DC Remote Power for Cost-Effective Broadband Networks
21 October 2003 14:48
Visitors to the recent ITU Telecom World, Geneva had the opportunity to see on the Cherokee Stand (N° 5050.019 in the Belgian Pavilion) the latest DC remote power concept, and have the opportunity to discuss the possibilities with Cherokee's marketing and engineering personnel.
Cherokee expects a rapid move towards local-powered VDSL networks in the coming years, and with this new DC remote power concept we are ready to help telcos implement these networks in the most cost-effective and reliable way possible.
With today’s ADSL networks longer distances to the subscriber of 7 km or more are acceptable, and interfaces between fibre trunk lines and the copper local loops are located in telco central offices. But with VDSL technology the acceptable distances to subscribers are reduced, and the fibre/copper interfaces need to be located much closer to the customer. This will bring with it the need for local power to field equipment, including the DSLAM (Digital Subscriber Line Access Multiplexer) which interfaces the fibre trunk line to the copper subscriber lines.
Cost-effective DC supply
Bringing a significantly more cost-effective solution, Cherokee has introduced a local power concept that uses the 48 VDC supply available in the central office to power the field equipment. Power is transported by existing copper pairs running in parallel to the fibre trunk line, and the designed redundancy can easily be provided by using multiple copper pairs.
The advantage of this DC remote power concept is that the required DC supply is already available at the telco central office, so the costs of numerous AC mains-powered rectifiers in the field are eliminated. The appropriate back-up measures are also provided centrally, and therefore do not need to be repeated by placing batteries in each field cabinet. The only power equipment required in the field cabinets are small remote power units to convert the DC source voltage to the required 48 V supply. This also means the field cabinets can be very compact, and can even be installed underground if necessary, thereby enabling telcos to overcome possible local objections to the installation of additional street cabinets.
To allow telcos to get the benefits of this cost-effective DC-based local power concept, Cherokee has developed ready-to-implement solutions for both central office and remote sites. Both systems offer high reliability over a wide temperature range (-25° to +70°C for the field cabinets), with cooling by natural convection to further increase reliability. Other benefits include a low-EMI design and ‘hot-swap’ field-replaceable modules.
For more information on this company:
Cherokee - Telecommunications Switch-Mode Power Supply Systems - Rectifiers, Converters and Supply Solutions
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