Subframe-Aware AGC for Heterogeneous Network Receivers
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Solution Overview
Problem
Conventional automatic gain control (AGC) algorithms in heterogeneous mobile communication networks fail to differentiate between Almost-Blank Subframes (ABS) and non-ABS subframes, leading to inappropriate signal adjustments that result in signal saturation or clipping, especially in networks with enhanced intercell interference coordination, which degrades receiver performance.
Innovation Solution
The implementation of an AGC system that distinguishes between ABS and non-ABS subframes by performing separate signal power measurements and adjustments for each, using techniques such as RSSI and RSRP measurements to determine optimal gain settings, thereby avoiding clipping errors and optimizing signal-to-quantization noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional AGC algorithms are used without differentiating between ABS and non-ABS subframes, then the system operation is simple, but signal saturation or clipping occurs leading to degraded receiver performance
Solution Approach 1:
The patent segments the subframes into two distinct types: ABS (Almost-Blank Subframes) and non-ABS subframes. The AGC algorithm is then applied separately to each subframe type, with different gain calculations performed based on the specific characteristics of each. This segmentation allows the system to avoid signal clipping in high-power non-ABS subframes while maintaining adequate signal levels in ABS subframes, thereby improving receiver performance without requiring a completely new complex system.
Solution Approach 2:
The patent implements dynamic AGC adjustment where the gain value is changed based on the detected subframe type. The system dynamically switches between different AGC gain settings: a first AGC gain for ABS subframes and a second AGC gain for non-ABS subframes. This dynamic adaptation allows the receiver to optimize its signal processing for each subframe type, preventing saturation during high-power transmissions while maintaining sensitivity during low-power ABS periods.
2Manufacturing precision
If separate AGC adjustments are performed for ABS and non-ABS subframes, then signal quality is improved by reducing clipping errors, but the processing complexity increases
Solution Approach 1:
The patent performs preliminary detection of the subframe type (ABS or non-ABS) before applying the AGC adjustment. The system identifies whether an incoming subframe is an ABS or non-ABS based on pre-configured patterns or detection mechanisms, and then applies the appropriate gain setting. This preliminary classification simplifies the overall processing by avoiding the need for complex real-time analysis during the AGC calculation phase.
Solution Approach 2:
The system implements feedback mechanisms where the received signal characteristics are measured and used to adjust the AGC gain. The patent measures signal power during different subframe types and uses this feedback to optimize the gain settings. This feedback loop ensures that the AGC algorithm adapts to actual channel conditions while maintaining the distinction between ABS and non-ABS processing.
Data Source
AI summary
The invention refers to performing an automatic gain control—AGC—with respect to a received signal comprising a plurality of consecutive subframes (S1 S12), comprising identifying subframes that are associated to a first subset of the consecutive subframes (S1, S3, S4, S5, S7. S8, S9, S11, S12), performing a first (10) signal power measurement with respect to the received signal during the first subset of the consecutive subframes, and performing the AGC according to the first signal power measurement. The invention further refers to a user equipment and to a corresponding computer program.