# Heterogeneous Network Switching Strategy Based on Communication Blind Area Dwell Time
## 1 Introduction  
With humans' constant research and experiments on information technology, wireless communication technology has been effectively developed, and a new communication method, VLC, through ongoing experiments and improvements, has gradually started to replace traditional wireless communication technology [1, 2]. Compared with traditional RF communication, VLC has the advantages of low carbon and environmental protection, abundant bandwidth resources, and high-security performance. In order to overcome the problems of unstable reception of signals from user-receiving equipment and high power consumption of communication systems under visible light communication, research on network handover technology is necessary. Visible light communication heterogeneous networking technology has attracted a lot of attention in today's academic circles due to its unique communication advantages [3]. In visible light communication heterogeneous networking technology, horizontal handover (HHO) is the switching between multiple visible light networks, and vertical handover (VHO) is the switching between Wi-Fi and visible light networks [4]. Indoor daily office areas generally adopt integrated networks of VLC and Wi-Fi, and because Wi-Fi can cover the whole area, the VHO scheme is proposed to be progressively popular in office areas [5]. [PERSON] et al. [6] came up with a dwell vertical handover (D-VHO) scheme where the vertical handover controller could predict the link recovery time by waiting for a fixed duration. However, the drawback is that the vertical handover is executed only when the optical link remains blocked at the end of the waiting time. [PERSON] et al. [7] proposed a channel adaptive residence vertical handover (CAD-VHO) scheme, which could use the channel blocking rate and recovery rate to determine the adaptive residence time and then determine whether to perform vertical handover. Nevertheless, the shortcoming is that it does not take real-time application operations into account. Subsequently, their team members, [PERSON] et al. [8], proposed the technique of hybrid application-aware VHO (HA-VHO), which took real-time applications into consideration. However, they only analyzed the communication in the overlapping region of visible light coverage. [PERSON] [9] made use of mines as an application scenario to learn the heterogeneous networks and proposed a received signal strength (RSS) horizontal handover scheme on the basis of fast Fourier transformation (FFT) fading detection for coal mine working faces and a dynamic residence time vertical handover scheme for roadways, while the communication between coal mine working faces and roadway handover areas failed to be considered. [PERSON] et al. [10] proposed a heterogeneous network handover strategy that depended on the quality of service of users, using network dwell time as the handover mechanism and combining vertical handover algorithms on top of horizontal handover, but also failed to analyze the communication in the region of severe fading of visible light signals. In summary, most of the current research on visible heterogeneous networking handover technology fails to take into account all visible signal attenuation areas, which are collectively referred to as communication blind areas in this article. ACO-OFDM technology is used to process visible signals and determine the communication blind zone by calculating the BER at the receiver side, which improves the recognition of the communication blind area, followed by considering the communication stability in the communication blind area, focusing on the dwell time of the user receiving device in the communication blind area, using the channel interruption time as the threshold time, and developing horizontal-vertical collaborative switching by comparing the dwell time with the threshold time.