Receiver I-Q Imbalance Compensation Using Frequency-Domain Signal Pairs
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Solution Overview
Problem
Conventional I-Q imbalance compensation methods in wireless communication systems face high computational complexity and long latency, and fail to account for noise and low-pass filter mismatches, which affect signal quality in high-speed wireless transmission.
Innovation Solution
A receiver with a calculation unit and compensation unit that selects specific receiving signals with positive and negative frequency data, calculates an I-Q imbalance compensation parameter, and compensates for third receiving signals, effectively reducing noise and low-pass filter mismatch influences while maintaining low computational complexity and short latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional I-Q imbalance compensation methods using time-domain or frequency-domain preamble signals are employed, then the I-Q imbalance effect can be compensated, but the computational complexity increases and hardware resources are consumed excessively
Solution Approach 1:
The patent extracts only the essential characteristics needed for I-Q imbalance compensation by using specific frequency domain data relationships (positive and negative frequency components) rather than processing complete preamble signals. This extraction approach maintains compensation effectiveness while reducing computational burden by focusing only on the critical frequency components.
Solution Approach 2:
Instead of using time-domain preamble signals and transforming them to frequency domain (conventional approach), the patent directly operates in the frequency domain by establishing relationships between positive and negative frequency components. This inverted approach eliminates the need for complex time-to-frequency transformation and reduces computational complexity.
2Reliability
If conventional I-Q imbalance compensation methods using time-domain filters are employed, then the I-Q imbalance effect can be compensated, but the latency increases and waiting time becomes long
Solution Approach 1:
The patent replaces the mechanical time-domain filtering process with a frequency-domain mathematical relationship approach. By directly establishing and applying the relationship between positive and negative frequency components, the system eliminates the need for lengthy time-domain convolution operations, thereby reducing latency while maintaining compensation effectiveness.
3Speed
If existing I-Q imbalance compensation methods are used in high-speed wireless transmission, then transmission speed increases, but noise and low-pass filter mismatches worsen the compensation accuracy
Solution Approach 1:
The patent exploits the asymmetric relationship between positive and negative frequency components in the frequency domain. By establishing that the product of positive frequency data and conjugate of negative frequency data equals the product of conjugate of positive frequency data and negative frequency data, the system creates an asymmetric compensation mechanism that is inherently more robust to noise and LPF mismatches in high-speed transmission scenarios.
Solution Approach 2:
The patent uses the conjugate relationship as a form of copying - by creating and utilizing the conjugate of frequency components, the system generates a reference that mirrors the original signal characteristics. This conjugate copying approach provides a robust reference for compensation that remains effective even under noisy conditions and LPF mismatches.
Data Source
AI summary
A receiver with Inphase-Quadrature (I-Q) imbalance compensation and an I-Q imbalance compensation method thereof are provided. The receiver chooses a first receiving signal which includes a first data and a first noise, as well as a second receiving signal which includes a second data and a second noise from a plurality of receiving signals. The first data have a first positive frequency data and a first negative frequency data, while the second data have a second positive frequency data and a second negative frequency data. The receiver calculates an I-Q imbalance compensation parameter according to the first receiving signal and the second receiving signal, and compensates for a third receiving signal according to the I-Q imbalance compensation parameter. The I-Q imbalance compensation method is applied to the receiver to implement the aforesaid operations.