TDD Automatic Gain Control Using Pre-Uplink Noise Measurement
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Solution Overview
Problem
Existing automatic gain control systems in mobile broadband networks operating in time division duplex mode are unable to react quickly enough to adjust gain during uplink communication time slots, leading to inefficiencies and noise interference.
Innovation Solution
Measure the noise level during non-uplink periods, such as downlink allocated time or gap periods, and set the gain for future uplink time slots to ensure the signal remains within the linear operating range of the receive chain, factoring out base station noise contributions when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the automatic gain control process uses conventional reaction time (2-3 ms) in TDD mode, then the gain adjustment can be calculated properly, but the gain cannot be adjusted quickly enough during uplink communication time slots
Solution Approach 1:
The patent measures the noise level during non-uplink periods (downlink allocated time or gap periods) in advance, before the uplink communication time slots begin. This preliminary measurement allows the system to calculate and prepare the appropriate gain setting beforehand, so that when uplink communication starts, the gain is already optimized and ready to be applied immediately, eliminating the conventional 2-3 ms reaction delay.
2Speed
If the system measures noise level continuously to adjust gain quickly, then the gain adjustment speed improves, but the system cannot distinguish between base station noise and actual uplink signal noise
Solution Approach 1:
The patent segments the measurement process into two distinct phases: (1) measuring the total noise level during non-uplink periods when only base station noise is present, and (2) measuring the combined noise level during uplink periods when both base station noise and uplink signal noise are present. By subtracting the base station noise measurement from the combined measurement, the system precisely isolates and determines the actual uplink signal noise level, enabling accurate gain adjustment.
3Productivity
If the system operates in synchronized TDD mode to maximize capacity, then network efficiency improves, but DL propagation time causes unwanted noise interference to other base stations
Solution Approach 1:
The patent performs noise level measurements during non-uplink periods (downlink allocated time or gap periods) before uplink communication begins. By determining the baseline noise level in advance when no uplink signals are present, the system can accurately calculate the appropriate gain setting for upcoming uplink time slots, ensuring optimal signal reception while minimizing the impact of propagation-induced noise interference in synchronized TDD networks.
Data Source
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AI summary
In TDD mobile networks, an incoming signal is received during a time period where no uplink communication takes place. The incoming signal is measured and analyzed to determine a noise level. Based on the noise level and on an uplink signal level from expected in a future uplink time slot, a gain for the automatic gain controller (510) is set for use in future uplink communications. The gain is set to optimize the operation of an analog-to- digital converter (520).