Spatial multiplexing multiple-input multiple-output (MIMO) visible light communication (VLC) has become a potential candidate for next-generation wireless networks. In this paper, novel superposed odd-order 32QAM constellation scheme is proposed in 2 × MIMO VLC systems. Two independent signals generated from two emitting diode (LED)-based transmitters with four-quadrature amplitude modulation (4QAM) and geometrically shaped square 8QAM, respectively, are transmitted over free space spatially...

In this study, a hybrid non-orthogonal multiple access / orthogonal frequency division (NOMA/OFDMA) scheme is proposed for multi-cell multi-user visible light communication (VLC) systems. Each cell divided into several sub-cells that are multiplexed using OFDMA. Users within the same sub-cell by NOMA. Thus, NOMA/OFDMA takes advantage of both NOMA and OFDMA, which not only improves spectral efficiency OFDMA but also avoids co-channel interference Moreover, coordinated multiple-point...

Multiple-input multiple-output (MIMO) visible-light communication (VLC) systems based on the concept of superposed constellation have attracted increasing attention because multiplexing gains can be achieved even in a highly correlated MIMO channel. In this paper, novel scheme is proposed for 2×2 VLC systems, where 2n-order quadrature amplitude modulation (QAM) signal obtained by superposing 4QAM and processed 2n-2-order QAM signals. Based original signal, generated adding an optimal offset,...

Multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) has been widely used to improve data rate in visible-light communication (VLC) systems. However, the high correlation of channels restricts application MIMO. A superposed constellation, combined with MIMO, can achieve considerable diversity gain even highly correlated MIMO channels. In this study, what we believe be novel three-dimensional 64-quadrature amplitude modulation (3D-64QAM) constellation schemes...

We propose and experimentally demonstrate an adaptive multiple-input multiple-output (MIMO) mode switching scheme for indoor visible light communication system combined with orthogonal frequency division multiplexing modulation. Only requiring 1 bit feedback from the receiver, MIMO at transmitter switches between spatial transmit diversity adapting to channel correlation. In such a way, we can take advantage of both diversity, where benefits its gain in low correlation environment, is robust...

Superposed constellation combined with spatial multiplexing multiple-input multiple-output (MIMO) techniques have been increasingly utilized in visible light communication (VLC) systems, as gains can be achieved regardless of the correlation extent VLC channel. Herein, we propose a novel superposed 64-quadrature amplitude modulation (QAM) scheme for 2 × MIMO systems. Considering nonlinearity light-emitting diodes (LEDs), two geometrically shaped 8QAM constellations are introduced to reduce...

Light-emitting diode- (LED-) based visible light communication (VLC) has become a potential candidate for next generation high-speed indoor wireless communication. Due to the limited modulation bandwidth of LED, orthogonal frequency division multiplexing (OFDM) is particularly preferred in VLC system overcome ISI, which suffers from high peak-to-average power ratio (PAPR) and leads severe performance loss. In this paper, we propose experimentally demonstrate novel Zadoff-Chu matrix (ZCM)...

We propose and experimentally demonstrate a simple visible light communication system by combining an adaptive transmission technique with orthogonal frequency division multiplexing. In the scheme, power allocation is performed in such way as to maximize channel capacity under electric constraints, modulation then introduced achieve maximum data rate given target bit error rate. Experimental results show that spectrum efficiency can be greatly improved through this technique.

Visible light communication (VLC) based on a light-emitting diode (LED) is considered to be potential candidate for the next-generation communication. In this paper, novel Zadoff–Chu matrix transform (ZCT) precoding proposed improve performance of traditional space-time block coding- (STBC-) multiple-input multiple-output and orthogonal frequency division multiplexing (MIMO-OFDM) system. Compared with existing circulant (OCT) scheme, ZCT achieves much lower peak-to-average power ratio (PAPR)...

Superposed constellation technology has received increasing attention due to its robustness the correlation of multiple-input multiple-output (MIMO) channels in visible-light communication (VLC) systems. In this study, a novel superposed three-dimensional 32-quadrature amplitude modulation (3D-32QAM) scheme combined with probabilistic shaping is proposed for MIMO VLC Tetrahedron-shaped 3D-4QAM and cube-shaped 3D-8QAM signals are transmitted from two separate LEDs, which at receiver obtain...

In this Letter, we propose and experimentally demonstrate a high-order non-equal probability quadrature amplitude modulation (NEP-QAM) scheme for visible light communication (VLC) systems, where NEP-72QAM is considered as an example. Nonlinear coding introduced to generate the NEP-18QAM signal in first quadrant, which then jointly mapped with other two bits obtain four-quadrant symmetric signal. Moreover, bit-to-symbol labeling proposed achieve thorough Gray mapping. The experimental results...

In this paper, we propose and experimentally demonstrate a switching multiple input output (MIMO) system combining with adaptive orthogonal frequency division multiplexing (OFDM) modulation for high-speed indoor visible light communications. The OFDM modulation, which is realized by power bit allocation on subchannels, utilized to achieve the maximum channel capacity under given target error rate (BER). Meanwhile, MIMO mode switches between spatial transmit diversity adapting correlation,...

With the rapid development of light-emitting diode, visible light communication (VLC) has become a candidate technology for next generation high-speed indoor wireless communication. In this paper, we investigate performance 32-quadrature amplitude modulation (32-QAM) constellation shaping schemes first time, where two special circular constellations, named Circular (4, 11, 17) and (1, 5, 15), triangular are proposed based on Shannon’s criterion. Theoretical analysis indicates that scheme...

In this paper, an orthogonal circulant matrix transform (OCT) precoding technique is proposed to combine with the entropy loading in multiple-input multiple-output and frequency division multiplexing (MIMO-OFDM) visible light communication (VLC) system where space-time coding (STBC) chosen for its robustness channel correlation. Benefitting from OCT technique, uniform signal-to-noise ratio (SNR) among all subchannels can be achieved. As a result, only one SNR value required fed back, same...

In this paper, a novel joint channel estimation and symbol detection method over fast flat fading is proposed, by applying sum-product algorithm on factor graph. An appropriate graph model derived from factoring the likelihood function of transmitting sequence. addition, particle filter introduced to reduce computational complexity continuous integral within algorithm. This provides an intuitive perspective detection, improves spectrum utilization efficiency compared with conventional...

We propose and experimentally demonstrate an adaptive transmission technique for MIMO VLC systems. In order to maximize the channel capacity, is realized by power bit allocation on de-correlated channels separately. Experimental results confirm performance improvement when applying spatial multiplexing space-time coding