Performance of a novel LED lamp arrangement to reduce SNR fluctuation for multi-user visible light communication systems

Abstract

This paper investigates the performance of our recently proposed LED lamp arrangement to reduce the SNR fluctuation from different locations in the room for multi-user visible light communications. The LED lamp arrangement consists of 4 LED lamps positioned in the corners and 12 LED lamps spread evenly on a circle. Our studies show that the SNR fluctuation under such a LED lamp arrangement is reduced from 14.5 dB to 0.9 dB, which guarantees that users can obtain almost identical communication quality, regardless of their locations. After time domain zero-forcing (ZF) equalization, the BER performances and channel capacities of 100-Mbit/s and 200-Mbit/s bipolar on-off-keying (OOK) signal with most significant inter-symbol interference (ISI) are very close to that of the channel without any ISI caused by this LED lamp arrangement.

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

“…• the initial design of the optical APs deployment [78]- [80], • the frequency planning within the optical spectrum available [81]- [84], as well as • the cell coordination between the multiple neighbouring optical attocells [85], [86]. …”

“…To elaborate a little further, the ICI avoidance methods were considered at the preliminary design stage of the entire VLC-network design cycle by the authors of [78]- [80], [83]. A novel VLC AP arrangement was advocated in [78], where 12 LEDs constitute a circle and 4 LEDs are placed in the corners, which are referred to here as the circular-LED arrangement and corner-LED arrangement, respectively, as shown in Figure 6.…”

“…A novel VLC AP arrangement was advocated in [78], where 12 LEDs constitute a circle and 4 LEDs are placed in the corners, which are referred to here as the circular-LED arrangement and corner-LED arrangement, respectively, as shown in Figure 6. Compared to the arrangement of [31], where a single LED lamp is placed in the centre of the ceiling illuminating the entire room with the same total emitted optical power as in Figure 6, the arrangement proposed in [78] provides a much lower variance of the received signal-to-noise ratio (SNR) and of the received power at different locations in the room. Furthermore, the radius of the circle constituted by the circular-LED arrangement may be optimized according to the receivers' specific locations as well as to the various layouts of the room considered.…”

Power Consumption Efficiency Evaluation of Multi-User Full-Duplex Visible Light Communication Systems for Smart Home Technologies

“…However, this scheme limited the operation of its users to their respective color cluster, thus making it difficult for the user to be mobile. Apart from the aforementioned papers, other work that has been proposed includes the deployment of LEDs on the room ceiling to control the SNR fluctuation for multi-user scenarios [12], a code division multiple access (CDMA)-based multi-user VLC transmission scheme [13], and a multi-user VLC scheme based on channel control [14,15]. The authors in [16] proposed a new single gallium nitride (GaN)-on-silicon platform that helps in making an in-plane full-duplex VLC system operate at the same frequency on a single chip.…”

Efficient frequency‐domain channel equalisation methods for OFDM visible light communications

“…LED based visible light communications (VLC) or also known as LiFi, offers a number of advantages including license free spectrum (bandwidth), free from electromagnetic interference, and inherent high security [1][2][3][4][5]. As a bottleneck in conventional indoor VLC systems, the bandwidth of LEDs has been increased by using post-and pre-equalization schemes [6][7].…”