mmWave Beam Switching With Coarse-to-Fine Beam Tracking

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Solution Overview

Problem

Millimeter wave (mmW) systems experience high path loss, requiring directional transmission and beam management to maintain effective communication, but existing methods are inefficient in adapting to changes in beam quality and user equipment (UE) positioning.

Innovation Solution

The system employs a method where a base station transmits beam reference signals in all directions for UE to identify 'coarse' beams, followed by beam refinement requests to track 'fine' beams, with UE reporting changes to the base station for continuous beam adjustment and quality measurement, enabling dynamic beam switching and refinement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If beam reference signals are transmitted in all directions for coarse beam identification, then beam coverage is improved, but system complexity and signaling overhead increase

Engineering Contradiction:

Improvebeam coverage areaVSAvoidbeam management complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The beam management process is segmented into two distinct phases: coarse beam identification using beam reference signals transmitted in all directions, and fine beam tracking using beam refinement requests. This segmentation allows the system to first establish broad coverage through omnidirectional signaling, then focus resources on precise beam alignment, thereby reducing overall system complexity while maintaining comprehensive coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary coarse beam identification before initiating fine beam tracking. By first transmitting beam reference signals in all directions to identify candidate beams, the system prepares the foundation for subsequent precise beam refinement, avoiding the need to perform exhaustive fine beam searching in all directions simultaneously.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If beam refinement requests are transmitted for fine beam tracking, then beam alignment precision is improved, but signaling overhead and transmission resources increase

Engineering Contradiction:

Improvebeam alignment precisionVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

Instead of continuously transmitting beam refinement requests for all beams, the system applies partial action by only initiating fine beam tracking for candidate beams identified during coarse beam identification. This selective approach achieves sufficient beam alignment precision while significantly reducing signaling overhead compared to exhaustive fine beam searching.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system implements feedback mechanisms where the UE reports beam measurements and quality information back to the base station. This feedback allows the base station to make informed decisions about which beams require refinement, optimizing the trade-off between alignment precision and signaling overhead by only refining beams that show promise based on coarse measurements.

Inventive Principle:

Principle #23Feedback

3Reliability

If UE reports beam changes to base station for continuous adjustment, then communication reliability is improved, but processing overhead and response time increase

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidbeam switching delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system merges beam change reporting with existing uplink communication channels and procedures. By integrating beam quality reports into regular uplink transmissions rather than requiring separate dedicated reporting channels, the system maintains communication reliability through continuous beam monitoring while minimizing additional processing overhead and response time.

Inventive Principle:

Principle #5Merging (Combining)

4Power

If directional transmission is used to mitigate path loss, then signal strength is improved, but system adaptability to UE movement and positioning changes deteriorates

Engineering Contradiction:

Improvesignal strengthVSAvoidadaptability to UE positioning

Core Design Contradiction:

PowerVSAdaptability or versatility

Solution Approach 1:

The system implements dynamic beam management where beam directions are continuously adjusted based on UE positioning and movement. Through the two-stage process of coarse beam identification followed by fine beam tracking, the system maintains directional transmission for signal strength while adapting beam directions in real-time to track UE movement, thereby achieving both high signal strength and adaptability to positioning changes.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11855737B2System and method for beam switching and reporting

Publication Date: 2023.12.26 QUALCOMM INC

AI summary

A method, an apparatus, and a computer-readable medium for wireless communication are provided. In some aspects, a base station may send a beam modification command that indicates a set of transmit beam indexes corresponding to a set of transmit beams of a base station, and each transmit beam index of the set of transmit beam indexes may indicate at least a transmit direction for transmitting a transmit beam by the base station. The base station may send, in association with the beam modification command, a reference signal using at least one transmit beam of the set of transmit beams, where a first portion of the reference signal is sent in a first set of symbols and a second portion of the reference signal is received in a second set of symbols.