Multi-Stage Beam Scanning for Millimeter Wave Networks

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Solution Overview

Problem

High-frequency wireless communication systems, such as those using millimeter wave bands, face challenges in efficiently identifying the proper beam direction due to high spatial uncertainty and path losses, leading to decreased Signal-to-Noise Ratio (SNR) and increased resource slots required for beam scanning.

Innovation Solution

A multi-stage beam scanning method that uses non-adaptive, non-receiver specific scanning beam patterns transmitted over non-overlapping radio resource slots, partitioning the service coverage area into disjoint scanning partition cells to efficiently identify the best transmit beam pattern, reducing the number of resource slots needed compared to conventional Sequential Beam Sweeping (SBS) approaches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If narrow beamforming is used to achieve high directional gain, then path loss is compensated, but spatial uncertainty increases and beam direction identification becomes difficult

Engineering Contradiction:
Improvedirectional gainVSAvoidbeam direction identification
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The beam scanning process is divided into multiple stages, where each stage further subdivides the spatial search space. In the first stage, wide beams cover large angular regions; in subsequent stages, narrower beams focus on specific sub-regions. This hierarchical segmentation allows the system to efficiently locate the optimal beam direction without requiring exhaustive scanning of all possible angles, thus resolving the contradiction between achieving high directional gain and efficiently identifying the beam direction.

Inventive Principle:
Principle #1Segmentation

2Reliability

If conventional Sequential Beam Sweeping is used to scan all beam directions, then complete coverage is achieved, but the number of resource slots increases significantly

Engineering Contradiction:
Improvebeam direction coverageVSAvoidresource slots for scanning
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary broad coverage scanning using wide beams in the first stage to identify promising directional regions. Based on the results from this preliminary action, subsequent stages focus their scanning efforts only on the identified promising regions using narrower beams. This preliminary action approach avoids the need to scan all possible beam directions exhaustively, significantly reducing the number of resource slots required while maintaining complete coverage of the service area.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If high spatial resolution is achieved through large number of antennas, then narrow beamforming capability is improved, but spatial uncertainty and beam finding complexity increase

Engineering Contradiction:
Improvespatial resolutionVSAvoidbeam finding procedure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The beam finding procedure is segmented into multiple stages with decreasing beam widths. The first stage uses a smaller number of antenna elements to create wide beams for coarse spatial search. Subsequent stages activate additional antenna elements to form narrower beams with higher spatial resolution, focusing only on the sub-regions identified in previous stages. This segmented approach maintains high spatial resolution where needed while reducing the overall complexity of the beam finding procedure by avoiding exhaustive high-resolution scanning across the entire spatial domain.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3216135B1Efficient beam scanning for high-frequency wireless networks
Publication Date: 2020.09.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3216135B1 patent drawingFigure 1
  • EP3216135B1 patent drawingFigure 2
  • EP3216135B1 patent drawingFigure 3A

AI summary

Systems and methods relating to non-adaptive beam scanning in a wireless network are disclosed. In some embodiments, a method of operation of a transmit node (12) to perform non-adaptive beam scanning for transmit beam patterns (16) of the transmit node (12) that partition a service coverage area (18) of the transmit node (12) into transmit partition cells (20) is provided. The method transmitting a known signal using each of multiple scanning beam patterns for each of multiple beam scanning stages over nonoverlapping radio resource slots. The scanning beam patterns for the beam scanning stages are such that each unique combination of scanning beam patterns consisting of one scanning beam pattern from each of the beam scanning stages corresponds to a different transmit beam pattern (16) of the transmit node (12). This multi-stage beam scanning approach provides an exponentially more efficient process for beam scanning than the conventional Sequential Beam Sweeping (SBS) approach.