1、 ETSI TR 1Digital cellular telecoAdaptive MultStu(3GPP TR 46.0TECHNICAL REPORT 146 076 V13.0.0 (2016communications system (Phaulti-Rate (AMR) speech codecStudy phase report .076 version 13.0.0 Release 13GLOBAL SYSTEMOBILE COMMUN16-01) hase 2+); ec; 13) TEM FOR ICATIONSRETSI ETSI TR 146 076 V13.0.0 (
2、2016-01)13GPP TR 46.076 version 13.0.0 Release 13Reference RTR/TSGS-0446076vd00 Keywords GSM ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfect
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9、 (2016-01)23GPP TR 46.076 version 13.0.0 Release 13Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can
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12、his Technical Report (TR) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corresponding ET
13、SI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under http:/webapp.etsi.org/key/queryform.asp. Modal verbs terminology In the present document “shall“, “shall not“, “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to
14、be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TR 146 076 V13.0.0 (2016-01)33GPP TR 46.076 version 13.0.0 Release 13Content
15、s Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 5g3Executive summary and recommendations 6g3Introduction . 6g3Benefits 6g3Performance 6g3Risk areas 7g3Codec development and selection . 7g3Recommendations . 8g30 Scope 9g31 Goals of AMR codec 9g32 Terminology . 9g
16、33 Overview of the AMR system and its applications 9g33.1 Basic operation . 9g33.2 Application scenarios . 10g34 Development Time-scales 10g35 Baseline description and working assumptions 11g35.1 Generic operation . 11g35.2 Constraints 11g35.3 Speech and channel codecs 12g35.4 Rate adaptation . 13g3
17、5.4.1 Channel mode adaptation 13g35.4.2 Codec mode adaptation . 13g35.5 Support of TFO 13g35.6 Support of DTX 14g35.7 Support of 8 and 16 kbit/s A-ter sub-multiplexing . 14g35.8 Active noise suppression 14g36 Feasibility issues 14g36.1 Codec performance. 14g36.1.1 Basic, error and background noise p
18、erformance . 15g36.1.2 Tandeming 16g36.1.3 Seamless codec mode bit-rate changes . 16g36.1.4 Complexity . 16g36.2 Quality and Capacity benefits of AMR 17g36.2.1 General AMR performance. 17g36.2.2 Improved coverage from the improved robustness in FR mode . 17g36.2.3 Capacity benefits from the improved
19、 robustness in FR mode 18g36.2.4 Quality/capacity trade-offs by use of the HR mode 18g36.2.5 System aspects of capacity/quality . 20g36.2.6 MS penetration 21g36.3 Codec adaptation 21g36.3.1 Codec mode 21g36.3.2 Channel mode . 22g36.3.3 Channel metrics (accuracy, update rate) . 22g36.3.4 Channel dyna
20、mics, effects on performance 22g36.3.5 Location of codec mode and channel mode control 23g36.3.6 Radio resource allocation 23g36.4 Support of other features 24g3ETSI ETSI TR 146 076 V13.0.0 (2016-01)43GPP TR 46.076 version 13.0.0 Release 136.4.1 TFO . 24g36.4.2 DTX 24g36.4.3 Power control 24g36.4.4
21、Handover 25g36.4.5 8 and 16 kbit/s A-ter sub-multiplexing . 25g36.5 Wideband service option 25g37 Requirements specification 26g38 Implementation factors . 26g39 Codec development and selection 26g39.1 Test and selection methodologies . 26g39.2 Asymmetry of up and down links 27g39.3 Speech traffic c
22、hannel simulation model 27g39.4 Schedule . 28g39.5 Programme management 29g310 Open issues and risks . 29g311 Recommendations 30g3Annex A: Terminology 31g3Annex B: Application scenarios 34g3Annex C: Codec requirement specification . 35g3C.1 Static conditions . 35g3C.2 Dynamic conditions 37g3Annex D:
23、 AMR implementation requirements . 38g3D.1 Network 38g3D.2 MS 40g3Annex E: Speech traffic channel simulator . 42g3Annex F: Schedule for AMR development 44g3Annex G: Work Item Description for AMR 46g3Annex H: Change history 48g3History 49g3ETSI ETSI TR 146 076 V13.0.0 (2016-01)53GPP TR 46.076 version
24、 13.0.0 Release 13Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The present technical report contains the GSM Adaptive Multi-Rate (AMR) speech codec Study Phase Report. The contents of the present document are subject to continuing work with
25、in the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG f
26、or information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes hav
27、e been incorporated in the document. ETSI ETSI TR 146 076 V13.0.0 (2016-01)63GPP TR 46.076 version 13.0.0 Release 13Executive summary and recommendations Introduction As tasked by SMG in October 1996, SMG11 and SMG2 have conducted a study into the feasibility of the AMR codec concept. The study not
28、only addressed technical feasibility but also the benefits of AMR in realistic applications, the development plan, time-scales and the resources needed to take the AMR codec and associated network support to completion of the standards. Benefits Unlike previous GSM speech codecs which operate at a f
29、ixed rate with a fixed level of error protection, the AMR system adapts to local radio channel and traffic conditions and selects the optimum channel (half- or full- rate) and codec mode (speech and channel bit rates) to deliver the best combination of speech quality and capacity. This flexibility p
30、rovides a number of important benefits: - improved speech quality in both half-rate and full-rate modes by means of codec mode adaptation i.e. varying the balance between speech and channel coding for the same gross bit-rate; - ability to trade speech quality and capacity smoothly and flexibly by a
31、combination of channel and codec mode adaptation; this can be controlled by the network operator on a cell by cell basis; - improved robustness to channel errors under marginal radio signal conditions in full-rate mode. This increased robustness to errors and hence to interference may instead be use
