1、 ETSI EN 300 395-2 V1.3.1 (2005-01)European Standard (Telecommunications series) Terrestrial Trunked Radio (TETRA);Speech codec for full-rate traffic channel;Part 2: TETRA codecfloppy3 ETSI ETSI EN 300 395-2 V1.3.1 (2005-01) 2 Reference REN/TETRA-05059 Keywords TETRA, radio, codec ETSI 650 Route des
2、 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-Prfecture de Grasse (06) N 7803/88 Important notice Individual copies of the present document can be downloaded from:
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6、t and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2005. All rights reserved. DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Members. TIPHONTMand the TIPHON logo are Trade Marks currently bein
7、g registered by ETSI for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. ETSI ETSI EN 300 395-2 V1.3.1 (2005-01) 3 Contents Intellectual Property Rights7 Foreword.7 1 Scope 9 2 References 9 3 Abbreviations
8、.9 4 Full rate codec 10 4.1 Structure of the codec.10 4.2 Functional description of the codec12 4.2.1 Pre- and post-processing.12 4.2.2 Encoder.13 4.2.2.1 Short-term prediction 14 4.2.2.2 LP to LSP and LSP to LP conversion .14 4.2.2.3 Quantization and interpolation of LP parameters16 4.2.2.4 Long-te
9、rm prediction analysis.17 4.2.2.5 Algebraic codebook: structure and search.19 4.2.2.6 Quantization of the gains 21 4.2.2.7 Detailed bit allocation .23 4.2.3 Decoder.23 4.2.3.1 Decoding process 24 4.2.3.1.1 Decoding of LP filter parameters 24 4.2.3.1.2 Decoding of the adaptive codebook vector24 4.2.3
10、.1.3 Decoding of the innovation vector 25 4.2.3.1.4 Decoding of the adaptive and innovative codebook gains.25 4.2.3.1.5 Computation of the reconstructed speech25 4.2.3.2 Error concealment .25 5 Channel coding for speech .26 5.1 General .26 5.2 Interfaces in the error control structure 26 5.3 Notatio
11、ns 28 5.4 Definition of sensitivity classes and error control codes 28 5.4.1 Sensitivity classes .28 5.4.2 CRC codes 28 5.4.3 16-state RCPC codes 30 5.4.3.1 Encoding by the 16-state mother code of rate 1/3.30 5.4.3.2 Puncturing of the mother code 30 5.5 Error control scheme for normal speech traffic
12、 channel.31 5.5.1 CRC code31 5.5.2 RCPC codes31 5.5.2.1 Puncturing scheme of the RCPC code of rate 8/12 (equal to 2/3).31 5.5.2.2 Puncturing scheme of the RCPC code of rate 8/18 .31 5.5.3 Matrix Interleaving .32 5.6 Error control scheme for speech traffic channel with frame stealing activated33 5.6.
13、1 CRC code33 5.6.2 RCPC codes34 5.6.2.1 Puncturing scheme of the RCPC code of rate 8/17 .35 5.6.3 Interleaving.35 6 Channel decoding for speech .35 6.1 General .35 6.2 Error control structure 35 7 Codec performance.36 8 Bit exact description of the TETRA codec.36 ETSI ETSI EN 300 395-2 V1.3.1 (2005-
14、01) 4 9 AMR speech codec.38 10 Channel coding for AMR speech .38 10.1 General .38 10.2 Interfaces in the error control structure 38 10.3 Notations 38 10.4 Definition of sensitivity classes and error control codes 38 10.4.1 Sensitivity classes .38 10.4.2 CRC codes 39 10.4.3 16-state RCPC codes 40 10.
15、4.3.1 Encoding by the 16-state mother code of rate 1/3.40 10.4.3.2 Puncturing of the mother code 41 10.5 Error control scheme for normal AMR speech traffic channel.41 10.5.1 CRC code41 10.5.2 RCPC codes41 10.5.2.1 Puncturing scheme of the RCPC code of rate 8/12 (equal to 2/3).42 10.5.2.2 Puncturing
16、scheme of the RCPC code of rate 8/18 .42 10.5.3 Matrix Interleaving .42 10.6 Error control scheme for AMR speech traffic channel with frame stealing activated43 10.6.1 Speech frames in stealing mode43 10.6.2 CRC code44 10.6.3 RCPC codes45 10.6.3.1 Puncturing scheme of the RCPC code of rate 14/8 .45
17、10.6.4 Interleaving.45 11 Channel decoding for AMR speech .45 11.1 General .45 11.2 Error control structure 45 12 Bit exact description of the AMR codec FEC46 Annex A (informative): Implementation of speech channel decoding.47 A.1 Algorithmic description of speech channel decoding 47 A.1.1 Definitio
18、n of error control codes 47 A.1.1.1 16-state RCPC codes 47 A.1.1.1.1 Obtaining the mother code from punctured code47 A.1.1.1.2 Viterbi decoding of the 16-state mother code of the rate 1/3 47 A.1.1.2 CRC codes 48 A.1.1.3 Type-4 bits48 A.1.2 Error control scheme for normal speech traffic channel.48 A.
