• 제목/요약/키워드: Dynamic channel coordination scheme

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Analytical Study of the Impact of the Mobility Node on the Multi-channel MAC Coordination Scheme of the IEEE 1609.4 Standard

  • Perdana, Doan;Cheng, Ray-Guang;Sari, Riri Fitri
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권1호
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    • pp.61-77
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    • 2017
  • The most challenging issues in the multi-channel MAC of the IEEE 1609.4 standard is how to handle the dynamic vehicular traffic condition with a high mobility, dynamic topology, and a trajectory change. Therefore, dynamic channel coordination schemes between CCH and SCH are required to provide the proper bandwidth for CCH/SCH intervals and to improve the quality of service (QoS). In this paper, we use a Markov model to optimize the interval based on the dynamic vehicular traffic condition with high mobility nodes in the multi-channel MAC of the IEEE 1609.4 standard. We evaluate the performance of the three-dimensional Markov chain based on the Poisson distribution for the node distribution and velocity. We also evaluate the additive white Gaussian noise (AWGN) effect for the multi-channel MAC coordination scheme of the IEEE 1609.4 standard. The result of simulation proves that the performance of the dynamic channel coordination scheme is affected by the high node mobility and the AWGN. In this research, we evaluate the model analytically for the average delay on CCHs and SCHs and also the saturated throughput on SCHs.

OFDMA 하향링크에서 적응적 변조와 여러 개의 재사용 지수를 동시에 사용하고 채널 상태를 고려한 동적 셀 코디네이션 (Channel State-Aware Joint Dynamic Cell Coordination Scheme using Adaptive Modulation and Variable Reuse Factor in OFDMA)

  • 변대욱;기영민;김동구
    • 한국통신학회논문지
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    • 제32권1A호
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    • pp.24-33
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    • 2007
  • 본 논문에서는 OFMDA 다중 셀 하향링크에서 채널 상태를 알고 있을 때, 주파수 비 선택적 페이딩과 선택적 페이딩의 경우에 대해 효율적인 부반송파 할당을 위해 적응적 변조와 여러 개의 주파수 재사용 지수를 동시에 고려한 두 개의 서로 다른 동적 셀 코디네이션 기법을 제안한다. 기존의 OFDMA 시스템이 다른 셀들에 의한 간섭으로 인해 시스템 수율이 떨어지는 것에 비해, 제안된 시스템은 시스템 수율을 높이고 각 사용자의 QoS(Quality of Service)를 보장하기 위해서 RNC(Radio Network Controller)가 각 부채널에 여러 종류의 재사용 지수를 동적으로 적용하고 각 사용자의 채널 상태와 간섭 정도를 고려해 스케줄링 한다. 비선택적 페이딩 환경에서는 제안된 방법이 기존에 제안된 동적 셀 코디네이션$^{[8]}$에 비해 평균적으로 3배 높은 시스템 수율을 보인다. 선택적 페이딩 환경에서는 모든 부채널의 주파수 재사용 지수를 1로 하는 경우에 비해 최대 2.6배 높은 시스템 수율을 보인다.

외식브랜드의 웹사이트 컬러분석에 관한 연구 - 패밀리 레스토랑 홈페이지를 중심으로 - (A Study on the Website Color Analysis of the Foodservice Brand: Concentrated on Homepage of Family Restaurants)

  • 이유주
    • 한국식생활문화학회지
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    • 제20권2호
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    • pp.261-272
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    • 2005
  • The color and its coordination should intensify the customer's memory and awareness in a brand website, through the consistent communication strategy by which a variety of brand identification in the offline could be expressed efficiently. We evaluated top 5 brand-valuable family restaurants in this study, how they made the best use of the website as a new communication channel, and how they constructed the brand identification by the coloring of a website. We found out that they employed colors with a dynamic and lilting feelings matching the concept of a family restaurant. In addition, A color scheme was well designed for the specific character of a brand, though web-safe colors were seldom employed. This report can be a guide to a corporation for the color and its coordination in the website, when existing brand images need to be intensified and enhanced, or when a new brand image need to be constructed.

Cooperative Interference Mitigation Using Fractional Frequency Reuse and Intercell Spatial Demultiplexing

  • Chang, Jae-Won;Heo, Jun;Sung, Won-Jin
    • Journal of Communications and Networks
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    • 제10권2호
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    • pp.127-136
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    • 2008
  • For mobile wireless systems with full frequency reuse, co-channel interference near the cell coverage boundaries has a significant impact on the signal reception performance. This paper addresses an approach to efficiently mitigate the effect of downlink co-channel interference when multi-antenna terminals are used in cellular environments, by proposing a signal detection strategy combined with a system-level coordination for dynamic frequency reuse. We demonstrate the utilization of multi-antennas to perform spatial demultiplexing of both the desired signal and interfering signals from adjacent cells results in significant improvement of spectral efficiency compared to the maximal ratio combining (MRC) performance, especially when an appropriate frequency reuse based on the traffic loading condition is coordinated among cells. Both analytic expressions for the capacity and experimental results using the adaptive modulation and coding (AMC) are used to confirm the performance gain. The robustness of the proposed scheme against varying operational conditions such as the channel estimation error and shadowing effects are also verified by simulation results.

A Joint Resource Allocation Scheme for Relay Enhanced Multi-cell Orthogonal Frequency Division Multiple Networks

  • Fu, Yaru;Zhu, Qi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제7권2호
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    • pp.288-307
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    • 2013
  • This paper formulates resource allocation for decode-and-forward (DF) relay assisted multi-cell orthogonal frequency division multiple (OFDM) networks as an optimization problem taking into account of inter-cell interference and users fairness. To maximize the transmit rate of system we propose a joint interference coordination, subcarrier and power allocation algorithm. To reduce the complexity, this semi-distributed algorithm divides the primal optimization into three sub-optimization problems, which transforms the mixed binary nonlinear programming problem (BNLP) into standard convex optimization problems. The first layer optimization problem is used to get the optimal subcarrier distribution index. The second is to solve the problem that how to allocate power optimally in a certain subcarrier distribution order. Based on the concept of equivalent channel gain (ECG) we transform the max-min function into standard closed expression. Subsequently, with the aid of dual decomposition, water-filling theorem and iterative power allocation algorithm the optimal solution of the original problem can be got with acceptable complexity. The third sub-problem considers dynamic co-channel interference caused by adjacent cells and redistributes resources to achieve the goal of maximizing system throughput. Finally, simulation results are provided to corroborate the proposed algorithm.