PBCH RACH Parameter Transmission for Millimeter Wave Access

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Solution Overview

Problem

In millimeter wave systems, user equipment may not be able to receive system information through a common control channel when the system information is transmitted with an omni-directional beam, leading to challenges in initial access and synchronization.

Innovation Solution

A method where a base station determines RACH parameters and transmits a subset of these parameters via a physical broadcast channel (PBCH), allowing user equipment to receive the necessary information for initiating a RACH procedure without relying on omni-directional beams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If system information is transmitted through a common control channel using omni-directional beams, then coverage area is improved, but user equipment cannot reliably receive the information in millimeter wave systems

Engineering Contradiction:

Improvecoverage areaVSAvoidreliability of system information reception

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent segments system information into two parts: critical RACH parameters are transmitted via PBCH (Physical Broadcast Channel) while other system information is transmitted via common control channel. This segmentation ensures that essential access parameters are reliably delivered even when omn directional beam reception fails in millimeter wave systems.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The PBCH acts as an intermediary channel that delivers RACH parameters to user equipment. This intermediary mechanism bypasses the reliability issues of common control channel reception in millimeter wave systems, ensuring that user equipment can obtain necessary access information through a more robust transmission path.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If all RACH parameters are transmitted via common control channel, then device complexity is reduced, but access latency increases in millimeter wave systems

Engineering Contradiction:

Improvedevice complexityVSAvoidaccess latency

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent performs preliminary action by transmitting critical RACH parameters via PBCH before user equipment attempts random access. This advance delivery of essential parameters eliminates waiting time and reduces access latency, as user equipment does not need to successfully receive information from the common control channel before initiating RACH procedure.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If system information is transmitted with omni-directional beams, then beam complexity is reduced, but reception reliability deteriorates in millimeter wave systems

Engineering Contradiction:

Improvebeam complexityVSAvoidreception reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the information transmission function: PBCH carries essential RACH parameters with simpler transmission requirements, while common control channel carries other system information. This segmentation allows the system to maintain simpler omn directional beam structures while ensuring reliable delivery of critical parameters through the more robust PBCH path.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3934362B9Conveying RACH information through pbch

Publication Date: 2025.04.02 QUALCOMM INC

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AI summary

In millimeter wave systems, user equipment may not be able to receive RACH parameters through a PDCCH when the information is transmitted with an omnidirectional beam. In an aspect of the disclosure, an apparatus, such as a base station, may determine the RACH parameters and transmit a subset of the RACH parameters via a PBCH. The user equipment may receive the RACH parameter subset and initiate a RACH procedure.