欢迎来到麦多课文档分享! | 帮助中心 海量文档,免费浏览,给你所需,享你所想!
麦多课文档分享
全部分类
  • 标准规范>
  • 教学课件>
  • 考试资料>
  • 办公文档>
  • 学术论文>
  • 行业资料>
  • 易语言源码>
  • ImageVerifierCode 换一换
    首页 麦多课文档分享 > 资源分类 > PDF文档下载
    分享到微信 分享到微博 分享到QQ空间

    ITU-T G 114-2003 One-way transmission time (Study Group 12)《单向传播时间 G系列 传输系统和媒介 数字系统和网络 国际电话连接和电路 整个国际电话连接传输质量的一般建议》.pdf

    • 资源ID:795963       资源大小:286.74KB        全文页数:20页
    • 资源格式: PDF        下载积分:10000积分
    快捷下载 游客一键下载
    账号登录下载
    微信登录下载
    二维码
    微信扫一扫登录
    下载资源需要10000积分(如需开发票,请勿充值!)
    邮箱/手机:
    温馨提示:
    如需开发票,请勿充值!快捷下载时,用户名和密码都是您填写的邮箱或者手机号,方便查询和重复下载(系统自动生成)。
    如需开发票,请勿充值!如填写123,账号就是123,密码也是123。
    支付方式: 支付宝扫码支付    微信扫码支付   
    验证码:   换一换

    加入VIP,交流精品资源
     
    账号:
    密码:
    验证码:   换一换
      忘记密码?
        
    友情提示
    2、PDF文件下载后,可能会被浏览器默认打开,此种情况可以点击浏览器菜单,保存网页到桌面,就可以正常下载了。
    3、本站不支持迅雷下载,请使用电脑自带的IE浏览器,或者360浏览器、谷歌浏览器下载即可。
    4、本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰。
    5、试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。

    ITU-T G 114-2003 One-way transmission time (Study Group 12)《单向传播时间 G系列 传输系统和媒介 数字系统和网络 国际电话连接和电路 整个国际电话连接传输质量的一般建议》.pdf

    1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T G.114TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2003) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS International telephone connections and circuits General Recommendations on the transmission quality for an entire intern

    2、ational telephone connection One-way transmission time ITU-T Recommendation G.114 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 General definitions G.100G.109 General Recommendations on the tran

    3、smission quality for an entire international telephone connection G.110G.119 General characteristics of national systems forming part of international connections G.120G.129 General characteristics of the 4-wire chain formed by the international circuits and national extension circuits G.130G.139 Ge

    4、neral characteristics of the 4-wire chain of international circuits; international transit G.140G.149 General characteristics of international telephone circuits and national extension circuits G.150G.159 Apparatus associated with long-distance telephone circuits G.160G.169 Transmission plan aspects

    5、 of special circuits and connections using the international telephone connection network G.170G.179 Protection and restoration of transmission systems G.180G.189 Software tools for transmission systems G.190G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299

    6、 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHON

    7、Y G.450G.499 TESTING EQUIPMENTS G.500G.599 TRANSMISSION MEDIA CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSIO

    8、N MEDIA CHARACTERISTICS G.6000G.6999 DIGITAL TERMINAL EQUIPMENTS G.7000G.7999 DIGITAL NETWORKS G.8000G.8999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.114 (05/2003) i ITU-T Recommendation G.114 One-way transmission time Summary This Recommendation provides g

    9、uidance on the effect of end-to-end one-way delay (sometimes termed latency), and an upper bound one-way network delay. While it is recommended that a one-way delay of 400 ms should not be exceeded for general network planning, it is important to appreciate that highly interactive tasks (e.g., many

    10、voice calls, interactive data applications, video conferencing) can be affected by much lower delays. The effects of delays below 500 ms on conversational speech are estimated using a curve derived from the E-model (ITU-T Rec. G.107). This version constitutes a major revision of this Recommendation

    11、in order to align with other ITU-T Recommendations of the G.100 series. Source ITU-T Recommendation G.114 was approved by ITU-T Study Group 12 (2001-2004) under the ITU-T Recommendation A.8 procedure on 6 May 2003. It includes the modifications introduced by ITU-T Rec. G.114 (2003) Appendix II appro

    12、ved on 30 September 2003. ii ITU-T Rec. G.114 (05/2003) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for

