A synchronization technique to provide quality of service in broadband ISDN
Thesis DisciplineElectrical Engineering
Degree GrantorUniversity of Canterbury
Degree NameMaster of Engineering
This thesis analyzes the different Quality of Service (QoS) parameters that are important in setting up multimedia calls in Broadband ISDN (B-ISDN). Unlike in traditional telecommunication networks, service providers of Broadband ISDN provide guaranteed Quality of Service. This requires a comprehensive QoS management framework. The users of B-ISDN are able to adapt the Quality of Service of multimedia to their requirements. The main adaptable QoS parameters include video parameters, audio parameters and synchronization parameters. Intra-media synchronization and inter-media synchronization are important aspects of overall QoS provision. The audio and video streams of a particular source can be transmitted in different paths as these streams may have varying QoS requirements. Thus the audio and video streams will incur different transfer delays. The encoder and decoder processing delays of audio and video are also different. When presenting audio and video, the video stream should not be allowed to lag or lead the audio stream beyond acceptable skew tolerances. In specialized applications, multiple audio and video streams have to be played out in synchrony at the receiver. Also the layers of a layered coding system may be transmitted in different paths and the layers should be perfectly synchronized at the receiver. Management of special resources such as layered encoders and decoders, media combiners code converters etc., ensures that intra-media and inter-media synchronization is maintained in isochronous communications. The different special resources and their relevance to QoS parameters such as intra-media and inter-media synchronization is discussed in detail. In this thesis, a comprehensive synchronization mechanism called Static Delay Compensation (SDC) is proposed to guarantee synchronization QoS. When synchronizing two or more media streams static delays are added to streams with lower end-to-end delays. It will be shown that SDC will satisfy almost all of the synchronization QoS requirements.