Grant-Free Downlink Decoding Within Repetition Windows
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Solution Overview
Problem
Existing wireless communication systems face challenges in achieving low latency downlink transmissions due to scheduling overhead, which increases latency and is undesirable for ultra-reliable low latency communications (URLLC).
Innovation Solution
Implementing grant-free downlink transmission frameworks that configure user equipment (UE) with parameters such as time/frequency resources, transport block size, redundancy version sequence, and repetition window size, allowing the UE to efficiently decode downlink transmissions within a threshold latency by reducing blind decoding attempts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scheduled downlink transmission is used, then transmission reliability is improved, but latency increases due to scheduling overhead
Solution Approach 1:
The patent extracts the scheduling function from the downlink transmission process by implementing grant-free transmission. The UE is pre-configured with resources and parameters through RRC signaling, eliminating the need for dynamic scheduling grants. This extraction of the scheduling step directly reduces latency while maintaining reliability through pre-configured robust transmission parameters.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the UE with all necessary transmission parameters (time/frequency resources, TBS, RV sequence, repetition window size) before the actual data transmission occurs. This preliminary configuration through RRC signaling allows the UE to immediately decode downlink transmissions without waiting for scheduling grants, thereby reducing latency while ensuring reliable transmission through pre-optimized parameters.
2Loss of time
If blind decoding attempts are reduced, then decoding latency is improved, but decoding accuracy may worsen
Solution Approach 1:
The patent changes the parameter configuration approach by providing the UE with a specific RV sequence and other transmission parameters through RRC signaling before grant-free transmission. This parameter pre-configuration allows the UE to perform fewer blind decoding attempts with higher accuracy, as the UE already knows the expected parameter values rather than having to search through multiple possibilities.
3Productivity
If grant-free transmission framework is implemented, then scheduling overhead is reduced, but system complexity increases
Solution Approach 1:
The patent segments the transmission configuration into two parts: (1) Semi-static parameters configured through RRC signaling (time/frequency resources, TBS, RV sequence, repetition window size), and (2) Dynamic transmission content. This segmentation allows the complex parameter configuration to be handled once during setup, while subsequent transmissions can proceed efficiently without repeated scheduling overhead, thus improving productivity while managing system complexity.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. The described techniques generally support downlink transmissions. For example, a user equipment (UE) may receive a resource configuration for reception of a downlink transmission within a repetition window, the resource configuration including an indicator of a repetition window size for the downlink transmission. The UE may monitor, according to the resource configuration, one or more transmission time intervals (TTIs) of the repetition window for reception of the downlink transmission. In some cases, the downlink transmission may be a grant-free downlink transmission. Here, the UE may attempt to decode the grant-free downlink transmission during the one or more TTIs based at least in part on the repetition window size. Using the described techniques, the UE may efficiently determine one or more decoding parameters for the grant-free downlink transmission, thereby providing benefits in terms of latency reduction, power consumption, etc.