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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 29, Issue 12C - Dec 2004
Volume 29, Issue 12B - Dec 2004
Volume 29, Issue 12A - Dec 2004
Volume 29, Issue 11C - Nov 2004
Volume 29, Issue 11B - Nov 2004
Volume 29, Issue 11A - Nov 2004
Volume 29, Issue 10C - Oct 2004
Volume 29, Issue 10B - Oct 2004
Volume 29, Issue 10A - Oct 2004
Volume 29, Issue 9C - Sep 2004
Volume 29, Issue 9B - Sep 2004
Volume 29, Issue 9A - Sep 2004
Volume 29, Issue 8C - Aug 2004
Volume 29, Issue 8B - Aug 2004
Volume 29, Issue 8A - Aug 2004
Volume 29, Issue 7C - Jul 2004
Volume 29, Issue 7B - Jul 2004
Volume 29, Issue 7A - Jul 2004
Volume 29, Issue 6C - Jun 2004
Volume 29, Issue 6B - Jun 2004
Volume 29, Issue 6A - Jun 2004
Volume 29, Issue 5C - May 2004
Volume 29, Issue 5B - May 2004
Volume 29, Issue 5A - May 2004
Volume 29, Issue 4C - Apr 2004
Volume 29, Issue 4B - Apr 2004
Volume 29, Issue 4A - Apr 2004
Volume 29, Issue 3C - Mar 2004
Volume 29, Issue 3B - Mar 2004
Volume 29, Issue 3A - Mar 2004
Volume 29, Issue 2C - Feb 2004
Volume 29, Issue 2B - Feb 2004
Volume 29, Issue 2A - Feb 2004
Volume 29, Issue 1C - Jan 2004
Volume 29, Issue 1B - Jan 2004
Volume 29, Issue 1A - Jan 2004
Selecting the target year
A Variable Transmission Window MAC protocol for QoS Support in EPON System.
Hwang Junho ; Yoo Myungsik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 891~899
Ethernet passive optical network (EPON) has drawn many attention as a promising access network technology because it can provide a high bandwidth with a low cost. Since the uplink in the EPON system is shared by many users, it is necessary for an EPON system to have an efficient bandwidth allocation mechanism. In addition, as the users demand more QoS-oriented applications, it is necessary for an EPON system to have an efficient mechanism supporting QoS. In this paper, we propose a variable window dynamic bandwidth allocation (DBA) algorithm for the EPON system. Unlike the previously proposed DBA algorithms, the variable window algorithm guarantees the QoS for the highest priority class, and at the same time provides more enhanced QoS for the lower priority classes by dynamically allocating bandwidth if necessary. It is verified through the simulations that the variable window algorithm can provide more enhanced QoS performance than other DBA algorithms.
Improving TCP Performance through Pre-detection of Route Failure in Mobile Ad Hoc Networks
Lee Byoung-Yeul ; Lim Jae-Sung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 900~910
Route failure is mainly caused by mobility of mobile host in ad hoc networks. Route failure, which may lead to sudden packet losses and delays, is losing the route from source to destination. In this situation, TCP assumes that congestion has occurred within the network and also initiates the congestion control procedures. Congestion control algorithm provides the means for the source to deal with lost packets. TCP performance in ad hoc environments will be degraded as TCP source cannot distinguish congestion from route failure. In this paper, we propose TCP-P as pre-detection approach to deal with route failure. TCP-P freezes TCP through pre-detection of route failure. Route failure information of the proposed mechanism is obtained not by routing protocol but by MAC protocol. The intermediated node, obtaining route failure information by its MAC layer, relays the information to TCP source and lets TCP source stop the congestion control algorithm. Results reveal that TCP-P responding with proactive manner outperforms other approaches in terms of communication throughput under the presence of node mobility.
Weighted Binary Prefix Tree for IP Address Lookup
Yim Changhoon ; Lim Hyesook ; Lee Bomi ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 911~919
IP address lookup is one of the essential functions on internet routers, and it determines overall router performance. The most important evaluation factor for software-based IP address lookup is the number of the worst case memory accesses. Binary prefix tree (BPT) scheme gives small number of worst case memory accesses among previous software-based schemes. However the tree structure of BPT is normally unbalanced. In this paper, we propose weighted binary prefix tree (WBP) scheme which generates nearly balanced tree, through combining the concept of weight to the BPT generation process. The proposed WBPT gives very small number of worst case memory accesses compared to the previous software-based schemes. Moreover the WBPT requires comparably small size of memory which can be fit within L2 cache for about 30,000 prefixes, and it is rather simple for prefix addition and deletion. Hence the proposed WBPT can be used for software-based If address lookup in practical routers.
