• Title/Summary/Keyword: VBR

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A Wireless MAC Scheduler based on Video Traces for One-to-one Video-on-demand Services in CDMA2000 1xEV-DO (CDMA2000 1xEV-DO 이동통신 망에서 일대일 주문형 비디오 서비스를 위한 비디오 트레이스 기반 무선 MAC 스케줄러)

  • Pyun, Ki-Hyun
    • Journal of KIISE:Information Networking
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    • v.36 no.4
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    • pp.351-359
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    • 2009
  • A wireless MAC scheduler for CDMA2000 IxEV-DO that provides a high level of quality-of-service(QoS) for video-on-demand(VOD) applications while achieving a reasonable level of system throughput is proposed, The proposed scheduler that exists in the MAC layer utilizes the video data information that resides in the application layer such that it improves the QoS for VOD applications. We show by simulations that our approach is better than the previous scheduler which is also based on video traces for VBR videos that have high variability between video frames.

The Method of Handoff Using CLP on the WATM Network (무선 ATM에서 CLP를 이용한 핸드오프 방식)

  • 김준배;황재문;강경식
    • Journal of the Korea Society of Computer and Information
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    • v.6 no.3
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    • pp.44-49
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    • 2001
  • In general. requirements for QoS are different according to the type of services in wireline and wireless ATM, and real-time video service is more sensitive to cell transmission delay than to cell loss. Existing handoff schemes emphasizing prevention of cell loss had limitations in cell transmission delay to satisfy QoS. In this paper, a novel scheme to transmit ATM cells with low CLP (when CLP = 0) prior to others and discarding cells with high CLP (when CLP = 1) in ATM cell header among cells to be forwarded during handoffs in real-time VBR service is proposed. The proposed scheme is proven to be suitable for the satisfaction of QoS and appropriate for fast handoffs by giving high CLP value to less meaningful MPEG frames through simulations.

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Dynamic Power Management Method Considering VBR Video Traffic in Wi-Fi Direct (Wi-Fi Direct에서 VBR 비디오 트래픽을 고려한 동적 에너지 관리 기법)

  • Jin, Mei-Hua;Jung, Ji-Young;Lee, Jung-Ryun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.11
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    • pp.2218-2229
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    • 2015
  • Recently Wi-Fi Alliance defined Wi-Fi direct, which can communicate through a direct connection between the mobile device anytime, anywhere. In Wi-Fi direct, all devices are categorized by group of owner (GO) and client. Since portability is emphasized in Wi-Fi direct devices, it is essential to control the energy consumption of a device very efficiently. In order to avoid unnecessary power consumed by GO, Wi-Fi direct standard defines two power management schemes: Opportunistic power saving scheme and Notice Of Absence (NOA) scheme. But, these two schemes do not consider the traffic pattern, so we cannot expect high energy efficiency. In this paper, we suggest an algorithm to enhance the energy efficiency of Wi-Fi direct power saving, considering the characteristics of multimedia video traffic. Proposed algorithm utilizes the statistical distribution for the size of video frames and adjusts the length of awake interval dynamically. Also, considering the inter-dependency among video frames, the proposed algorithm assigns priorities to video frames and ensures that a video frame with high priority is transmitted with higher probability than other frames with low priority. Simulation results shows that the proposed method outperforms the traditional NOA in terms with average delay and energy efficiency.

Joint video coding for multiple video program transmission based on rate-distortion estimation (다중 비디오 프로그램 전송을 위한 비트율-왜곡 추정 기반의 결합 비디오 부호화)

  • 홍성훈;김성대
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.5
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    • pp.1325-1341
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    • 1998
  • A conventional CBR channel is now capable of delivering several digitally compressed video programs due to recent advances in video compression, such as MPEG-2, and digital transmission technology. This paper presents a joint video coding scheme that is to maintain a constant sum of bit rates for all the programs but to allow the variable bit rate for individual program in the transimission environment mentioned above. Thus advantages of VBR video compression can be obtained. This paper contributes in two aspects. First, a rate-distortion estimation method for MPEG-2 video is proposed, which enavle us predict the amount of bits and the distortion generated from an encoded picture at a given quantization step size and vice versa. The most attractive features of the proposed rate-distortion estimation method are its accuracy and a computational complexity low enough to be applied to real-time video coding applications. Second, this paper presents an efficient and accurate joint rate control scheme using the rate-distortion estimation results and verifies its performance with experiments. The experimental results show that our coding scheme gives a significant gain even though a small number of video programs are coded jointly. For example, a stable picture quality is maintained among the video programs as well as within a program, and additional extra programs can be transmitted over the same channel bandwidth if the proposed joint video coding scheme is used.

