• ETRI Journal
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• 제45권1호
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• pp.45-59
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• 2023

In this paper, to optimize the average delay and power allocation (PA) for system users, we propose a resource scheduling scheme for wireless networks based on Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) according to the first fifth-generation standards. For delay minimization, we solve a throughput maximization problem that considers CPOFDM systems with carrier aggregation (CA). Regarding PA, we consider an approach that involves maximizing goodput using an effective signal-to-noise ratio. An algorithm for jointly solving delay minimization through computation of required user rates and optimizing the power allocated to users is proposed to compose the resource allocation approach. In wireless network simulations, we consider a scenario with the following capabilities: CA, 256-Quadrature Amplitude Modulation, millimeter waves above 6 GHz, and a radio frame structure with 120 KHz spacing between the subcarriers. The performance of the proposed resource allocation algorithm is evaluated and compared with those of other algorithms from the literature using computational simulations in terms of various Quality of Service parameters, such as the throughput, delay, fairness index, and loss rate.

• 한국컴퓨터정보학회논문지
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• 제21권11호
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• pp.65-71
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• 2016

This paper proposes a novel traffic and resource management scheme based on Service Level Agreement (SLA) which allows to guarantee the quality of experience (QoE) for various high-quality mobile multimedia service users to a certain level. For this purpose, QoE-SLA coupling structure is considered and a novel scheme is suggested to suppress the processing delay of the mobile terminal and to decrease the transfer delay in the transmission network. According to simulation results, our proposed scheme can increase the total throughput and decrease the average delay by adjusting SLA.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권12호
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• pp.5174-5190
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• 2016

Recent years have witnessed an explosive growth of mobile devices, mobile cloud computing services offered by these devices and the remote clouds behind them. In this paper, we noticed ultra-low latency service, as a type of mobile cloud computing service, requires extremely short delay constraints. Hence, such delay-sensitive applications should be satisfied with strong QoS guarantee. Existing solutions regarding this problem have poor performance in terms of throughput. In this paper, we propose an end-to-end bandwidth resource reservation via software defined scheduling inspired by the famous SDN framework. The main contribution of this paper is the end-to-end resource reservation and flow scheduling algorithm, which always gives priority to delay sensitive flows. Simulation results confirm the advantage of the proposed solution, which improves the average throughput of ultra-low latency flows.

• Journal of Information Processing Systems
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• 제18권3호
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• pp.389-401
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• 2022

The business of Internet of Vehicles (IoV) is growing rapidly, and the large amount of data exchange has caused problems of large mobile network communication delay and large energy loss. A strategy for resource allocation of IoV communication based on mobile edge computing (MEC) is thus proposed. First, a model of the cloud-side collaborative cache and resource allocation system for the IoV is designed. Vehicles can offload tasks to MEC servers or neighboring vehicles for communication. Then, the communication model and the calculation model of IoV system are comprehensively analyzed. The optimization objective of minimizing delay and energy consumption is constructed. Finally, the on-board computing task is coded, and the optimization problem is transformed into a knapsack problem. The optimal resource allocation strategy is obtained through genetic algorithm. The simulation results based on the MATLAB platform show that: The proposed strategy offloads tasks to the MEC server or neighboring vehicles, making full use of system resources. In different situations, the energy consumption does not exceed 300 J and 180 J, with an average delay of 210 ms, effectively reducing system overhead and improving response speed.

• 한국통신학회논문지
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• 제28권9B호
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• pp.774-782
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• 2003

일반적으로 Mobile IP 기술에 있어 이동 노드에게 실시간 서비스를 제공하기 위한 방안으로 RSVP 사용이 제시되고 있다. 그러나 Mobile IP와 RSVP(Resource Reservation Protocol) 연동시 이동 노드의 핸드오프는 등록 지연, RSVP 예약 지연 및 시그널링 오버헤드를 증가시킨다. 특히 이동 노드와 대응 노드 사이의 경로에 대한 자원 예약은 핸드오프 이전과 이후 경로가 대부분 같기 때문에 중복 예약이며, 불필요한 시그널링의 생성과 자원 낭비를 초래한다. 만약 무선 인터페이스를 제공하는 셀의 반경이 작다면 이동 노드의 핸드오프는 증가할 것이며 따라서 시그널링 오버헤드와 자원 중복 예약이 크게 증가할 것이다. 본 논문은 RSVP proxy 방안의 Cellular IP와 RSVP 통합 모델을 제안한다. Cellular IP 프로토콜은 마이크로 셀 네트워크에서 핸드오프에 의한 등록 지연, 전송 지연 및 손실을 최소화하며, RSVP proxy는 자원 중복 예약을 최소화하는 방안으로 이동 노드의 예약 주소를 사용하여 Cellular IP 외부 네트워크에서의 RSVP 세션 경로 변경이 일어나지 않도록 한다. 제안 방안은 셀 반경과 핸드오프율에 대해 자원 예약 실패 확률을 이용 기존 Mobile IP와 RSVP 연동 방안과 비교 평가하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권1호
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• pp.211-232
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• 2024

