• Title/Summary/Keyword: QoS 저하

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A Study on Service Quality Diagnosis Techniques for LTE/5G Network Backhaul (LTE/5G 네트워크 백홀(Backhaul)의 서비스 품질진단 기법에 관한 연구)

  • Ji-Hyun Yoo
    • Journal of IKEEE
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    • v.27 no.4
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    • pp.617-623
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    • 2023
  • With the evolution of communication networks, there is a growing demand for stable high-speed data connections to support services relying on large-capacity data. The increasing volume of packet data aggregated from user devices underscores the significance of quality diagnostics for the backhaul network, an intermediate link transmitting data to the core network. This paper conducts empirical research on techniques to diagnose issues within the backhaul network through practical case studies, through diagnosing various factors such as circuit bandwidth, speed disparities within switches, network segment-specific buffer sizes, routing policies, among other factors that could potentially cause RTT (Round Trip Time) delays and performance degradation.

Channel allocation scheme according to the user's location via IR from the VLC systems (VLC 시스템에서 IR을 통한 사용자 위치에 따른 채널 할당 기법)

  • Han, Doohee;Cho, Juphil;Kim, GyunTak;Lee, Kyesan;Lee, Kyujin
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.2
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    • pp.443-449
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    • 2015
  • In this paper, we proposed Channel allocation scheme according to the user's location with IR. In VLC System, LED can generate various colors of light by controlling the mixing ratio of each individual RGB color element. Thus, each RGB channel will have a different signal power, and each channel will have different performance. This proposed system using Visible light(RGB) as way to transmit signals, it depends on the mixture RGB, which decided the color of light, moreover, each things determined their performance. However, if the signal were fixed allocated RGB to transmit such as the original system, the importance of the each signals a different occur the limit on the quality of signals. To solve this problem in this paper, according to the RGB mixture ratios analyze the performance for the LED, which analyzed based on allocating the signal by transmitting to improve the quality was about how researched. In addition, our proposed system is able to improve the performance of BER and satisfied the Qos to desire users.

Clustering based Novel Interference Management Scheme in Dense Small Cell Network (밀집한 소형셀 네트워크에서 클러스터링 기반 새로운 간섭 관리 기법)

  • Moon, Sangmi;Chu, Myeonghun;Lee, Jihye;Kwon, Soonho;Kim, Hanjong;Kim, Daejin;Hwang, Intae
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.5
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    • pp.13-18
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    • 2016
  • In Long Term Evolution-Advanced (LTE-A), small cell enhancement(SCE) has been developed as a cost-effective way of supporting exponentially increasing demand of wireless data services and satisfying the user quality of service(QoS). However, there are many problems such as the transmission rate and transmission quality degradation due to the dense and irregular distribution of a large number of small cells. In this paper, we propose a clustering based interference management scheme in dense small cell network. We divide the small cells into different clusters according to the reference signal received power(RSRP) from user equipment(UE). Within a cluster, an almost blank subframe(ABS) is implemented to mitigate interference between the small cells. In addition, we apply the power control to reduce the interference between the clusters. Simulation results show that proposed scheme can improve Signal to Interference plus Noise Ratio(SINR), throughput, and spectral efficiency of small cell users. Eventually, proposed scheme can improve overall cell performance.

Packet Loss Concealment Algorithm Based on Speech Characteristics (음성신호의 특성을 고려한 패킷 손실 은닉 알고리즘)

  • Yoon Sung-Wan;Kang Hong-Goo;Youn Dae-Hee
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.7C
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    • pp.691-699
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    • 2006
  • Despite of the in-depth effort to cantrol the variability in IP networks, quality of service (QoS) is still not guaranteed in the IP networks. Thus, it is necessary to deal with the audible artifacts caused by packet lasses. To overcame the packet loss problem, most speech coding standard have their own embedded packet loss concealment (PLC) algorithms which adapt extrapolation methods utilizing the dependency on adjacent frames. Since many low bit rate CELP coders use predictive schemes for increasing coding efficiency, however, error propagation occurs even if single packet is lost. In this paper, we propose an efficient PLC algorithm with consideration about the speech characteristics of lost frames. To design an efficient PLC algorithm, we perform several experiments on investigating the error propagation effect of lost frames of a predictive coder. And then, we summarize the impact of packet loss to the speech characteristics and analyze the importance of the encoded parameters depending on each speech classes. From the result of the experiments, we propose a new PLC algorithm that mainly focuses on reducing the error propagation time. Experimental results show that the performance is much higher than conventional extrapolation methods over various frame erasure rate (FER) conditions. Especially the difference is remarkable in high FER condition.

