Multi-TTI PUSCH Grant Scheduling to Cut Uplink Signaling Overhead

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Solution Overview

Problem

Existing wireless communication systems, particularly in NR and LTE, face challenges in efficiently scheduling physical uplink shared channels (PUSCHs) across multiple transmission time intervals (TTIs), leading to increased overhead and potential loss of medium access due to frequent switches between downlink and uplink in unlicensed spectrum.

Innovation Solution

Implementing multi-TTI grants that schedule multiple PUSCH transmissions, utilizing hybrid automatic repeat request (HARQ) process identifiers and downlink control information (DCI) to manage HARQ IDs, scramble CRC portions, and utilize unused bits for code block group transmission information, while ensuring timely channel state information reporting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple separate grants are used to schedule PUSCH transmissions in each TTI, then each transmission can be independently controlled, but signaling overhead increases and medium access efficiency decreases

Engineering Contradiction:

Improvemedium access efficiencyVSAvoidsignaling overhead

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple separate grant signaling into a single multi-TTI grant that schedules PUSCH transmissions across multiple TTIs. The DCI format includes a multi-TTI indicator field that, when set to a specific value, indicates that the grant applies to multiple TTIs. This merging approach reduces the number of separate DCI messages required, thereby reducing signaling overhead and improving medium access efficiency by minimizing the frequency of downlink-to-uplink switches.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If HARQ process IDs are assigned sequentially for each grant-based transmission, then HARQ management is simplified, but potential conflicts arise with configured grant transmissions that use fixed HARQ IDs

Engineering Contradiction:

ImproveHARQ management simplicityVSAvoidHARQ ID conflict avoidance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces dynamic HARQ ID assignment where the starting HARQ ID for multi-TTI grant-based transmissions is indicated by the base station through the DCI message. This dynamic approach allows the base station to select starting HARQ IDs that avoid conflicts with configured grant transmissions. The UE then sequentially assigns HARQ IDs to each TTI within the multi-TTI grant based on this starting value, ensuring both simplified management and conflict avoidance.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements feedback mechanisms where the base station monitors configured grant transmissions and provides feedback information to the UE. This feedback includes indications of which HARQ IDs are currently in use by configured grants, allowing the UE to adjust its HARQ ID assignments for grant-based transmissions to avoid conflicts. This feedback loop ensures reliable HARQ ID management while maintaining operational simplicity.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12526794B2Multi-transmission time interval (TTI) grant scheduling

Publication Date: 2026.01.13 QUALCOMM INC

AI summary

Certain aspects of the present disclosure provide techniques for scheduling physical uplink shared channels (PUSCHs) across multiple transmission time intervals (TTIs) using multi-TTI grants.