A 750 Mbps with Zero BER Space-Wavelength-Time Division Multiple Access Scheme for Bidirectional VLC Network

Visible light communication (VLC), which uses an irregular visible band to offer ultra-high bandwidth, ultra-high data rates, lower latency, low energy consumption and reduced implementation costs, is one of the most promising complementary wireless technologies for Sixth Generation Mobile Communications(6G). With the deployment of massive access points for bidirectional VLC network, the problem of user service quality is also brought correspondingly, such as how to increase user Quality of Experience (QoE) and reduce user access delay. In this paper, a space-wavelength-time division multiple access (SWT-MA) scheme is proposed based on Tri-color Light Emitting Diode(LEDs). The principle of SWT-MA scheme is descripted. The metrics of the VLC based on the SWT-MA scheme is analyzed in throughput, access delay in detail respectively. And finally, the experimental measurements of BER for each color signals are illustrated. The access scheme proposed in this paper solves the above problems by improving the data transmission rate through space division multiplexing and wavelength division multiplexing, and increasing the system capacity through time division multiplexing. The feasibility of this scheme is verified by theoretical analysis, simulation and experiment. We showed that the proposed access scheme is suitable for large-scale bidirectional VLC access networks and can be used for 6G.

I. Introduction

In order to meet the demand of Sixth Generation Mobile Communications(6G) in the future, many scholars regard Visible Light Communication (VLC) as one of the most promising wireless communication technologies to supplement 6G [1], [2]. In the case of massive VLC Access Points(APs), in order to satisfy the capacity, latency, and seamless connectivity of 6G for the terminal users, an additional network architecture should be adopted for the 6G+VLC network. Thus, the user communicates with one or more unspecified cooperative APs instead of being associated with a single AP. A Voronoi-coordinated multipoint technique was proposed in a user- central cell-less architecture network to address the severe interference in densely deployed same-frequency small base stations [3]. Local moving software-defined cloudlet transmission and scheduling management-aided 5G cell-less moving vehicle access network was proposed in [4]. Three simple but workable strategies were proposed for vehicle selection by the cooperative moving APs to ensure secure communications, low latency, high connectivity, and high data rate between vehicles. For dense deployments cloud radio access network (C-RAN), a context-tailored time-division-duplex (TDD) network was investigated in [5]. This network enabled a cell-less experience within overlapping areas by optimizing power control and delay targets.