Majlesein ◽  
Asghar Gholami ◽  
Zabih Ghassemlooy
Keyword(s):  
Wireless Communications ◽  
Optical Wireless ◽  
Clear Water ◽  
Optical Wireless Communications ◽  
Channel Bandwidth ◽  
Phase Variations ◽  
Transmission Link ◽  
Channel Dependent ◽  
First Time ◽  
Scattering Noise

In underwater optical wireless communications (UOWC), scattering of the propagating light beam results in both intensity and phase variations, which limit the transmission link range and channel bandwidth, respectively. Scattering of photons while propagating through the channel is a random process, which results in the channel-dependent scattering noise. In this work, we introduce for the first time an analytical model for this noise and investigate its effect on the bit error rate performance of the UOWC system for three types of waters and a range of transmission link spans. We show that, for a short range of un-clear water or a longer range of clear water, the number of photons experiencing scattering is high, thus leading to the increased scattering noise. The results demonstrate that the FEC limit of 3×10−3 and considering the scattering noise, the maximum link spans are 51.5, 20, and 4.6 m for the clear, coastal, and harbor waters, respectively.

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