Power Amplifier Saturation Management in Beamforming Arrays
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Solution Overview
Problem
Current power control mechanisms for distributed power amplifiers in wireless communication systems, especially in beamforming scenarios, face challenges in maintaining signal quality and minimizing interference, particularly at higher frequencies and in multi-carrier systems, where phase-only precoding leads to increased interference and optimal precoding normalization results in premature signal quality deterioration.
Innovation Solution
A communication entity with an antenna array and multiple power amplifiers, controlled by a unit that adjusts the phase and amplitude of each antenna to generate a directional combined transmission signal, detects saturation in power amplifiers and increases power emission from non-saturated antennas to maintain signal quality and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If phase-only precoding is used to transmit at full power, then the transmitted power is maximized, but side-lobes increase and interference spreads which deteriorates system performance
Solution Approach 1:
The patent applies local quality by allowing different power amplifier configurations (saturated vs. non-saturated) to have different operational characteristics. Non-saturated PAs operate in their linear region with lower input power, while saturated PAs operate at maximum power. This local differentiation enables the system to achieve full transmitted power while reducing overall interference through intelligent power distribution across antenna elements.
Solution Approach 2:
The patent changes the operational parameter of power amplifiers from a uniform state to a differentiated state based on saturation conditions. By monitoring PA saturation status and dynamically adjusting input power levels for non-saturated PAs, the system optimizes the balance between transmitted power and interference generation, resolving the contradiction between maximizing power and minimizing harmful interference.
2Object-generated harmful factors
If optimal precoding with amplitude tapering is used to reduce side-lobes, then interference is reduced, but transmitted power decreases
Solution Approach 1:
The patent implements partial action by applying amplitude tapering only to non-saturated power amplifiers while allowing saturated PAs to operate at full power. This partial application of power reduction maintains the interference reduction benefits of amplitude tapering while compensating for power loss through the saturated PAs operating at maximum capacity, thus achieving both reduced interference and maintained transmitted power.
3Reliability
If output power is normalized to prevent PA saturation, then PA saturation is avoided, but received signal quality deteriorates prematurely
Solution Approach 1:
The patent introduces dynamic operation where power amplifiers can transition between saturated and non-saturated states based on real-time conditions. Rather than statically normalizing all PA outputs, the system dynamically adjusts input power levels for non-saturated PAs to compensate for saturation effects, maintaining received signal quality while allowing flexible PA operation. This dynamic approach resolves the contradiction by adapting PA operation to actual system needs rather than applying fixed normalization.
Data Source
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AI summary
The invention relates to a communication entity (100) comprising: -an antenna array (110) with a plurality of different antennas (111-114) for transmitting and receiving signals, wherein a combined transmission signal is generated by a superposition of the transmission signals from the plurality of different antennas of the antenna array,and a plurality of power amplifiers (121-124), each power amplifier being connected to one of the antennas (111-114),. The communication entity further comprises a control unit (130) configured to control an input signal of each of the plurality of power amplifiers (121-124) and configured to generate a directional combined transmission signal by controlling the phase and amplitude of each antenna of the array (110), wherein the control unit (130) is configured to determine a total output power for the directional combined transmission signal, and to determine a saturation state in which at least one power amplifier of the connected antenna is operating in a saturation state at maximum power, wherein when the saturation state is detected for said at least one power amplifier (121 -124), the control unit is configured to control an input signal of at least one non-saturated power amplifier in such a way that the power emitted by at least one corresponding antenna connected to the at least one non-saturated power amplifier is increased.