1、 ETSI TS 126 231 V15.0.0 (2018-07) Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Cellular text telephone modem; Minimum performance requirements (3GPP TS 26.231 version 15.0.0 Release 15) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBI
2、LE COMMUNICATIONSRETSI ETSI TS 126 231 V15.0.0 (2018-07)13GPP TS 26.231 version 15.0.0 Release 15Reference RTS/TSGS-0426231vf00 Keywords GSM,UMTS 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 A
3、ssociation but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document can be downloaded from: http:/www.etsi.org/standards-search The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
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9、 registered and owned by the GSM Association. ETSI ETSI TS 126 231 V15.0.0 (2018-07)23GPP TS 26.231 version 15.0.0 Release 15Intellectual Property Rights Essential patents IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information pertaining to
10、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, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Lat
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13、y of ETSI, and conveys no right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical Specification (TS) has b
14、een 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 ETSI deliverables. The cross refe
15、rence 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 be interpreted as described in
16、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 TS 126 231 V15.0.0 (2018-07)33GPP TS 26.231 version 15.0.0 Release 15Contents Intellectual Property Rights
17、2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 Normative references . 5g33 Definitions and abbreviations . 5g34 Test vectors 6g35 Test Scripts . 6g36 Scoring program . 6g37 Description of the test. 7g37.1 Test of the negotiation between two CTM Adaptation Modules 7g37.2 Test
18、of the CTM receivers performance for transmission via the PCS 1900 AMR speech channel 9g37.3 Test of the text telephone demodulators robustness against false detections . 11g37.4 Typing Mode 13g37.5 Test of the resynchonization . 13g3Annex A (informative): Change history . 15g3History 16g3ETSI ETSI
19、TS 126 231 V15.0.0 (2018-07)43GPP TS 26.231 version 15.0.0 Release 15Foreword This technical description has been produced by the 3rdGeneration Partnership Project, Technical Specification Group Services and System Aspects, Working Group 4 (Codec). The present document is a description of the Cellul
20、ar Text Telephone Modem solution for reliable transmission of a text telephone conversation via the speech channel of cellular or PSTN networks. The contents of the present document is subject to continuing work within 3GPP and may change following formal 3GPP approval. Should the 3GPP TSG modify th
21、e contents of this TS, it will be re-released by the 3GPP 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 3GPP for information; 2 presented to 3GPP for approval; 3 Indicates 3GPP approved document und
22、er 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 have been incorporated in the specification; ETSI ETSI TS 126 231 V15.0.0 (2018-07)53GPP TS 26.231 v
23、ersion 15.0.0 Release 151 Scope This Technical Standard (TS) describes the minimum performance requirements for the Cellular Text Telephone Modem (CTM) for reliable transmission of text telephone text via the speech channel of cellular or PSTN networks. The transmitting parts of the Cellular Text Te
24、lephone Modem are specified in 1. CTM is a general technology, independent of text telephone types. The tests are made only for one specific type of text telephone, the Baudot type. The tests are applicable only to a combination of a Baudot codec and CTM and tests the combined performance. A bit-exa
25、ct implementation of the CTM transmitter as well as an example implementation of the remaining functions of such a combination are provided in 2. The test scripts and test vectors required to perform this testing are included in a supplement, which is located in the zip archive ctm_testing.zip. The
26、path and file names given in this specification refer to the file structures associated with this supplement. A second supplement (zip archive ctm_score.zip) provides the scoring program that is described in clause 6. 2 Normative references The following documents contain provisions which, through r
27、eference in this text, constitute provisions of the present document. - References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. - For a specific reference, subsequent revisions do not apply. - For a non-specific reference, the latest
28、version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. 1 3GPP TS 26.226: “Cellular Text Telephone Modem (CTM), General Description“. 2 3G
29、PP TS 26.230: “Cellular Text Telephone Modem (CTM), Transmitter Bit Exact C-Code“. 3 TIA/EIA-IS 840: “Minimum Performance Standards for Text Telephone Signal Detector and Text Telephone Signal Regenerator“. 4 GSM 05.02: “Digital cellular telecommunications system (Phase 2+); Multiplexing and multipl
30、e access on the radio path“. 5 GSM 05.05: “Digital cellular telecommunications system (Phase 2+); Radio transmission and reception“. 3 Definitions and abbreviations For the purposes of this TS, the following abbreviations apply: AMR Adaptive Multi Rate Codec CTM Cellular Text Telephone Modem FR Full
31、 Rate Codec HCO Hearing Carry Over, (individual may be able to hear, but cannot speak); Alternating of sending speech and text. MS Mobile StationPCM Pulse Code Modulation PCS Personal Communication System TCER Total Character Error Rate TTY Text Telephone VCO Voice Carry Over, Alternating use of spe
