TIA-1095-2006 Discontinuous Transmission (DTX) of Speech in cdma2000 Systems《CDMA2000系统中对话的间断传输》.pdf

1、 TIA STANDARD Discontinuous Transmission (DTX) of Speech in cdma2000 Systems TIA-1095 April 2006 TELECOMMUNICATIONS INDUSTRY ASSOCIATION Representing the telecommunications industry in association with the Electronic Industries Alliance NOTICE TIA Engineering Standards and Publications are designed

2、to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for their particular need. The existence

3、of such Standards and Publications shall not in any respect preclude any member or non-member of TIA from manufacturing or selling products not conforming to such Standards and Publications. Neither shall the existence of such Standards and Publications preclude their voluntary use by Non-TIA member

4、s, either domestically or internationally. Standards and Publications are adopted by TIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, TIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties ado

5、pting the Standard or Publication. This Standard does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicab

6、ility of regulatory limitations before its use. (From Project No.3-0233, formulated under the cognizance of the TIA, TR-45.5 Subcommittee on Spread Spectrum Digital Technology ). Published by TELECOMMUNICATIONS INDUSTRY ASSOCIATION Standards and Technology Department 2500 Wilson Boulevard Arlington,

7、 VA 22201 U.S.A. PRICE: Please refer to current Catalog of TIA TELECOMMUNICATIONS INDUSTRY ASSOCIATION STANDARDS AND ENGINEERING PUBLICATIONS or call Global Engineering Documents, USA and Canada (1-800-854-7179) International (303-397-7956) or search online at http:/www.tiaonline.org/standards/catal

8、og/ All rights reserved Printed in U.S.A. NOTICE OF COPYRIGHT This document is copyrighted by the TIA. Reproduction of these documents either in hard copy or soft copy (including posting on the web) is prohibited without copyright permission. For copyright permission to reproduce portions of this do

9、cument, please contact TIA Standards Department or go to the TIA website (www.tiaonline.org) for details on how to request permission. Details are located at: http:/www.tiaonline.org/standards/catalog/info.cfm#copyright OR Telecommunications Industry Association Standards (b) there is no assurance t

10、hat the Document will be approved by any Committee of TIA or any other body in its present or any other form; (c) the Document may be amended, modified or changed in the standards development or any editing process. The use or practice of contents of this Document may involve the use of intellectual

11、 property rights (“IPR”), including pending or issued patents, or copyrights, owned by one or more parties. TIA makes no search or investigation for IPR. When IPR consisting of patents and published pending patent applications are claimed and called to TIAs attention, a statement from the holder the

12、reof is requested, all in accordance with the Manual. TIA takes no position with reference to, and disclaims any obligation to investigate or inquire into, the scope or validity of any claims of IPR. TIA will neither be a party to discussions of any licensing terms or conditions, which are instead l

13、eft to the parties involved, nor will TIA opine or judge whether proposed licensing terms or conditions are reasonable or non-discriminatory. TIA does not warrant or represent that procedures or practices suggested or provided in the Manual have been complied with as respects the Document or its con

14、tents. If the Document contains one or more Normative References to a document published by another organization (“other SSO”) engaged in the formulation, development or publication of standards (whether designated as a standard, specification, recommendation or otherwise), whether such reference co

15、nsists of mandatory, alternate or optional elements (as defined in the TIA Engineering Manual, 4thedition) then (i) TIA disclaims any duty or obligation to search or investigate the records of any other SSO for IPR or letters of assurance relating to any such Normative Reference; (ii) TIAs policy of

16、 encouragement of voluntary disclosure (see Engineering Manual Section 6.5.1) of Essential Patent(s) and published pending patent applications shall apply; and (iii) Information as to claims of IPR in the records or publications of the other SSO shall not constitute identification to TIA of a claim

17、of Essential Patent(s) or published pending patent applications. TIA does not enforce or monitor compliance with the contents of the Document. TIA does not certify, inspect, test or otherwise investigate products, designs or services or any claims of compliance with the contents of the Document. ALL

18、 WARRANTIES, EXPRESS OR IMPLIED, ARE DISCLAIMED, INCLUDING WITHOUT LIMITATION, ANY AND ALL WARRANTIES CONCERNING THE ACCURACY OF THE CONTENTS, ITS FITNESS OR APPROPRIATENESS FOR A PARTICULAR PURPOSE OR USE, ITS MERCHANTABILITY AND ITS NONINFRINGEMENT OF ANY THIRD PARTYS INTELLECTUAL PROPERTY RIGHTS.

