• Title, Summary, Keyword: multiplexing

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Resolution of Temporal-Multiplexing and Spatial-Multiplexing Stereoscopic Televisions

  • Kim, Joohwan;Banks, Martin S.
    • Current Optics and Photonics
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    • v.1 no.1
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    • pp.34-44
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    • 2017
  • Stereoscopic (S3D) displays present different images to the two eyes. Temporal multiplexing and spatial multiplexing are two common techniques for accomplishing this. We compared the effective resolution provided by these two techniques. In a psychophysical experiment, we measured resolution at various viewing distances on a display employing temporal multiplexing, and on another display employing spatial multiplexing. In another experiment, we simulated the two multiplexing techniques on one display and again measured resolution. The results show that temporal multiplexing provides greater effective resolution than spatial multiplexing at short and medium viewing distances, and that the two techniques provide similar resolution at long viewing distance. Importantly, we observed a significant difference in resolution at the viewing distance that is generally recommended for high-definition television.

Improved Orthogonal Code Hopping Multiplexing Using Both Division and Hopping

  • Kwon, Jae-Kyun;Park, Su-Won;Sung, Dan-Keun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.3A
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    • pp.277-285
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    • 2008
  • We previously proposed an Orthogonal Code Hopping Multiplexing (OCHM) scheme for statistical multiplexing on a synchronous downlink. OCHM enables a large number of users to share a limited number of code channels through statistical multiplexing. We here improve the performance of OCHM by prioritizing encoded symbols according to their importance using both the conventional code division and the previously proposed code hopping multiplexing schemes. Prioritization is useful for channel coding schemes with different levels of importance for encoded symbols such as turbo-codes. Scheme performance is evaluated by simulation in terms of the required Eb/N0 for a 1% block error rate.

Multiplexing methods of volume holograms using fiber speckle patterns

  • Kang, Yong-Hoon;Kim, Ki-Hyun;Lee, Byoung-Ho
    • Journal of the Optical Society of Korea
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    • v.2 no.1
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    • pp.38-41
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    • 1998
  • The method of using fiber speckle patterns can be applied to the multiplexing of volume holograms. Fiber speckle patterns enable various multiplexing techniques such as shift, angular, and mode-scrambling methods Hybrid methods involving more than one multiplexing technique are also possible. Some images are stored and retrieved with one or two of multiplexing methods, and the experimental results are discussed.

An Analysis on Multiplexing Gain vs. Variable Input Bit Rate Relation for Designing the ATM Multiplexer (ATM 멀티플렉서의 설계를 위한 다중화이득과 가변입력비트율과의 관계 해석)

  • 여재흥;임인칠
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.8
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    • pp.34-40
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    • 1992
  • This paper shows a new relational formula of multiplexing gain versus variable input bit rates useful for designing Nx1 ATM(Asynchronous Transfer Mode) multiplexer which mixes several asynchronous bit streams with different transmission rates. The relation between multiplexing gain and input bit stream speeds is derived from the occupied mean lenght(the width per unit time) of cells and the occupation probability of the number of cells at an arbitrary instant when the rates of the periodic cell strams change randomly. And the relation between multiplexing gain and variable bit rates from different number of input bit streams is analyzed accordingly. Under the condition of unlimited multiplexing speed, the more number of input bit streams increases, the bigger the multiplexing gain becomes. While for the case which restricts the multiplexing speed to a limited value, the multiplexing gain becomes smaller contrarily as the number of input bit streams continues too invrease beyond a boundary value. It is shown that for designing an ATM multiplexer according to the latter case, the combination of input bit streams should be determined such as its total bit rate is lower thean, but most apprpaximate to, the multiplexed output speed. Also the general formula evaluating the most significant parameters which should be needed to design the multiplexer is derived.

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Multiplexing VoIP Packets over Wireless Mesh Networks: A Survey

  • Abualhaj, Mosleh M.;Kolhar, Manjur;Qaddoum, Kefaya;Abu-Shareha, Ahmad Adel
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.8
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    • pp.3728-3752
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    • 2016
  • Wireless mesh networks (WMNs) have been increasingly applied in private and public networks during the last decade. In a different context, voice over IP (VoIP) has emerged as a new technology for making voice calls around the world over IP networks and is replacing traditional telecommunication systems. The popularity of the two technologies motivated the deployment of VoIP over WMNs. However, VoIP over WMNs suffers from inefficient bandwidth utilization because of two reasons: i) attaching 40-byte RTP/UDP/IP header to a small VoIP payload (e.g., 10 bytes) and ii) 841 μs delay overhead of each packet in WMNs. Among several solutions, VoIP packet multiplexing is the most prominent one. This technique combines several VoIP packets in one header. In this study, we will survey all the VoIP multiplexing methods over WMNs. This study provides a clear understanding of the VoIP bandwidth utilization problem over WMNs, discusses the general approaches in which packet multiplexing methods could be performed, provides a detailed study of present multiplexing techniques, shows the aspects that hinder the VoIP multiplexing methods, discusses the factors affected by VoIP multiplexing schemes, shows the merits and demerits of different multiplexing approaches, provides guidelines for designing a new improved multiplexing technique, and provides directions for future research. This study contributes by providing guidance for designing a suitable and robust method to multiplex VoIP packets over WMNs.