Integrating Portable Internet with cdma2000 Mobile Communication Networks for Seamless Service
Cho Jinsung ; Kim Jeong Gem ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 920~929
Nowadays, wireless packet data services are provided over cdma2000 1x/1xEV-DO mobile communication network and Portable Internet are being standardized for users demanding higher data rate services. Portable Internet can provide high data rate services, but its service coverage is relatively small. If Portable Internet may be integrated with cdma2000 mobile networks, users are able to choose the best service according to service areas and get seamless services while they are moving around. At the same time, it is cost-effective for operators to construct and maintain the integrated network. For the purpose of effectively integrating Portable Internet into cdma2000 networks, we propose an integration scheme including network architecture, protocol architecture, functions in network elements, interfaces between them, and call-flow procedures. The integration scheme proposed in this paper adopts a tightly-coupled architecture for unified authentication/accounting and seamless services. In addition, the scheme can be implemented without modifying the existing cdma2000 mobile communication networks. It is also simple to develop the dual-mode mobile station. Through the simulation results based on the performance model for handoffs between cdma2000 and Portable Internet, it has teen validated that the proposed scheme diminishes packet losses compared with the loosely-coupled architecture.
Delay Analysis of Selective Repeat ARQ for a Markovian Source Over a Wireless Channel
Kim Jeong Geun ; Kim Young Soo ; Lee Kyesan ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 930~937
In this paper, we analyze the delay performance for a Markovian source transported over a wireless channel with time-varying error characteristics. To improve the reliability of the channel, the end points of the wireless link implement a selective-repeat (SR) ARQ error control protocol. We provide an approximate discrete-time analysis of the end-to-end mean packet delay, which consists of transport and resequencing delays. Numerical results and simulations indicate that our approximate analysis is sufficiently accurate for a wide range of parameter values.
Lambda Routing Table based Dynamic Routing Scheme and Its Characteristics on GMPLS Network
Kwon Ho-jin ; Kim Young-bu ; Han Chi-moon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 938~945
This paper describes the problems of the existing two multi-layer routing policies(policy 1 and policy 2) and suggests new multi-layer routing policy(policy 3) which is established the packet LSP by inquiry on packet LSP lambda routing tables for GMPLS based optical If Network. All policies of multi-layer routing schemes first try to allocate a newly requested electrical path to an existing optical path that directly connects the source and destination nodes. U such a path is not available, all policies employ different procedures. Policy 1 tries to find available existing optical paths with two or more hops that connect the source and destination nodes and policy 2 tries to establish a new one-hop optical path between source and destination nodes. Policy 3 tries to establish a new one-hop optical path by inquiry on information of the packet LSP lambda routing tables between source and destination nodes. The performances of the three multi-routing policies are evaluated by computer simulation. Simulation results show that policy 3 is the excellent of routing time and traffic acceptance capabilities compare to existing two polices if p is large, where p is the number of packet-switching-capable ports p.
Fault free Shortest Path routing on the de Bruijin network
Ngoc Nguyen Chi ; Nhat Vo Dinh Minh ; Zhung Yonil ; Lee Sungyoung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 946~955
It is shown that the do Bruijn graph (dBG) can be used as an architecture for interconnection network and a suitable structure for parallel computation. Recent works have classified dBG based routing algorithms into shortest path routing and fault tolerant routing but investigation into fault free shortest path (FFSP) on dBG has been non-existent. In addition, as the size of the network increase, more faults are to be expected and therefore shortest path dBG algorithms in fault free mode may not be suitable routing algorithms for real interconnection networks, which contain several failures. Furthermore, long fault free path may lead to high traffic, high delay time and low throughput. In this paper we investigate routing algorithms in the condition of existing failure, based on the Bidirectional do Bruijn graph (BdBG). Two FFSP routing algorithms are proposed. Then, the performances of the two algorithms are analyzed in terms of mean path lengths and discrete set mean sizes. Our study shows that the proposed algorithms can be one of the candidates for routing in real interconnection networks based on dBG.
A Restoration Method for Improving Fault Recovery in MPLS Networks Routing Protocol
In Chi-Hyung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 956~966
Nowadays, NGN(Next Generation Network) is evolving into network with packet based QoS.\ulcorner This paper presents the recovery method as a selecting way of more efficient path in MPLS network that reduces the service interruption time. In order to increase the efficiency of usage of recovering resource which is one of major functions of disorder recovering, it opens the state information of each Node both to fault detector and bandwidth broker so that it reduces message transmission time for recovery when functional disorder occurs. in addition, by effective management and adjustment of required bandwidth of entire network depending on the changes of traffic load, it improves the efficiency of bandwidth usage. and in MPLS network supporting priority selection function, it allocates domains depending on the traffic relating to priority order to the entire network so that\ulcorner it efficiently allocates proper resources to the restoring process between the entry and the end for the traffic of high priority and for low priority traffic, it restores path oかy inside disordered domain. by doing this, it reduces resetting time and unnecessary massage transmission.