    13、 studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study

    14、 groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis w

    15、ith ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory pro

    16、visions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of s

    17、uch words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no posit

    18、ion concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protec

    19、ted by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2003 All rights reserved. No part of this publication may be reprodu

    20、ced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. G.114 (05/2003) iii CONTENTS Page 1 Introduction 1 2 References. 1 3 Applicability to speech transmission quality Use of the E-model. 2 4 Recommendations for one-way transmission time. 2 5 Estimating end-to-end del

    21、ay based on assemblies of transmission elements. 3 Annex A End-to-end delay estimation 4 A.1 Planning values for the delay of transmission elements. 4 A.2 Codec delay 5 A.3 Delay due to IP delay variation buffer . 7 Appendix I Delay introduced by coder-related processing. 8 Appendix II Guidance on o

    22、ne-way delay for voice over IP . 12 II.1 Introduction 12 II.2 Achieving satisfactory delay 12 ITU-T Rec. G.114 (01/2003) 1 ITU-T Recommendation G.114 One-way transmission time 1 Introduction This Recommendation provides guidance on the effect of end-to-end one-way delay (sometimes termed latency), a

    23、nd an upper bound on one-way network delay. The effect of delay on speech transmission quality can be estimated by the use of a curve derived from the Transmission Rating Model of ITU-T Rec. G.107 3, which is the recommended ITU-T method for end-to-end speech transmission planning. ITU-T Rec. G.108

    24、4 gives detailed examples on how to use the model to assess the transmission performance of connections involving various impairments, including one-way delay; and ITU-T Rec. G.109 5 maps transmission rating predictions of the model into categories of speech transmission quality. Thus, while ITU-T R

    25、ec. G.114 provides useful information regarding one-way delay as a parameter by itself, ITU-T Rec. G.107 3 (and its ITU-T Rec. G.108 4 and ITU-T Rec. G.109 5 companions) should be used to assess the effects of delay in conjunction with other impairments (e.g., distortions due to speech processing).

    26、Highly interactive tasks (e.g., some speech, video conferencing and interactive data applications) may be affected by delays below 100 ms, as per test result documented in Annex B of previous versions of ITU-T Rec. G.114. For this reason, previous versions of this Recommendation noted that if delays

    27、 were kept below 150 ms, then most applications would not be significantly affected. Additionally, an upper limit of 400 ms for network planning purposes was always a part of ITU-T Rec. G.114. However, this parallel treatment of network delays on one hand, with application (“mouth-to-ear“) level del

    28、ays on the other hand, led to confusion in how ITU-T Rec. G.114 should be applied. Fortunately, with the development and approval of the E-model (ITU-T Rec. G.107 3), which is based on subjective tests of delay (among other parameters), there now exists an agreed way of estimating the effects of del

    29、ay on mouth-to-ear speech transmission quality. Accordingly, simple and straightforward guidance can now be provided for the effects of delay on speech transmission and is given in the present Recommendation. The lack of similar tools for non-speech applications is a subject for further study, so th

    30、is Recommendation can only provide general planning guidance. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. A

    31、ll Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is r

    32、egularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 1 ITU-T Recommendation G.100 (2001), Definitions used in Recommendations on general characteristics of international telephone connections and circu

    33、its. 2 ITU-T Recommendation G.101 (1996), The transmission plan. 3 ITU-T Recommendation G.107 (2003), The E-Model, a computational model for use in transmission planning. 4 ITU-T Recommendation G.108 (1999), Application of the E-model: A planning guide. 2 ITU-T Rec. G.114 (05/2003) 5 ITU-T Recommend

    34、ation G.109 (1999), Definition of categories of speech transmission quality. 6 ITU-T Recommendation G.131 (1996), Control of talker echo. 7 ITU-T Recommendation G.168 (2002), Digital network echo cancellers. 8 ITU-T Recommendation G.763 (1998), Digital circuit multiplication equipment using G.726 AD

    35、PCM and digital speech interpolation. 9 ITU-T Recommendation G.764 (1990), Voice packetization Packetized voice protocols. 10 ITU-T Recommendation G.766 (1996), Facsimile demodulation/remodulation for digital circuit multiplication equipment. 11 ITU-T Recommendation G.767 (1998), Digital circuit mul

