1、 ETSI TS 126 231 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Cellular text telephone modem; Minimum performance requirements (3GPP TS 26.231 version 14.0.0 Release 14) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBI
2、LE COMMUNICATIONSRETSI ETSI TS 126 231 V14.0.0 (2017-04)13GPP TS 26.231 version 14.0.0 Release 14Reference RTS/TSGS-0426231ve00 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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7、 and microfilm except as authorized by written permission of ETSI. The content of the PDF version shall not be modified without the written authorization of ETSI. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2017. Al
8、l rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE are Trade Marks of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered
9、 and owned by the GSM Association. ETSI ETSI TS 126 231 V14.0.0 (2017-04)23GPP TS 26.231 version 14.0.0 Release 14Intellectual 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, i
10、s 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. Latest updates are available on th
11、e ETSI Web server (https:/ipr.etsi.org/). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee 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 b
12、e, or may become, essential to the present document. Foreword This Technical Specification (TS) 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. T
13、hese should be interpreted as being references to the corresponding ETSI 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 n
14、ot“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to 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 TS 126
15、 231 V14.0.0 (2017-04)33GPP TS 26.231 version 14.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 Normative references . 5g33 Definitions and abbreviations . 5g34 Test vectors 6g35 Test Scripts . 6g36 Scoring program . 6g37 De
16、scription of the test. 7g37.1 Test of the negotiation between two CTM Adaptation Modules 7g37.2 Test 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
17、Test of the resynchonization . 13g3Annex A (informative): Change history . 15g3History 16g3ETSI ETSI TS 126 231 V14.0.0 (2017-04)43GPP TS 26.231 version 14.0.0 Release 14Foreword This technical description has been produced by the 3rdGeneration Partnership Project, Technical Specification Group Serv
18、ices and System Aspects, Working Group 4 (Codec). The present document is a description of the Cellular 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 con
19、tinuing work within 3GPP and may change following formal 3GPP approval. Should the 3GPP TSG modify the 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 presen
20、ted to 3GPP for information; 2 presented to 3GPP for approval; 3 Indicates 3GPP 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
21、 have been incorporated in the specification; ETSI ETSI TS 126 231 V14.0.0 (2017-04)53GPP TS 26.231 version 14.0.0 Release 141 Scope This Technical Standard (TS) describes the minimum performance requirements for the Cellular Text Telephone Modem (CTM) for reliable transmission of text telephone tex
22、t via the speech channel of cellular or PSTN networks. The transmitting parts of the Cellular Text Telephone 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 app
23、licable only to a combination of a Baudot codec and CTM and tests the combined performance. A bit-exact 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
24、 this testing are included in a supplement, which is located in the zip archive ctm_testing.zip. The 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 desc
25、ribed in clause 6. 2 Normative 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, edition number, version number, etc.) or non-specific. For a s
26、pecific reference, subsequent revisions do not apply. For a non-specific reference, the latest 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 prese
27、nt document. 1 3GPP TS 26.226: “Cellular Text Telephone Modem (CTM), General Description“. 2 3GPP 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“
28、. 4 GSM 05.02: “Digital cellular telecommunications system (Phase 2+); Multiplexing and multiple 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 followi
29、ng abbreviations apply: AMR Adaptive Multi Rate Codec CTM Cellular Text Telephone Modem FR Full Rate Codec HCO Hearing Carry Over, (individual may be able to hear, but cannot speak); Alternating of sending speech and text. MS Mobile Station PCM Pulse Code Modulation PCS Personal Communication System
30、 TCER Total Character Error Rate TTY Text Telephone VCO Voice Carry Over, Alternating use of speech and text ETSI ETSI TS 126 231 V14.0.0 (2017-04)63GPP TS 26.231 version 14.0.0 Release 144 Test vectors The following test signals are provided for use in testing compliance to the minimum performance
31、requirements. All signals are raw data, linear 16-bit signed PCM coded audio data at a sampling 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
32、 zip-archive ctm_testing.zip. baudot.pcm sine1400.pcm sine1800.pcm test1.pcm test2.pcm test3.pcm 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
33、and test_false_detections. Furthermore, a file zeros4000.pcm is provided that contains a zero-valued 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
34、files ctm_typingmode.pcm and ctm_test_resync.pcm are required for the tests in subclauses 7.4 and 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 tes
35、t_false_detections test_resynchonization All test scripts assume that the tested CTM modules have 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
36、 program A tool “ctm_score“ for the calculation of the character error rate is provided in the attachment 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 charac
37、ter as well as every line feed is counted as one character (even in case that line feeds are coded 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 V14.0.0 (2017-04)73GPP
38、TS 26.231 version 14.0.0 Release 147 Description of the test 7.1 Test of the negotiation between 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
39、are written into the directory ./output. baudot.pcmCTMadaptationmodule #1/dev/nullctm_forwardctm_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 implem
40、entation of this CTM adaptation module is provided in 2. The code provided in 2 allows to generate 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 acknow
41、ledge, so that the transmission falls back to Baudot Tones. Then signal adaptation module #2 is 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 acknowled
42、ge, so that CTM signals are transmitted. At last, adaptation module #2 is executed for the second 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
43、. This analysis is also performed by the program adaptation_switch. First, the Baudot detector of 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 exami
44、ned whether the regenerated signal still contains any CTM preambles. This investigation is performed 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 t
45、he script test_negotiation the following text output shall be generated: = Execute adaptation module #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 Bur
46、st generated! Enquiry Burst generated! Enquiry Burst generated! CTM from far-end detected! Enquiry 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 de
47、coding the received CTM signal, adaptation_switch should be called using the following syntax (a 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
48、signal that has been transmitted via the speech channel. denotes the output text file with the decoded message, which will be generated by adaptation_switch. The decoded text message has to be analyzed in order to determine the number of character errors that have been caused due to the transmission. The character error rate is defined as number_of_all_errors character_error_rate = - length_of_reference_text number_of_all_errors = number_of_deleted_characters + number_of_inserted_characters + number_of_replaced_characters A tool “ctm_score“ for the calculation of the chara
