1、 IEC TR 63094 Edition 1.0 2017-06 TECHNICAL REPORT Multimedia systems and equipment Multimedia signal transmission Dependable line code with error correction IEC TR 63094:2017-06(en) colour inside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2017 IEC, Geneva, Switzerland All rights reserved. Un
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12、7 IEC 2017 CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope 8 2 Normative references 8 3 Terms, definitions and abbreviated terms 8 3.1 Terms and definitions 8 3.2 Abbreviated terms . 9 4 4b/10b line code 9 4.1 Overview. 9 4.2 Forward error correction (FEC) . 9 4.3 Embedded clock . 9 4.4 DC balance .
13、9 4.5 4b/10b data encoding 10 4.6 Frame format 10 4.6.1 Frame 10 4.6.2 Setup command . 10 4.6.3 Idle command 11 4.7 Encoding. 11 4.8 Decoding 11 4.9 Error handling . 11 4.9.1 1-bit error 11 4.9.2 2-bit error 12 4.9.3 Over 3-bit error 12 Annex A (informative) Real-time scheduling . 13 Annex B (inform
14、ative) Characteristics of embedded clock 14 Annex C (informative) Characteristics of DC balance . 15 Annex D (informative) Implementation of a decoder . 16 Bibliography 17 Figure 1 A humanoid robot . 6 Figure A.1 EDF scheduling 13 Table 1 The 4b/10b data transform 10 Table 2 Setup command 10 Table 3
15、 Idle command 11 Table 4 The 4b/10b look-up . 11 Table B.1 The length of successive 0 or 1 in case of 1-bit error 14 Table C.1 An example of the isomery of 0 and 1 in a successive 10-bit window 15 IEC TR 63094:2017 IEC 2017 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ MULTIMEDIA SYSTEMS AND EQUIPME
16、NT MULTIMEDIA SIGNAL TRANSMISSION DEPENDABLE LINE CODE WITH ERROR CORRECTION FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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27、epare International Standards. However, a technical committee may propose the publication of a technical report when it has collected data of a different kind from that which is normally published as an International Standard, for example “state of the art“. IEC TR 63094, which is a technical report
28、, has been prepared by IEC technical committee 100: Audio, video and multimedia systems and equipment. The text of this technical report is based on the following documents: Enquiry draft Report on voting 100/2823A/DTR 100/2871/RVDTR Full information on the voting for the approval of this technical
29、report can be found in the report on voting indicated in the above table. 4 IEC TR 63094:2017 IEC 2017 This document has been drafted in accordance with the ISO/IEC Directives, Part 2. The committee has decided that the contents of this document will remain unchanged until the stability date indicat
30、ed on the IEC website under “http:/webstore.iec.ch“ in the data related to the specific document. At this date, the document will be reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. IMPORTANT The colour inside l
31、ogo on the cover page of this publication indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer. IEC TR 63094:2017 IEC 2017 5 INTRODUCTION This document defines a line code
32、 that incorporates error correction capability to communicate reliably among multimedia components, I/O peripherals and computers. A number of complex multimedia machines, in particular robots, automobiles, and network routers, have a growing demand for distributed processing. In addition, moderniza
33、tion of facilities such as factories, offices, schools, and homes is creating a ubiquitous and multimedia computing environment. Unlike conventional PC applications for documentation and Internet applications that exchange texts without hard time constraints, these types of cooperative computing req
34、uire reliable real-time responses to physical events occurring in the real world. In order for distributed nodes to cooperate in real-time, an interconnecting network shall realize real-time and dependable communication without re-sending on noisy environments. The 4b/10b provides a dependable line
35、code for such real-time communications between multimedia components, I/O peripherals and/or computers by providing embedded clock, DC balance, error detection and error correction features. The real-time aspect means that the exactness of the system including operations and communications depends n
36、ot only on the result, but also on the time it took to achieve the result. In the narrow sense, the real-time aspect means that the time constraint, including deadlines or cycles, must be met. Real-time tasks with the time constraints are generally scheduled and executed by a real-time scheduler and
37、 a real-time operating system. Most real-time scheduling algorithms assume that the WCET (worst-case execution time) of each task is given. A real-time scheduling algorithm converts a time constraint of each real-time task to a priority. Most real-time operating systems based on such real-time sched
38、ulers pre-empt and execute tasks in order of priority at every tick to meet the time constraint. As real-time scheduling algorithms, the earliest deadline first (EDF) scheduler, the rate monotonic (RM) scheduler, and their variations have been established, as explained in Annex A. These algorithms c
39、ommonly schedule tasks based on priorities determined by the time constraints. Most real-time scheduling algorithms assume that the WCRT (worst-case response time) of each communication packet is given in case of communication. In order to apply real-time scheduling algorithms to real-time communica
40、tions, pre-emptive communication, which is achieved by Responsive Link (ISO/IEC 24740), and the error correction capability to prevent the re-sending a broken packet are required. A line code is a lowest-level communication protocol on a communication line. Most current line codes have a few typical
41、 functions including embedded clock, DC balance and basic error detection features. The 8b/10b codec is a major example, which is used for PCI Express, USB 3.0, SATA, IEEE1394b, and 10GbE. But no conventional line code has an error correction capability. When an encoded code (a 10b code) is broken d
42、uring communication, the multi-bits of the decoded code (the 8b code) are corrupted. In other words, when a single bit error occurs in an encoded 10-bit code, the decoded 8-bit code (a byte) is completely broken. When an error is detected on the decoder, the broken data is normally re-transmitted un
43、der an upper-level communication protocol. However, re-transmission is not allowed in order to realize real-time communication. It is hard for a bit-level error correction code that includes the Hamming code and the BCH code to incorporate error correction capability, because multi-bits of the decod
44、ed code are broken even if a single-bit error occurs on the encoded code. 6 IEC TR 63094:2017 IEC 2017 In order to incorporate error correction capability on the 8b/10b codec, a block-level error correction including RS (Reed-Solomon) is required as a large packet-level error correction. But the blo
45、ck-level error correction is not suitable for real-time communication, because the communication latency becomes longer as it is impossible to correct the corrupted data until all corresponding packets are received. The line code 4b/10b has the following distinctive features for real-time communicat
46、ions: a) embedded clock; b) DC balance; c) error detection; d) error correction. No conventional line code supports the above features at one time. For example, the industry- wide standard 8b/10b codec can be easily replaced with the 4b/10b line code for highly reliable communications. Figure 1 show
47、s a distributed control configuration of a humanoid robot as one of the typical applications of the 4b/10b line code. The electronic control part of the humanoid robot consists of several control nodes with local sensing and actuating devices. The distributed controllers are connected to each other
48、by Responsive Link. In this figure, rectangles represent node controllers, and dotted lines show communication links such as the Responsive Link that is a point-to-point serial link. IEC Figure 1 A humanoid robot For a humanoid robot to walk stably, a servo loop of 1 ms or shorter is needed. In this
49、 configuration, the farthest two nodes can exchange a 16-byte packet within 5 s. Since the time is guaranteed not to fluctuate, the distributed control of a humanoid is considered to be sufficiently possible. Since many actuators that generate noises are embedded inside the robot, the line code is required for noise tolerance. The 4b/10b is the line code that has error correction capability. Currently many I/O interfaces and communication standards, including PCI Express (PCIe), USB 3.0, SATA, IE
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