DMRS Port Determination for 2-Step Random Access

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Solution Overview

Problem

In the 2-step random access procedure, collisions occur on DMRS ports used by a large quantity of terminal devices to send uplink data, affecting the random access effect.

Innovation Solution

A DMRS port determining method that avoids all terminal devices using the same DMRS port, ensuring orthogonality between DMRS ports in different sets and reducing interference, thereby improving random access stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If all terminal devices use the same DMRS port specified in protocol for 2-step random access, then the procedure is simple to implement, but collisions occur on DMRS ports affecting random access effect

Engineering Contradiction:

Improvesimplicity of implementationVSAvoidrandom access effect

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent divides the single DMRS port into multiple DMRS ports (first DMRS port and second DMRS port). Terminal devices are segmented into different groups that use different DMRS ports based on their random access preamble selection, thereby avoiding collisions while maintaining procedural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic DMRS port selection based on the random access preamble type. Terminal devices dynamically choose between first and second DMRS ports according to whether they send a first or second random access preamble, making the system adaptive rather than static.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If multiple terminal devices send uplink data using the same DMRS port, then resource configuration is simplified, but interference between terminal devices increases

Engineering Contradiction:

Improveresource configuration complexityVSAvoidinterference between terminal devices

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent segments terminal devices into different groups based on their random access preamble selection. Devices sending first random access preambles use the first DMRS port, while devices sending second random access preambles use the second DMRS port, thereby segmenting the interference problem into separate channels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces the random access preamble as an intermediary that mediates between terminal devices and DMRS port selection. The preamble type serves as a signaling mechanism that determines which DMRS port a terminal device should use, indirectly resolving the interference issue.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP4013175B1DMRS port determination method and communication apparatus

Publication Date: 2025.02.19 HUAWEI TECH CO LTD

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AI summary

This application relates to the field of communications technologies, and discloses a DMRS port determining method and a communications apparatus, to resolve a problem that collisions occur on DMRS ports used by a large quantity of terminal devices to send uplink data and a random access effect is affected during 2-step random access. The method includes: receiving, by a terminal device, configuration information sent by a network device, where the configuration information includes DMRS configuration information and indication information of a DMRS port set, the DMRS configuration information is used to configure a plurality of DMRS ports, and the indication information of the DMRS port set is used to indicate one or more available DMRS ports in the plurality of DMRS ports; and determining, by the terminal device, a target DMRS port in the DMRS port set.