• Title, Summary, Keyword: Constant Bit Rate

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Transmission Performance of Application Traffic on LTE Networks (LTE 네트워크에서 응용 트래픽의 전송 성능)

  • Kim, Young-Dong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.641-644
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    • 2017
  • Usage of LTE(Long Term Evolution) technology is expanded to industrial an emergency service field beyond commercial communications of mobile internet focused on smartphone. In this paper, transmission performance of LTE technology be supplied to various service area is analyzed on the level of application traffics. Performance is evaluated with compter simulation based NS(Network Simulator)-2, CBR(Constant Bit Rate), VBR(Variable Bit Rate File) traffic is used as simulation target. Results and methods of this paper can be used for research and developmemt of LTE based networks.

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Performance Analysis of GCRA Policing Algorithm for Constant-Bit Rate Service (항등비트율 서비스를 위한 GCRA 폴리싱 알고리즘의 성능 해석)

  • Kim, Young-Beom
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.12
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    • pp.2157-2165
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    • 2006
  • In implementing GCRA, well known as the representative user traffic policing algorithm for constant-bit rate service, it is essential to set proper values for delay variation tolerance in order to prevent network overload and excessive user data loss due to delay variation incurred inevitably during transmission process. In this paper, we investigate the performance of GCRA algorithm for various values of delay variation tolerance and suggest a guideline for setting proper delay variation tolerance values.

Improved H.263+ Rate Control via Variable Frame Rate Adjustment and Hybrid I-frame Coding

  • 송환준
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.5A
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    • pp.726-742
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    • 2000
  • A novel rte control algorithm consisting of two major components, i.e. a variable encoding frame rate method and a hybrid DCT/wavelet I-frame coding scheme, is proposed in this work for low bit rate video coding. Most existing rate control algorithms for low bit rate video focus on bit allocation at the macroblock level under a constant frame rate assumption. The proposed rate control algorithm is able to adjust the encoding frame rate at the expense of tolerable time-delay. Furthermore, an R-D optimized hybrid DCT/wavelet scheme is used for effective I-frame coding. The new rate-control algorithm attempts to achieve a good balance between spatial quality and temporal quality to enhance the overall human perceptual quality at low bit rates. It is demonstrated that the rate control algorithm achieves higher coding efficiency at low bit rates with a low additional computational cost. The variable frame rate method and hybrid I-frame coding scheme are compatible with the bi stream structure of H.263+.

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Optimizing Bit Rate Control for Realtime TV Broadcasting Transmission using LTE Network (LTE 무선통신을 활용한 TV 생방송 중계화면 안정화 비트레이트 조정 연구)

  • Kwon, Mahnwoo;Lim, Hyunchan
    • Journal of Korea Multimedia Society
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    • v.21 no.3
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    • pp.415-422
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    • 2018
  • Advances of telecommunication technology bring various changes in journalism field. Reporters started to gather, edit, and transmit content to main server in media company using hand-held smart media and notebook computer. This paper tried to testify valid bit-rate of visual news content using LTE network and mobile phone. Field news like natural disasters need real-time transmission of video content. But broadcasting company normally use heavy ENG system and transmission satellite trucks. We prepared and experimented different types of visual content that has different bit-rates. Transmission tool was LU-60HD mobile system of LiveU Corporation. Transmission result shows that bit-rate of 2Mbps news content is not suitable for broadcasting and VBR (Variable Bit Rate) transmission has better definition quality than CBR (Constant Bit Rate) method. Three different bit-rate of VBR transmission result shows that 5Mbps clip has better quality than 1Mbps and 3Mbps. The higher bit-rate, the better video quality. But if the content has much movements, that cause delay and abnormal quality of video. So optimizing the balance between stability of signal and quality of bit-rate is crucial factor of real-time broadcasting news gathering business.

Joint Quality Control of VBR MPEG Video Programs (VBR MPEG 비디오 프로그램들의 결합 화질 제어)

  • 홍성훈;김성대
    • Proceedings of the IEEK Conference
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    • pp.591-596
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    • 1999
  • In this paper, we present a joint quality control system to be able to accurately control the relative picture quality among the video programs in terms of PSNR. The joint quality control system allows variable bit rate (VBR) for each video program to maintain the pre-determined relative picture quality among the aggregated video programs while keeping a constant sum of the bit rates for all programs to be transmitted over a single constant bit rate (CBR) channel. This is achieved by simultaneous controlling the video encoders to generate VBR video streams at the central controller. Furthermore we also suggest buffer regulation method based on the analysis of the constraints imposed by sender/receiver buffer sizes and total transmission rate. Through various simulation results, it is found that our quality control systems guarantee that the video buffers do not overflow and underflow and the quality control errors do not exceed 0.1 ㏈.