Effective Multiplexing Method for Conditional Access System in Terrestrial DMB

  • Lee, Yong-Hoon;Lee, Gwang-Soon;Lee, Jin-Hwan;Ahn, Chung-Hyun;Lee, Soo-In;Kim, Nam
    • ETRI Journal
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    • v.30 no.6
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    • pp.859-861
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    • 2008
  • This letter proposes a conditional access system (CAS) suitable for use in terrestrial digital multimedia broadcasting (T-DMB), based on an effective multiplexing method to provide encrypted T-DMB services. Specifically, the proposed multiplexing method for a CAS is designed to reduce the additional bit rate while assuring easy access to the designated encrypted services. Finally, the performance of the implemented CAS is confirmed through implementation and a broadcasting experiment under various service environments.

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Experimental demonstration of holographic storage with discrete random phase-code multiplexing

  • Park, Youn-Sup;Shin, Dong-Hak;Jang, Ju-Seog
    • Journal of the Optical Society of Korea
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    • v.4 no.1
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    • pp.43-47
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    • 2000
  • We studied experimentally a discrete random phase-code multiplexing technique for holographic data storage, which we believe can overcome some disadvantages of conventional random phase-code multiplexing adopting either a diffusion plate or a multimode fiber. Experimental demonstration is presented to show the potential usefulness and some characteristics of the discrete random phase-code multiplexing technique.

Development of Multiplexing Model for Moire-Fringe-Based Fiber Optic Sensor (무아레 프린지 기법 적용 광섬유 센서를 위한 다점 측정 모델의 개발)

  • Kim, Dae-Hyun;Lee, Yeon-Gwan;Kim, Chun-Gon
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.1
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    • pp.36-45
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    • 2010
  • This paper shows a multiplexing technique to maximize the application of a moire-fringe based fiber optic sensor to lots of structure. Especially, a novel fringe-based fiber optic sensor was proposed to overcome the difficulty of multiplexing of a previous moire-fringe-based fiber optic sensor. The novel fringe-based fiber optic sensor is composed of a single reflective fringe and two optical fibers. Therefore, the multiplexing is easily realized because of the simplicity of optic structure inside the sensor. This paper also proposed four models of the multiplexing techniques. The models are based on a wavelength division multiplexing(WDM) technique and a time division multiplexing(TDM) one. Basically, the models would be profitable for a general extrinsic fiber optic sensor such as the fringe-based fiber optic sensor. Finally, the real optic system was manufactured by using the proposed model and successfully examined to prove the feasibility of the model for the application.

Bandwidth allocation on VBR source traffic in high capacity ATM link (고용량 ATM 링크에서 VBR 소스트래픽을 위한 대역할당 알고리즘)

  • 김영선;최진규;노승환
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.8
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    • pp.1899-1906
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    • 1998
  • In ATM switching system link bandwidth is one of the improtant resources. Thus ATM switching system must allocate the bandwidth to the users efficiently and guarantee the QoS. Especially to guarantee the QoS of the VBR traffic source such as video, users must declare the traffic characteristics and QoS expectations using UPC parameters. The CAC can use two multiplexig models in variation to link capacity and connection number. One is loseless multiplexing model; the second is a statistical multiplexing model. The loseless multiplexing model performs best when the number of mutiplexed sources is small, but as the number of multiplexed sources is increase the CAC must use the statistical multiplexing model. In this paper, the statistical multiplexing models are studied, which are suitable for high capacity ATM link on VBR traffic sources. The satistical multiplexing model and the loseless multiplexing model are combined. In statistical model we map the UPC parameters provided by new VBR connection to appropriate source traffic model. In the high capacity ATM link, as the connection number increases, the statical multiplexing gain increases.

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On the Diversity-Multiplexing Tradeoff of Cooperative Multicast System with Wireless Network Coding

  • Li, Jun;Chen, Wen
    • Journal of Communications and Networks
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    • v.12 no.1
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    • pp.11-18
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    • 2010
  • Diversity-multiplexing tradeoff (DMT) is an efficient tool to measure the performance of multiple-input and multiple-output (MIMO) systems and cooperative systems. Recently, cooperative multicast system with wireless network coding stretched tremendous interesting due to that it can drastically enhance the throughput of the wireless networks. It is desirable to apply DMT to the performance analysis on the multicast system with wireless network coding. In this paper, DMT is performed at the three proposed wireless network coding protocols, i.e., non-regenerative network coding (NRNC), regenerative complex field network coding (RCNC) and regenerative Galois field network coding (RGNC). The DMT analysis shows that under the same system performance, i.e., the same diversity gain, all the three network coding protocols outperform the traditional transmission scheme without network coding in terms of multiplexing gain. Our DMT analysis also exhibits the trends of the three network coding protocols' performance when multiplexing gain is changing from the lower region to the higher region. Monte-Carlo simulations verify the prediction of DMT.