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A Window-Based Permit Distribution Scheme to Support Multi-Class Traffic in ATM Passive Optical Networks (ATM 기반 광 가입자망에서 멀티클래스 트래픽의 효율적인 전송을 위한 윈도우 기반 허락 분배 기법)

  • Lee, Ho-Suk;Eun, Ji-Suk;No, Seon-Sik;Kim, Yeong-Cheon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.1
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    • pp.12-22
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    • 2000
  • This paper presents the window-based permit distribution scheme for efficient medium access control to support multiclass traffic in APON(ATM over passive optical network). The proposed MAC protocol considers the characteristics of QoS(Quality of Service) for various traffic classes. A periodic RAU(request access unit) in upstream direction, includes dedicative request fields for each traffic category within the request slot. The transmission of upstream cell is permitted by the proposed window-based spacing scheme which distributes the requested traffic into several segments in the unit of one spacing window. The delay sensitive traffic source such as CBR or VBR with the stringent requirements on CDV and delay, is allocated prior to any other class. In order to reduce the CDV, so that the permit arrival rate close to the cell arrival rate, Running-Window algorithm is applied to permit distribution processing for these classes. The ABR traffic, which has not-strict CDV or delay criteria, is allocated flexibly to the residual bandwidth in FIFO manner. UBR traffic is allocated with the lowest priority for the remaining capacity. The performance of proposed protocol is evaluated in terms of transfer delay and 1-point CDV according to various offered load. The simulation results show that our protocol has the prominent improvement on CDV and delay performance with compared to the previous protocol.

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Evaluation of Call Routing Rules in Call Centers Using Simulation and its Application of Value Based Routing (서비스 산업의 콜 센터 라우팅 룰의 수익성 평가 방법 및 가치 기반 라우팅의 적용 예제)

  • Kong, Joo-Hoe;Choi, Byung-Kyu
    • IE interfaces
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    • v.22 no.1
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    • pp.56-62
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    • 2009
  • This paper presents a methodology of evaluating call routing rules in call centers using simulation. The proposed methodology enables the call centers to reduce trial and error costs from applying different routing rules. Additionally, a Value Based Routing (VBR) has been evaluated with the proposed methodology in terms of profit, and finally compared it with a Homogeneous Routing (HR).

Configuration of ATM switching system supporting ABR services (ABR 서비스를 지원하기 위한 ATM 교환 시스템 구조)

  • 안윤영;정민영김화숙최대우
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.277-280
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    • 1998
  • As user's demands for high-speed data traffic are recently increased, ABR services are considered as one of important service requirements in ATM networks. Unfortunately, a number of existing ATM switching systems have structural drawbacks as to support ABR services because these switching systems have been developed to support realtime(rt) services such as CBR and rt-VBR services. To support ABR services in the existing ATM switching systems, new traffic control mechanisms for ABR services are required. This paper proposes a method for supporting ABR services in ATM swithcing systems without back-pressure mechanisms and evaluates the performance of the proposed method using simulation.

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A Study on Cell Scheduling for ABR Traffic in ATM Multiplexer (ATM 멀티플렉서에서 ABR 트랙픽을 위한 셀 스케쥴링에 관한 연구)

  • 이명환;이병호
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.95-98
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    • 1998
  • In this paper, we propose a cell scheduling algorithm for ABR traffic in ATM multiplexer. Proposed Algorithm can support ABR service more efficiently than existing WRR and DWRR algorithm. We evaluate the performances of proposed algorithm through computer simulation. Also, we model the VBR and the ABR traffics as ON/OFF source, and the CBR traffic as a Poisson source. And the simulation shows that proposed algorithm better performance over other cell scheduling algorithm in tem of mean cell delay time.

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A Study on Real-Time Multimedia Service Considering Network Performance in ATM Networks (ATM망에서 Network Performance를 고려한 Real-Time Multimedia Service에 관한 연구)

  • 김영준;이병호
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.91-94
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    • 1998
  • ATM technology is reaching a certain level of maturity that allow for its deployment in local as well as in wide area networks. Concurrently, audiovisual applications are foreseen as one of the major users of such broadband networks. We present in this paper requriement of real-time multimedia service on B-ISDN networks and simulating the transport of MPEG-2 encoded multimedia data over ATM networks using CBR, VBR, ABR of ATM Traffic Service. We compare each delay time considering network performance and propose need for real-time multimedia service.

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MAC Scheme for Guaranteed QoS on WATM (무선 ATM에서 서비스 품질 보장을 위한 매체 접근 제어 방식)

  • 문필주;전문석이철희
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.79-82
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    • 1998
  • This paper proposes the MAC scheme based on variable reservation slots for the guaranteed QoS of ATM services on RF and evaluates the performance. This scheme has improved the utilization of channel and success ratio of reservation by using the variable number of RES(REServation) slots according to the collisions. It is the results of performance evaluation that the CTD of CBR Service is 7.9ms with overall $load(\rho)$ 85%. And also VBR service of it is 3.5ms, ABR service of it is 9.8ms with overall load 85%.

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