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In this paper, we present a unified resource allocation and mobility management algorithm based on particle swarm optimization (PSO) for indoor visible light communication (VLC) networks. We consider a VLC network where multiple LEDs serve as access points (APs). A centralized controller collects channel state information, quality of service requirements of the users, and the overload status of the APs. Based on the available information, in each time interval, the controller decides which user is served by which AP and assigns subcarriers to the users with the objective of maximizing both the system throughput and user satisfaction. We formulate the resource allocation problem as a constrained nonlinear integer programming problem and solve it using meta-heuristic PSO. Through an extensive simulation study, the superiority of the proposed algorithm in terms of system throughput and user satisfaction over round robin, best channel quality information, and genetic algorithms is demonstrated.

Visible light communication (VLC) has emerged as 1 a potential wireless connectivity solution for infrastructure-to-2 vehicle networks where street lights can be configured to serve 3 as access points. In this letter, we propose dynamic soft handover 4 algorithm based on coordinated multipoint (CoMP) transmission. 5 The proposed algorithm takes the rate of change in the received 6 power as an input and accordingly revises the handover margin 7 and time-to-trigger value without explicit information of the vehi-8 cle velocity. Our simulation results demonstrate that the proposed 9 algorithm outperforms conventional CoMP and hard handover 10 and maintains a stable signal quality regardless of vehicle velocity.

In this paper, we consider a visible light communication (VLC) system with direct currentbiased orthogonal frequency division multiplexing (DC-OFDM) and investigate resource allocation for a multi-user environment. Based on the user satisfaction index as a function of data rate, we aim to optimally determine the allocation of the users to different LEDs (acting as access points) and OFDM subcarriers. We propose a simulated annealing-based heuristic to maximize the average user satisfaction index. In an effort to make the proposed solution practically feasible, the runtime of the proposed heuristic is kept less than the channel coherence time, whose value is in order of tens of milliseconds. We evaluate the performance of the proposed heuristic algorithm in different scenarios that vary in the number of users, the number of LEDs, and the separation between users. Our results demonstrate that the proposed heuristic outperforms other wellknown heuristics (such as standard simulated annealing, iterative greedy, particle swarm optimization, and tabu search) while achieving good quality solutions within a short execution time, i.e., 40-80 ms.INDEX TERMS Visible light communications, resource allocation, optimization, simulated annealing, heuristics.

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Bu çalışmada, görünür ışıkla haberleşme (VLC) ağları için genetik algoritma (GA) temelli kaynak atama tekniği önerilmiştir. Optik VLC agı mevcut aydınlatma altyapısının kullanıldığı iç mekanlarda çok küçük boyutlu hücrelerden oluşur. Sistem kapasitesini artırmak ve kaynakları kullanıcılar arasında daha adaletli bir şekilde dağıtmak için VLC ağlarında etkili kaynak atama mekanizmalarına gerek vardır. Bu nedenle, bu çalışmada GA temelli kaynak atama tekniği önerilerek toplam kanal kapasitesini maksimize etme amaçlanmıştır. Önerilen kaynak atama algoritması Round Robin ve Best CQI algoritmalarına göre sistem kapasitesini arttırma açısından daha iyi sonuçlar vermiştir.In this paper, we present a genetic algorithm (GA) based resource allocation technique for indoor optical visible light communication (VLC) networks. Optical VLC network using existing lighting infrastructure in an indoor environment is a cellular network with very small size cells. It is necessary to have effective resource allocation mechanisms for VLC networks to maximize system throughput and fairness among users. We propose a GA based resource allocation scheme to improve total system throughput. Our proposed scheme gives better results compared to Round Robin and Best CQI algorithms in terms of system throughput.TÜBİTA

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In this paper, we propose a relay-assisted handover technique for vehicular visible light communication net works where streetlights are configured to serve as Access Points (APs). In the proposed system, the vehicle is served by a relay terminal in the form of a neighbor vehicle in addition to the serving AP if the measured bit error rate becomes higher than a threshold value. We evaluate the system performance using realistic site specific channel models developed through non sequential ray tracing features of OpticStudio for various deployment scenarios. The simulation results show that our technique provides a superior performance compared to conventional handover schemes.

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