Assisted mmWave Initial Access Power Control for RACH Uplink

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Solution Overview

Problem

There is a need for improved power control mechanisms in wireless communication systems, particularly for user equipment (UE) accessing base stations operating in millimeter wave (mmWave) frequency spectrum, to enhance initial access and conserve mmWave resources.

Innovation Solution

A base station operating in a lower frequency spectrum assists the UE by providing transmit power control information for a RACH procedure with a base station in the mmWave spectrum, allowing the UE to determine optimal transmission power for communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UE performs traditional initial access to mmWave BS without assistance, then UE can establish direct connection, but power control is difficult and mmWave resources are not conserved

Engineering Contradiction:

Improveinitial access reliabilityVSAvoidpower control complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a first base station (operating in lower frequency spectrum) as an intermediary to assist the UE in determining transmit power for accessing a second base station (operating in mmWave spectrum). The first base station provides assistance information including reference signal receive power (RSRP) and path loss values, enabling the UE to calculate appropriate transmit power without direct power control complexity from the mmWave base station.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If UE transmits at high power for RACH procedure, then transmission reliability improves, but mmWave resources are wasted

Engineering Contradiction:

ImproveRACH transmission reliabilityVSAvoidmmWave energy consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by having the first base station provide assistance information (RSRP, path loss values) before the UE actually transmits the RACH preamble to the mmWave base station. This allows the UE to pre-calculate the optimal transmit power level based on channel conditions, ensuring reliable transmission while avoiding excessive power consumption that would waste mmWave resources.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If BS operates in mmWave spectrum, then spectral efficiency and data rate improve, but coverage and penetration ability deteriorate

Engineering Contradiction:

Improvespectral efficiencyVSAvoidcoverage area

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The patent segments the access process into two parts: initial connection establishment through the first base station (lower frequency, better coverage) and subsequent connection to the second base station (mmWave, high spectral efficiency). The first base station operates in a lower frequency spectrum that provides better coverage and penetration, while the second base station utilizes mmWave spectrum for high-speed data transmission, allowing each to operate in its optimal frequency range.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3530041B1Methods and apparatuses for power control in assisted millimeter wave initial access

Publication Date: 2026.04.15 QUALCOMM INC

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AI summary

Certain aspects of the present disclosure provide techniques for assisted power control for an uplink signal transmitted during a RACH procedure. A UE may determine a transmit power for transmitting a message during a RACH procedure with a secondary BS, based at least in part, on communication between the UE and a primary BS. The UE may transmit the message to the second BS during the RACH procedure based, at least in part, on the determined transmit power.