• International journal of advanced smart convergence
• /
• 제13권2호
• /
• pp.16-24
• /
• 2024

With an increase in the relevance of next-generation integrated networking environments, the need to effectively utilize advanced networking techniques also increases. Specifically, integrating Software-Defined Networking (SDN) with Multi-access Edge Computing (MEC) is critical for enhancing network flexibility and addressing challenges such as security vulnerabilities and complex network management. SDN enhances operational flexibility by separating the control and data planes, introducing management complexities. This paper proposes a reinforcement learning-based network path optimization strategy within SDN environments to maximize performance, minimize latency, and optimize resource usage in MEC settings. The proposed Enhanced Proximal Policy Optimization (PPO)-based scheme effectively selects optimal routing paths in dynamic conditions, reducing average delay times to about 60 ms and lowering energy consumption. As the proposed method outperforms conventional schemes, it poses significant practical applications.

• 산업경영시스템학회지
• /
• 제28권1호
• /
• pp.129-133
• /
• 2005

Slotted ALOHA(S-ALOHA) is widely used in local wireless network. We analyze the performance of contention-based model in wireless LAN using S-ALOHA protocol. We analyze the performance of binary exponential backoff (BEB) algorithm under the slotted ALOHA protocol: whenever a node's message which tries to reserve a channel is involved in a collision for the ith time, it chooses one of the next $2^i$ frames with equal probability and attempts the reservation again. We derive the expected access delay and throughput which is defined as the expected number of messages that reserve a channel in a frame. A simulation study is performed to verify our method.

• Journal of information and communication convergence engineering
• /
• 제11권3호
• /
• pp.153-166
• /
• 2013

A hierarchical time division multiple access (HTDMA) medium access control (MAC) protocol is proposed for clustered mobile underwater acoustic networks. HTDMA consists of two TDMA scheduling protocols (i.e., TDMA1 and TDMA2) in order to accommodate mobile underwater nodes (UNs). TDMA1 is executed among surface stations (e.g., buoys) using terrestrial wireless communication in order to share mobility information obtained from UNs which move cluster to cluster. TDMA2 is executed among UNs, which send data to their surface station as a cluster head in one cluster. By sharing mobility information, a surface station can instantaneously determine the number of time slots in a TDMA2 frame up to as many as the number of UNs which is currently residing in its cluster. This can enhance delay and channel utilization performance by avoiding the occurrence of idle time slots. We analytically investigate the delay of HTDMA, and compare it with that of wellknown contention-free and contention-based MAC protocols, which are TDMA and Slotted-ALOHA, respectively. It is shown that HTDMA remarkably decreases delay, compared with TDMA and Slotted-ALOHA.

• 한국통신학회논문지
• /
• 제19권1호
• /
• pp.159-169
• /
• 1994

다채널 광 슬러티드 링 통신망은 파장 분할 다중화 방식(wavelength division multiplexing ; WDM)이 채택된 다 채널 구조로서 전광(全光) 패킷 교환 장치를 엑세스 메카니증으로 이용하기 때문에, 전기적 속도 제한 요소를 망의 바깥으로 옮겨서 결국 고속 광통신 매체의 모든 전송 용량을 이용할 수 있다. 링 채널은 B-ISDN 엑세스 망(Access Network)으로 이용하기 위하여 ATM셀과 같은 크기의 슬롯들로 나뉘어져서 수신 노드에서 셀 데이터를 링으로부터 제거하는 슬러티드 링의 개념으로 설계된다. 본 논문에서는 이 통신망의 성능 측정을 위해서 수학적 모델량에 의한 새로운 해석 방법을 제안하였다, 시뮬레이션으로 그 결과를 검증하였다. 수학적 해석법과 시뮬레이션의 결과를 이용하여 여러 가지 망 매개변수(network parameters)의 변화에 EK른 다채널 광 슬러티드 링 통신망의 성능을 고찰하였다.

• 융합신호처리학회 학술대회논문집
• /
• 한국신호처리시스템학회 2005년도 추계학술대회 논문집
• /
• pp.306-309
• /
• 2005

We consider the multi-objective optimization of a multi-service arrayed-waveguide grating-based single-hop metro WDM network with the two conflicting objectives of maximizing throughput while minimizing delay. We develop and evaluate a genetic algorithm based methodology for finding the optimal throughput-delay tradeoff curve, the so-called Pareto-optimal frontier. Our methodology provides the network architecture and the Medium Access Control protocol parameters that achieve the Pareto-optima in a computationally efficient manner. The numerical results obtained with our methodology provide the Pareto-optimal network planning and operation solution for a wide range of traffic scenarios. The presented methodology is applicable to other networks with a similar throughput-delay tradeoff.

• Journal of Internet Technology
• /
• 제20권1호
• /
• pp.293-300
• /
• 2019

The Internet of Things (IoT) enables embedded devices to connect to the internet either through IP or the web in a physical environment. The increase in performance of wireless access services, adaptive load balancing, and interference routing metric becomes the key challenges in Wireless Mesh Networks (WMN). However, in the case of IoT over WMN, a large number of users generate abundant net flows, which can result in network traffic jam. Therefore, in this paper, we propose a Load Balancing and Interference Delay Aware routing metric algorithm to efficiently address the issues present in the current work. The proposed scheme efficiently utilizes the available mesh station queue information and the number of mesh stations suffering from channel interference in the available path. The simulations results show that the proposed scheme performed superior to the existing routing metrics present in the current literature for similar purposes.

