Quadrature Receiver AGC Using Split I/Q Gain States
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing automatic gain control (AGC) mechanisms in communication systems are inefficient, particularly in quadrature receivers, as they require a significant amount of time to complete the sequence of operations necessary for proper reception, which is a bottleneck in the process.
Innovation Solution
The proposed solution involves splitting the AGC activity between the I and Q branches, allowing one branch to be in a certain gain state and the other to be in a next possible gain state, with the final receiver gain state determined using saturation detection or RSSI measurement, potentially 'looking ahead' one or more steps during an AGC time interval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sequential AGC method is used, then the receiver can achieve proper gain control, but the AGC duration becomes too long and becomes a bottleneck in the reception process
Solution Approach 1:
The patent divides the AGC activity into two separate branches (I and Q branches), allowing parallel execution of gain control operations. Each branch independently performs saturation detection and RSSI measurement, enabling the system to evaluate multiple gain states simultaneously rather than sequentially, thus reducing AGC duration while maintaining control accuracy.
Solution Approach 2:
The patent implements preliminary saturation detection and RSSI measurement in both I and Q branches before final gain state determination. By pre-evaluating signal conditions in parallel across both branches, the system prepares gain state candidates in advance, allowing faster convergence to the optimal gain state without compromising accuracy.
2Productivity
If AGC duration is shortened to meet timing requirements, then the reception process efficiency improves, but the complexity of the AGC algorithm increases
Solution Approach 1:
The patent merges the AGC operations of both I and Q branches into a unified parallel processing framework. By combining saturation detection and RSSI measurement operations across both branches simultaneously, the system achieves faster AGC convergence without requiring completely separate algorithms for each branch, thus managing complexity while improving productivity.
Solution Approach 2:
The patent employs universal saturation detection and RSSI measurement mechanisms that function identically in both I and Q branches. This multi-functional approach allows the same algorithmic structure to serve dual purposes in parallel, reducing overall system complexity compared to implementing separate specialized algorithms for each branch.
3Adaptability or versatility
If the receiver processes all tasks (DC Offset compensation, signal presence detection, AGC, frequency offset compensation, symbol synchronization, channel estimation) within the standard timing budget, then compliance with standards is achieved, but the AGC algorithm must be highly optimized to fit within constrained time
Solution Approach 1:
The patent ensures continuous useful action by implementing parallel AGC processing in both I and Q branches simultaneously, rather than alternating between them. This continuous parallel operation maximizes the utilization of available time budget, allowing all required tasks to be completed within standard timing constraints without requiring excessive optimization of individual algorithm steps.
Data Source
AI summary
A device and method of fast automatic gain control in quadrature receivers are disclosed. The AGC activity between the I and Q branches is split where in one branch the receive chain is in a certain gain state and in the other branch the receive chain is in another possible gain state, resulting in a significant shortening of the AGC duration of any IQ receiver.