DC Bias Cancellation for Blocker and Leakage Signal Rejection
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Solution Overview
Problem
Conventional wireless communication systems at 60 GHz face challenges in rejecting blocker and leakage signals due to high attenuation and interference, which affects data rates and security in applications like wireless personal area networks and high-definition television signals.
Innovation Solution
The method employs undersampling and dynamic DC bias cancellation, where the received signal is undersampled at a frequency equal to or an integer sub-harmonic of the blocker/leakage signal, and the DC bias is controlled using successive approximation logic and a digital-to-analog converter to minimize or eliminate unwanted signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wireless communication systems operate at 60 GHz, then very high data rates can be achieved due to large bandwidth availability, but blocker and leakage signals cause interference that reduces communication reliability
Solution Approach 1:
The patent extracts and removes the unwanted DC component containing blocker and leakage signal information from the received signal. By using a DC blocker circuit to eliminate the DC offset, the system separates the harmful DC-containing component from the useful AC signal components, thereby removing interference while preserving the high data rate capability of 60 GHz communication
Solution Approach 2:
The patent introduces a DC blocker circuit as an intermediary component between the receiver antenna and subsequent signal processing stages. This intermediary element specifically targets and removes DC offsets without affecting the AC signal components, enabling reliable communication by eliminating blocker and leakage signals while maintaining the benefits of 60 GHz operation
2Length of moving object
If high transmission power is used to overcome oxygen absorption and achieve longer communication distance, then coverage is improved, but blocker and leakage signals become more prominent causing interference
Solution Approach 1:
The patent converts the harmful effect of prominent blocker and leakage signals (which become more significant at higher transmission powers) into a detectable and removable DC offset component. By intentionally designing the system to identify these signals as DC components, the patent enables their systematic elimination through DC blocking, thereby allowing high transmission power to be used for extended coverage without suffering from interference
3Measurement precision
If DC blocking is implemented to remove blocker and leakage signals, then signal-to-noise ratio is improved, but system complexity increases due to additional circuit components
Solution Approach 1:
The patent segments the signal processing function by separating DC component removal from the main signal processing chain. The DC blocker circuit operates independently to eliminate DC offsets, allowing the rest of the system to process only the useful AC signal components. This segmentation improves signal-to-noise ratio while keeping the added complexity localized and manageable
Data Source
AI summary
Methods and systems for blocker and/or leakage signal rejection by DC bias cancellation are disclosed and may include undersampling a received signal including a desired signal and an undesired signal. A biasing current in the wireless system may be utilized to reduce a measured DC signal generated by the undersampling of the received signal. The received signal may be undersampled at a frequency of or an integer sub-harmonic of the undesired signal, which may include a leakage signal and/or a blocker signal. The DC biasing current may be controlled utilizing successive approximation, control logic and a digital to analog converter. The output DC voltage may correspond to said undesired signal, and the received signal may be undersampled utilizing a mixer.