• Journal of IKEEE
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• v.2 no.1 s.2
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• pp.134-138
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• 1998

Because of the statistical fluctuations and the high 'time-variability' nature of the traffic, managing the resources of the network require highly dynamic techniques with minimal Intervention and reaction times, and adaptive and learning capabilities. The neural networks normalizes the ATM cell arrival rate and queue length and has the adaptive learning algorithm, and experimentally investigated the method to prevent the congestion generated in ATM networks.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1201-1204
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• 2002

인터넷의 폭발적인 발전과 더불어 온라인 게임은 인터넷 산업을 주도하는 원동력이 되고 있다. 최근 온라인 게임은 유선통신망에서 무선통신망으로 사업범위를 넓혀 핸드폰이나 PDA 등의 무선단말기에서도 게임을 즐길 수 있게 되었다. 그러나, 온라인 게임의 전송프로토콜로 이용되고 있는 TCP 프로토콜은 무선통신 환경의 높은 비트 오류율로 인하여 폭주제어 알고리즘이 오동작을 일으키며 이로 인하여 전체적인 게임 서비스의 성능이 저하된다. 따라서 본 논문에서는 무선 온라인 게임 네트워크에서 TCP 프로토콜의 성능을 개선시키기 위한 응답패킷 분할 기법을 제안하였다. 제안된 기법은 컴퓨터 시뮬레이션을 통해 성능을 분석하였으며, 그 결과 기존의 TCP 프로토콜에 비하여 성능이 향상되었음을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.833-841
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• 1997

In this paper, the hybrid LB-TJW(Leaky Bucket-Triggered Jumping Window) algorithm for multimedia traffic control is proposed and its performance is evaluated and analyzed. Its architecture is composed of the peak bit rate controller and the average bit rate controller. Generally, the cell which violates the peak bit rate is discraded in LBalgorithm, and the average bit rate of JW or TJW algorithm is better than that of LB algorithm. However, the hybrid LB-TJW algorithm passes it though the network if the cell does not violate the peak bit rate. If the cell violates the peak bit rate, the hybrid LB-TJW algorithm passes it to the average bit rate controller which perforithm to monitor the average bit rate of input traffic. The TJW algorithm monitors the cell that violates the average bit rate. If the cell does not violate the average bit rare, the LB-TJW algorithm passes it through the network. As simulation results, the cell loss rate and the buffer size of the LB-TJW algorithm is reduced to half as much as those of LB algortihm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2A
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• pp.86-96
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• 2006

In recent year, EPON(Ethernet PON) system is expected to be more attractive solutions for high speed, broadband access networks in next generation access networks due to the conversionce of low-cost ethernet equipment and low-cost fiber infrastructure. Upstream channel control algorithm is essential to hare upstream bandwidth in EPON. In this paper, we suggest HUHG(High Utilization and Hybrid Granting) algorithm for supporting high bandwidth utilization and QoS for different service class. This algorithm improves bandwidth utilization as removing or diminishing idle time of upstream channel using characteristics of fixed EF(Expedited Forwarding) sub-cycle. The proposed algorithm also minimizes the packet delay and delay variation of EF class. We conduct detailed simulation experiments using OPNET to study the performance and validate the effectiveness of the proposed algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.837-840
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• 2003

Recently the multimedia streaming traffic such as digital audio and video in the Internet has increased tremendously. Unlike TCP, the UDP protocol, which has been used to transmit streaming traffic through the Internet, does not apply any congestion control mechanism to regulate the data flow through the shared network. If this trend is let go unchecked, these traffic will effect the performance of TCP, which is used to transport data traffic, and may lead to congestion collapse of the Internet. To avoid any adverse effort on the current Internet functionality, A study on a new protocol of modification or addition of some functionality to existing transport protocol for transmitting streaming traffic in the Internet is needed. TCP-frienly congestion control mechanism is classified with window-based congestion control scheme and rate-based congestion control scheme. In this paper, we propose an algorithm for improving the transmitting rate on a hybrid TCP-friendly congestion control scheme combined with widow-based and rate-based congestion control for multimedia streaming in the internet.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.634-636
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• 2005

