Pilot Allocation Strategy for MU-MIMO Channel Estimation

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Solution Overview

Problem

In MU-MIMO wireless communication systems, high pilot overheads lead to congestion and reduced accuracy in user channel estimation due to interference between users sharing the same pilot, affecting data reception.

Innovation Solution

A base station determines interference between users before allocating a pilot, allocating the same pilot if interference is below a threshold and a different pilot if interference is above, ensuring accurate channel estimation while reducing pilot overheads by allowing multiple users to share a pilot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple users share the same pilot signal to reduce pilot overheads, then pilot overhead is reduced, but interference between users increases and channel estimation accuracy deteriorates

Engineering Contradiction:
Improvepilot overheadVSAvoidchannel estimation accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of pilot signal by introducing virtual pilots generated through precoding matrices. Instead of using traditional orthogonal pilot signals, the system generates virtual pilot signals by multiplying precoding matrices with actual pilot signals, allowing non-orthogonal pilots to be treated as orthogonal through mathematical transformation, thus reducing interference while maintaining estimation accuracy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces precoding matrices as an intermediary element between the physical pilot signals and the channel estimation process. These precoding matrices transform the received signals into virtual pilot signals that appear orthogonal even when derived from non-orthogonal physical pilots, effectively mediating the interference problem

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If traditional orthogonal pilot signals are used for each user, then channel estimation accuracy is maintained, but pilot overhead increases causing system congestion

Engineering Contradiction:
Improvechannel estimation accuracyVSAvoidpilot overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent merges multiple non-orthogonal pilot signals into a unified virtual pilot structure through precoding. By combining multiple physical pilots and transforming them into virtual pilots via precoding matrices, the system achieves orthogonality in the virtual domain, allowing multiple users to share pilot resources without sacrificing estimation accuracy

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from the physical domain to the virtual domain by applying precoding transformations. In this new dimension (virtual pilot space), signals that were non-orthogonal in the physical domain become orthogonal, effectively solving the interference problem through dimensional transformation

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

Data Source

PatentEP3136802B1Pilot configuration method and apparatus
Publication Date: 2019.07.10 HUAWEI TECH CO LTD
  • EP3136802B1 patent drawingFigure 1~2
  • EP3136802B1 patent drawingFigure 3~4
  • EP3136802B1 patent drawingFigure 5

AI summary

Embodiments of the present invention disclose a pilot configuration method and an apparatus, which are applied to the communications field, and can reduce pilot overheads in a case in which accuracy of user channel estimation is ensured. The method is specifically: before allocating a pilot to a first user, determining, by a base station, interference between the first user and a second user if the base station allocates a pilot of the second user to the first user; if the interference between the first user and the second user is less than a preset threshold, the pilot allocated by the base station to the first user is the same as a pilot used by the second user; or if the interference between the first user and the second user is greater than or equal to the preset threshold, the pilot allocated by the base station to the first user is different from the pilot used by the second user. The present invention is used to configure a pilot.