Performance evaluation of BWA protocol according to uplink frame size and contention slot
Oh Sung-Min ; Kim Jae-Hyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 967~973
DOCSIS and IEEE 802.16 define the usage and element of a MAP which is uplink control message. Standards does not include the details of MAP size and the number of contention slots affecting the performance of MAC protocols for DOCSIS and IEEE 802.16. In this paper, we analyzed the performance of throughput and access delay according to the MAP size and contention slot size. Based on the analytical results, we found the optimal MAP size and the number of contention slots. We found that the protocol shows best performance when the MAP size is 2msec and the number of contention slots is 8. The simulation results can apply to the network system parameters. The simulator can be used to optimize the system parameters in cable network, BWA and WiBro.
Adaptive MAC Scheduling Scheme using Partial Queue Length Information in IEEE Wireless LAN
Shin Soo-Young ; Jang Yeong Min ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 974~979
In the IEEE 802.1 Ib, DCF provides contention based services and PCF provides contention free services for QoS suppof. DCF uses CSMA/CA (Carrier Sense Multiple Access/collision Avoidance) as an access protocol. In this paper, an enhanced PCF, which gives weights to channels with heavy traffic load, was proposed. The weight is depending on the partial queue length information from STAs. NS-2 simulation results show that the proposed scheme is an promising approach for enhancing the PCF.
Performance Evaluation of a Dynamic Bandwidth Allocation Algorithm with providing the Fairness among Terminals for Ethernet PON Systems
Park Ji-won ; Yoon Chong-ho ; Song Jae-yeon ; Lim Se-youn ; Kim Jin-hee ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 980~990
In this paper, we propose the dynamic bandwidth allocation algorithm for the IEEE802.3ah Ethernet Passive Optical Network(EPON) system to provide the fairness among terminals, and evaluate the delay-throughput performance by simulation. For the conventional EPON systems, an Optical Line Termination (OLT) schedules the upstream bandwidth for each Optical Network Unit (ONU), based on its buffer state. This scheme can provide a fair bandwidth allocation for each ONU. However, it has a critical problem that it does not guarantee the fair bandwidth among terminals which are connected to ONUs. For an example, we assume that the traffic from a greedy terminal increases at a time. Then, the buffer state of its ONU is instantly reported to the OLT, and finally the OW can get more bandwidth. As a result, the less bandwidth is allocated to the other ONUs, and thus the transfer delay of terminals connected to the ONUs gets inevitably increased. Noting that this unfairness problem exists in the conventional EPON systems, we propose a fair bandwidth allocation scheme by OLT with considering the buffer state of ONU as welt as the number of terminals connected it. For the performance evaluation, we develop the EPON simulation model with SIMULA simulation language. From the result of the throughput-delay performance and the dynamics of buffer state along time for each terminal and ONU, respectively, one can see that the proposed scheme can provide the fairness among not ONUs but terminals. Finally, it is worthwhile to note that the proposed scheme for the public EPON systems might be an attractive solution for providing the fairness among subscriber terminals.
Application Layer Multicast Tree Constructing Algorithm for Real-time Media Delivery
Song Hwangjun ; Lee Dong Sup ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 991~1000
This paper presents an application layer multicast tree constructing algorithm to minimize the average time delay from the sender to end-systems for the effective real-time media delivery. Simultaneously, the proposed algorithm takes into account the computing power and the network condition of each end-system as a control variable and thus avoids the undesirable case that loads are concentrated to only several end-systems. The multicast tree is constructed by clustering technique and modified Dijkstra's algorithm in two steps, i.e. tree among proxy-senders and tree in each cluster. By the experimental results, we show that the proposed algorithm can provide an effective solution.
The Evaluation on EU′s Info-Communication Regulatory Policy in Preparation for Media Convergence
Kim Pang-Ryong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 11B, 2004, Pages 1001~1011
The structure of info-communications industry has been changing from vertical integration to horizontal layered disintegration as the Internet technology has been rapidly developed. Considering with this background, EU has decided to introduce new regulatory framework called 2003 framework and asked member states to shift to new framework by July 2003. The key words of the new framework is to be denoted by the following three characteristics: Introduction of cross-media regulatory framework Alleviation of entry regulation by general authorization, Transition from ex ante regulation to ex post regulation.