Noise Variance Estimation Circuit for Wireless Communication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, the interaction between noise variance estimation and channel smoothing coefficient adjustment leads to significant bias, causing error propagation and degrading channel estimation accuracy.
Innovation Solution
A noise variance estimation circuit and method that includes a first estimation unit, a first noise reduction unit, a second estimation unit, and a second noise reduction unit, where the first estimation unit generates a signal based on a reception and reference signal, and subsequent noise reduction processes are performed to improve noise variance estimation, reducing bias and enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the noise variance estimation circuit calculates noise variance by subtracting the output of the LS algorithm estimation circuit from the output of the CSS circuit, then the noise variance can be provided for CSS coefficient determination, but the interaction between noise variance estimation and CSS coefficient adjustment leads to significant bias and error propagation
Solution Approach 1:
The patent segments the noise variance estimation process into two distinct phases: a training phase where noise variance is estimated using training sequences, and a data transmission phase where the pre-estimated noise variance is utilized. This segmentation eliminates the harmful interaction between noise variance estimation and CSS coefficient adjustment by performing the estimation independently during the training phase, thereby resolving the technical contradiction between measurement precision and reliability
Solution Approach 2:
The patent applies preliminary action by estimating the noise variance in advance during the training phase before the actual data transmission begins. The CSS coefficients are then adjusted using this pre-estimated noise variance, rather than performing real-time estimation that would create interaction bias. This preliminary estimation ensures accurate noise variance values are available when needed without causing error propagation
2Adaptability or versatility
If the CSS circuit adjusts coefficients according to noise variance from the noise variance estimation circuit, then the coefficient determination can adapt to current channel environment, but the interaction leads to serious error propagation and degrades channel estimation accuracy
Solution Approach 1:
The patent segments the system operation into training phase and data transmission phase. During the training phase, the CSS circuit adjusts its coefficients using noise variance estimated from training sequences. During data transmission, the pre-adjusted coefficients and pre-estimated noise variance are used without further interaction. This temporal segmentation maintains adaptability while eliminating the harmful real-time interaction that causes error propagation
Solution Approach 2:
The CSS coefficients are preliminarily adjusted during the training phase using the estimated noise variance before actual data transmission begins. This preliminary adjustment ensures the CSS circuit is adapted to the current channel environment while preventing the interaction-induced error propagation that would occur during real-time operation
Data Source
AI summary
The present invention includes a noise variance estimation circuit for wireless communication. An embodiment of the noise variance estimation circuit includes: a first estimation unit operable to generate a first estimation signal according to a reception signal and a reference signal in which the reception signal is derived from the equivalent of the reference signal; a first noise reduction unit operable to generate a first noise reduction signal by performing a first noise reduction process to the first estimation signal; a second estimation unit operable to generate a second estimation signal according to the difference between the first estimation signal and the first noise reduction signal; and a second noise reduction unit operable to execute a noise reduction adjustment according to the second estimation signal and perform a second noise reduction process to the first estimation signal in which the noise reduction adjustment affects the second noise reduction process.