19、1.2.1 Matrix Interleaving .48 A.1.2.2 RCPC codes48 A.1.2.2.1 Puncturing scheme of the RCPC code of rate 8/12 (equal to 2/3).49 A.1.2.2.2 Puncturing scheme of the RCPC code of rate 8/18 .49 A.1.2.3 CRC code49 A.1.2.4 Speech parameters 49 A.1.3 Error control scheme for speech traffic channel with fram
20、e stealing activated49 A.1.3.1 Interleaving.49 A.1.3.2 RCPC codes49 A.1.3.2.1 Puncturing scheme of the RCPC code of rate 8/17 .50 A.1.3.3 CRC code50 A.1.3.4 Speech parameters 50 A.2 C Code for speech channel decoding .50 Annex B (informative): Indexes 51 B.1 Index of C code routines 51 B.2 Index of
21、files.54 Annex C (informative): Codec performance55 C.1 General .55 ETSI ETSI EN 300 395-2 V1.3.1 (2005-01) 5 C.2 Quality55 C.2.1 Subjective speech quality .55 C.2.1.1 Description of characterization tests.55 C.2.1.2 Absolute speech quality55 C.2.1.3 Effect of input level 55 C.2.1.4 Effect of input
22、frequency characteristic 55 C.2.1.5 Effect of transmission errors.56 C.2.1.6 Effect of tandeming 56 C.2.1.7 Effect of acoustic background noise .56 C.2.1.8 Effect of vocal effort.56 C.2.1.9 Effect of frame stealing.56 C.2.1.10 Speaker and language dependency .56 C.2.2 Comparison with analogue FM 56
23、C.2.2.1 Analogue and digital systems results56 C.2.2.2 All conditions57 C.2.2.3 Input level .57 C.2.2.4 Error patterns 58 C.2.2.5 Background noise .58 C.2.3 Additional tests.58 C.2.3.1 Types of signals 58 C.2.3.2 Codec behaviour .58 C.3 Performance of the channel coding/decoding for speech.59 C.3.1
24、Classes of simulation environment conditions .59 C.3.2 Classes of equipment59 C.3.3 Classes of bits.60 C.3.4 Channel conditions.60 C.3.5 Results for normal case 60 C.4 Complexity.61 C.4.1 Complexity analysis .61 C.4.1.1 Measurement methodology.61 C.4.1.2 TETRA basic operators 61 C.4.1.3 Worst case p
25、ath for speech encoder63 C.4.1.4 Worst case path for speech decoder64 C.4.1.5 Condensed complexity values for encoder and decoder .65 C.4.2 DSP independence66 C.4.2.1 Program control structure .66 C.4.2.2 Basic operator implementation .66 C.4.2.3 Additional operator implementation .66 C.5 Delay 66 A
26、nnex D (informative): Results of the TETRA codec characterization listening and complexity tests 67 D.1 Characterization listening test 67 D.1.1 Experimental conditions.67 D.1.2 Tables of results .68 D.2 TETRA codec complexity study 76 D.2.1 Computational analysis results .76 D.2.1.1 TETRA speech en
27、coder76 D.2.1.2 TETRA speech decoder84 D.2.1.3 TETRA channel encoder and decoder 87 D.2.2 Memory requirements analysis results .89 D.2.2.1 TETRA speech encoder89 D.2.2.2 TETRA speech decoder90 D.2.2.3 TETRA speech channel encoder.90 D.2.2.4 TETRA speech channel decoder.90 Annex E (informative): Desc
28、ription of attached computer files 91 E.1 Directory C-WORD .91 ETSI ETSI EN 300 395-2 V1.3.1 (2005-01) 6 E.2 Directory C-CODE.91 E.3 Directory AMR-Code.91 Annex F (informative): Bibliography.92 History 93 ETSI ETSI EN 300 395-2 V1.3.1 (2005-01) 7 Intellectual Property Rights IPRs essential or potent
29、ially 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 be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential,
30、IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No gua
31、rantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (Telecommunications series) has been produced by ETSI Project Terres
32、trial Trunked Radio (TETRA). The present document is part 2 of a multi-part deliverable covering speech codec for full-rate traffic channel, as identified below: Part 1: “General description of speech functions“; Part 2: “TETRA codec“; Part 3: “Specific operating features“; Part 4: “Codec conformanc
33、e testing“. Clause 4 provides a complete description of the full rate speech source encoder and decoder, whilst clause 5 describes the speech channel encoder and clause 6 the speech channel decoder. Clause 7 describes the codec performance. Clause 8 introduces the bit exact description of the codec.
