• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.1
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• pp.79-95
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• 2016

In order to improve the Quality-of-Service (QoS) of latency sensitive applications in next-generation cellular networks, multi-path is adopted to transmit packet stream in real-time to achieve high-quality video transmission in heterogeneous wireless networks. However, multi-path also introduces two important challenges: out-of-order issue and reordering delay. In this paper, we propose a new architecture based on Software Defined Network (SDN) for flow aggregation and flow splitting, and then design a Multiple Access Radio Scheduling (MARS) scheme based on relative Round-Trip Time (RTT) measurement. The QoS metrics including end-to-end delay, throughput and the packet out-of-order problem at the receiver have been investigated using the extensive simulation experiments. The performance results show that this SDN architecture coupled with the proposed MARS scheme can reduce the end-to-end delay and the reordering delay time caused by packet out-of-order as well as achieve a better throughput than the existing SMOS and Round-Robin algorithms.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.251-256
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• 2012

In this paper, we addressed the problem of upstream bandwidth in EPONs. We presented a wavelength division EPON supporting QoS in the differentiated services framework. It was shown that the bandwidth allocation by priority scheduling, under our assumptions for traffic behavior, will result in an unexpected behavior for high priority class and we suggested the use of weighted priority scheduling to alleviate this problem. Our wavelength division EPON supporting QoS allocates effectively and fairly bandwidths and wavelengths between ONUs in the differentiated services framework. Moreover, we showed better performance in terms of average and maximum end-to-end delay, as well as network throughput, utilization compared with some other algorithms. We used simulation experiments to study the performance and validate the effectiveness of the proposed network and algorithm.

• Journal of KIISE:Information Networking
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• v.30 no.6
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• pp.787-798
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• 2003

The flow label field in IPv6 has been proposed to provide the QoS. Since the existing flow label specification scheme like random-number format utilizes the label only as the identifier of flow, it is not appropriate for providing differentiated services according to the characteristics of various types of real-time traffic. This paper proposes a hybrid scheme that makes use of the flow label fields as components of flow and QoS parameters as well. To be specific, this paper investigates a scheme that both guarantees the end-to-end service quality and utilizes efficiently backbone resources by allowing users to specify QoS parameters using flow labels. Assuming an MLPS-TE network as the backbone, we compare the performance of our proposed scheme with that of random-number scheme through simulation. The simulation result shows that our scheme is more efficient than the existing one in terms of the transmission rate as well as the resource utilization of the backbone.

• Journal of the Korea Society for Simulation
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• v.12 no.4
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• pp.73-81
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• 2003

An Ad Hoc network is a dynamic multi-hop wireless network that is established by a group of mobile hosts on a shared wireless channel by virtue of their proximity to each other. Since wireless transmissions are locally broadcast in the region of the transmitting host, hosts that are in close proximity can hear each other and are said to be neighbors. The transitive closure of the neighborhood of all the hosts in the set of mobile hosts under consideration forms an Ad Hoc network. Thus, each host is potentially a router and it is possible to dynamically establish routes by chaining together a sequence of neighboring hosts from a source to a destination in the Ad Hoc network. In a network, various real-time services require the network to guarantee the Quality of Services provided to the receiver. End-to-end QoS can be provided most efficiently when each layer of the protocol stack translates the requirements of the application into layer classified requirements and satisfies them. In this study, a mechanism to guarantee the QoS in Ad Hoc networks with buffer nodes is proposed. They effectively prevent traffic congestion and yield better transmission rate. In this way QoS is enhanced.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1453-1460
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• 2014

WFQ (Weighted Fair Queuing) provides not only fairness among traffic flows in using bandwidth but also guarantees the Quality of Service (QoS) that individual flow requires, which is why it has been applied to the resource reservation protocol (RSVP)-capable router. The RSVP allocates an enough resource to satisfy both the rate and end-to-end delay requirements of the flow in the condition of no packet loss, and the WFQ scheduler guarantees those QoS requirements with the allocated resource. In practice, however, most QoS-guaranteed services allow a degree of packet loss, especially from 0.1% to 3% for Voice over IP. This paper discovers that the packet loss rate of each traffic flow is determined by only its time-stamp adjustment value, and then enhances the WFQ to provide a differentiated packet loss guarantee under general traffic conditions in terms of both traffic characteristics and QoS requirements. The performance evaluation showed that the proposed WFQ could increase the utilization of bandwidth by 8~11%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6B
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• pp.433-442
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• 2012