    36、tiplication equipment using 16 kbit/s LD-CELP, digital speech interpolation and facsimile demodulation/remodulation. 12 ITU-T Recommendation Q.551 (2002), Transmission characteristics of digital exchanges. 13 ITU-T Recommendation Y.1541 (2002), Network performance objectives for IP-based services. 3

    37、 Applicability to speech transmission quality Use of the E-model This Recommendation provides end-to-end limits for mean one-way delay, independent of other transmission impairments. The need to consider the combined effects of all impairments on speech transmission quality is addressed by the Trans

    38、mission Rating Model of ITU-T Rec. G.107 3, which is the recommended ITU-T method for end-to-end speech transmission planning. ITU-T Rec. G.108 4 gives detailed examples on how to use the model to assess the transmission performance of connections involving various impairments, including delay; and

    39、ITU-T Rec. G.109 5 maps transmission rating predictions of the model into categories of speech transmission quality. Thus, while this Recommendation provides useful information regarding mean one-way delay as a parameter by itself, ITU-T Rec. G.107 3 (and its ITU-T Rec. G.108 4 and ITU-T Rec. G.109

    40、5 companions) should be used to assess the effects of delay in conjunction with other impairments (e.g., distortions due to speech processing). 4 Recommendations for one-way transmission time Regardless of the type of application, it is recommended to not exceed a one-way delay of 400 ms for general

    41、 network planning (i.e., UNI to UNI, as illustrated, for example, in ITU-T Rec. Y.1541 13), a value that allows flexibility in deploying global networks, without making an excessive number of user experiences unacceptable. However, it is desirable to keep the delays seen by user applications as low

    42、as possible. The E-model should be used to estimate the effect of one-way delay (including all delay sources, i.e., “mouth-to-ear“) on speech transmission quality for conversational speech as shown below. For non-speech applications such as interactive data or video, there are no agreed-upon assessm

    43、ent tools like the E-model, so the effects of delay on such applications must be carefully monitored. Although a few applications may be slightly affected by end-to-end (i.e., “mouth-to-ear“ in the case of speech) delays of less than 150 ms, if delays can be kept below this figure, most applications

    44、, both speech and non-speech, will experience essentially transparent interactivity. While delays above 400 ms are unacceptable for general network planning purposes, it is recognized that in some exceptional cases this limit will be exceeded. An example of such an exception is an unavoidable double

    45、 satellite hop for a hard-to-reach location, the impact of which can be estimated by use of the advantage factor in the E-model. ITU-T Rec. G.114 (01/2003) 3 Regarding the use of the E-model for speech applications, the effect of delay can be seen in the following graph of Transmission Rating, R, ve

    46、rsus delay. Also shown are the speech quality categories of ITU-T Rec. G.109 5, which translate the R values to levels of user acceptance. G.114_F010 100 200 300 400 5005060708090100Nearly allusersdissatisfiedMany usersdissatisfiedSome usersdissatisfiedUserssatisfiedUsersvery satisfiedMouth-to-ear-d

    47、elay/msE-modelratingRFigure 1/G.114 Determination of the effects of absolute delay by the E-model NOTE 1 The curve in Figure 1 is based on the effect of pure delay only, i.e., in the complete absence of any echo. This is calculated by setting the G.107 E-model parameter Ta equal to the total value o

    48、f one-way delay from mouth-to-ear, with all other E-model input parameter values set to their default values. The effect of echo, as would be incurred due to imperfect echo control, will result in lower speech quality for a given value of one-way delay. NOTE 2 The calculation also assumes an Equipme

    49、nt Impairment Factor (Ie) of zero. Non-zero values, as would be incurred due to speech coding/processing, will result in lower speech quality for a given value of one-way delay. NOTE 3 For one-way delay values exceeding 500 ms, the graph is continued as a dashed line to indicate that these results are not fully validated, but is the best estimate of what should be expected, and, therefore, provides useful guidance. 5 Estimating end-to-end delay based on assemblies of transmission elements


    注意事项

    本文(ITU-T G 114-2003 One-way transmission time (Study Group 12)《单向传播时间 G系列 传输系统和媒介 数字系统和网络 国际电话连接和电路 整个国际电话连接传输质量的一般建议》.pdf)为本站会员(feelhesitate105)主动上传,麦多课文档分享仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知麦多课文档分享(点击联系客服),我们立即给予删除!




    关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

    copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
    备案/许可证编号:苏ICP备17064731号-1 

    收起
    展开