A Bridge-Station Packet Marker for Performance Improvement of DiffServ QoS in WiMedia WLP-based Networks (WiMedia WLP 망에서의 DiffServ QoS 성능 향상을 위한 Bridge-Station 패킷 Marker)

  • Lee, Seung-Beom;Hur, Kyeong;Eom, Doo-Seop;Joo, Yang-Ick
    • Journal of Korea Multimedia Society
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    • v.13 no.5
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    • pp.740-753
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    • 2010
  • Performance of TCP can be severely degraded in WLP-based Mobile IP wireless networks where packet loss not related to network congestion occurs frequently during WLP-based inter-subnetwork handoff by user mobility. To resolve such a problem in the networks using WLP-based Mobile IP, the packet buffering method recovering seamlessly the packets dropped due to user mobility has been proposed. The packet buffering method at a bridge station recovers those packets dropped during handoff by forwarding buffered packets at the old bridge station to the WLP device. But, when the WLP device moves to a congested bridge station in a new WLP foreign subnetwork, those buffered packets forwarded by the old bridge station are dropped and TCP transmission performance of a WLP device in the congested bridge station degrades due to increased congestion by those forwarded burst packets. In this paper, a PBM(Packet Bridge Marker) is proposed for preventing buffered out-of-profile(OUT) packets from reducing the throughput of in-profile(IN) packets of an Assured Service WLP device. From this operation, the packet losses of buffered OUT packets are avoided and the throughput of IN and Total packets of an AS WLP device are increased.

Analysis on the Performance Degradation of MIMO-OFDM Receiver and Hybrid Interference Cancellation with Low Complexity for the Performance Improvement Under High-Mobility Condition (MIMO-OFDM 수신기의 성능 열화 분석 및 고속 이동환경에서의 성능 향상을 위한 저복잡도 HIC 간섭제거 기법)

  • Kang, Seung-Won;Kim, Kyoo-Hyun;Chang, Kyung-Hi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2C
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    • pp.95-112
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    • 2007
  • Spatial Multiplexing techniques, which is a kind of Multiple antenna techniques, provide high data transmission rate by transmitting independent data at different transmit antenna with the same spectral resource. OFDM (Orthogonal Frequency Division Multiplexing) is applied to MIMO (Multiple-Input Multiple-Output) system to combat ISI (Inter-Symbol Interference) and frequency selective fading channel, which degrade MIMO system performance. But, orthogonality between subcarriers of OFDM can't be guaranteed under high-mobility condition. As a result, severe performance degradation due to ICI is induced. In this paper, both ICI and CAI (Co-Antenna Interference) which occurs due to correlation between multiple antennas, and performance degradation due to both ICI and CAI are analyzed. In addition to the proposed CIR (Channel Impulse Response) estimation method for avoiding loss in data transmission rate, HIC (Hybrid Interference Cancellation) approach for guaranteeing QoS of MIMO-OFDM receiver is proposed. We observe the results on analytical performance degradation due to both ICI & CAI are coincide with the simulation results and performance improvement due to HIC are also verified by simulation under SCM-E Sub-urban Macro MIMO channel.

A Network Adaptive SVC Streaming Protocol for Improving Video Quality (비디오 품질 향상을 위한 네트워크 적응적인 SVC 스트리밍 프로토콜)