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Error Compensation Study for QoS Support on a Wireless ATM (무선 ATM에서의 QoS 지원을 위한 에러 보상 연구)

  • Yun, Hong-Il;Jang, Kyung-Soo;Shin, Dong-Ryeol
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.1393-1396
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    • 2002
  • 무선 ATM(Asynchronous Transfer Mode) 망을 기본으로 하여 ATM망에서 사용하는 서비스 종류인 CBR(Constant Bit Rate), rtVBR(Real-Time Variable Bit Rate), nrtVBR(Non-Real-Time Variable Bit Rate), ABR(Available Bit Rate), UBR(Unspecified Bit Rate)에 따른 플로우를 우선 각 서비스 흐름에 따라서 공평하게 패킷 스케줄링 한다. 그리고 각 서비스 종류에 따라 대역이나 지연에 따라 모든 사용자의 다양한 서비스 트래픽에 공평하게 서비스하는 구조를 갖는다. 아울러 무선 통신망 채널에 에러가 발생할 경우를 고려하여 각 서비스 트래픽에 대한 QoS(Quality of Service)를 보장해주는 무선 ATM 통신망에서 동작하는 스케줄링 알고리즘을 제안하여 시뮬레이션과을 통해 기존의 방법과 성능을 비교하여 기존의 유선 통신망 스케줄링 알고리즘과 달리 무선망의 에러에 대한 각 트래픽의 에러에 대한 성능 향상에 대해 알아본다.

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Performance Relation Analysis of CLR, Buffer Capacity and Delay Time in the ATM Access Node (ATM 접속노드에서 셀 손실율과 버퍼용량 및 지연시간의 상관관계 분석)

  • 이하철;이병섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.10C
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    • pp.945-950
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    • 2002
  • In this paper the performance evaluations on Asynchronous Transfer Mode(ATM) access node are performed in the ATM access network which consists of access node and channel. The performance factors of access node are Cell Loss Ratio(CLR), buffer capacity and delay time. Both the ATM cell-scale queueing model and burst-scale queueing model are considered as the traffic model of access node for various traffic types such as Constant Bit Rate(CBR), Variable Bit Rate(VBR) and random traffic in the ATM access networks. Based on these situations, the relation of CLR, buffer capacity and delay time is analyzed in the ATM access node.

Constant-Amplitude Biorthogonal Multi-Code Modulation (정 진폭 다중 보호 이진 직교 변조)

  • Hong Dae ki;Kang Sung jin;Ju Min chul;Kim Young sung;Seo Kyeung hak;Cho Jin woong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.3C
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    • pp.69-76
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    • 2005
  • In this paper, we propose a biorthogonal modulation employing a constant-amplitude transmission of multi-code signals by introducing a simple constant-amplitude coding scheme with redundant bits. The proposed constant-amplitude biorthogonal multi-code (CABM) modulation can provide high spectral efficiency compared with a conventional direct sequence/spread spectrum (DS/SS) modulation. Nevertheless the proposed CABM modulation can keep up a constant-amplitude signal. Additionally, we propose various types of demodulation structures for the CABM modulation. Simulation results show that bit error rate (BER) performance and hardware complexity of the proposed CABM modulation are highly improved in comparison with those of a constant-amplitude orthogonal multi-code (CAOM) modulation.

Fractal coding of Textural Images (텍스처 영상의 프락탈 코딩)

  • Jang, Jong-Whan
    • The Journal of Natural Sciences
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    • v.8 no.2
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    • pp.77-82
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    • 1996
  • New very low bit rate segmentation image coding technique is proposed by segmenting image into textually homogeneous regions. Regions are classified into on of three perceptually distinct texture classes (perceived constant intensity (class I), smooth texture (class II), and rough texture (class III) using the human Visual System (HVS) and the fractals. To design very low bit rate image coder, it is very important to determine nonoverlap and overlap segmentation method for each texture class. Good quality reconstructed images are obtained with about 0.10 to 0.21 bit per pixel (bpp) for many different types of imagery.

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Distortion Variation Minimization in low-bit-rate Video Communication

  • Park, Sang-Hyun
    • Journal of information and communication convergence engineering
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    • v.5 no.1
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    • pp.54-58
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    • 2007
  • A real-time frame-layer rate control algorithm with a token bucket traffic shaper is proposed for distortion variation minimization. The proposed rate control method uses a non-iterative optimization method for low computational complexity, and performs bit allocation at the frame level to minimize the average distortion over an entire sequence as well as variations in distortion between frames. The proposed algorithm does not produce time delay from encoding, and is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better visual and PSNR performances than the existing rate control method.