모바일 단말 기반 동영상 서비스 기술에 관한 연구는 현재 활발히 수행되고 있으며, 유선 인터넷 기반에서 상용화가 가능한 기술 분야까지도 모바일 단말의 성능과 무선 네트워크 플랫폼의 빠른 발전에 힘입어 모바일에 응용하고자하는 시도 또한 계속되고 있다. 현재 모바일 단말 기반 영상서비스와 관련된 기술은 하드웨어적으로 구현하여 운영되고 있다. 그러나 하드웨어 기반으로 구현되어 서비스되고 있는 현재의 서비스 형태는 새로운 동영상 코덱 알고리즘과 동영상 데이터 통신에 대한 여러 제어 구조 변화에 대하여 탄력적으로 대응할 수 없다는 단점을 지니고 있다. 따라서 하드웨어적으로 구현된 영상서비스 기술을 소프트웨어적으로 처리하기 위한 디코더 개발은 필수적이라고 볼 수 있다. 이러한 소프트웨어 디코더의 개발을 통하여 새로운 동영상 미디어 플레이어 개발과 동영상 데이터 전송 방법 및 트래픽 제어 등과 같은 부가적인 기술의 변화에 즉각적 대응이 가능하다. 또한 추가적인 하드웨어 칩의 내장에 따른 모바일 단말기의 제조 원가절감과 모바일 단말기 재사용을 통한 자원 절감에 많은 기여가 가능하다. 본 논문에서는 WIPI 플랫폼을 기반으로 컴포넌트 기반 설계를 이용한 H.264 동영상 소프트웨어 디코더를 설계한다.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.409-414
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• 2008

In mobile ad hoc networks, most of on demand routing protocols such as DSR and AODV do not deal with traffic load during the route discovery procedure. To solve the congestion and achieve load balancing, many protocols have been proposed. However, the existing load balancing schemes has only considered avoiding the congested route in the route discovery procedure or finding an alternative route path during a communication session. To mitigate this problem, we have proposed a new scheme which considers the packet bursting mechanism in congested nodes. The proposed packet bursting scheme, which is originally introduced in IEEE 802.11e QoS specification, is to transmit multiple packets right after channel acquisition. Thus, congested nodes can forward buffered packets promptly and minimize bottleneck situation. Each node begins to transmit packets in normal mode whenever its congested status is dissolved. We also propose two threshold values to define exact overloaded status adaptively; one is interface queue length and the other is buffer occupancy time. Through an experimental simulation study, we have compared and contrasted our protocol with normal on demand routing protocols and showed that the proposed scheme is more efficient and effective especially when network traffic is heavily loaded.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.889-896
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• 2006

ATM Forum has defined a guaranteed frame rate (GFR) service to serve Internet traffic efficiently. The GFR service provides virtual connections (VCs) for minimum cell rate (MCR) guarantees and allows them to fairly share the residual bandwidth. And ATM Forum has recommended a frame-based generic cell rate algorithm (F-GCRA) as a frame classifier, which determines whether an Am cell is eligible to use the guaranteed bandwidth in a frame level. An ATM switch accommodates cells in its buffer or drops them in a frame level according to current buffer occupancy. A FIFO shared buffer has so simple structure as to be feasibly implemented in switches, but has not been able to provide an MCR guarantee for each VC without buffer management based on per-VC accounting. In this paper, we enhance the F-GCRA frame classifier to guarantee an MCR of each VC without buffer management based on per-VC accounting. The enhanced frame classifier considers burstness of TCP traffic caused by congestion control algorithm so as to enable each VC to use its reserved bandwidth sufficiently. In addition, it is able to alleviate the unfairness problem in usage of the residual bandwidth. Simulation results show that the enhanced frame classifier satisfies quality of services (QoSs) of the GFR service for the TCP traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.1135-1144
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• 2013

Deploying small cells is a reliable and influential solution to handle the skyrocketing traffic increase in the cellular network, and the small cell technology is evolving to ultra-dense network (UDN). In this paper we propose a small cell on/off algorithm with a simple but essential framework composed of access point (AP), user equipment (UE), and small cell controller (SCC). We propose Device-Assisted Networking for Cellular grEening (DANCE) algorithms that save the energy consumption by tying to minimize the number of turned-on APs while maintaining the network throughput. In doing so, SCC firstly gathers the feedback messages from UEs and then makes a decision including a set of turned-on APs and user association. DANCE algorithm has several variations depending on the number of bits of the UE's feedback message (1 bit vs. N bit), and is divided into AP-first, UE-first, or Proximity ON according to the criteria of selecting the turned-on APs. We perform extensive simulations under the realistic UDN environment, and the results confirm that the proposed algorithms, compared to the baseline, can significantly enhance the energy efficiency, e.g., more than a factor of 10.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.600-607
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• 2007

In this paper, we propose a MLKA (Multi-Level Keep-Alive) algorithm based on PRCG (Periodic In this paper, we propose a MLKA (Multi-Level Keep-Alive) algorithm based on PRCG (Periodic Ranging Code Group), in which periodic ranging codes are divided into groups. The AP (Access Point) performs this algorithm when a periodic ranging code arrives at the AP in a WiBro (Wireless Broadband Internet) system. In order to increase the traffic radio bandwidth resource efficiency in this system, we propose the multi-level keep-alive algorithm for finding abnormal AT (Access Terminal). From simulation results, it is verified our proposed MLKA algorithm based on PRCG can provide higher traffic radio resource efficiency compared to message-driven keep-alive algorithms.