B-ISDN upgrading strategies for residential subscribers

Upgrading strategies for broadband-ISDN residential subscribers are investigated to consider phase-to-phase upgrading from existing narrowband ISDN to future superbroadband ISDN. A typical example is chosen to show the efficacy of a five-step process for strategy optimization. In the first step, an upgrading strategy, called alternate capacity upgrading, as well as associated upgrading families and their members are defined. After environmental definitions in step 2 and optimization of the installation topology in step 3, optimization of the upgrading strategy is demonstrated in step 4. In step 5, the upgradability of alternate-capacity upgrading is checked for application in a residential environment. It is shown that straightforward application of alternate capacity upgrading is not necessarily efficient with resident subscribers from the standpoint of upgradability as well as providing new services such as HDTV. It is suggested that a combined use of digital alternate capacity upgrading and analog distributive-capacity upgrading should prove efficient in solving the above problem