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

Gebeyehu, Zelalem Hailu; Langat, Kibet; Maina, Ciira wa

doi:10.1155/2018/9575281

Cited by 5 publications

(12 citation statements)

References 12 publications

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“…However, it is also possible to use only even subcarriers, leaving the odd subcarriers blank; therefore, ACO‐OFDM wastes even or odd index subcarriers. Waste of odd or even subcarriers makes ACO‐OFDM spectrally inefficient compared with DCO‐OFDM 31,32 . For ACO‐OFDM with conventional M‐QAM modulation,

N

subcarrier, and

N_{CP}

CP, the spectral efficiency is given by the following equation:

S_{Eff} goodbreak= \frac{\log_{2} M ((), N)}{4 ((), N goodbreak+ N_{CP})} .

In ACO‐OFDM, odd subcarriers are loaded with the symbol M‐QAM, whereas even subcarriers are loaded with zero.…”

Section: Ber Analysis Of the Proposed Lwt‐aco‐ofdm Systemsmentioning

confidence: 99%

“…To facilitate interframe interference cancelation at the receiver, the entire frame is split into two subframes, each N/2 sample length, and reversal of samples is performed on the second subframe before clipping of negative samples is performed. Therefore, the two subframes

y_{italicsf 1} ([], n)

and

y_{italicsf 2} ([], n)

can be written as follows 32 :

y_{italicsf 1} ([], n) goodbreak= y ([], n), n goodbreak= 0, 1, 2, \dots, \frac{N}{2} goodbreak- 1,

y_{italicsf 2} ([], n) goodbreak= goodbreak- y ([], n goodbreak+ \frac{N}{2}), n goodbreak= 0, 1, 2, \dots, \frac{N}{2} goodbreak- 1 .

Then, after clipping negative samples from both subframes, they will have clipped

{\overset{true¯}{y}}_{italicsf 1} ([], n)

and

{\overset{true¯}{y}}_{italicsf 2} ([], n)

signals as follows:

{\overset{true¯}{y}}_{italicsf 1} ([], n) goodbreak= ({, \begin{matrix} 0, for y_{italicsf 1} ([], n) \leq 0, n goodbreak= 0, 1, 2, \dots, \frac{N}{2} goodbreak- 1 \\ y_{italicsf 1} ([], n), for y_{italicsf 1} ([], n) > 0, n goodbreak= 0, 1, 2, \dots, \frac{N}{2} goodbreak- 1 \end{matrix}),

{\overset{true¯}{y}}_{italicsf 2} ([], n) goodbreak= ({, \begin{matrix}  \end{matrix})

…”

Section: Ber Analysis Of the Proposed Lwt‐aco‐ofdm Systemsmentioning

confidence: 99%

“…It is known that the real bipolar time domain ACO‐OFDM signal has a Gaussian distribution for a sufficient number of available subcarriers 32 . The average electrical power of the ACO‐OFDM signal is equal to

σ^{2}

, the variance of the signal samples distribution.…”

Section: Ber Analysis Of the Proposed Lwt‐aco‐ofdm Systemsmentioning

confidence: 99%

“…Therefore, the obtained average SNR per bit in the k th subcarrier of the entire ACO‐OFDM system is given as follows 17,32 :

γ_{k} goodbreak= \frac{ξ_{k} P_{italicel, italicavg}}{B N_{0} S_{Eff}} .

From here, the theoretical BER calculation on the k th subcarrier using M‐QAM modulation can be given as follows:

{BER}_{k} goodbreak= \frac{4}{\log_{2} M} ((), 1 goodbreak- \frac{1}{\sqrt{M}}) \sum_{i = 1}^{\sqrt{M} / 2} Q ((), ((), 2 i goodbreak- 1) \sqrt{\frac{3 \log_{2} M γ_{k}}{M - 1}}) .

The

Q (() .)

function used in the above and below equations can be given as in the following equation.

Q ((), x) goodbreak= \frac{1}{\sqrt{2 π}} \int_{x}^{\infty} e^{- z^{2} / 2} italicdz .

…”

Section: Ber Analysis Of the Proposed Lwt‐aco‐ofdm Systemsmentioning

confidence: 99%

See 3 more Smart Citations

A novel asymmetrically clipped optical orthogonal frequency division multiplexing system based on lifting wavelet transform for visible light communications

Avcı

Aykiri

Savaşcıhabeş

et al. 2022

Int J Communication

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Summary In multicarrier visible light communication (VLC) systems, orthogonal frequency division multiplexing (OFDM) has attracted a lot of attention due to its high data rate, simple equalization, and resistance to intersymbol interference (ISI). However, high peak‐to‐average‐power ratio (PAPR) and Light Emitting Diodes (LED) nonlinearity have important effects on the performance of indoor VLC‐OFDM systems. Asymmetrically clipped optical (ACO)‐OFDM is a technique that waste spectral efficiency to transmit a single pole frequency division multiplexed signal over a single pole channel. In this study, a new ACO‐OFDM method based on lifting wavelet transform (LWT)‐ACO‐OFDM is proposed to restore this spectral efficiency and increase the performance of the ACO‐OFDM system. The performance of the proposed method is verified by computer simulation studies over additive white Gaussian noise (AWGN) channel and multipath optical channel for analytical and simulated bit error rate (BER) performance criterion. From the obtained simulation results, it is seen that the proposed method provides approximately 16‐dB SNR gain against the classic VLC‐OFDM, roughly 12‐dB Signal to Noise Ratio (SNR) improvement versus the Direct Current (DC)‐biased optical (DCO)‐OFDM, and nearly 6‐dB SNR enhancement against ACO‐OFDM on the additive white Gaussian noise channel. It is observed from computer simulation results that similar SNR gains are obtained in multipath optical channels.

