由於每一代的移動網路都會明顯的提高對於吞吐量的要求，因此需要提高現有射頻(RF)系統的頻譜效率以及實現新的互補技術。在這項研究中我們探討在設備到設備(D2D)的場景中結合RF以及可見光通訊(VLC)的概念。VLC可以提供比RF更高的吞吐量，但對於信號的阻塞以及遮蔽非常敏感。因此在RF/VLC的網路中開發快速且有效率的垂直切換(VHO)的演算法是很重要的。VHO會決定用戶設備(UE)是否有益於從VLC切換到RF，或是從RF切換到VLC。在這個研究中，停留計時器是根據系統中D2D對的數量計算的。然後使用層次分析法（AHP），合作博弈（CG）和合理性程度（RD）來做出關於VHO的決定。除此之外，這個研究也討論了所提出的通信系統的實際應用面臨的挑戰。我們將這個研究所提出的VHO演算法與基本的方法和兩個不考慮用D2D的解決方法做了比較，模擬的結果顯示我們所提出的演算法確實提高了大多數測試環境中的平均比特率。

The requirements on throughput are increased significantly with every new generation of mobile networks. Therefore it is necessary to improve the spectral efficiency of existing radio frequency (RF) systems as well as implement new complementary technologies.
The concept of combining RF and Visible Light Communication (VLC) in Device-to-Device (D2D) scenario is investigated in this work.
VLC can provide much higher throughput than RF but is very sensitive to signal blockage and shadowing events. Therefore, it is important to develop fast and effective vertical handover (VHO) algorithm in RF/VLC network. This VHO decides whether or not it is beneficial for a user equipment (UE) to switch from VLC to RF, or vice versa. In this work, the dwell timer is calculated in relation to the number of D2D pairs in the system. The Analytic Hierarchy Process (AHP), Cooperative Game (CG) and Rationality Degree (RD) are then used to make a decision about VHO. Further, the challenges for practical application of proposed communication system are discussed in this work. The VHO algorithm proposed in this work is compared to basic approaches and two other solutions that did not consider D2D. The results of the performed simulations show that the proposed algorithm does increase the average bit-rate in the majority of tested environments.

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