D. Bogaerts

DC Remote and AC Local Power Feeding of xDSL Networks A real-world deployment experience

Access networks require more and more active equipment to be deployed close to the subscriber, i.e. in locations where no power was available so far. The paper discusses two possible powering solutions, namely DC remote power feeding and local power feeding, weighing their respective advantages from both the technical and economical points of view. The discussion is based on a real-world deployment experience by Belgacom, the Belgian incumbent wireline operator

Flexible Power Management For Evolving Networks

New services and new competitive environments are changing the demands on all telecom equipment, including the traditionally steady power plants. In particular, the need of monitoring and control over these unglamorous but vital elements is evolving towards no-nonsense, low cost sophistication. This paper summarises these needs and details a practical implementation.

A New Very Compact Front End Power System For Indoor-outdoor Applications

New services and new competitive environments are changing the demands on all telecom equipment, including ?he traditionnaly stea& power plants. The very agressive market of mobile communication calls for major new requirements. The cost of sites has led to drastic reduction in size for the equipment. Base stations installed in concrete buildings are progressively replaced by outdoor shelters. Increased penetration of the services lead to an exceptional growth of base stations with reduced power per site but increased total power consumption. Increased reliability and eficiency are key parameters to control operation costs as well as systems. Manufacturers certified quality and conformity to standards are issues for operators as they cannot overload their engineering group wirh component certijication. This paper lists the resulting new demands on power systems and describes a practical implementation. r 1. APPLICATION AND REQUIREMENT§ Most of the emerging or recently emerged new telecommunication services (cellular telephony, broadband networks ...) can only be supported by denser network architectures; this means an increase in decentralisation, i.e. more and more sites or nodes geographically spread over the area they cover. On the other hand, the generalised liberalisation has logically resulted in a multiplication of operators, increasing dramatically the competitiveness of the market. both in terms of costs and of speed of network deployment. These trends make it less and less economically viable to install these sites and their equipment in buildings, because both the associated costs of purchase and maintenance and as the time needed from planning stage to operational use become prohibitive. For these motives, new equipment are nowadays often installed in shelters and outdoor cabinets, which allow much faster installation at lower cost. e integration : as all of the site sub-assemblies have to be physically integrated in the same cabinets, it is no longer possible to install them totally independently; more specifically, power plants have to fit in the form factors of the rest of the equipment, both in terms of mechanical shapes and sizes, and in terms of thermal design. e thermal design : outdoor cabinets are naturally submitted to more severe environmental stresses than indoor equipment. Above a totai power dissipation of a few hundred watts, heat exchangers and cooling systems become necessary, with forced circulation of (( refreshed n air through all sub-assemblies. Maximum operational temperatures of up to 65 or 7OoC are not uncommon, a far cry from the 45°C ususally encountered in indoor installations. 0 power density : as all equipment are put in a common, expensive and size limited housing, there is a strong demand for smaller and smaller shapes. Power density, less critical for indoor designs, is thus now becoming an important economical factor for outdoor applications. This puts new demands on all parts of the sites equipment:

Powering the mobile base stations

The paper describes the impact of the mobile communication market on power equipment/systems such as power level, size, modularity; operating temperature and equipment functions. Trends on major technical characteristics are discussed and illustrated by some product examples. The paper also discusses front end systems and DC/DC converters.

Intelligent energy system for telecommunications

The telecommunications world is undergoing severe technological and structural changes. These changes not only affect the operators and telecommunication equipment manufacturers, but also have serious repercussions on the energy systems providers. More particularly, the monitoring and control problematic is becoming a key issue, that can no longer be neglected nor treated on an ad hoc basis. This paper lists some of the fundamental factors driving these evolutions, checks briefly the existing equipments and standards against the evolving needs, analyses the monitoring and control structure at local level, and suggests an open, object oriented approach based on field bus standards.