Satellite Downlink Interference Compensation via Pre-Distortion
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Solution Overview
Problem
Satellite communications systems face interference issues due to overlapping frequencies in both satellite and terrestrial communication links, which can lead to unreliable service, especially in densely populated areas, and result in underutilization of satellite spectrum.
Innovation Solution
The method involves generating a measure of error and interference in the communication waveform at a radioterminal, processing this information to obtain interference compensation values, and combining these values with the transmitted waveform to create an interference-compensated waveform that reduces interference from overlapping frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If terrestrial networks reuse satellite frequencies to enhance capacity and coverage, then system productivity and service availability improve, but interference between satellite and terrestrial signals increases
Solution Approach 1:
The patent applies preliminary anti-action by pre-distorting the satellite transmit signal in advance to counteract the expected interference from terrestrial networks. The satellite ground station receives interference information from the terrestrial network, processes it to determine compensation values, and applies these values to pre-distort the signal before transmission. This proactive approach allows the satellite signal to arrive at the radioterminal already compensated for anticipated interference, thereby maintaining signal quality while enabling frequency reuse.
Solution Approach 2:
The patent implements preliminary action by performing interference compensation calculations and signal pre-distortion before the actual satellite transmission occurs. The system receives interference information from terrestrial networks, calculates compensation values in advance, and applies these values to the satellite signal before it is transmitted. This advance preparation ensures that the signal is optimized to counteract known interference patterns, improving reception quality without requiring real-time adjustments during transmission.
2Area of stationary object
If satellite signals are transmitted to densely populated areas, then service coverage improves, but signal reliability deteriorates due to blockage by high-rise structures and building penetration issues
Solution Approach 1:
The patent introduces terrestrial networks as an intermediary to bridge the gap between satellite signals and radioterminals in densely populated areas. The terrestrial network receives and retransmits satellite band frequencies locally, providing coverage in areas where direct satellite signals are blocked by buildings or other structures. This intermediary approach allows satellite spectrum to be utilized effectively in urban environments while maintaining service reliability where direct satellite paths are obstructed.
3Device complexity
If a single global antenna pattern is used to cover the entire service region, then device complexity is reduced, but interference management becomes less effective in densely populated areas
Solution Approach 1:
The patent applies universality by enabling the satellite ground station to perform multiple functions: it serves as both a traditional satellite transponder and an interference compensation processor for terrestrial network coordination. The ground station receives interference information from terrestrial networks, processes this data to calculate compensation values, and applies these values to satellite signals. This multi-functional approach allows the same infrastructure to address both satellite communication and terrestrial interference management without requiring separate dedicated systems.
Data Source
AI summary
Methods of compensating for interference in communications in a satellite communications system are provided. At a first radioterminal, a measure of an error in communications received through a first service down-link from a satellite is generated. A communications waveform is identified which causes interference to communications through the first service down-link to the first radioterminal when it is transmitted to a second radioterminal at a frequency that is substantially the same as a frequency of the first service down-link. The measure of the error and a measure of the interfering communications waveform are processed to obtain at least one interference compensation value. The at least one interference compensation value is combined with a waveform that is to be transmitted to the first radioterminal to obtain an interference compensated waveform. The interference compensated waveform is transmitted to the first radioterminal through the first service down-link.