32、ech and text ETSI ETSI TS 126 231 V15.0.0 (2018-07)63GPP TS 26.231 version 15.0.0 Release 154 Test vectors The following test signals are provided for use in testing compliance to the minimum performance requirements. All signals are raw data, linear 16-bit signed PCM coded audio data at a sampling
33、rate of 8000 Hz. All files are coded in Big-Endian format (most significant byte first) as it is used e.g. by SUN Microsystems SparcTMWorkstations. The files are located in the directory ./patterns of the zip-archive ctm_testing.zip. baudot.pcm sine1400.pcm sine1800.pcm test1.pcm test2.pcm test3.pcm
34、 zeros4000.pcm ctm_master_clean.pcm ctm_master.txt ctm_typingmode.pcm ctm_test_resync.pcm The first six files contain test signals with Baudot tones and are required for the test scripts test_negotiation and test_false_detections. Furthermore, a file zeros4000.pcm is provided that contains a zero-va
35、lued signal. The files ctm_master.txt and ctm_master_clean.pcm contain a text message with random characters and the corresponding CTM signal. These files are required for the tests in subclause 7.2. The files ctm_typingmode.pcm and ctm_test_resync.pcm are required for the tests in subclauses 7.4 an
36、d 7.5, respectively. 5 Test Scripts For the tests in subclauses 7.1, 7.3 and 7.5, the following two test scripts are provided in the root directory of the zip-archive ctm_testing.zip: test_negotiation test_false_detections test_resynchonization All test scripts assume that the tested CTM modules hav
37、e interfaces as defined in 2 (e.g., the procedure calls, syntax, parameters). All test scripts have been tested using a C-shell (csh) command interpreter on a SUN Microsystems SolarisTMplatform. 6 Scoring program A tool “ctm_score“ for the calculation of the character error rate is provided in the a
38、ttachment ctm_score.zip. This zip archive includes the source code of the scoring program as well as a short documentation (provided in the file Readme.txt). For the scoring process, each printable character as well as every line feed is counted as one character (even in case that line feeds are cod
39、ed by a pair of two characters, like in ASCII code). A description how to use this tool in the context of this Technical Standard is provided in subclause 7.2. ETSI ETSI TS 126 231 V15.0.0 (2018-07)73GPP TS 26.231 version 15.0.0 Release 157 Description of the test 7.1 Test of the negotiation between
40、 two CTM Adaptation Modules The test script test_negotiation performs a test of the negotiation between two CTM devices using the following structure. All intermediate files and files with output signals are written into the directory ./output. baudot.pcmCTMadaptationmodule #1/dev/nullctm_forwardctm
41、_backwardbaudot_out.pcm/dev/zeroCTMadaptationmodule #2A CTM implementation and a Baudot 45.45 baud codec shall be combined to form a CTM adaptation module under test. The source code for an example implementation of this CTM adaptation module is provided in 2. The code provided in 2 allows to genera
42、te the executable program adaptation_switch. First, the adaptation module #1 is executed. At this first run, the signal ctm_backward is not known. Therefore, the negotiation does not get a positive acknowledge, so that the transmission falls back to Baudot Tones. Then signal adaptation module #2 is
43、executed for the first time. After that, adaptation module #1 is executed for the second time. With this second run, the signal ctm_backward is valid. Therefore, the negotiation receives a valid acknowledge, so that CTM signals are transmitted. At last, adaptation module #2 is executed for the secon
44、d time. With this run, adaptation module #2 receives a valid CTM signal so that the baudot_out.pcm signal can be generated. After executing each of the modules twice, the signal baudot_out.pcm is analyzed. This analysis is also performed by the program adaptation_switch. First, the Baudot detector o
45、f adaptation_switch is used for this analysis in order to examine whether the regenerated Baudot signal can be decoded correctly. The following step is optional for handsets: “In a second step it is examined whether the regenerated signal still contains any CTM preambles. This investigation is perfo
46、rmed by means of the CTM detector that is integrated in adaptation_switch. This last test fails if the CTM detector is able to detect any CTM preamble in the regenerated signal“. During the execution of the script test_negotiation the following text output shall be generated: = Execute adaptation mo
47、dule #1 (first pass) = * Cellular Text Telephone Modem (CTM) - Example Implementation for Conversion between CTM and Baudot Code (use option -h for help) * number of samples to process: 100000 Enquiry Burst generated! Enquiry Burst generated! Enquiry Burst generated! CTM from far-end detected! Enqui
48、ry From Far End Detected! Enquiry From Far End Detected! Enquiry From Far End Detected! Enquiry Burst generated! CTM from far-end detected! CTM from far-end detected! Enquiry From Far End Detected! For decoding the received CTM signal, adaptation_switch should be called using the following syntax (a
49、 UNIX environment is assumed): adaptation_switch ctmin -textout -baudotout /dev/null baudotin zeros4000.pcm ctmout /dev/null denotes a file with raw PCM data (16 bit signed integer), which represents the signal that has been transmitted via the speech channel. denotes the output text file with the decoded mes
