Downlink Beam Selection in Active Antenna Systems

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Solution Overview

Problem

Current wireless communication systems lack a mechanism to effectively select a downlink transmit beam in multi-sector networking environments with active antenna systems, particularly when user equipment is located in overlapping beam areas, affecting network performance and stability.

Innovation Solution

A method that involves acquiring multipath information for each receive port, performing multipath matching to determine matching paths, and using energy estimation of equivalent signals at transmit ports to select a downlink transmit beam, either combining beams in overlapping areas or using the beam with the highest energy when not overlapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multi-sector networking is implemented by beam splitting in AAS, then system capacity is improved, but the complexity of beam selection for user equipment increases

Engineering Contradiction:
Improvesystem capacityVSAvoidbeam selection complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary mechanism using uplink reference signals and multipath information as mediators to infer downlink channel characteristics. By using the uplink channel as an intermediary to obtain channel state information, the system can determine appropriate downlink beams without direct downlink measurement feedback from UE, thus managing the complexity of multi-sector beam selection while maintaining high system capacity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies copying by using uplink channel characteristics to copy or infer downlink channel properties through channel reciprocity. The multipath information obtained from uplink signals is copied to guide downlink beam selection, avoiding the need for separate downlink measurements and reducing the complexity of beam management in multi-sector networks

Inventive Principle:
Principle #26Copying

2Area of stationary object

If beam splitting is used to create more sectors, then coverage is improved, but the difficulty of determining the optimal transmit beam increases

Engineering Contradiction:
Improvecoverage areaVSAvoidbeam selection difficulty
Core Design Contradiction:
Area of stationary objectVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies inversion by reversing the traditional approach: instead of having the base station transmit multiple beams and have the UE measure and report back for beam selection, the system inverts the process by having the UE transmit uplink reference signals and using those signals to determine the downlink transmit beam. This inversion simplifies beam selection in multi-sector networks by eliminating the need for complex downlink measurement and reporting mechanisms

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The system applies self-service by enabling the base station to autonomously determine the optimal downlink transmit beam using uplink channel information without requiring explicit feedback from the UE. The base station services itself by extracting channel state information from uplink signals and independently making beam selection decisions, reducing the complexity of inter-device communication for beam management

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2938008B1Wave beam selection method and base station
Publication Date: 2017.06.14 HUAWEI TECH CO LTD
  • EP2938008B1 patent drawingFigure 1a~1b
  • EP2938008B1 patent drawingFigure 1c~2
  • EP2938008B1 patent drawingFigure 3~4

AI summary

Embodiments of the present invention provide a beam selection method and a base station. The method includes: separately acquiring multipath information of each receive port of M receive ports, where the multipath information is used to indicate at least one path corresponding to each receive port; performing multipath matching between the M receive ports of the base station according to the multipath information to determine i groups of matching paths; separately determining equivalent signals at N transmit ports of the base station according to uplink signals on the i groups of matching paths; and determining, according to energy of the equivalent signals at the N transmit ports, a downlink transmit beam used for sending a signal to a user equipment. In the embodiments of the present invention, equivalent signals at transmit ports are determined according to uplink signals on matching paths at receive ports, and a downlink transmit beam is determined according to energy of the equivalent signals at the transmit ports, so that selection of a downlink transmit beam can be implemented in an AAS-capable system.