LTE Radio Front End with Envelope Tracking for Dual Carriers
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Solution Overview
Problem
Current front end radio architectures for LTE-Advanced networks face inefficiencies due to the lack of practical envelope following systems, leading to increased peak-to-average ratio (PAR) and energy wastage, especially in dual intra-band carrier operations, which hinder efficient power amplifier performance and multi-carrier operation.
Innovation Solution
The implementation of a front end radio architecture that employs modulated switchers with a modulation bandwidth of at least 20 MHz, enabling envelope tracking modulation and selective power supply to power amplifiers, allowing for efficient operation in both intra-band and inter-band scenarios, thereby reducing the peak-to-average ratio and improving energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope following techniques are implemented for LTE-Advanced multi-carrier transmission, then energy efficiency of power amplifiers is improved, but bandwidth requirement for switching power supply increases significantly
Solution Approach 1:
The patent divides the power amplifier system into multiple independent PA units (first PA, second PA, third PA, fourth PA) each with dedicated switchers. This segmentation allows each power supply to handle a narrower bandwidth individually, while collectively supporting wideband multi-carrier operation. The dual intra-band carriers are assigned to different PA groups, eliminating the need for a single high-bandwidth switcher.
Solution Approach 2:
The patent transitions from a single-dimensional power supply approach to a multi-dimensional architecture where multiple power amplifiers operate in parallel across different frequency bands. By distributing carriers across multiple PAs with moderate bandwidth switchers, the system achieves wideband coverage without requiring any single switcher to handle the full bandwidth.
2Productivity
If dual intra-band carriers are transmitted simultaneously, then multi-carrier data rate is improved, but peak-to-average ratio increases by 2 dB reducing transmitter efficiency
Solution Approach 1:
The patent segments the dual intra-band carriers into separate transmission chains with dedicated power amplifiers. The first and second carriers are transmitted through separate PA units, allowing independent power management and envelope following control. This segmentation enables efficient energy usage while maintaining high data rates through multi-carrier operation.
3Adaptability or versatility
If envelope following system is designed for large bandwidth to support dual intra-band carriers, then multi-carrier operation is enabled, but device complexity and cost increase
Solution Approach 1:
The patent divides the multi-carrier transmission system into multiple independent transmitter chains, each handling a subset of carriers with a dedicated moderate-bandwidth switcher. This segmentation approach enables versatile multi-carrier operation without requiring any single power supply to have excessive bandwidth, thereby controlling device complexity.
4Device complexity
If single power amplifier is used for dual intra-band carriers, then device complexity is reduced, but intermodulation distortion increases
Solution Approach 1:
The patent segments the power amplification function into multiple independent PAs, each handling specific carriers. This physical separation of transmission chains prevents intermodulation distortion between carriers that would occur in a single PA system, while maintaining manageable device complexity through modular architecture.
Data Source
AI summary
A front end radio architecture (FERA) with power management is disclosed. The FERA includes a first power amplifier (PA) block having a first-first PA and a first-second PA, and a second PA block having a second-first PA and a second-second PA. First and second modulated switchers are adapted to selectively supply power to the first-first PA and the second-first PA, and to supply power to the first-second PA and the second-second PA, respectively. The first and second modulated switchers have a modulation bandwidth of at least 20 MHz and are both suitable for envelope tracking modulation. A control system is adapted to selectively enable and disable the first-first PA, first-second PA, the second-first PA, and the second-second PA. First and second switches are responsive to control signals to route carriers and received signals between first and second antennas depending upon a selectable mode of operation such as intra-band or inter-band operation.