In this paper, we consider the resource allocation and offloading decisions of device-to-device (D2D) cooperative UAV-assisted mobile edge computing (MEC) system, where the device with task request is served by unmanned aerial vehicle (UAV) equipped with MEC server and D2D device with idle resources. On the one hand, to ensure the fairness of time-delay sensitive devices, when UAV computing resources are relatively sufficient, an optimization model is established to minimize the maximum delay of device computing tasks. The original non-convex objective problem is decomposed into two subproblems, and the suboptimal solution of the optimization problem is obtained by alternate iteration of two subproblems. On the other hand, when the device only needs to complete the task within a tolerable delay, we consider the offloading priorities of task to minimize UAV computing resources. Then we build the model of joint offloading decision and power allocation optimization. Through theoretical analysis based on KKT conditions, we elicit the relationship between the amount of computing task data and the optimal resource allocation. The simulation results show that the D2D cooperation scheme proposed in this paper is effective in reducing the completion delay of computing tasks and saving UAV computing resources.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권9호
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• pp.3008-3028
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• 2022

In this paper, we investigate traffic scheduling for a delay-sensitive multi-hop relay network, and aim to minimize the priority-based end-to-end delay of different data packet via joint relay selection, subcarrier assignment, and power allocation. We first derive the priority-based end-to-end delay based on queueing theory, and then propose a two-step method to decompose the original optimization problem into two sub-problems. For the joint subcarrier assignment and power control problem, we utilize an efficient particle swarm optimization method to solve it. For the relay selection problem, we prove its convexity and use the standard Lagrange method to deal with it. The joint relay selection, subcarriers assignment and transmission power allocation problem for each hop can also be solved by an exhaustive search over a finite set defined by the relay sensor set and available subcarrier set. Simulation results show that both the proposed routing scheme and the resource allocation scheme can reduce the average end-to-end delay.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.237-239
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• 2007

In the paper, we analyze the performances of random access channels in multi-service multi-user OFDMA systems. The resource of the random access channels in OFDMA systems is the nubmer of available sub-channels and PN-codes. For given available sub-channels and PN-codes. we analyze the performances of the random access channels of OFDMA systems according to three resource allocation methods (resource full sharing, resource partial sharing, resource partition) in tenus of the access success probability, the blocking probability, the access delay and the throughput of each service class. Further, we find the feasible region of the access probability of each service class in which the allowable minimum access success probability, the allowable maximum blocking probability and the allowable maximum access delay are satisfied. The results also can be utilized to find proper region of the access probabilities of each service class for differentiated quality of service(QoS)s, and for the system operations.

• Journal of Information Processing Systems
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• 제19권4호
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• pp.450-464
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• 2023

To address the problems of large system overhead and low timeliness when dealing with task scheduling in mobile edge cloud computing, a task scheduling and resource management strategy for edge cloud computing based on an improved genetic algorithm was proposed. First, a user task scheduling system model based on edge cloud computing was constructed using the Shannon theorem, including calculation, communication, and network models. In addition, a multi-objective optimization model, including delay and energy consumption, was constructed to minimize the sum of two weights. Finally, the selection, crossover, and mutation operations of the genetic algorithm were improved using the best reservation selection algorithm and normal distribution crossover operator. Furthermore, an improved legacy algorithm was selected to deal with the multi-objective problem and acquire the optimal solution, that is, the best computing task scheduling scheme. The experimental analysis of the proposed strategy based on the MATLAB simulation platform shows that its energy loss does not exceed 50 J, and the time delay is 23.2 ms, which are better than those of other comparison strategies.

• 정보처리학회논문지C
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• 제13C권3호
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• pp.331-338
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• 2006

실시간 멀티미디어 응용의 서비스 품질을 지원하는 공평 패킷 스케줄러는 대부분 패킷의 예상되는 전송 종료시점을 그 패킷의 타임스탬프로 사용하는 종료시각 방식을 채택하고 있다. 이 방식은 예약속도로 레이턴시를 통제할 수 있는 장점을 가지나 속도-지연 결합 특성으로 인해 스케줄러 대역폭의 이용 효율이 저하되는 문제점이 있다. 본 연구에서는 지연 자원 개념을 도입하고, 속도-지연 결합 특성에 의해 손실되는 지연 자원을 속도 자원으로 변환하여 스케줄러 대역폭의 이용 효율을 높이는 스케줄링 방식을 제안한다. 성능 평가 결과 기존 방식보다 50% 이상 우수한 대역폭 이용도 특성을 보였다.