19、 TIA EXPRESSLY DISCLAIMS ANY AND ALL RESPONSIBILITIES FOR THE ACCURACY OF THE CONTENTS AND MAKES NO REPRESENTATIONS OR WARRANTIES REGARDING THE CONTENTS COMPLIANCE WITH ANY APPLICABLE STATUTE, RULE OR REGULATION, OR THE SAFETY OR HEALTH EFFECTS OF THE CONTENTS OR ANY PRODUCT OR SERVICE REFERRED TO I

20、N THE DOCUMENT OR PRODUCED OR RENDERED TO COMPLY WITH THE CONTENTS. TIA SHALL NOT BE LIABLE FOR ANY AND ALL DAMAGES, DIRECT OR INDIRECT, ARISING FROM OR RELATING TO ANY USE OF THE CONTENTS CONTAINED HEREIN, INCLUDING WITHOUT LIMITATION ANY AND ALL INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAG

21、ES (INCLUDING DAMAGES FOR LOSS OF BUSINESS, LOSS OF PROFITS, LITIGATION, OR THE LIKE), WHETHER BASED UPON BREACH OF CONTRACT, BREACH OF WARRANTY, TORT (INCLUDING NEGLIGENCE), PRODUCT LIABILITY OR OTHERWISE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. THE FOREGOING NEGATION OF DAMAGES IS A FU

22、NDAMENTAL ELEMENT OF THE USE OF THE CONTENTS HEREOF, AND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIMITATIONS. TIA-1095 1 INTRODUCTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 In circuit-switched calls over CDMA, acoustic

23、background noise is encoded in eighth rate packets and transmitted periodically, for example every 20 msec. Although it is necessary for circuit-switched calls to transmit a packet periodically, the same is not true for packet-switched calls. It is possible to achieve capacity savings and extend bat

24、tery life for VoIP calls by using a discontinuous transmission scheme (DTX). This specification provides requirements for source controlled variable rate vocoders to implement DTX. It is recognized that there exists a great deal of flexibility in the way DTX can be implemented. The purpose of this s

25、pecification is not to specify a particular solution, but to provide a set of requirements to ensure interoperability between different implementations. This specification uses the following verbal forms: “Shall” and “shall not” identify requirements to be followed strictly to conform to the standar

26、d and from which no deviation is permitted. “Should” and “should not” indicate that one of several possibilities is recommended as particularly suitable, without mentioning or excluding others; that a certain course of action is preferred but not necessarily required; or that (in the negative form)

27、a certain possibility or course of action is discouraged but not prohibited. “May” and “need not” indicate a course of action permissible within the limits of the standard. “Can” and “cannot” are used for statements of possibility and capability, whether material, physical, or causal. 2 DEFINITIONS

28、Comfort Noise (CN): Output of the decoder to represent acoustic background noise. Discontinuous Transmission (DTX): Gaps inserted in the media stream during periods of non-active speech. DTX Stream: A bit stream resulting from DTX processing, i.e., a bit stream in which silence has been suppressed.

29、DTX Update Interval: The number of frames from one SID frame to the next. For example, an update interval of 10 frames means that a SID frame is sent once every 10 frames. This interval may be variable between updates. DTX min: The minimum acceptable DTX interval. DTX max: The maximum acceptable DTX

30、 interval. Silence Insertion Description (SID): Packets used to convey acoustic background information during DTX periods. Eighth-Rate Hangover: A number of eighth-rate frames transmitted at the end of active speech but before DTX. DSP: Digital Signal Processor PDSN: Packet Data Serving Node RTP: Re

31、al Time Protocol 3 APPLICABILITY This section describes the applicability of this specification. Page 2 TIA-1095 3.1 Non-DTX-Capable Legacy Vocoders 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Modifying an existing vocoder that is not DTX capable to comply with this specification is

32、optional. 3.2 DTX-Capable Legacy Vocoders This specification does not supercede native DTX schemes defined in legacy vocoders, like VMR-WB 2. 3.3 Future Vocoders Future vocoders have the option of adopting this specification for DTX operation. 3.4 Other DTX/CN Schemes This specification does not pro

33、hibit the use of other DTX schemes, such as 1. In addition, other DTX schemes may be negotiated simultaneously with this DTX scheme if more than one vocoder is sharing the same session. The mechanism by which the endpoints negotiate this DTX scheme and its parameters is beyond the scope of this spec

