Multibeam Satellite Frequency Reuse via Zone Segmentation
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Solution Overview
Problem
Current multibeam satellite radiocommunication systems face limitations in increasing capacity density of the return channel when using fractional or full frequency reuse schemes, particularly due to interference from internal zones of adjacent spots, which restricts the size of internal zones without compromising the signal-to-interference ratio.
Innovation Solution
A broadband multibeam satellite radiocommunication system that allocates a main frequency band to central internal zones and secondary sub-bands to peripheral zones, using a cellular pattern and polarization states to optimize frequency reuse, allowing for geographical positioning to determine resource allocation and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of internal zones is increased to improve capacity density, then the transmission capacity increases, but the signal-to-interference ratio C/I deteriorates due to interference from adjacent spots
Solution Approach 1:
The patent divides the coverage spot into two distinct zones: an internal zone and a peripheral zone. The internal zone uses a first frequency sub-band while the peripheral zone uses a second frequency sub-band. This segmentation allows the internal zone to be enlarged for higher capacity density while the peripheral zone acts as a buffer to maintain C/I ratios by using different frequencies that are less susceptible to interference from adjacent spots.
Solution Approach 2:
Different frequency sub-bands are assigned to different spatial zones within the coverage spot. The internal zone, which requires higher capacity, receives a dedicated first sub-band, while the peripheral zone, which is more prone to interference, receives a second sub-band with better interference characteristics. This local differentiation optimizes both capacity and signal quality in their respective regions.
2Productivity
If fractional or full frequency reuse schemes are used to increase bandwidth per spot, then the transmission capacity improves, but interference from adjacent spots increases
Solution Approach 1:
The frequency band is segmented into multiple sub-bands, with specific sub-bands assigned to internal and peripheral zones. This frequency segmentation allows the system to achieve fractional frequency reuse benefits (increased bandwidth utilization) while controlling interference by ensuring that adjacent spots use different sub-bands in their peripheral zones, reducing the harmful interference effect.
Solution Approach 2:
The peripheral zone acts as an intermediary buffer between the high-capacity internal zone and adjacent coverage spots. By assigning a dedicated second frequency sub-band to the peripheral zone that differs from adjacent spots, it mediates the interference problem, allowing the internal zone to operate at high capacity while the peripheral zone absorbs and isolates interference from neighboring spots.
Data Source
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AI summary
A broadband multibeam satellite radio communication system configured to implement a frequency reuse scheme of a total allocated bandwidth on a return channel comprises a satellite with a multibeam receiving antenna that forms adjacent receiving spots (26, 28, 30, 32, 34, 36, 38) of terrestrial coverage. Each receiving spot (26, 28, 30, 32, 34, 36, 38) consists of a central internal zone (106, 108, 110, 112, 114, 116, 118) and a peripheral zone (126, 128, 130, 132, 134, 136, 138). Each central internal zone (106, 108, 110, 112, 114, 116, 118) is a cellular pattern (146) identical to a scale factor of geographic cells in which the main frequency sub-bands of a bouquet of main sub-bands, separate or adjacent, are distributed unitarily, and whose union equals a main band, included in the total band.