Power Amplifier Bias Control for Variable-Bandwidth Modulation
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Solution Overview
Problem
Modern mobile communication devices face high power consumption due to the current used in transmission chains, particularly in the power amplifier, which is a major source of energy consumption, and existing technologies have not effectively optimized power amplifier operation to reduce this consumption.
Innovation Solution
The method involves varying the bias voltage of the power amplifier based on characteristics such as channel bandwidth and number of subcarriers to optimize current consumption, by selecting predetermined bias voltages that reduce the operating point of the power amplifier, thereby minimizing current and power consumption while maintaining adequate adjacent channel leakage ratio (ACLR) performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power amplifier operates at high power to meet transmission requirements, then the transmission performance is improved, but the power consumption increases significantly
Solution Approach 1:
The patent applies dynamics by making the bias voltage adjustable and adaptive rather than fixed. The bias voltage is dynamically changed based on the modulation scheme being used, allowing the power amplifier to optimize its operating point for each specific modulation type, thereby reducing power consumption while maintaining required transmission performance
Solution Approach 2:
The patent changes the bias voltage parameter of the power amplifier according to different modulation schemes. By selecting optimal bias voltages tailored to each modulation type (e.g., different voltages for QPSK vs. 64-QAM), the system achieves better power efficiency without sacrificing transmission quality
2Device complexity
If a fixed bias voltage is used in the power amplifier, then the circuit design is simplified, but power consumption cannot be optimized for different modulation schemes
Solution Approach 1:
The patent applies preliminary action by pre-determining and storing optimal bias voltage values for different modulation schemes in a lookup table. During operation, the system simply retrieves the appropriate bias voltage based on the current modulation scheme, avoiding complex real-time calculations while achieving optimized power consumption
Solution Approach 2:
The system serves itself by automatically selecting the appropriate bias voltage based on the modulation scheme without requiring external manual adjustment. The lookup table mechanism enables the power amplifier to self-optimize its bias setting according to the active modulation mode
Data Source
AI summary
One embodiment of the present invention relates to a method for improving the power consumption of a transmission chain by varying the operating point of a power amplifier to optimize (e.g., reduce) the current that is consumed by the amplifier. The operating point is varied by changing the bias voltage(s) (e.g., supply voltage, quiescent voltage) of the amplifier to a predetermined value that is chosen based upon the effect that a given transmitted signal modulation scheme characteristic (e.g., channel bandwidth and/or number of subcarriers) has on the operating point of a power amplifier. For example, if the characteristics indicate a good power amplifier performance the linear output power capability of a power amplifier can be lowered, by changing the bias voltage(s) supplied to the power amplifier, to reduce the output power capability and current consumption of the power amplifier.