Abstract-As the demand for wireless bandwidth rapidly increases, alternative methods to radio frequency-based communication are investigated to overcome the limited bandwidth problem. Visible light communication (VLC) using light emitting diodes (LEDs) is one of these alternatives. LEDs are estimated to replace the incandescent bulbs within the decade. Since, LEDs can be intensity modulated faster than the human eye can detect, illumination and communication can both be provided by the same lighting system. Indoors communication constitutes 70% of the overall traffic, and VLC is a promising technology to complement Wi-Fi and cellular wireless systems. However, proper handover mechanism should be developed for VLC to be a complete indoors solution. In this paper, we present two soft handover methods for VLC. Simulation results indicate our solutions provide higher data rate for both the overall system and individual users in the handover region. Index Terms-Visible light, Handover, OFDMA, FFR I. INTRODUCTION High data rate applications such as high definition video streaming are being widely used. Meeting the required wireless bandwidth for these applications is one of the prominent challenges of new wireless communication systems. As a result, alternative wireless systems are being investigated. Visible light communication (VLC) is one of the alternatives. LEDs offer various advantages such as lower cost, lower energy consumption and higher lifetime, compared to incandescent light bulbs widely used today. Therefore, LED based illumination is predicted to become the dominant lighting method in the near future. Since LEDs support high switching rates, it is possible to modulate the intensity of LED-generated light faster than human eye can perceive, enabling their use for communication as well as illumination. VLC using LEDs was first demonstrated at Nakagawa Laboratory, in 2003 [1]. Since then, high data rates up to 500 Mbps were reported [2]. With such high data rates, VLC is envisioned to be used in high data rate indoors applications. Some of these applications include information dissemination in shopping malls for product information, and in museums for data on exposition pieces. In such applications, users move from one light source to the next. Meanwhile, their communication should not be effected by this switch over different light sources. Therefore, effective handover mechanisms for VLC are needed. In this paper, we propose two different VLC handover mechanisms. We first show the need for such handover mechanisms quantitatively, on a scenario case. Then, we explain our
In REF power and frequency-based soft handover methods were proposed to reduce data rate fluctuations as the mobile device moves from one cell to another.
Soft Handover in OFDMA Based Visible Light Communication Networks
2015 IEEE 82nd Vehicular Technology Conference (VTC2015-Fall)
2015 IEEE 82nd Vehicular Technology Conference (VTC2015-Fall)
Computer Science