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N

subcarrier, and

N_{CP}

CP, the spectral efficiency is given by the following equation:

S_{Eff} goodbreak= \frac{\log_{2} M ((), N)}{4 ((), N goodbreak+ N_{CP})} .

In ACO‐OFDM, odd subcarriers are loaded with the symbol M‐QAM, whereas even subcarriers are loaded with zero.…”

Section: Ber Analysis Of the Proposed Lwt‐aco‐ofdm Systemsmentioning

confidence: 99%

y_{italicsf 1} ([], n)

and

y_{italicsf 2} ([], n)

can be written as follows 32 :

y_{italicsf 1} ([], n) goodbreak= y ([], n), n goodbreak= 0, 1, 2, \dots, \frac{N}{2} goodbreak- 1,

y_{italicsf 2} ([], n) goodbreak= goodbreak- y ([], n goodbreak+ \frac{N}{2}), n goodbreak= 0, 1, 2, \dots, \frac{N}{2} goodbreak- 1 .

Then, after clipping negative samples from both subframes, they will have clipped

{\overset{true¯}{y}}_{italicsf 1} ([], n)

and

{\overset{true¯}{y}}_{italicsf 2} ([], n)

signals as follows:

{\overset{true¯}{y}}_{italicsf 1} ([], n) goodbreak= ({, \begin{matrix} 0, for y_{italicsf 1} ([], n) \leq 0, n goodbreak= 0, 1, 2, \dots, \frac{N}{2} goodbreak- 1 \\ y_{italicsf 1} ([], n), for y_{italicsf 1} ([], n) > 0, n goodbreak= 0, 1, 2, \dots, \frac{N}{2} goodbreak- 1 \end{matrix}),

{\overset{true¯}{y}}_{italicsf 2} ([], n) goodbreak= ({, \begin{matrix}  \end{matrix})

…”

Section: Ber Analysis Of the Proposed Lwt‐aco‐ofdm Systemsmentioning

confidence: 99%

σ^{2}

, the variance of the signal samples distribution.…”

Section: Ber Analysis Of the Proposed Lwt‐aco‐ofdm Systemsmentioning

confidence: 99%

“…Therefore, the obtained average SNR per bit in the k th subcarrier of the entire ACO‐OFDM system is given as follows 17,32 :

γ_{k} goodbreak= \frac{ξ_{k} P_{italicel, italicavg}}{B N_{0} S_{Eff}} .

From here, the theoretical BER calculation on the k th subcarrier using M‐QAM modulation can be given as follows:

{BER}_{k} goodbreak= \frac{4}{\log_{2} M} ((), 1 goodbreak- \frac{1}{\sqrt{M}}) \sum_{i = 1}^{\sqrt{M} / 2} Q ((), ((), 2 i goodbreak- 1) \sqrt{\frac{3 \log_{2} M γ_{k}}{M - 1}}) .

The

Q (() .)

function used in the above and below equations can be given as in the following equation.

Q ((), x) goodbreak= \frac{1}{\sqrt{2 π}} \int_{x}^{\infty} e^{- z^{2} / 2} italicdz .

…”

Section: Ber Analysis Of the Proposed Lwt‐aco‐ofdm Systemsmentioning

confidence: 99%

See 2 more Smart Citations

A novel asymmetrically clipped optical orthogonal frequency division multiplexing system based on lifting wavelet transform for visible light communications

Avcı

Aykiri

Savaşcıhabeş

et al. 2022

Int J Communication

View full text Add to dashboard Cite

show abstract

“…However, the issue of low modulation bandwidth of LEDs is a well-known challenge towards the implementation of practical VLC. Therefore, spectrally efficient modulation and multiple access schemes are highly needed to maximize the capacity of LED-based VLC systems [3,4]. To accommodate high-speed communication and massive connectivity in cases of internet of things (IoT) and overly growing mobile internet, VLC should adopt spectrally efficient multiple access and modulation schemes such as NOMA and DCO-OFDM, respectively.…”

Section: Introductionmentioning

confidence: 99%

Impact of clipping noise on the sum rate of NOMA with PD-DCO-OFDM and conventional DCO-OFDM

Gebeyehu

2020

Heliyon

Self Cite

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sIn visible light communication (VLC) systems, a non-orthogonal multiple access (NOMA) scheme is deemed promising technology to offer better spectral efficiency than the Orthogonal multiple access (OMA) scheme. The feasibility of power domain NOMA for VLC system has been studied with different variants of unipolar OFDM schemes. However, few research works have been presented on the impact of clipping noise on the achievable sum rate of NOMA with DC-biased optical OFDM (DCO-OFDM) and polarity divided DCO-OFDM (PD-DCO-OFDM). This paper presents the impact of clipping noise on the achievable sum rate of NOMA-DCO-OFDM and NOMA-PD-DCO-OFDM VLC systems. Moreover, NOMA-DCO-OFDM and NOMA-PD-DCO-OFDM systems are compared based on achievable sum rates for different total power constraints and signal clipping levels. For the two-user scenario, Simulation results have confirmed that NOMA-PD-DCO-OFDM can offer a better sum rate compared to NOMA-DCO-OFDM system.

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Modified quality video: transmission control protocol (TCP) friendly for controlling a congestion

Bakhati

Alsadoon

Prasad

et al. 2021

Multimed Tools Appl

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

Cited by 5 publications

References 12 publications

A novel asymmetrically clipped optical orthogonal frequency division multiplexing system based on lifting wavelet transform for visible light communications

A novel asymmetrically clipped optical orthogonal frequency division multiplexing system based on lifting wavelet transform for visible light communications

Impact of clipping noise on the sum rate of NOMA with PD-DCO-OFDM and conventional DCO-OFDM

Modified quality video: transmission control protocol (TCP) friendly for controlling a congestion

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