Telco evolution to broadband

Written on 7:33 AM by ooe

There are then a bewildering number of choices for an existing Telco to consider when upgrading the access network. One key element will be capital cost since this will have a major bearing on the commercial case for upgrade. Figure 1.11 compares the cost of potential broadband upgrade technologies as a function of penetration expressed as a percentage of homes passed. The figure assumes that these are costs to an existing PTT with a copper access network already installed. Not surprisingly therefore the DSL technologies come out lowest cost since they exploit the presence of copper pairs. FTTE represents ADSL technology in a fibre to the exchange architecture. FTTCab represents VDSL in a fibre to the cabinet architecture (Figure 1.8). HFC assumes the use of some existing BT duct but otherwise demands new infrastructure. FTTK and FTTH represent fibre to the kerb and home respectively. Figure 1.11 clearly shows that ADSL is the lowest risk way of offering higher bandwidths since it is by far the lowest cost technology, particularly at the low penetrations experienced during the early phases of the market. FTTCab would similarly be the lowest risk way of offering higher bandwidths required for a full range of new interactive services, including broadcast TV.

However, it should be recognised that it will take some time to roll-out any broadband technology in high volume, and migration steps are indicated in Table 1.4. Lowband is essentially ISDN technology and offers a digital service with 3–4 times the data capacity available to users of current voice band modems. Midband is the current step offering the first big leap in bandwidths. Highband could then be introduced at a later date when demand for even greater bandwidth emerges and when the cost of the requisite technology becomes commensurate with potential network revenues.