Effect of LED Radiation Pattern on BER Performance in Indoor Multipath MIMO-VLC System

Kumar, Ajit; Ghorai, S.K.

doi:10.1007/s11277-020-07305-2

Cited by 2 publications

(2 citation statements)

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“…Authors extend this study [24] in [25] for a dimmable VLC system considering up to three reflections. The BER performance of multiplexed VLC systems has recently been analyzed in [26] and [27] for no reflections and up to first-order reflections, respectively. However, although the works [24,25,27] try to incorporate the multipath effect, these studies do not consider the channel delay characteristics.…”

Section: A Related Workmentioning

confidence: 99%

“…The BER performance of multiplexed VLC systems has recently been analyzed in [26] and [27] for no reflections and up to first-order reflections, respectively. However, although the works [24,25,27] try to incorporate the multipath effect, these studies do not consider the channel delay characteristics. Hence, the effect of ISI on BER performance has not been accounted.…”

Section: A Related Workmentioning

confidence: 99%

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On the Effect of Multipath Reflections in Indoor Visible Light Communication Links: Channel Characterization and BER Analysis

2020

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Owing to its several advantages over other wireless schemes, visible light communication (VLC) shall be at the forefront of optical wireless communication technology. However, due to multipath reflections and spatial distribution of light-emitting diode (LED) transmitters, there is an inherent delay spread in the VLC channels. We perform a comprehensive quantitative study on the effect of several practical factors like LED semi-angle, wall reflectivity, number of reflections, number of LED panels, room size, and user locations on the channel delay parameters, namely RMS delay spread and coherence bandwidth of the channel. We present the detailed derivation of the multipath VLC channel model and incorporate the effect of inter-symbol interference in bit error rate (BER) performance of the multipath VLC system. We analyze the average BER of the system under different practical scenarios and determine the penalty in signal to noise ratio entailed by a change in the system parameters mentioned above. We conclude that it is sufficient to model up to three reflections in the VLC channel to emulate the effect of multipath propagation on the channel characterization and BER analysis of the system. The results and analyses presented herein provide critical insights into the effect of multipath reflections in indoor VLC links, particularly the BER performance and channel delay characteristics. We also provide some key recommendations for the design of practical VLC systems by outlining the data rates that can be served under different system configurations. INDEX TERMS multipath channel, delay spread, coherence bandwidth, inter-symbol interference, bit error rate, visible light communication. I. INTRODUCTION Visible light communication (VLC) is an upcoming optical wireless communication technology that integrates communication and illumination by utilizing the illumination infrastructure of white light-emitting diodes (LEDs) for data communication [1-4]. Due to rapid advancements in the field of solid-state lighting devices [5] and a simultaneous boom in Internet traffic over the last few decades, the research on VLC has garnered much interest in the area of wireless communication systems. VLC opens up the untapped visible range (~ 400-700 THz) of the electromagnetic spectrum that is unlicensed and free. Thus, VLC promises to support very high data rates and enables inexpensive indoor wireless communication. Besides this, VLC also benefits from advantages like radiation safety and less electromagnetic interference as compared to other wireless communication technologies. Moreover, since visible light signals cannot penetrate through walls, so the transmission of user data over such signals is confined to a room, which makes it difficult for eavesdroppers to intercept data [3]. However, the non-penetrability of visible light signals means that they suffer reflections at the walls. These reflections create multiple paths from the LED source to the receiver, giving rise to the problem of delay spread because the light signals...

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Section: A Related Workmentioning

confidence: 99%

Section: A Related Workmentioning

confidence: 99%

On the Effect of Multipath Reflections in Indoor Visible Light Communication Links: Channel Characterization and BER Analysis

2020

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Performance analysis of downlink multipath multi-user NOMA-VLC system

Kumar¹,

Sharan²,

Ghorai³

2022

Opt Quant Electron

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In the present paper, the performance of non-orthogonal multiple access (NOMA) in a downlink multipath multi-user Visible Light Communication (VLC) system has been evaluated w.r.t bit-error rate (BER), sum rate & outage probability. The results show that the sum rate and BER performance improve with the increase in semi-angle 𝝋 𝟏 𝟐 ⁄ of the LED using both Line-of-sight (LOS) and LOS plus first reflection (L-R1) signals. The simulation results display that there is optimal value of 𝝋 𝟏 𝟐⁄ at which minimum BER is achieved. However, the optimal angle of semi-angle varies with the number of users and order of reflection of signal. In case of two-user system with LOS signal, the optimal angle is 𝟓𝟎 𝟎 and 𝟕𝟎 𝟎 for user-1 & user-2 respectively, whereas, for three-user system the optimal angle is 𝟑𝟎 𝟎 for user-1 and it is 𝟓𝟎 𝟎 for each user-2 and user-3. The BER simulation results for L-R1 signal reveal that the successive interference cancellation (SIC) efficiently decodes the signal for two-user system with optimum performance at 𝝋 𝟏 𝟐 ⁄ equals to 𝟕𝟎 𝟎 but as the number of users increases to three, it fails to decode the signal. The results of sum rate vs. offset using LOS signal show that sum rate for two-user system monotonically increases & then decreases with the increase in semi-angle. The optimal angle is 𝟓𝟎 𝟎 for the maximum sum rate which also supports the BER results. The effect of shadowing (blocked LOS signal) shows that the sum rate is zero for lower values of semi-angle of LED. Finally, the outage probability against target rate of far user confirms the key finding results of shadowing.

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Effect of LED Radiation Pattern on BER Performance in Indoor Multipath MIMO-VLC System

Cited by 2 publications

References 18 publications

On the Effect of Multipath Reflections in Indoor Visible Light Communication Links: Channel Characterization and BER Analysis

On the Effect of Multipath Reflections in Indoor Visible Light Communication Links: Channel Characterization and BER Analysis

Performance analysis of downlink multipath multi-user NOMA-VLC system

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