34、ification. 3.5 Intermediaries DTX streams defined by this specification can be converted to continuous streams, and vice versa, with a minimum of computational complexity. For example, a continuous stream can be converted to a DTX stream by discarding eighth-rate frames between SID frames. Likewise,

35、 at a minimum, a DTX stream can be converted to a continuous stream by replicating eighth-rate SID frames. Since the conversion can be achieved without requiring the processing horsepower of a DSP, the conversion can be performed in “wrapper” code outside the DSP, in de-jitter buffers, or in network

36、 elements that handle the RTP packets but have limited processing power, such as the PDSN. This specification permits the use of a network element to act as an intermediary between two endpoints to convert DTX streams into continuous streams, and vice versa. 3.6 Network This DTX specification applie

37、s to the cdma20001access network as well as the core network. 1cdma2000is the trademark for the technical nomenclature for certain specifications and standards of the Organizational Partners (OPs) of 3GPP2. When applied to goods and services, the cdma2000mark certifies their compliance with cdma2000

38、standards. Geographically (and as of the date of publication), cdma2000 is a registered trademark of the Telecommunications Industry Association (TIA-USA) in the United States. Page 3 TIA-1095 4 ENCODER REQUIREMENTS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

39、32 33 34 35 4.1 SID Frame Format The vocoders existing eighth rate packet format shall be used as the SID frame format. SID frames shall not consist of full, half, or quarter rate packets, nor shall a separate packet format be defined for the purpose of providing SID updates. 4.2 Eighth-Rate Hangove

40、r The encoder shall implement eighth-rate hangover. The length of the hangover is negotiated in signaling, which is beyond the scope of this document. 4.3 DTX Parameters Signaling may be used to negotiate the use of DTX, following an offer/answer model. An endpoint capable of DTX shall communicate t

41、he following parameters: Willingness to use DTX (i.e. on/off) Default value: on for RFC 35583, off for all other RTP formats. Minimum DTX Update Interval Default value: 12 frames. Maximum DTX Update Interval Default value: 32 frames. The DTX max shall be greater than or equal to the DTX min. Eighth-

42、Rate Hangover Default value: 1 frame. 4.3.1 The values for DTX max, DTX min, and eighth-rate hangover shall be represented as unsigned 8-bit integers, i.e. limited to the range 0-255. 4.3.2 For vocoders using the RTP format defined in RFC 3558 3, the default for willingness to use DTX support define

43、d in this specification shall be “on”, and the default values for DTX min, DTX max, and eighth-rate hangover shall be used, unless negotiated otherwise. That is to say, for those vocoders that use the RTP format in RFC 3558 3, DTX support defined in this specification is always assumed enabled unles

44、s the negotiation specifically disables it. For all other vocoders, if all four of the DTX parameters defined above are absent from either the offer or the answer, it is assumed that DTX support defined in this specification is not available in the endpoint(s). 4.3.3 If the offer as well as the answ

45、er contains DTX parameters, the value of DTX min in the answer shall be greater than or equal to the value of DTX Min in the offer, and the value of DTX max in the answer shall be less than or equal to the value of DTX max in the offer. Furthermore, the eighth-rate hangover in the answer shall be gr

46、eater than or equal to the eighth-rate hangover in the offer. 4.3.4 If both offer and answer contain DTX parameters, then both sides shall use the values for DTX parameters that are proposed in the answer. 4.3.5 If none or only one of offer or answer contains DTX parameters: The default values for t

47、he DTX parameters shall initially be used by both sides. Page 4 TIA-1095 For vocoders using the RTP format defined in RFC 3558 3, if at any time during the flow, a vocoder detects the remote vocoder as DTX-incapable, it should stop sending SID frames. That is to say that the vocoder shall still cont

48、inue to send non-eighth rate frames as well as eighth rate hangover frames, but should not send eighth rate frames as SID frames. Silence should be suppressed from the end of the eighth rate hangover until the beginning of the next talk spurt. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

49、 23 24 25 26 27 28 29 30 31 32 33 34 It may be determined that a vocoder is DTX incapable if the number of eighth rate frames with contiguous RTP timestamps exceeds the default value of the eighth rate hangover. For vocoders using the RTP format defined in RFC 3558 3, if a vocoder is suppressing SID frames because it detected that the remote vocoder is not DTX capable and subsequently detects that the remote vocoder is DTX capable, the default values for the DTX parameters shall be used. It may be determined that a vocod