• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.9
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• pp.24-30
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• 2009

This paper presents a simple resource allocation scheme for throughput enhancement in relay based orthogonal frequency division multiple access (OFDMA) cellular systems. The resource allocation schemes, which are based on the optimization problem, have high computational complexity. That is why a searching process is required on the overall allocable resources. Since these schemes should be performed in real time, we propose a simple resource allocation scheme which has very low computational complexity. Firstly, we formulate the optimization problem and draw observations for throughput maximization. Based on observations, we propose a three step allocation scheme that separates the allocable resources into three (i.e. relay, frequency and time). By doing so, the computational complexity can be reduced. Simulation results show that the proposed scheme has near-optimum performance in spite of its low computational complexity.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.466-468
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• 2003

그리드 컴퓨팅은 네트워크 상의 유휴 자원 및 다수의 저성능 자원을 활용함으로써 보다 고 성능의 컴퓨팅 환경을 요구하는 응용 문제를 해결할 수 있다. 따라서, 그리드 컴퓨팅의 자원 관리 시스템의 자원 선택 및 할당 기능은 주어진 응용 문제에 대하여 보다 높은 성능의 그리드 컴퓨팅 환경을 제공하기 위한 매우 중요한 요소이다. 본 논문에서는 보다 효율적으로 자원을 선택하기 위하여 환경 내 자원들의 종합적인 CPU 성능을 평가하는 UC 단위 모델을 제안하고, 보다 효율적인 자원 할당을 위하여 그리디 방식(Greedy Method)을 변형한 최적 자원 우선(8est-Fit-First) 알고리즘을 제안한다. 또한, 기존의 자원선택, 할당방식과 비교하는 모의실험을 통하여 제안하는 모델 및 알고리즘의 향상된 성능을 나타내 보인다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.82-91
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• 2009

Routing (or path selection) is one of the key issues of multi-hop relay networks such as the IEEE 802.16j. Moreover, the allocation of appropriate resource such as bandwidth should not only be made in accordance with the paths selected, but the utilization of radio resource of an entire cell should also be maximized. Due to this interdependency between the problems of resource allocation and routing, it is desired these two problems are addressed simultaneously. In this paper, we propose a joint resource allocation and routing scheme for an OFDMA-based multi-hop cellular system. This scheme uses a polynomial time heuristic algorithm called Multi-Dimensional Multi-choice Knapsack Problem (MMKP) in order to find an approximate solution maximizing the total downlink throughput. In the simulation results, we show that the proposed scheme finds a sub-optimal solution which is superior to a link quality-based routing scheme, but slightly worse than the optimal solution.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.191-194
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• 2012

클라우드 컴퓨팅은 클라우드 서버에서 제공되는 자원을 이용하여 사용자에게 고사양의 컴퓨팅 환경을 제공된다. 클라우드 서비스 환경 구축을 제공하는 유칼립투스에서 사용되는 라운드로빈, 그리디, 파워세이브 등의 가상머신 할당 기법은 자원들을 같은 성능으로 판단하고 사용여부만으로 가상머신을 할당할 노드를 선택하기 때문에 노드의 공정한 사용이 가능하다. 그러나 다른 성능의 자원을 고려하지 않아 자원 사용의 효율성이 결여되었다. 본 논문에서는 가상머신이 최적의 노드에 할당하기 위해 다양한 성능의 노드들을 미리 분석하고 조건에 가장 적합한 노드에 가상머신을 할당하여 사용자에게 제공하는 가상머신 할당 기법을 제안한다. 시스템이 시작되면 노드들의 성능이 분석되어 데이터베이스에 저장되고 이를 바탕으로 가상머신은 노드에 할당된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.87-90
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• 2012

클라우드 컴퓨팅은 기존의 컴퓨팅 환경에 제약을 받지 않고 가상머신을 활용하여 고사양 컴퓨팅 환경을 제공해준다. 고사양의 컴퓨팅 환경을 제공해주는 서버는 분산 파일 시스템을 통해 자원을 관리하고 매치메이킹, Haizea 등의 가상머신 스케줄러를 통해 노드에 가상머신을 할당한다. 본 논문은 노드가 가지는 CPU, 메모리, 스토리지 자원의 처리 속도를 반영하여 최적의 노드에 가상머신을 할당 할 수 있는 다중 자원의 성능을 고려한 가상머신 할당 기법을 제안한다. 노드 성능 분석 결과를 가진 데이터베이스에서 하드웨어 성능이 지원되는 노드들 중 성능 분석 결과가 좋은 노드에 가상머신을 할당해 주는 방법으로 자원의 단편화를 최소화하고 신속한 할당이 가능하다.

