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Content for TR 43.058 Word version: 18.0.0

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4 Characteristics, test methods and quality assessment p. 7

4.1 Environmental conditions for a car type handsfree Mobile Station p. 7

4.1.1 Data available on real use environment p. 7

4.1.1.1 Reverberation and echo p. 7

4.1.1.2 Sources and types of noise. Level and Spectra of the noise p. 8

4.1.1.2.1 Noise due to engine, tyres and moving situations p. 8

4.1.1.2.2 Noise due to equipment inside the cars p. 13

4.1.1.2.3 Signal to noise ratio in the car situation p. 14

4.1.1.3 Noise and echo p. 15

4.1.2 Environment for testing handsfree mobile station p. 17

4.1.2.1 Classification of handsfree mobile terminals p. 17

4.1.2.2 Vehicle simulator p. 17

4.1.2.2.1 Cost estimation for a vehicle simulator for handsfree testing p. 17

4.1.2.3 Advisory text for installation of handsfree MS in a vehicle environment p. 18

4.1.2.4 Test environment p. 18

4.1.2.4.1 Anechoic room p. 18

4.1.2.4.2 " Real use " situation (Handsfree in a real car or in a car simulator) p. 18

4.1.3 Measurements on a GSM handsfree telephone - Influence of the environment and the test conditions on frequency responses and loudness ratings p. 19

4.2 Delay in handsfree terminals implemented with signal processing techniques p. 22

4.2.1 Signal processing techniques for acoustic echo cancelling and noise reduction p. 22

4.2.2 Examples of delays due to signal processing techniques p. 22

4.2.2.1 Data produced by Matra Communication p. 22

4.2.2.2 Data produced by Ericsson p. 23

4.3 Speech quality assessment p. 24

4.3.1 General - Factors affecting the speech quality of the GSM system and derivatives p. 24

4.3.2 Main Assessment Criteria for Handsfree processing used in GSM mobile environment p. 27

4.3.3 Evaluation Methodology for Full-Duplex Acoustic Echo Controllers developed within the FREETEL-Esprit project p. 28

4.3.3.1 Objective Evaluation procedure p. 28

4.3.3.1.1 Objective Evaluation methodology of AEC devices p. 29

4.3.3.1.2 Test Signals used from the FREETEL-Esprit Database p. 32

4.3.3.2 Adapted objective evaluation procedure to a GSM Handsfree mobile p. 32

4.3.3.2.1 Motivation of an adapted evaluation procedure p. 32

4.3.3.2.2 Objective evaluation procedure for prototyping the GSM Handsfree AEC algorithms p. 33

4.3.3.2.3 Proposed Objective-Subjective Evaluation procedure p. 35

4.3.3.2.4 Derived Evaluation schemes for Handsfree mobile telephones p. 35

4.3.4 Subjective tests p. 38

4.3.4.1 Subjective opinion tests p. 38

4.3.4.1.1 Listening opinion tests p. 38

4.3.4.1.2 Conversation Opinion Tests p. 38

4.3.4.1.3 Proposed test method p. 38

4.3.4.2 Subjective tests extracted from "Ultimate test set" p. 39

A Subjective Tests from UTS p. 41

B Bibliography p. 45

B.1 References of TD presented in SMG2/ad hoc 03.50 meetings p. 45

B.2 References from subclause 4.1 p. 45

B.3 References from subclause 4.2.1 p. 46

B.4 References from subclause 4.3.1 p. 46

B.5 References from subclause 4.3.3 p. 46

$ Change history p. 47