• 한국통신학회논문지
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• 제38B권4호
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• pp.247-256
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• 2013

2011년 9월 IEEE 802.15.7 워킹그룹(Working group)을 통해 LED와 PD를 이용하는 가시광 무선 통신 기술에 대한 물리 계층과 MAC 계층에 대한 표준 규격이 완성됨에 따라 가시광 무선 통신 기술을 이용한 다양한 응용 서비스 기술 개발의 토대가 마련되었다. 이에 따라 가시광 무선 통신 기술은 상용화를 위한 응용 연구 단계로 진입하였으나 대부분의 가시광 무선 통신 환경 개발 현황이 PtP(Peer to peer) 환경을 고려하고 있다. 따라서 보다 다양한 응용 서비스의 개발을 위해서는 PtMP(Point to multi-point) 환경에 대한 연구가 요구된다. 이에 따라 본 논문에서는 IEEE 802.15.7 표준에서 정의한 물리계층과 MAC 계층의 특성을 반영한 스타 토폴로지 기반의 VPAN(Visible personal area network) 시스템 시뮬레이터를 구현하였고, 이를 기반으로 MAC 프로토콜에 영향을 끼치는 주요 파라미터들에 대한 네트워크 성능을 분석하였다.

• 한국통신학회논문지
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• 제38C권8호
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• pp.719-724
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• 2013

Visible light communication based wireless personal area network (WPAN) has recently remained in the center of attention, as it shows a lot of promise to a be a perfect replacement for the contemporary Radio frequency (RF) communication at least in the indoor environment. A commercially deployable VLC based WPAN must support diverse traffic requirement for different kinds of service. In this paper, we have proposed an innovative bandwidth allocation scheme for VLC based WPAN. We wish to allocate bandwidth adaptively for users in a network where bandwidth for each user is allocated scalably. Our aim is to allow maximum number of users in a VLC based WPAN where each user is guaranteed their required QoS. The simulation results justify that the proposed scheme is better than the conventional scheme.

• 한국통신학회논문지
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• 제37권3C호
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• pp.224-232
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• 2012

Priority MAC is an important issue in every communication system when we consider differentiated service applications. In this paper, we propose a mechanism to support priority MAC based on multi-parameters for IEEE 802.15.7 visible light communication (VLC). By using three parameters such as number of backoff times (NB), backoff exponent (BE) and contention window (CW), we provide priority for multi-level differentiated service applications. We consider beacon-enabled VLC personal area network (VPAN) mode with slotted version for random access algorithm in this paper. Based on a discrete-time Markov chain, we analyze the performance of proposed mechanism under non-saturation environments. By building a Markov chain model for multi-parameters, this paper presents the throughput and transmission delay time for VLC system. Numerical results show that we can apply three parameters to control the priority for VLC MAC protocol.

• International journal of advanced smart convergence
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• 제1권1호
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• pp.14-18
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• 2012

This paper presents a fair MAC protocol based on the CSMA/CA algorithm in visible light communication (VLC) networks. The problem of bandwidth sharing among differentiated priority in VLC networks can be solved by using number of backoff time and backoff exponent parameters with AIFS. The proposed algorithm can achieve fair allocation of the bandwidth resource among differentiated priority. The two dimension Markov chain is assisted for analyzing the proposed mechanism about throughput and delay metrics. Numerical results show that our proposed algorithm improves the fairness among different traffic flows.