  • Kim, Jong-Hyun;Koo, Ja-Hon;Chung, Kwang-Sue
    • Journal of KIISE:Information Networking
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    • v.37 no.5
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    • pp.363-373
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    • 2010
  • The existing QoS mechanisms for video streaming are short of the consideration for various user environments and the characteristic of streaming applying programs. In order to overwhelm this problem, studies on the video streaming protocols exploiting scalable video coding (SVC), which provide spatial, temporal, and qualitative scalability in video coding, are progressing actively. However, these protocols also have the problem to deepen network congestion situation, and to lower fairness between other traffics, as they are not equipped with congestion control mechanisms. SVC based streaming protocols also have the problem to overlook the property of videos encoded in SVC, as the protocols transmit the streaming simply by extracting the bitstream which has the maximum bit rate within available bandwidth of a network. To solve these problems, this study suggests TCP-friendly network adaptive SVC streaming(T-NASS) protocol which considers both network status and SVC bitstream property. T-NASS protocol extracts the optimal SVC bitstream by calculating TCP-friendly transmission rate, and by perceiving the network status on the basis of packet loss rate and explicit congestion notification(ECN). Through the performance estimation using an ns-2 network simulator, this study identified T-NASS protocol extracts the optimal bitstream as it uses TCP-friendly transmission property and perceives the network status, and also identified the video image quality transmitted through T-NASS protocol is improved.

Resource Allocation Algorithm for Throughput Enhancement in IEEE 802.11e (IEEE 802.11e의 전송률 향상을 위한 자원할당 알고리듬)

  • Joung, Soo-Kyoung;Park, In-Kap
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.47 no.4
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    • pp.63-70
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    • 2010
  • In IEEE 802.11e system providing differentiated services, there exist some problems as follows; collision probability increase due to the increase in the number of nodes by employing CSMA/CA transmission mode, transmission speed declining tendency towards the worst of it, which is caused by different transmission mode and decrease of TCP transmission rate as the result of the link occupancy by UDP when TCP shares the link with UDP by the TCP’s flow control characteristic. In this thesis, the initial minimum and maximum CW are set differently according to the number of connected nodes in the network to avoid collisions and TXOP is adjusted according to the channel state, in which ACs with low priority but better channel state will get gradually more chances to transmit leading to optimal channel capacity. Also, by allowing higher priority for ACK frames which control the TCP transmission, the flow control becomes better because that reduces the channel occupancy by UDP flow, and by this, fair transmission is obtained from the result of the more fair transmission and active resource allocation.

An Efficient Network Resource Reservation Mechanism with Mobility in Nested Heterogeneous Mobile Networks (중첩 이종 무선 망 환경에서 단말의 이동 속도를 고려한 효과적인 망 자원 예약)

  • Park, In-Soo;Tak, Dong-Kuk;Kim, Won-Tae;Park, Yong-Jin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.10
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    • pp.83-98
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    • 2007
  • The handover between different radio access networks, especially where their coverage overlaps, suffers various complications since the different access networks provide different service characteristics. One way to reduce service interruptions and QoS (i.e., bandwidth, throughput, delay) degradations during the inter-technology handover is to reserve the required resource in advance. The resource reservation algorithm should minimize the handover latency and maximize the resource utilization based on the accurate estimation on mobile's location, velocity, movement pattern and service requirements. In this paper, we propose a resource reservation algorithm based on the mobile terminal velocity and the cell selection probability, which maximizes resource utilization ana reduces network overhead. We compare the proposed algorithm with PMS(Predictive Mobility Support) and VCDS(Velocity and Call Duration Support scheme) based on 3-layer network model under various scenarios.

Semi-Dynamic Digital Video Adaptation System for Mobile Environment (모바일 환경을 위한 준-동적 디지털 비디오 어댑테이션 시스템)

  • 추진호;이상민;낭종호
    • Journal of KIISE:Software and Applications
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    • v.31 no.10
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    • pp.1320-1331
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    • 2004
  • A video adaptation system translates the source video stream into appropriate video stream while satisfying the network and client constraints and maximizing the video quality as much as possible. This paper proposes a semi-dynamic video adaptation scheme, in which several intermediate video streams and the information for the measuring of video quality are generated statically. The intermediate video streams are generated by reducing the resolution of the video stream by a power of two several times, and they are stored as the intermediate video streams on the video server. The statically generated information for the input video stream consists of the degrees of smoothness for each frame rate and the degree of frame definition for each pixel bit rate. It helps to dynamically generate the target video stream according to the client's QoS at run-time as quickly as possible. Experimental result shows that the proposed adaptation scheme can generate the target video stream about thirty times faster while keeping the quality degradation as less than 2% comparing to the target video stream that is totally dynamically generated, although the extra storages for the intermediate video streams are required.