Radio Receiver Gain Control for Saturation-Free Signal Leveling
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Solution Overview
Problem
Existing AGC methods in radio receivers fail to simultaneously prevent saturation of radio frequency devices and analog nodes in the digital domain while adjusting useful signal power to a certain level, especially under strong signal interference conditions.
Innovation Solution
The proposed solution divides the AGC function into two parts: analog auto gain control (AAGC) and digital auto gain control (DAGC), where AAGC is used to prevent saturation by subtracting total signal power from a preset target power, and DAGC adjusts useful signal power by subtracting interference signal power from a digital baseband target power, ensuring both domain non-saturation and power level adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If WB-RSSI is used to calculate AGC gain, then radio frequency devices and analog devices remain non-saturated, but useful signal power cannot be adjusted to a certain power level
Solution Approach 1:
The patent segments the AGC function into two independent parts: AAGC (analog AGC) that ensures non-saturation of RF and analog devices by controlling total signal power, and DAGC (digital AGC) that adjusts useful signal power to a target level by controlling narrowband signal power. This segmentation allows each part to independently optimize its specific function without interfering with the other.
2Measurement precision
If NB-RSSI is used to calculate AGC gain, then useful signal power is adjusted to a certain power level, but radio frequency devices and analog devices may become saturated
Solution Approach 1:
The patent separates the AGC control into AAGC and DAGC components. AAGC uses wideband RSSI to control overall signal power and prevent saturation, while DAGC uses narrowband RSSI to adjust useful signal power to the target level. This segmentation resolves the contradiction by assigning each RSSI type to its appropriate control function.
3Reliability
If both WB-RSSI and NB-RSSI are used to calculate AGC gain, then both non-saturation and power level adjustment are attempted, but no valid AGC gain can be determined when signal interference is very strong
Solution Approach 1:
The patent divides AGC into two independent control loops: AAGC handling saturation prevention and DAGC handling power level adjustment. Each loop independently calculates its gain based on appropriate RSSI measurements, avoiding the need to find intersections of gain ranges and eliminating the problem of no valid gain determination under strong interference.
Solution Approach 2:
The patent introduces separate control paths for AAGC and DAGC, each with its own gain calculation and application mechanism. The AAGC gain is applied in the analog domain before ADC, while DAGC gain is applied in the digital domain after ADC, serving as intermediaries that independently resolve their respective control objectives without conflict.
4Device complexity
If a single AGC gain is used to control both analog and digital signal power, then device complexity is reduced, but it cannot simultaneously ensure non-saturation and power level adjustment
Solution Approach 1:
The patent segments the single AGC control into two independent controls: AAGC for analog domain saturation prevention and DAGC for digital domain power level adjustment. Although this increases control structure complexity, it enables simultaneous achievement of both non-saturation and precise power level control, which is the primary reliability requirement.
Solution Approach 2:
The patent applies different quality requirements to different parts of the signal processing chain: AAGC ensures non-saturation at critical analog nodes (RF amplifier, ADC input) by controlling total signal power, while DAGC ensures proper power level at the digital baseband by controlling useful signal power. Each control is optimized for its specific local requirement.
Data Source
AI summary
The present invention relates to the field of communication technologies and discloses a method and an apparatus for auto gain control (AGC) in a radio receiver, which can ensure that a radio frequency device, an analog device, and various nodes in a digital domain are non-saturated and that useful signal power is adjusted to a certain power level. According to the present invention, total signal power on an air interface is subtracted from a preset first target power to obtain an analog auto gain control (AAGC) gain, and then a second target power is subtracted from an interference signal power in a digital baseband to obtain a digital auto gain control (DAGC) gain.