CONTENTS

 1     Introduction
 2     Scope
 3     Structure of the Recommendation
 4     Related documents
 5     Abbreviations and acronyms (see Note 1)
 6     Definitions
        6.1     QoS
        6.2     Speech quality
        6.3     Connection performance
        6.4     Service retainability performance
        6.5     Reliability performance
        6.6     Guidelines of design
        6.7     Guidelines of management
 7     Considerations
 8     Recommendations
        8.1     Overview of different levels of QoS
                  8.1.1     The end-to-end service and IMT-2000 bearer service
                  8.1.2     The radio access bearer service and the CN bearer service
                  8.1.3     The radio bearer service and the RANI bearer service
                  8.1.4     The backbone network service
        8.2     IMT-2000 QoS classes
                  8.2.1     Conversational class
                  8.2.2     Interactive class
                  8.2.3     Streaming class
                  8.2.4     Background class
        8.3     Range of QoS requirements
                  8.3.1     Supported end user QoS
        8.4     Principal speech quality requirements
                  8.4.1     Subjective quality
                  8.4.2     Natural speech quality and speaker recognition
                  8.4.3     Ease of conversation
                  8.4.4     Loss of interactivity due to delay in the speech path
                  8.4.5     Freedom from echo
                  8.4.6     Uniformity in different environments
                  8.4.7     Effects of transcoding
                  8.4.8     Quality of end-to-end connections
                  8.4.9     Terminal acoustics
                  8.4.10     Call progress tones, announcements and music
                  8.4.11     Handover
                  8.4.12     Robustness
                  8.4.13     Background acoustic noise
                  8.4.14     Interconnection of IMT-2000 users in different networks
                  8.4.15     Speech performance testing
Annex 1  Planning tool to assess end-to-end voice transmission quality