Satellite Receiver OFDM Erasure for Terrestrial Narrowband Interference
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Solution Overview
Problem
Satellite receivers experience performance degradation due to interference from terrestrial signals, which existing technologies fail to mitigate effectively without significant changes or relocation.
Innovation Solution
A system and method that utilize OFDM-like signaling with erasure of interference-corrupted signal components, employing decimation filtering and log-likelihood ratio processing to reconstruct the signal, minimizing changes to the transmitter and receiver, and maintaining performance in non-interfered sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If satellite receivers operate in areas with terrestrial communication systems using the same frequency spectrum, then receiver deployment flexibility is improved, but performance degradation occurs due to interference
Solution Approach 1:
The patent converts the harmful interference from terrestrial signals into a detectable pattern by using OFDM subcarrier structure. The interference appears as concentrated energy on specific subcarriers, which can be identified and erased. This transforms the harmful effect into a useful indicator for interference detection and mitigation, allowing receivers to operate in previously unusable environments.
Solution Approach 2:
The patent extracts and removes the interfered subcarrier components from the received signal before decoding. By identifying subcarriers with excessive power (indicating interference) and erasing them (setting to zero), the harmful interference components are separated and removed from the signal processing chain, preventing them from degrading overall receiver performance.
2Reliability
If interference mitigation techniques are applied to satellite receivers, then receiver performance in interfered areas is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal interference mitigation approach that works with standard OFDM receivers without requiring specialized hardware. The same receiver architecture processes both interfered and non-interfered signals, using the existing FFT and subcarrier processing infrastructure. This multi-functional approach handles both cases with a single unified algorithm, minimizing additional complexity.
Solution Approach 2:
The patent applies partial action by selectively erasing only the interfered subcarriers rather than processing the entire signal differently. The interference mitigation is applied exactly where needed (on affected subcarriers) while leaving the rest of the signal processing unchanged, thus avoiding unnecessary complexity in non-interfered portions of the signal.
3Reliability
If subcarriers affected by interference are erased and signal reconstruction is performed, then interference mitigation is achieved, but throughput is reduced
Solution Approach 1:
The patent changes the state parameter of affected subcarriers from corrupted signal values to erased (zero) values. This parameter change allows the forward error correction decoder to detect and correct errors in the remaining subcarriers, recovering throughput that would otherwise be lost. The erasure operation transforms unusable data into a form that can be recovered through coding.
Solution Approach 2:
The patent converts the throughput-reducing effect of interference into a recoverable situation by using the structured OFDM format. The interference, which would normally cause complete packet loss, is instead converted into identifiable erasures that can be corrected by forward error correction, turning a harmful throughput reduction into a manageable error correction problem.
4Ease of manufacture
If minimal changes are made to the transmitter and receiver, then ease of implementation is improved, but interference mitigation capability may be limited
Solution Approach 1:
The patent implements self-service by using the receiver's existing signal processing infrastructure to perform interference mitigation. The FFT, subcarrier processing, and forward error correction components that are already present in the receiver are utilized to detect and correct interference without requiring external assistance or complex additional circuitry. The system serves itself using its own built-in capabilities.
Solution Approach 2:
The patent uses feedback from the received signal power measurements to control the interference mitigation process. By monitoring subcarrier power levels and comparing against thresholds, the system automatically identifies interfered subcarriers and applies erasure selectively. This feedback mechanism enables effective interference mitigation using simple, existing receiver components.
Data Source
AI summary
A receiver, transmitter and system are programmed to communicate based on a signal including a plurality of signal components associated respectively with a plurality of subcarriers over a communications channel. The receiver is programmed to determine, from the plurality of subcarriers, a subcarrier subject to interference and erase the signal component associated with the subcarrier subject to interference. The receiver is further programmed to reconstruct the signal based on the plurality of first signal components excluding the erased first signal component.