Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
This degree project, Life cycle assessment of radio relay systems, was conducted at Telia AB, Telia Network Services AB, Farsta, and the section of Industrial Ecology of the Department of Chemical Engineering and Technology, Royal Institute of Technology, Stockholm. Life cycle assessment (LCA) is a tool with which it is possible to calculate the environmental load from a product, material or service during all the phases in its life cycle. The results presented in this study are based on such an LCA. Radio relay is an alternative to optical fibre cables, but little information was available within Telia on the environmental impact from the use of radio relay systems as a transmission media. The goal of the project is to provide Telia with useful information regarding the systems involved and where and how the environment is affected by the use of the systems. Two types of radio links are looked at in this project: one high capacity, long hop radio link, and one low capacity radio link. The high capacity link is the Nera NL290, a Norwegian radio link system with an n+1 STM1 capacity. This system is of an older, bulky design. The second radio link in the study is the Ericsson Mini-link E. This radio link is one of the most common radio links on the market. Six scenarios, or cases, are the basis for the study: two Nera NL290 cases, two Mini-link E cases, and two optical fibre cable cases. For all systems, there is one worst case scenario, and one best case scenario. The best case scenarios are distinguished by having a higher capacity overall, and covers longer distances. The best case scenarios have the following properties - Product (distance between stations [km] (capacity [Mbps])):
•Optical fibre cable (50 (2.5 Gbps))
•Nera NL290 radio link (50 km (310)
•Ericsson Mini-link E radio link (30 ( 34 )) The worst case scenarios have the following properties:
•Optical fibre cable (30 (155)
•Nera NL290 radio link (30 (155 ))
•Ericsson Mini-link E radio link (15 ( 42 )) Included in the study are production of materials constituting the systems, transports to and from building sites, manufacture of radio links, infrastructure, network elements, and station equipment. The results of the study are:
•No clear difference can be seen between the use of radio links or buried optical fibre cables as a transmission media in regards to the environmental impact.
•The environmental impact is mainly dependent on the capacity, and secondarily on the distance.
•Optical fibre cables have one phase that is clearly more polluting than the res, and that is the actual work of burying the cable in the ground.
•The Nera NL290 is a radio link system with a relatively high content of circuit boards in the construction.
•For the Ericsson Mini-link E, there is no obvious phase that is more polluting than the rest, but the overall environmental load is high.
•The operation, or use, of the different systems gives an almost negligible contribution to the total environmental load. Suggestions for improvement:
•When planning new routes for optical fibre cables, the direction should be chosen so that as much as possible of the cable can be buried with ploughing.
•For optical fibre cables, strive to build the cable together with other construction efforts.
•Secure the cable installation for the long term.
•For radio links, use existing infrastructure to as high degree as possible.
•Build flexible systems that can handle additional capacity with upgrades.
•When building new infrastructure for radio relay or mobile phone sites, endeavour to build the mast/tower on solid rock base.
•The use of LED-type obstruction lights can
1999. , 148 p.