34、 This description is given as an ANSI C code, fixed point, bit exact. The whole C code corresponding to the TETRA codec is given in computer files attached to the present document, and are an integral part of this multi-part deliverable. Clause 9 describes the optional AMR codec. Clause 10 describes
35、 the AMR speech channel encoder. Clause 11 describes the AMR speech channel decoder. Clause 12 introduces the AMR speech channel encoder and decoder. This description is given as an ANSI C code. In addition to these clauses, five informative annexes are provided. Annex A describes a possible impleme
36、ntation of the speech channel decoding function. Annex B provides comprehensive indexes of all the routines and files included in the C code associated with the present document. Annex C describes the actual quality, performance and complexity aspects of the codec. Annex D reports detailed results f
37、rom codec characterization listening and complexity tests. Annex E contains instructions for the use of the attached electronic files. Annex F lists informative references relevant to the speech codec. ETSI ETSI EN 300 395-2 V1.3.1 (2005-01) 8 National transposition dates Date of adoption of this EN
38、: 21 January 2005 Date of latest announcement of this EN (doa): 30 April 2005 Date of latest publication of new National Standard or endorsement of this EN (dop/e): 31 October 2005 Date of withdrawal of any conflicting National Standard (dow): 31 October 2005 ETSI ETSI EN 300 395-2 V1.3.1 (2005-01)
39、9 1 Scope The present document contains the full specification of the speech codecs for use in the Terrestrial Trunked Radio (TETRA) system. The TETRA codec specified in clauses 4 to 8 is mandatory for all TETRA mobiles and networks. The AMR codec specified in clauses 9 to 12 is optional. If the AMR
40、 codec is implemented, the equipment shall conform to the whole of clause 9 to 12. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication and/or ed
41、ition number or version number) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. Referenced documents which are not found to be publicly available in the expected location might be found at http:/docbox.etsi.org/R
42、eference. 1 ETSI EN 300 392-2: “Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air Interface (AI)“. 2 ETSI TS 126 073: “Universal Mobile Telecommunications System (UMTS); ANSI-C code for the Adaptive Multi Rate speech codec (3GPP TS 26.073 Release 4)“. 3 ETSI TS 126 074: “Universa
43、l Mobile Telecommunications System (UMTS); Mandatory speech codec speech processing functions; AMR speech codec test sequences (3GPP TS 26.074 Release 4)“. 4 ETSI TS 126 090: “Universal Mobile Telecommunications System (UMTS); Mandatory Speech Codec speech processing functions AMR Speech Codec - Tra
44、nscoding functions (3GPP TS 26.090 Release 4)“. 3 Abbreviations For the purposes of the present document, the following abbreviations apply: ACELP Algebraic CELP AMR Adaptive Multi-Rate ANSI American National Standards Institute BER Bit Error Ratio BFI Bad Frame Indicator BS Base Station CELP Code-E
45、xcited Linear Predictive CRC Cyclic Redundancy Code DSP Digital Signal Processor DTMF Dual Tone Multiple Frequency EP Error Pattern EQ EQualizer testFIR Finite Impulse Response GSM Global System for Mobile communications HT Hilly TerrainIRS Intermediate Reference System ETSI ETSI EN 300 395-2 V1.3.1
46、 (2005-01) 10LP Linear Prediction LPC Linear Predictive Coding LSF Line Spectral Frequency LSP Line Spectral Pair MER Message Error Rate MNRU Multiplicative Noise Reference Unit MOPS Million of Operations per Second MOS Mean Opinion Score MS Mobile Station MSE Mean Square Error PDF Probability Densi
47、ty Function PUEM Probability of Undetected Erroneous Message RAM Random Access Memory RCPC Rate-Compatible Punctured Convolutional RF Radio Frequency ROM Read-Only Memory SCR Source Controlled Rate STCH STealing CHannel TDM Time Division Multiplex TU Typical Urban VQ Vector Quantization V+D Voice +
48、Data 4 Full rate codec 4.1 Structure of the codec The TETRA speech codec is based on the Code-Excited Linear Predictive (CELP) coding model. In this model, a block of N speech samples is synthesized by filtering an appropriate innovation sequence from a codebook, scaled by a gain factor gc, through
49、two time varying filters. A simplified high level block diagram of this synthesis process, as implemented in the TETRA codec, is shown in figure 1. SHORT-TERM SYNTHESIS FILTER ALGEBRAIC Output Speech CODEBOOK ADAPTIVE CODEBOOK GAIN PREDICTION AND VQ Gains LPC Info T k Pitch delay Algebraic codebook index Excitation Past g p g c D E M U L T I P L E X Digital Input LONG-TERM SYNTHESIS FILTER Figure 1: High level block diagram of the TETRA speech synthesizer The first filter is a long-term prediction filter (pitch filter) aiming at modelling the pseudo-periodicity in
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