Relay RACH Occasion Coordination for Synchronized Preamble Forwarding

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing random access channel (RACH) occasions, particularly in scenarios involving relays, which can lead to inefficiencies and interference.

Innovation Solution

The implementation of a relay that receives a network node synchronization signal block (SSB), transmits a relay SSB to a user equipment (UE), and coordinates RACH occasions with the network node, enabling synchronized communication through relay beams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a relay transmits relay SSB to UE and coordinates RACH occasions, then communication efficiency is improved, but system complexity increases

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The relay acts as an intermediary between the network node and the UE, receiving SSB from the network node and transmitting relay SSB to the UE. The relay also forwards RACH occasions and preambles between the UE and network node, enabling efficient coordinated communication while managing the complexity at the relay level.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If RACH occasions are aligned between relay and network node, then interference is reduced, but coordination overhead increases

Engineering Contradiction:

ImproveinterferenceVSAvoidcoordination overhead

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The network node configures the relay with RACH occasion alignment information in advance, indicating which RACH occasions should be aligned between the relay and network node. This preliminary configuration reduces interference by ensuring synchronized RACH timing while minimizing coordination overhead through pre-established rules.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If relay receives and forwards preambles during coordinated RACH occasions, then access reliability is improved, but processing load increases

Engineering Contradiction:

Improveaccess reliabilityVSAvoidprocessing load

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The relay receives preambles transmitted by the UE during first RACH occasions associated with relay SSB, and forwards these preambles during second RACH occasions associated with network node SSB. This copying and forwarding mechanism improves access reliability by ensuring preambles are properly transmitted through the relay infrastructure while keeping processing requirements manageable.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS12375941B2Random access channel occasions associated with a relay

Publication Date: 2025.07.29 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a relay may receive, from a network node and via a network node beam, a network node synchronization signal block (SSB). The relay may transmit, to a user equipment (UE) and via a relay beam, a relay SSB that is based at least in part on the network node SSB. The relay may receive, from the UE and via the relay beam, a preamble during a first random access channel (RACH) occasion that is associated with the relay SSB. The relay may transmit, to the network node and via the network node beam, the preamble during a second RACH occasion that is associated with the network node SSB. Numerous other aspects are described.