PAPR Control via Proximal Operator Trade-offs
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Solution Overview
Problem
Existing PAPR reduction techniques in wireless communication systems often increase computational complexity and error vector magnitude (EVM), leading to suboptimal performance.
Innovation Solution
A method for PAPR control in wireless communication transmitters using a PAPR cost function with a proximal operator, allowing for a trade-off between PAPR and other characteristics like EVM, implemented through optimization algorithms such as the Douglas-Rachford operator splitting algorithm, with a tuning parameter λ to manage these trade-offs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If PAPR reduction techniques (clipping and filtering) are applied, then energy efficiency is improved, but computational complexity and error vector magnitude increase
Solution Approach 1:
The patent changes the parameter of the cost function from a standard indicator function to a differentiable approximation (log-barrier or Huber function), which allows the use of proximal operators with closed-form solutions. This parameter change enables efficient optimization without increasing computational complexity while achieving PAPR reduction.
Solution Approach 2:
The patent replaces complex iterative optimization procedures with a proximal operator approach that uses closed-form solutions. By substituting the optimization mechanism with a direct proximal operator application, the system achieves PAPR control without the computational burden of traditional iterative methods.
2Use of energy by moving object
If PAPR reduction techniques are applied, then energy efficiency is improved, but error vector magnitude increases
Solution Approach 1:
The patent incorporates feedback through the optimization process that iteratively adjusts the precoding matrix to minimize the cost function. This feedback mechanism allows the system to achieve PAPR reduction while maintaining signal quality by continuously monitoring and adjusting the transmission parameters.
Solution Approach 2:
By changing the cost function to a differentiable approximation with a proximal operator, the patent enables smoother optimization that reduces abrupt changes in signal parameters, thereby reducing error vector magnitude while maintaining energy efficiency improvements.
3Loss of energy
If existing PAPR reduction approaches are used, then PAPR is reduced, but computational complexity increases
Solution Approach 1:
The patent employs a self-service optimization approach where the proximal operator directly computes the optimal precoding matrix without requiring external iterative optimization algorithms. The closed-form solution to the proximal operator allows the system to self-optimize PAPR reduction without increasing computational complexity.
Solution Approach 2:
The patent substitutes complex iterative optimization mechanisms with a direct proximal operator approach. This substitution replaces multiple iterative steps with a single closed-form computation, achieving PAPR reduction without the computational complexity associated with traditional iterative methods.
Data Source
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AI summary
A method of a wireless communication transmitter is disclosed for peak-to-average power ratio (PAPR) control of communication symbols with N time-domain signal samples for transmission via each of M antenna elements. The method comprises: applying a PAPR cost function f(x) which has a proximal operator with closed form and is differentiable in an interval, and the proximal operator comprises a parameter lambda for tuning; selecting a value for lambda to perform a trade-off between PAPR and at least one other characteristic of the wireless communication transmitter; selecting a precoding for the collection of samples as a solution to an optimization problem for the selected value for lambda, wherein the optimization problem comprises minimization of an overall cost function comprising at least the PAPR cost function, and wherein solving the optimization problem comprises using the proximal operator of the PAPR cost function. Corresponding apparatus, wireless communication transmitter, radio base station, and computer program product are also disclosed.