The proposed non-geostationary Ku-band satellite systems

At the 1997 World Radio Conference, France was able to secure agreement for Alcatel-Alsthom to launch a nongeostationary satellite system, called SkyBridge, operating at Ku-band and using the same spectrum employed by existing Ku-band geostationary satellites. Provisional power flux density limits for the level of unwanted interference into existing satellite and ground antennas were also adopted and are currently being reviewed by an ITU-R Joint Task Group. SkyBridge subsequently petitioned the US Federal Communications Commission (FCC) for a license to operate in the United States, causing the FCC to open a window for others to file for such systems. Five new filings were received. This paper describes the six designs (including SkyBridge) that have now been proposed. Some of the relative merits of the various designs and the issues of interference with existing geostationary satellites (which may be solvable albeit with the latter losing some capacity) and mutual interference among non-geostationary systems (which may not be solvable in a manner acceptable to proponents of these systems) are examined.