ANN Precoding Engine for Massive MIMO PAPR Reduction

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Solution Overview

Problem

Massive MIMO-OFDM systems face high Peak-to-Average Power Ratio (PAPR) issues, leading to expensive linear RF components and costly digital predistortion to manage nonlinear signal distortions, which can be mitigated by adopting low-PAPR precoding schemes but existing methods are complex and latency-prone due to iterative computations.

Innovation Solution

The implementation of an artificial neural network (ANN) precoding engine that processes input signals to achieve low PAPR precoding in a non-iterative manner, trained using signals from existing low PAPR massive MIMO precoding algorithms, reducing hardware complexity and latency by about 80% compared to state-of-the-art techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If iterative low-PAPR precoding algorithms are used, then PAPR is reduced, but hardware complexity and latency increase significantly

Engineering Contradiction:
ImprovePAPRVSAvoidhardware complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent pre-calculates and stores precoding matrices offline that are optimized for low-PAPR characteristics. During actual transmission, the system simply selects and applies pre-computed matrices rather than performing iterative optimization in real-time, thereby reducing hardware complexity while maintaining low-PAPR performance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a simplified copy of the complex iterative algorithm by pre-computing the results offline and storing them in lookup tables. The runtime system uses these pre-computed solutions instead of executing the full iterative algorithm, achieving low-PAPR without the associated computational complexity

Inventive Principle:
Principle #26Copying

2Object-affected harmful factors

If iterative low-PAPR precoding algorithms are used, then PAPR is reduced, but transmission latency increases

Engineering Contradiction:
ImprovePAPRVSAvoidtransmission latency
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent performs the time-consuming iterative optimization offline before transmission occurs. The pre-computed precoding matrices are stored and quickly retrieved during actual data transmission, eliminating iterative computation latency while maintaining low-PAPR benefits

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent skips the iterative optimization steps during real-time transmission by using pre-computed solutions. The system rushes through the transmission process using ready-made precoding matrices, avoiding the time-consuming iterative computations that would otherwise be necessary

Inventive Principle:
Principle #21Skipping (Rushing through)

3Productivity

If conventional OFDM signaling is used, then capacity gains are achieved, but expensive linear RF components and digital predistortion are required

Engineering Contradiction:
Improvecapacity gainsVSAvoidRF components complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the key parameter of PAPR by using pre-computed precoding matrices specifically optimized for low-PAPR characteristics. This parameter change allows the system to maintain high capacity while avoiding the need for expensive linear RF components and digital predistortion that are required by conventional high-PAPR OFDM signaling

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11411794B2Artificial neutral network precoding for massive MIMO systems
Publication Date: 2022.08.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US11411794B2 patent drawing
  • US11411794B2 patent drawing
  • US11411794B2 patent drawing

AI summary

A method and apparatus for artificial neural network precoding for massive MIMO systems are disclosed. In one embodiment, a method includes processing, by an artificial neural network, ANN, precoding engine, at least one input signal by 5 performing a low peak-to-average-power ratio, PAPR, precoding on the at least one input signal; and transmitting, via at least one antenna array having at least one antenna, at least one precoded output signal processed by the ANN precoding engine.