LiFi and Hybrid WiFi/LiFi indoor networking: From theory to practice

Abstract

Light fidelity (LiFi) is a wireless optical communication (WOC) technology that holds the key to solving the challenges of 5th and higher generation mobile networks. LiFi is a two-way wireless communication technology that enables high-speed transmission on both up and down links simultaneously. Today, researchers and manufacturers consider LiFi technology as an essential solution for radio frequency (RF) spectrum limitation due to growing demand of Internet users. In addition, integration of various communication technologies such as wireless fidelity (WiFi) and LiFi can help to overcome the traffic restriction challenge caused by the growing demand of Internet users. Although LiFi provides high-speed data transfer capability, it has some weaknesses such as coverage. So, hybrid WiFi/LiFi network can uses fast data transfer from LiFi and wide coverage from WiFi. Their integration can complement the shortcomings of each of these technologies and increases the network performance. In this work, while describing LiFi theory, the recent studies in this field are presented. Theoretical and practical concepts of LiFi-based indoor networks, issues such as network structures, cell deployment models, modulation techniques, multiple access schemes, criteria for measuring network performance, and scenario-based architectures for implementing a real LiFi-based indoor network based on up-to-date equipment manufactured by some LiFi manufacturers are discussed in detail.

Introduction

Studies show that at the end of 2020, mobile data transmission accounted for 71% of Internet traffic, which more than 80% of this data transmission being in indoor areas such as offices and homes. Due to the limited resources of the radio frequency (RF) spectrum and the dense establishment of WiFi hubs, radio systems will have difficulty meeting the growing demand for mobile Internet, especially in the fifth and higher generations of cellular networks. To deal with the shortage of RF spectrum, using LiFi technology is recommended [1].

In LiFi, using light as a carrier, a wide spectrum (around 300 THz) can be achieved. For example, LiFi with a light emitting diode (LED) can achieves data rates above 10 Gbps [2]. However, despite the high data transmission speed, LiFi networks also have some problems such as coverage area limitation and light blockage. In return, in WiFi networks, wider coverage can be achieved and the problem of the carrier route blockage is reduced greatly. Therefore, using hybrid WiFi/LiFi network is proposed. Combining LiFi and WiFi is a practical proposition for face to pure LiFi challenges. Hybrid WiFi/LiFi network uses fast data transfer from LiFi technology and wide coverage area from WiFi. Therefore, hybrid WiFi/LiFi can complement the shortcomings of each of these technologies. Hybrid WiFi/LiFi can use the LiFi fast data transfer and WiFi wide coverage [3]. The hybrid WiFi/LiFi networks have better performance than either LiFi or WiFi systems separately [4].

In this paper, we present the issues related to the theory and practice of LiFi and hybrid WiFi/LiFi networks for practical purposes. Matters include; 1) design of LiFi and hybrid WiFi/LiFi networks to determine the location of LiFi and WiFi access points (APs), 2) allocation of resources to balance the load on the network, 3) mobility and challenges such as user path, light path blockage, and handover, and 4) network performance improvement in terms of efficiency will be discussed in detail. In the following, while introduce LiFi new productions, we show how can to implement a LiFi-based indoor network. The rest of the article is formed in two parts include theoretical concepts and practical concepts as follows. Theoretical concepts include sections 2 Related works, 3 LiFi and Hybrid WiFi/LiFi components, 4 LiFi and Hybrid WiFi/LiFi attributes, 5 LiFi and hybrid WiFi/LiFi performance criteria and practical concepts include section 6. In section 2 the related works are summarized and in section 3, LiFi and Hybrid WiFi/LiFi components are explained. In section 4, the attributes of LiFi and Hybrid WiFi/LiFi networks are discussed, and in section 5, the performance of the LiFi and hybrid WiFi/LiFi networks is evaluated. In section 6, which is constructed for presenting practical concepts, we introduce LiFi equipment and show how a LiFi-based indoor network can be implemented. Finally, in section 7, the article is concluded.