Spectrally efficient techniques for MSS systems operating between 1525-1530/1626.5-1660.5 MHz

With the demand for access to the L-band mobile satellite service (MSS) spectrum allocation 1525-1559/1626.5-1660.5 MHz predicted to far exceed the 34 MHz available before the end of the decade, the efficient use of these allocations is of critical importance. This paper deals with the work undertaken by Inmarsat in seeking the development of spectrally efficient sharing scenarios i.e. a sharing plan that seeks to fit the stated requirements of a number of operators into the available allocation. The paper begins by indicating the size of the task that currently faces MSS operators seeking to coordinate access to the L-band MSS spectrum; it proceeds to list a number of tools developed by Inmarsat for use in this coordination, and in particular the development of feasible and optimal spectrum sharing scenarios; and concludes with the detailing of a general approach to development of spectrum scenarios which, although unable to alleviate the inherent shortfall in MSS spectrum, seeks to use the available spectrum in the most efficient manner possible