PRACH Detection Filtering Mask for Interference Attenuation
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Solution Overview
Problem
Mobile communication systems face challenges in detecting Physical Random Access Channel (PRACH) preambles due to interference from simultaneous Physical Uplink Shared Channel (PUSCH) transmissions, which degrades signal quality and increases noise, making it difficult to filter out interference without impacting the PRACH signal.
Innovation Solution
An apparatus and method that obtain time domain samples of a received radio frequency signal, determine an estimated power distribution, set a filtering threshold to identify interference, and apply a filtering mask to attenuate or null samples above the threshold, using a Rayleigh distribution and fading scale parameter to generate the mask, which can also consider neighboring samples for improved filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filtering mask is applied to attenuate time domain samples above a threshold to reduce interference, then signal quality is improved, but the complexity of the detection process increases
Solution Approach 1:
The patent applies a filtering mask to time domain samples before PRACH detection to pre-remove interference peaks. By performing this filtering action in advance, the actual detection process becomes simpler and more reliable, as the interference has already been attenuated based on the estimated Rayleigh distribution threshold.
Solution Approach 2:
The filtering mask acts as an intermediary component between the raw received signal and the PRACH detection process. It mediates by selectively attenuating interfering samples while preserving valid PRACH signals, based on the statistical threshold derived from Rayleigh distribution, thus improving overall detection reliability without requiring complex detection algorithms.
2Object-affected harmful factors
If a filtering threshold is set to identify and attenuate interference samples, then noise is reduced, but the risk of attenuating valid PRACH signals increases
Solution Approach 1:
The patent dynamically sets the filtering threshold based on the estimated Rayleigh distribution parameter (sigma) of the received signal. By changing the threshold parameter adaptively rather than using a fixed value, the system can adjust to different signal conditions, reducing noise while minimizing the risk of attenuating valid PRACH signals that fall below the statistically determined threshold.
Solution Approach 2:
The system uses feedback from the signal statistics (Rayleigh distribution estimation) to determine the appropriate filtering threshold. By continuously estimating the distribution parameters from the received samples and adjusting the threshold accordingly, the system achieves optimal noise reduction while preserving valid signals, as the threshold adapts to the actual signal conditions.
Data Source
AI summary
An apparatus, method and computer program is described comprising: obtaining time domain samples of a received radio frequency signal of a mobile communication system, wherein the radio frequency signal comprises a Physical Random Access Channel; determining an estimated power distribution for the time domain samples; determining a filtering threshold value at which a time domain sample is deemed to be due to interference, based on a defined probability level of the estimated power distribution; defining a filtering mask based on the time domain samples and the filtering threshold; and applying the filtering mask to the time domain samples to generate a filtered signal samples, wherein the filtering mask is configured to attenuate time domain samples that are above the filtering threshold.