• Journal of Advanced Navigation Technology
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• v.15 no.3
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• pp.386-391
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• 2011

CRU (contiguous resource unit) composed of adjacent OFDMA subcarriers is popularly adopted for recently developed cellular communication standards, e.g. IEEE 802.16e/m. If multiple CRUs having different SNR are assigned to a mobile station, and multiple packet streams are independently transmitted by using H-ARQ transmission, an achievable data rate can be varied according to the channel allocation method of re-transmission packets and new transmission packets. In this paper, the optimum channel allocation method for the above stated problem, and several sub-optimum channel allocation methods to reduce the computational complexity of the optimum allocation method are proposed. According to the simulation results, a sub-optimum allocation method assigning a CRU having good SNR to new transmission packet shows marginal performance loss compared with optimum method, however, the computational complexity can be significantly reduced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8C
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• pp.819-827
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• 2002

Personal mobile communication has been developed up to IMT-2000 which is called the third generation mobile communication. The first generation of personal mobile communication was analog cellular, the second was digital cellular, and the 2.5 generation was PCS. Before the third generation had been developed, the personal mobile communication service was focused mainly on the voice-oriented service. But, we can expect that multimedia service after the third generation system will be the core of the subject. T In this thesis, we propose a dynamic resource allocation algorithm in the UTRA TDD systems which can support the asymmetric traffic propensity and multimedia traffic. The proposed algorithm consists two sub-algorithms. One is the dynamic channel allocation method that determines the amount of bandwidth assigned between uplink and downlink according to resource allocation status list through asymmetric traffic propensity. The other is the channel access mechanism that assigns RU to bearer service generated in a cell. By simulation, the proposed dynamic resource allocation algorithm is proved to support asymmetric propensity of traffic and shows a better throughput for multimedia traffic.

• Journal of Broadcast Engineering
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• v.13 no.6
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• pp.883-891
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• 2008

Multiple antenna orthogonal frequency division multiplexing (OFDM) is a promising technique for the high downlink-capacity in the next generation wireless systems, in which adaptive resource allocation is an important research issue that can significantly improve the performance with guaranteed QoS for users. However, most of the current resource allocation algorithms are limited to unicast system. In this paper, dynamic resource allocation is studied for multiple antenna OFDM based systems with multicast service. In the simulation, the performance of multicast system was compared with that of the unicast system. Numerical results also show that by using the proposed algorithms the system capacity is significantly improved compared with the conventional scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1340-1346
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• 2022

In this paper, we consider a downlink non-orthogonal multiple access (NOMA) using multiple transmit antennas, where the transmit antenna selection scheme is used to reduce the system complexity. Thus, in this paper, we propose radio resource allocation and receiver selection schemes in order to improve the outage probability performance of the downlink NOMA system using the transmit antenna selection scheme. In particular, the receiver selection scheme is a method of grouping the receivers to improve the outage probability performance, and the radio resource allocation scheme is a method of allocating radio resources to each group in order to enhance the outage probability performance. In addition, through the computer simulation under the assumption of independent Rayleigh fading channels, we show that the proposed radio resource allocation and receiver selection schemes can improve the outage probability performance at the expense of the sum rate performance.

• Journal of Korea Multimedia Society
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• v.4 no.2
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• pp.130-135
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• 2001

When a networked virtual reality system handles composite media audio and video as well as three dimensional computer graphics, the quality of the virtual space is greatly affected by the current available network, and end system resources. Even if the network can preserve a certain amount of resources, the required resources change dynamically according to the user\`s navigation of a large virtual space, and then it may decrease the quality of the virtual space. In this paper, a method for resource allocation is proposed and the proposed system copes with the deterioration of quality of virtual spaces in case that the starvation of system resources occurs. The experimental results show that the proposed method is efficient.