Envelope Tracking PA Sharing for MIMO RF Signal Paths
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Solution Overview
Problem
Conventional envelope tracking (ET) power amplifier circuits for 5G-NR capable mobile communication devices require multiple power amplifiers and ET integrated circuits, leading to increased cost and footprint due to the need for separate ET voltages for each RF signal, especially when supporting MIMO diversity and spatial multiplexing.
Innovation Solution
The ET power amplifier apparatus configures a pair of RF signals to be split and recombined, allowing them to be amplified using a single pair of power amplifiers and a single ET integrated circuit, with pre-processing to create composite RF signals of similar average power, thereby reducing the number of power amplifiers and ETICs needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate ET voltages are provided for each RF signal, then signal transmission quality is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple RF signals into composite RF signals that share common power envelopes, allowing a single ETIC to generate a common ET voltage that serves multiple power amplifiers. This merging approach reduces the number of ETICs from multiple to one, and reduces power amplifiers from separate units to a shared pair, while maintaining signal transmission quality through proper signal combination and separation circuits.
Solution Approach 2:
The patent implements multi-functionality by designing a system where a single ETIC serves multiple power amplifiers simultaneously. The common ET voltage generated by one ETIC is distributed to multiple power amplifiers that process different RF signals, making the ETIC universal for multiple functions rather than dedicated to a single signal path.
2Reliability
If multiple power amplifiers are used for each RF signal, then signal transmission capability is improved, but footprint and cost increase
Solution Approach 1:
The patent merges multiple RF signal paths into shared power amplifier units by creating composite RF signals. Instead of having separate power amplifiers for each RF signal, the system combines signals such that pairs of power amplifiers can serve multiple signal paths, reducing the total number of power amplifier units and thereby reducing circuit footprint.
Solution Approach 2:
The patent segments RF signals into composite RF signals with similar average power levels, allowing efficient sharing of power amplifier resources. By dividing and recombining signals in a structured manner, the system achieves effective signal transmission with fewer physical components.
3Power
If power amplifiers operate at full peak power, then output power is improved, but operating efficiency decreases
Solution Approach 1:
The patent implements dynamic envelope tracking where the power supply voltage to power amplifiers is modulated to follow the envelope of the RF signal. This dynamic adjustment allows power amplifiers to operate efficiently across varying power levels rather than constantly at full peak power, improving overall energy efficiency while maintaining the ability to deliver full output power when needed.
Solution Approach 2:
The patent changes the operating parameters of power amplifiers by providing time-varying ET voltages that track the signal envelope. This parameter modulation allows the power amplifiers to operate in their most efficient region for each instantaneous power level, rather than operating statically at full peak power, thereby improving efficiency without sacrificing output power capability.
Data Source
AI summary
An envelope tracking (ET) power amplifier apparatus is provided. The ET power amplifier apparatus includes a pair of power amplifiers configured to amplify a pair of radio frequency (RF) signals based on a pair of ET voltages. In one aspect, each of the RF signals is split before amplification and recombined after amplification. As such, the power amplifiers can operate based on half the peak power of the RF signals to help improve operating efficiency of the power amplifiers. In another aspect, the RF signals are pre-processed prior to amplification to form a pair of composite RF signals with similar average power such that the power amplifiers can operate based on substantially similar ET voltages. As a result, it may be possible to employ a single ET integrated circuit (ETIC) to provide the ET voltages, thus helping to reduce cost and footprint of the ET power amplifier apparatus.