Broadband Access Networks - Technologies, Building Blocks and System Evolution

摘要

Future access networks have to provide conventional services (POTS, ISDN, CATV) as well as emerging broadband interactive services (VOD, B-ISDN ...) with very high bandwidth requirements in the local loop. To find the right technologies and implementation strategies for the subscriber loop and to realize most flexible service multiplexing techniques are the key problems to be solved by the telecommunications industry in cooperation with the network operators. All options of available or emerging systemetwork technologies have to enable the operators to offer a stepwise evolution of capacity, service features and quality of services mainly via an upgrading of the existing network or - in some cases -, by the building up a new network infrastructure. The bandwidth requirements of all multimedia services like distributed services, digital TV, video-conferencing, on-line services, file transfer will depend on overall content volume and service specific allowable latency time (Fig. 1). Based on these fundamental requirements this paper reviews major options for residential full service access technologies like ADSL, VDSL, HFC, HFR, BWLL, FTTB/H/T and proposes evolution strategies for tel-cos and cable operators.