32、d to increase capacity by operating a tighter frequency re-use pattern; - ability to tailor AMR operation to meet the many different needs of operators; - potential for improved handover and power control resulting from additional signaling transmitted rapidly in-band. To investigate the feasibility
33、 of realizing these benefits, a wide-ranging study has been carried out. This has considered not only speech and channel codec performance, but perhaps more critically, channel and codec mode adaptation, the associated signaling and the operation of AMR in realistic radio environments. The one-year
34、timeframe allowed for the Study Phase has prevented a thorough assessment of all aspects. However, it has been possible to assess expected performance (quality and capacity) and to identify and assess the risks of the critical areas from a feasibility perspective. Performance The performance benefit
35、s have been estimated for some of the main applications of AMR, assuming certain system assumptions such as frequency hopping and making a number of simplifications: - in full-rate mode only, the robustness to high error levels is substantially increased such that the quality level of EFR at a C/I o
36、f 10dB is extended down to a C/I of 4 dB, measured at the input to the channel equalizer. This will give coverage in-fill advantages in areas of marginal radio coverage. This equates to an improvement of sensitivity of between 4 dB and 6 dB depending on the robustness of the signaling channels; - qu
37、ality and capacity can be traded against each other in a controlled manner. Using as a reference an EFR/HR combination with a conventional resource allocation, for the same capacity improvement, AMR will give an average quality improvement corresponding to about 70 % of the difference between FR and
38、 EFR. This improvement is relatively insensitive to C/I. It has also been estimated that for a capacity improvement of about 30 % (relative to FR only), 80 % of calls would have G.728 quality of better, i.e. “wireline“ quality. This tradeoff between % capacity improvement and % of mobiles having wir
39、eline quality is sensitive to the local C/I distributions. These have proved to be difficult to estimate reliably. Other individual estimates have shown more optimistic results and the figures quoted probably represent the lower end of the range. ETSI ETSI TR 146 076 V13.0.0 (2016-01)73GPP TR 46.076
40、 version 13.0.0 Release 13- In half-rate mode only which gives the maximum capacity advantage (in excess of 100 % as for normal half-rate), quality improvements are also given (deriving from codec mode adaptation) especially in background noise conditions and at low errors. Under these conditions, t
41、he quality level will be at least as good as that of FR. - The increased resilience channel errors in full-rate mode may allow a tighter frequency re-use giving capacity improvements estimated at up to 30 %, but at the expense of lower speech quality. However, it is unclear at present how terminals
42、without AMR e.g. with FR or EFR codecs or data terminals should be handled, as they do not have the improved resilience to errors and the speech quality would be degraded. This application requires further study. Risk areas The main performance limitations and technical risk areas have been identifi
43、ed as follows: - codec performance: to achieve the wireline quality benchmark of G.728 in HR mode, the C/I threshold had to be increased from 10 dB to about 18 dB. This will allow the speech quality target still to be achieved but at the expense of lower capacity gain. This is already reflected in t
44、he performance results above. - background noise: the original performance objective in HR mode was G.728 is better than EFR. This is too demanding and was relaxed to “the better of GSM-FR or G.729“ quality for each type of background noise (vehicle, street, office). This still represents a substant
45、ial improvement over the existing HR codec. - the difficulties of measuring C/I distributions representative of high capacity networks using other capacity enhancing techniques (e.g. power control, frequency hopping) has made it difficult to make accurate estimates of capacity and quality. Pessimist
46、ic forecasts have therefore been made to illustrate the lower limit. Risk: medium. - channel and codec mode adaptation algorithms. These are crucial to the success of AMR operation and improvements to initial implementations will be possible to optimize performance for real network operating conditi
47、ons. Risk: medium. - channel quality metric. It is important that the estimate of the channel quality is sufficiently accurate to ensure that the optimum codec mode is selected. While some solutions have been considered, the feasibility of providing such an accurate metric remains a risk. Risk asses
48、sment by SMG2, high; by SMG11, medium. - TFO. Although some potential candidate TFO solutions for AMR have been identified, effective solutions will require significant development. Risk to TFO: medium. - AMR system complexity. The AMR system is relatively complex and introduces new techniques. Risk
49、 level: medium. At the conclusion of the Study Phase, there remain open design issues. However, working assumptions have been reached for most critical areas and other open issues can be resolved in due course without prejudice. Codec development and selection It is recommended that the optimum AMR solution be selected from a number of candidate proposals. To promote integrated solutions with the greatest flexibility for innovative techniques, designers should submit complete solutions including not only the speech and channel codecs, but also the control and signaling syst
