CINR Estimation Using Segmented Preamble and Guard Interval Analysis
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Solution Overview
Problem
Conventional CINR estimation methods in communication systems, such as the IEEE 802.16 system, face inaccuracies when there is no interference or when interference is negligibly small, and when operating in multi-path environments, leading to errors in noise and interference power estimation.
Innovation Solution
The method involves generating a signal with a traffic allocation area and a preamble allocation area, calculating power values of preamble tones, determining a partial noise-interference power value by comparing preamble tones with adjacent tones, estimating noise power from a separate area unaffected by multi-path environments, and using these values to accurately calculate the CINR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the conventional CINR estimation method subtracts carrier power and noise power from signal power, then the CINR can be calculated, but the estimation accuracy deteriorates when interference is negligible or in multi-path environments
Solution Approach 1:
The patent segments the signal power into three distinct components: carrier power (from preamble tones), interference power (estimated separately using time-domain averaging), and noise power (estimated from guard intervals). This segmentation allows each component to be estimated independently and accurately, resolving the contradiction by enabling precise CINR calculation even when interference is negligible, as each component can be measured with appropriate methods for its specific characteristics
Solution Approach 2:
The patent introduces an intermediary interference estimation process that operates separately from the direct subtraction method. By using time-domain averaging of received signals to estimate interference power independently, the system creates a mediator measurement that can be combined with carrier and noise power estimates to achieve accurate CINR calculation in conditions where direct subtraction fails
2Ease of manufacture
If noise power is estimated using time-domain preamble signal, then the estimation process is simple, but accuracy deteriorates when actual CINR is large in multi-path environments
Solution Approach 1:
The patent applies preliminary action by estimating noise power from guard intervals before proceeding with the main CINR calculation. The guard intervals, which contain only noise and no signal components, are processed first to establish an accurate noise baseline. This preliminary noise estimation from clean guard interval data eliminates the multi-path interference problem that plagues time-domain preamble signal-based estimation, while maintaining computational simplicity
3Power
If preamble tones are used for carrier power estimation, then the carrier power can be obtained, but interference power estimation becomes inaccurate when interference is negligible
Solution Approach 1:
The patent segments the power measurement process into distinct carrier power estimation (from preamble tones) and interference power estimation (from time-domain averaging of received signals). This segmentation resolves the contradiction by allowing carrier power to be accurately measured from the known preamble structure while interference power is independently estimated through statistical processing of the received signal, enabling accurate differentiation even when interference is negligible
Data Source
AI summary
An apparatus and method for estimating a Carrier-to-Interference and Noise Ratio (CINR) in a communication system are provided. In the apparatus and method a signal having a traffic allocation available area that includes a preamble allocation available area is generated by Fast Fourier Transform (FFT)-processing a received symbol, power values of preamble tones included in the preamble allocation available area are calculated, a carrier power value is calculated using the power values of the preamble tones, a partial noise-interference power value is calculated using power differences between the preamble tones and power values of remaining tones other than the preamble tones, a noise power value is calculated using power values of tones included in a noise power estimation area being an area except for the preamble allocation available area in the traffic allocation available area, and the CINR is calculated using the carrier power value, the partial noise-interference power value, and the noise power value.