Terminal Device HARQ Process ID Disambiguation via NDI

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Solution Overview

Problem

In new radio (NR) systems, terminal devices face challenges in determining whether scheduling signaling is for initial data transmission or retransmission due to HARQ process IDs being shared across different transmission types, leading to incorrect data reception handling.

Innovation Solution

A method where a terminal device receives scheduling signaling scrambled by a first RNTI, carrying an HARQ process ID and NDI, and determines whether the NDI is toggled or fixed based on the RNTI and previous scheduling mode, allowing it to differentiate between initial and retransmitted data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If HARQ process IDs are shared across multicast and unicast services, then resource utilization is improved, but the terminal device cannot determine whether scheduling is for initial transmission or retransmission

Engineering Contradiction:

Improveresource utilizationVSAvoidtransmission type identification

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent introduces the NDI as an intermediary indicator that mediates between the shared HARQ process ID space and the need to identify transmission type. The NDI acts as an additional signaling element that disambiguates whether a scheduled transmission is initial or retransmission when HARQ process IDs are reused across different service types.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the terminal device uses the same HARQ process ID for different transmission types, then device complexity is reduced, but measurement precision of transmission type deteriorates

Engineering Contradiction:

ImproveHARQ process managementVSAvoidtransmission type determination

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the parameter used for transmission type determination from relying solely on HARQ process ID to using the NDI parameter. By monitoring changes in the NDI value, the terminal device can accurately identify transmission type without increasing the complexity of HARQ process management, thus resolving the contradiction between device complexity and measurement precision.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If HARQ process IDs are unified across service types, then system simplicity is improved, but reliability of data reception handling deteriorates

Engineering Contradiction:

ImproveHARQ process ID managementVSAvoiddata reception handling

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The NDI serves as a reliable intermediary indicator that ensures correct data reception handling despite unified HARQ process IDs. The terminal device uses the NDI to reliably determine whether to perform HARQ retransmission or new data reception, thereby maintaining high reliability in data reception handling while keeping the HARQ process ID management simple and unified.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20240313904A1Method for information determination, terminal device, and chip

Publication Date: 2024.09.19 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

A method for information determination includes the following. A terminal device receives first scheduling signaling. The first scheduling signaling is scrambled by a first radio network temporary identity (RNTI), and the first scheduling signaling carries a hybrid automatic repeat request (HARQ) process identifier (ID) and a new data indication (NDI). The terminal device determines, according to the first RNTI and/or a previous scheduling mode corresponding to the HARQ process ID, whether the NDI is toggled and/or a value of the NDI.