Two approaches to the provision of pan-European paging services are now becoming established. One of these relies on satellite-based services to be provided by INMARSAT, BT and others at L-Band. The second, the European Radio Messaging Service (ERMES), is a terrestrial system currently under development and scheduled to operate at 169 MHz. Both of these systems may however encounter a problem in delivering adequate signal strength within multi-storey buildings. In the case of the satellite systems due to the necessarily limited transmitter power, and in the terrestrial case due to increasing use of RF opaque glass in new building construction. One solution could be to transpond paging signals down through the building from the roof. Since ERMES is a multichannel service, it is technically feasible to transpond both satellite and ERMES originated paging signals on whatever ERMES channel can be identified as free of other users. The work described here is the result of an extensive radio wave propagation measurement campaign carried out for both approaches. Propagation effects on satellite-mobile systems in the lower microwave part of the spectrum have been the subject of considerable study in the last few years. Most of the interest has been centered at frequencies near 900 MHz and 1.5 GHz, where tree attenuation is considered one of the dominant effects for rural and suburban areas. Since several frequency bands have been considered for future mobile satellite systems, it was thought appropriate to perform measurements of the attenuation induced by trees on satellite-like paths over a wide range of frequencies (1-4 GHz). These measurements could then be used to evaluate the comparable performance of mobile satellite systems at different elevation angles and over a wide frequency range. They could also provide a further insight into the applicability of the empirical formula on vegetation effects quoted in the CCIR report AB/5.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:572430 |
| Date | January 1993 |
| Creators | Benzair, Belkassem |
| Publisher | University of Bradford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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