Reception Device Interference Power Estimation via Null Symbols
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Solution Overview
Problem
Existing reception devices struggle to accurately estimate interference power in wireless communication systems due to noise power contamination, especially when noise power is significant relative to interference power.
Innovation Solution
The reception device employs a null-symbol insertion method, where null symbols are inserted into the transmission symbol sequence, allowing for precise interference power estimation by separating desired signal power from noise power through signal interpolation and cancellation processes, enabling improved interference power estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reception device uses the pilot signal to define average correlation power as desired signal power and subtracts it from average received power to calculate residual power, then the interference power can be estimated, but the residual power includes noise power in addition to interference power, reducing estimation accuracy when noise power is significant
Solution Approach 1:
The patent segments the residual power into two distinct components: interference power and noise power. By inserting null symbols at specific positions in the received signal, the system can separately measure and calculate the noise power component, then subtract it from the total residual power to obtain accurate interference power estimation. This segmentation resolves the contradiction by isolating the harmful noise power from the useful interference power measurement.
Solution Approach 2:
The patent introduces null symbols as an intermediary element that enables separate measurement of noise power. These null symbols, which contain only noise and interference without desired signal components, serve as a mediator to extract and quantify the noise power component. This intermediary approach allows the system to distinguish between noise and interference, thereby improving interference power estimation accuracy when noise power is significant.
2Measurement precision
If null symbols are inserted into transmission symbol sequence, then precise interference power estimation is enabled by separating desired signal power from noise power, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-inserting null symbols into the transmission symbol sequence at predetermined positions before transmission. This preliminary arrangement ensures that the received signal contains known positions with only noise and interference components, enabling straightforward separation and measurement of noise power without requiring complex real-time processing. The null symbol positions are predetermined and communicated to the reception device, simplifying the overall processing complexity while maintaining high measurement precision.
Data Source
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AI summary
A reception device includes an interference cancellation unit (304) to extract a symbol from a received signal with a first signal inserted in a time direction of a data symbol, the first signal being a signal with a value of amplitude smaller than that of the data symbol and the symbol being a signal during an interval corresponding to the first signal, to perform a signal interpolation process to reproduce an interference signal during an interval corresponding to the data symbol, and to output a first interference-cancelled signal obtained by extracting the data symbol from a signal obtained by cancelling the interference signal from the received signal, and an interference-power estimation unit (305) to estimate desired signal power by subtracting second average power of a symbol of a first signal, extracted from the received signal, from first average power of a data symbol extracted from the received signal, to estimate first noise power included in the first interference-cancelled signal by subtracting the desired signal power from third average power of a data symbol of the first interference-cancelled signal, to estimate second noise power included in the received signal from the first noise power, and to estimate interference power by subtracting the second noise power from the second average power.