• KIPS Transactions on Computer and Communication Systems
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• v.4 no.1
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• pp.5-10
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• 2015

D2D (Device-to-Device) communication underlaying LTE-advanced networks is a promising technology to improve the system capacity and spectral efficiency. By sharing the same radio resources with cellular user equipments, D2D communications can significantly enhance the overall spectral efficiency. However, it may cause interference between D2D link and cellular link. Careful resource allocation and interference coordination between cellular and D2D communications are very important and need to be properly handled. This paper proposes a radio resource allocation scheme based on FFFR (Flexible Fractional Frequency Reuse) for D2D communication underlaying cellular networks. The base station selects randomly resource blocks assigned to cellular users, and reuses them for a D2D pair. Through simulations, we have confirmed that the proposed scheme improves the system throughput, reduces the computational complexity, and mitigates the interference of D2D link and cellular link.

• Proceedings of the KSEEG Conference
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• 2002.04a
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• pp.214-216
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• 2002

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.5
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• pp.103-108
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• 2016

In this paper, we propose a resource allocation scheme that guarantees transmission rate for each mobile stations by mitigating interference between a base station-to-mobile station link and a relay station-to-mobile station link. Specifically, we dynamically adjust the boundary between access zone and relay zone using signal to interference plus noise ratio. Moreover, we cluster the mobile stations under sever interference and manage the channel quality of these mobile stations by allocating additional radio resource. Our simulation results show that the proposed scheme can improve the efficiency of radio resources and ensure fairness among mobile stations.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.597-599
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• 2012

D2D(Device-to-Device) 통신은 이동통신망을 기반으로 동작할 경우 이동통신망의 자원을 재사용함으로써 자원이용의 효율성을 높일 수 있다. 그러나 동일자원을 사용하는 이동통신개체와 D2D 통신 단말(DUE) 사이에 신호 간섭이 발생할 수 있어 이를 고려한 자원할당기법에 대한 연구가 필요하다. 본 논문에서는 D2D 통신이 이동통신망의 상향링크자원을 재사용할 때 DUE로부터 기지국으로의 간섭으로 인한 CUE의 상향링크 전송률 손실 대비 DUE로 얻는 전송률 이득이 극대화하는 DUE에게 자원을 할당함으로써 동일자원을 사용하는 DUE와 이동통신개체 간 간섭을 완화하고 망의 수율 성능을 향상시킬 수 있는 자원할당기법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.155-156
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• 2013

VM 간섭은 VM 프로비저닝을 할 때 예상된 VM 의 컴퓨팅 자원이 실제와 다르지 않도록 하기 위해 반드시 고려되어야 할 사항이다. 이에 본 논문에서는 예상된 VM 의 컴퓨팅 자원을 사용자가 보장받을 수 있도록 랜덤 워크를 이용해 간섭을 고려한 필요 자원을 구하는 방법에 대해 다루고 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.10
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• pp.1986-1993
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• 2015

We investigate the optimal resource and power allocation for device-to-device (D2D) communications in a multicell environment. When D2D links reuse the cellular radio resources, each D2D user will interfere with a cellular link and other D2D links, in its own cell as well as in adjacent cells. Under such situation, we propose a coordinated resource allocation scheme that can handle the intercell interferences as well as the intracell interference. For a given resource allocation, we also formulate a power optimization problem and present an algorithm for finding the optimal solution. The resource and power allocation algorithms are designed to maximize the achievable rate of the D2D link, while limiting the generated interference to the cellular link. The performance of the proposed algorithms is evaluated through simulations in a multicell environment. Numerical results are presented to verify the coordination gain in the resource and power allocation.

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.96-99
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• 2007

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.329-332
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• 2013

본 논문에서는 매크로기지국과 펨토기지국의 간섭을 회피하는 방법인 자원대체 간섭회피기법을 제안한다. 이 기법은 펨토셀 영역의 여유로운 자원을 할당받은 후에, 이기종망 간의 발생할 수 있는 충돌을 미리 검사하고 충돌이 예상되면 충돌가능자원을 회피하고 여유로운 자원으로 대체하여 통신을 한다. 본 기법을 적용하면 하향링크 및 상향링크에서 이기종망 간의 직교주파수를 적용하면서 발생할 수 있는 지연을 최소화 할 수가 있으며, 이기종망 간에서 주파수를 분할하여 통신을 하는 SFR 기법과 비교하여, 자원의 효율성을 높일 수가 있다.

• KIISE Transactions on Computing Practices
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• v.22 no.9
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• pp.473-478
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• 2016

Server virtualization provides abstraction of physical resources to users and thus accomplishes high resource utilization and flexibility. However, the characteristics of server virtualization, such as the limited number of physical resources shared by virtual machines, can cause problems, mainly performance interference. The performance interference is caused by the fact that the CPU scheduler running on the host operating system schedules virtual machines without considering the characteristics of the virtual machine's internal process. To address performance interference, a number of research activities to improve performance interference have been conducted, but do not deal with the fundamental analysis of performance interference. In this paper, in order to analyze the cause of performance interference, we carry out profiling in a variety of scenarios in a virtualized environment based on KVM. As a result, we analyze the phenomenon of the performance interference in terms of CPU scheduling and propose an efficient scheduling solution.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.12
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• pp.729-738
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• 2014

In this paper, we propose interference avoidance resource allocation scheme based on graph-coloring algorithm to introduce performance gain using spatial reuse in D2D (Device-to-Device) system. By assigning multiple D2D pairs to a single D2D resource, interference from neighboring D2D pairs is inevitable, which leads to performance degradation. Therefore, we first introduce the feedback information and the method considering the amount of information that can be practically provided by a D2D pair. Then, we propose how to construct a graph, which is corresponding to the D2D system, using the feedback information and adopt a graph-coloring algorithm to efficiently avoid interference. Simulation results show that the proposed resource allocation scheme outperforms traditional resource allocation schemes in both overall sum rate and spectral efficiency of D2D system while reducing the outage probability. Moreover, the outage probability, which indicates a failure rate of D2D communication, can be reduced by adopting the proposed scheme.