We have proposed a solution to multicast services and an advanced quality of service (QoS) mechanism on a packet transport system (PTS) based on PBB-TE. The point-to-multipoint (PtMP) connection in the PBB-TE system have been realized by grouping point-to-point (PtP) PTL trunks and mapping a BSI onto the PtP PTL trunks using a multicast backbone destination address. To provide end-to-end QoS of the PtMP services, the hierarchical QoS scheme for backbone service instances and connection-oriented paths has been implemented in the PTS. For providing different capabilities for service selection and priority selection, the PTS offers to customers three basic types of the port-based, C-tagged, and S-tagged service interface defined by the IEEE 802.1ah. To offer to customers different capabilities of the layer 3 applications and services, moreover, an IP-flow service interface have been added. In order to evaluate traffic performance for PtMP services in the PTS, the PtMP throughputs for the link capacity of 1 Gbps at the four service interfaces were measured in the leaves of the ingress edge node, the transit node, and the egress edge node. The throughputs were about 96 % because the B-MAC overhead of 22 bytes occupies 4% of the 512-byte packet. The QoS performance is ability to guarantee an application or a user a required bandwidth, and could be evaluated by the accuracy of policing or shaping. The accuracy of the policing scheme and the accuracy of the shaping scheme were 99% and 99.3% respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2219-2225
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• 2016

Mobile communication systems should be able to support multimedia traffics with limited transmit power due to the frequency reuse for maximizing the channel accommodation. Real-time data is very sensitive to delay, and they need to be transmitted instantly. On the other hand, non-real time data is less sensitive to delay, and their packet loss can be handled more flexibly. Therefore an adaptive resource management scheme is essentially required which enables to keep the minimal power allocated in the base station while guaranteeing the user requirements for QoE within a permissible range. Power-saving techniques are required in order to support multimedia services in the mobile networks because the power consumption increases greatly with the transmission rate increase. This paper proposes a novel scheme which enables to keep the allocated power minimal while guaranteeing the user requirements for QoE within a permissible range.

• Journal of Communications and Networks
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• v.8 no.4
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• pp.369-377
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• 2006

Recently, the metropolitan area network (MAN) has attracted much attention in telecommunication research and has emerged as one of the most important research topics in the community. Several standards representing the first step for developing metropolitan networks have been published; IEEE 802.16 (WiMAX) has taken a relevant role in reaching the goal of realizing a full-service network all over a urban and suburban area. At the same time, the wireless local area networks (WLAN) have been widely used for in-home or short range communications, mainly basing on the IEEE 802.11 (WiFi) standard. A consequence is the increasing interest in interworking technology, that allows an interconnection between different standards by maintaining certain properties, mainly in terms of quality of service (QoS). One of the major issues is to design bridging devices capable of transparently interconnect different wireless technologies. In this paper, we propose two interconnection bridging solutions between WiMAX and WiFi links; the first is more based on the concept of maintaining a certain end-to-end QoS level independently from the wireless technologies used. The second method is more devoted to the reduction of the implementation complexity at the cost of no QoS assurance. The performance of the two methods are compared by resorting to computer simulations showing the advantages of each one technique.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.1059-1075
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• 1997

The transprot layer protocol for distrubuted multimedia applications in high speed network should gurantee the Quality of Serivce(QoS)requested by uwer.,The QoS Parmenters can be divied into two calssifications:those depend on the speed of a network such as bandiwidth,end-to-end transmission delay and throughput;and net- woek independent parameters such as various typed of group communications, retransmission method based on multimeda characteristic,acceptable packet wrror rate and transmission priority.In this proposed protocol,we divided user's QoS into performance redated parmeters and non-performance related parameters.The perform- ance-related paramenters are mapped into ATM traddic paramenters by the Distributed QoS Manger(DQM),the QoS manager,and the non-performance redlted paramenters are supported by the Distributed Multimedia Trans-port protocol(DMTP),a high-performance group transport protocol.Especially,becaues the DMTP is designed with considering the IP protocol,it can be efficiently used as an underlying protocol not onlu in ATM,but also in Ethernet,Token ring and FDDI LAN.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.51-55
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• 2008

Request High-Images, High-quality, duplex transmission, BcN Voice telephone, Broadcast, Data internet service came to be all possible and demolished original communication service area. Also, The quality is guaranteed stablely to new business and ISP the requirement comes to become a multicasting quality guarantee mechanism which there is the reliability for a information communication and High-quality multimedia service. Like this, a multicast mechanism to be guaranteed must become air control End-to-End QoS for a service supply, a transmission delay a packet loss or requirement which the user requests guarantee and multicast Path-NET which there is the reliability must be provided. Therefor, we proposed IP base multicast new join the present the multicast mechanism of Probing packet foundation which there is the efficiently a linking acceptance, we used ns-2 simulator for the performance evaluation of the proposed.