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This paper describes the simulation results and hardware implementation of an inexpensive, low-complexity LED based indoor positioning system. Localization by multiple LEDs estimation model (MLEM) approximates position of a mobile receiver by the acquisition of positional information from LED transmitters. Multiple LED orientation can either be with or without overlap. Receivers in a no-overlap LED...
One of the evolved technologies which has the prospect of providing huge data rate is visible light communication (VLC). Use of optical orthogonal frequency-division multiplexing (OFDM) has been demonstrated as one of the viable schemes in achieving high data rate in VLC system. However, the limitation of optical OFDM still remains the high peak-to-average power ratio (PAPR) which results in signal...
In this paper we experimentally demonstrate a 10 Mb/s error free visible light communications (VLC) system using polymer light-emitting diodes (PLEDs) for the first time. The PLED under test is a blue emitter with ∼600 kHz bandwidth. Having such a low bandwidth means the introduction of an intersymbol interference (ISI) induced penalty at higher transmission speeds and thus the requirement for an...
In this paper, the performance of binary polarisation shift keying (BPOLSK) with the direct detection (DD) scheme is experimentally investigated. BPOLSK scheme is used to mitigate the atmospheric turbulence induced fading in a free space optical (FSO) communication link. For comparison the experimental and analytical results for the non-return-to-zero on-off keying (NRZ-OOK) have also been presented...
A coherent differential circular polarization shift keying (DCPOLSK) scheme for free space optical (FSO) communications is proposed and analyzed. No polarization coordinate alignment is needed and the complexity is thus reduced. The unconditional bit error rate (BER) expression for DCPOLSK in a weak turbulence has been derived, and its performance is compared with the coherent amplitude shift keying...
In this paper, we present simulation results for the bit error rate (BER) performance and the fading penalty of a BPSK subcarrier intensity modulation (BPSK-SIM) free-space optical (FSO) communication link in a log-normal atmospheric turbulence model. The results obtained are based on the Monte-Carlo simulation. Multiple subcarrier modulation schemes offer increased system throughput and require no...
A binary polarization shift keying (2PolSK) scheme with a coherent heterodyne receiver for a free space optical (FSO) link through atmospheric turbulence channel is proposed and discussed. The maximum ratio combining (MRC) and equal gain combining (EGC) spatial diversity techniques have been applied to mitigate the turbulence induced irradiance fluctuation with bit error rate (BER) expressions derived...
In this work, the performance of subcarrier intensity modulated terrestrial free-space optical communication link is analysed in the presence of noise and atmospheric turbulence induced fading. To ameliorate channel fading we propose subcarrier time delay diversity (TDD) in which delayed versions of the original data are retransmitted on different subcarriers. The most efficient TDD is obtained with...
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