• Journal of Communications and Networks
• /
• 제13권6호
• /
• pp.639-654
• /
• 2011

In this paper, we present a channel access mechanism, referred to as the enhanced mesh coordinated channel access (eMCCA) mechanism, for IEEE 802.11s-based wireless mesh networks. The current draft of IEEE 802.11s includes an optional medium access control (MAC), denoted as MCCA, which is designed to provide collision-free and guaranteed channel access during reserved periods. However, the MCCA mechanism fails to achieve the desired goal in the presence of contending non-MCCA nodes; this is because non-MCCA nodes are not aware of MCCA reservations and have equal access opportunities during reserved periods. We first present a probabilistic analysis that reveals the extent to which the performance of MCCA may be affected by contending non-MCCA nodes. We then propose eMCCA, which allows MCCA-enabled nodes to enjoy collision-free and guaranteed channel access during reserved periods by means of prioritized and preemptive access mechanisms. Finally, we evaluate the performance of eMCCA through extensive simulations under different network scenarios. The simulation results indicate that eMCCA outperforms other mechanisms in terms of success rate, network throughput, end-to-end delay, packet-loss rate, and mesh coordinated channel access opportunity-utilization.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.2787-2794
• /
• 2011

A mesh node, a component of a mesh network, is connected with the network by dynamic routing using routing protocol and collects the information of adjacent or connected mesh nodes for its self-management and settings. Also, it relays packets between the mesh nodes and provides AP(Access Point) with its corresponding functions based on IEEE 802.11 a/b/g for clients' access to the network. In this paper, the study focused on the design and performance tests of Wireless Mesh Network(WMN) which is applied to the wireless communication network for the CBTC(Communications Based Train Control) system. The WMN was established on a K-AGT test-line (Kyeongsan city, Gyeongsangbuk-do), and to verify the applicability, its operation and performances are checked by measuring the data throughput, delay latency, quality measurements such as transmission loss, radio interference and path recovery and setup between the on-board and wayside.

• 한국정보과학회논문지:시스템및이론
• /
• 제26권12호
• /
• pp.1529-1538
• /
• 1999

광대역 액세스 망은 B-ISDN 환경에서 다양한 유형의 가입자들을 서비스 노드로 집선하는 기능을 수행한다. ITU-T의 SG13에서는 광대역 액세스 망과 서비스 노드 사이에서 ATM 자원의 동적인 할당 및 해제를 위하여 연결 제어 프로토콜의 표준화를 수행하고 있다. ATM 연결의 설정을 위한 연결 제어 프로토콜과 신호 프로토콜의 연동 기능은 서비스 노드에서 수행되며, ITU-T에서는 순차적 연동 모델을 채택하고 있다. 순차적 연동 모델은 SN에서 각 프로토콜의 절차가 순차적 방식으로 연동되므로 연결 지연이 크다. 본 논문에서는 광대역 액세스 망의 도입으로 인한 연결 설정 지연을 최소화하기 위하여 병렬형으로 수행되는 연동 모델을 제시하였다. 그리고 본 논문에서 제안한 병렬형 연동 모델의 성능 분석을 통하여 순차적 연동 모델과의 연결 설정 지연 및 완료비에 대한 비교, 분석을 수행하였다. 성능 분석에서 사용된 워크로드 파라미터는 RACE MAGIC 프로젝트의 결과를 적용하였다. Abstract In B-ISDN environment, various subscribers are concentrated into a service node via a broadband access network. The SG13 of ITU-T is standardizing a connection control protocol which provides dynamic allocation of ATM resources between an access network and a service node. To establish an ATM connection, interworking functions between the connection control protocol and the signaling protocol are performed at the service node. ITU-T adopts the sequential interworking model. In this paper, we propose the parallel interworking model which minimizes the overall connection setup delay by introducing the access network. Using the performance analysis, we compare our proposed parallel model with the existing sequential model in terms of connection setup delay and completion ratio. The workload parameters of RACE MAGIC project are applied to the analysis and simulation.

• 인터넷정보학회논문지
• /
• 제22권5호
• /
• pp.9-16
• /
• 2021

Recently, the traffic volume of mobile communications increases rapidly and the small-cell is one of the solutions using two offload schemes, i.e., local IP access (LIPA) and selected IP traffic offload (SIPTO), to reduce the end-to-end delay and amount of mobile data traffic in the core network (CN). However, 3GPP describes the concept of LIPA and SIPTO and there is no decision algorithm to decide the path from source nodes (SNs) to destination nodes (DNs). Therefore, this paper proposes a dynamic mobile data traffic offload scheme using small-cells to decide the path based on the SN and DN, i.e., macro user equipment, small-cell user equipment (SUE), and multimedia server, and type of the mobile data traffic for the real-time and non-real-time. Through analytical models, it is shown that the proposed offload scheme outperforms the conventional small-cell network in terms of the delay of end-to-end mobile data communications and probability of the mobile data traffic in the CN for the heterogeneous networks.