Massive MIMO Beam Domain Channel Model Using Refined Sampling Steering Vector Matrix

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Solution Overview

Problem

Current massive MIMO systems face challenges in accurately acquiring statistical channel information due to limited antenna sizes and increased user density, leading to errors in instantaneous channel estimation and limited time-frequency resources, which affects downlink multi-user precoding transmission.

Innovation Solution

A method for acquiring massive MIMO beam domain a priori and a posteriori statistical channel information using a refined sampling steering vector matrix with more steering vectors than antennas, transforming pilot signals and channel information into a refined beam domain, and solving for channel energy matrices using sampling statistics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional DFT matrix-based beam domain channel model is used, then the model is simple and easy to implement, but it deviates from the actual physical channel model to a considerable extent due to limited antenna size

Engineering Contradiction:
Improveease of implementationVSAvoidmodel accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the fundamental parameter of the beam domain transformation by replacing the DFT matrix with a refined sampling steering vector matrix that has more steering vectors than antennas. This parameter change allows the model to better represent the actual physical channel while maintaining computational feasibility through the specific structure of the refined sampling approach.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an additional dimension by using more steering vectors than the number of antennas. The refined sampling steering vector matrix has dimensions that exceed the antenna count, adding a new dimensional aspect to the beam domain representation that captures more physical channel characteristics without requiring more physical antennas.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If the number of user antennas occupying the same time-frequency resources is increased, then user density is improved, but time-frequency resources for pilots are limited leading to errors in instantaneous channel estimation

Engineering Contradiction:
Improveuser densityVSAvoidchannel estimation accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent performs preliminary action by acquiring a priori statistical channel information before actual data transmission. The refined beam domain a priori statistical model is established in advance, allowing the system to prepare robust precoding strategies before channel conditions deteriorate or change, thereby maintaining accuracy even with limited pilot resources.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using both a priori statistical information and a posteriori instantaneous channel information. The system continuously updates and refines channel estimates by combining prior statistical knowledge with current channel measurements, creating a feedback loop that improves estimation accuracy despite resource constraints.

Inventive Principle:
Principle #23Feedback

3Productivity

If downlink multi-user precoding transmission is implemented, then spectral efficiency is improved, but mobility of users poses significant challenges requiring robust transmission methods

Engineering Contradiction:
Improvespectral efficiencyVSAvoidtransmission reliability under mobility
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent performs preliminary action by establishing the refined beam domain a priori statistical channel model in advance of actual transmission. This pre-established model provides a foundation for robust precoding that can adapt to user mobility, allowing the system to maintain reliability while achieving high spectral efficiency through multi-user precoding.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS12155427B2Method and system for acquiring massive MIMO beam domain statistical channel information
Publication Date: 2024.11.26 SOUTHEAST UNIV
  • US12155427B2 patent drawing
  • US12155427B2 patent drawing
  • US12155427B2 patent drawing

AI summary

Disclosed are a method and system for acquiring massive MIMO beam domain statistical channel information. A refined beam domain channel model involved in the disclosed method is based on a refined sampling steering vector matrix. Compared with a traditional DFT matrix-based beam domain channel model, when antenna size is limited, said model is closer to a physical channel model, and provides a model basis for solving the problem of the universality of massive MIMO for various typical mobile scenarios under a constraint on antenna size. The present invention provides a method for acquiring massive MIMO refined beam domain a priori statistical channel information and a posteriori statistical channel information, the a posteriori statistical channel information comprising mean and variance information of the a posteriori channel. The method of the present invention has low complexity, can be applied to an actual massive MIMO system, provides support for a robust precoding transmission method, and has large application value.