Terminal Device MCS Configuration for URLLC PUSCH Reliability
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Solution Overview
Problem
In New Radio (NR) systems, there is a challenge in efficiently determining the modulation and coding scheme (MCS) for retransmissions of the physical uplink shared channel (PUSCH) during the random access process, particularly in indicating the correct MCS index and number of repetitions for improved transmission reliability and latency in ultra-reliable and low-latency communications (URLLC).
Innovation Solution
The method involves determining a target MCS for the PUSCH based on a target MCS parameter and information field, where the parameter indicates multiple MCS indexes, allowing the terminal device to configure the PUSCH for message 3 transmission during the random access process, and the network device transmits the target MCS parameter to the terminal device to ensure accurate MCS selection for both initial and retransmission scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single MCS index is used for PUSCH transmission, then the configuration is simple, but the transmission reliability for URLLC services is insufficient
Solution Approach 1:
The MCS parameter is segmented into multiple MCS indexes (first MCS index and second MCS index) that can be independently selected and configured. This segmentation allows the system to choose different MCS indexes for different transmission scenarios (initial transmission vs. retransmission), thereby improving transmission reliability for URLLC services while maintaining manageable configuration complexity through structured parameter design.
2Reliability
If multiple MCS indexes are configured for different scenarios, then the transmission reliability improves, but the signaling overhead increases
Solution Approach 1:
The patent extracts and independently configures the second MCS index specifically for retransmission scenarios, separating it from the first MCS index used for initial transmission. This extraction allows the system to optimize MCS selection for retransmissions without affecting initial transmission configuration, improving reliability while managing signaling overhead through targeted parameter configuration rather than comprehensive reconfiguration.
Solution Approach 2:
Different MCS indexes are applied to different transmission scenarios: the first MCS index is used for initial PUSCH transmission while the second MCS index is specifically used for retransmission. This local quality approach ensures that each transmission scenario uses the most appropriate MCS configuration, optimizing reliability for URLLC services while avoiding unnecessary signaling overhead by not applying uniform configuration across all scenarios.
3Speed
If the MCS parameter is optimized for initial transmission, then the initial access speed is fast, but the retransmission reliability is compromised
Solution Approach 1:
The MCS configuration becomes dynamic by introducing a second MCS index that is specifically activated for retransmission scenarios. The terminal device can flexibly switch between the first MCS index (optimized for initial transmission speed) and the second MCS index (optimized for retransmission reliability) based on the transmission scenario. This dynamic parameter adjustment allows the system to optimize for speed during initial access while ensuring reliability during retransmissions, addressing both requirements effectively.
Data Source
AI summary
Provided is a method for wireless communication. The method includes: determining, by a terminal device, a target modulation and coding scheme (MCS) for transmitting a physical uplink shared channel (PUSCH) based on a target MCS parameter and a target MCS information field, wherein the target MCS parameter indicates N MCS indexes, N being a positive integer greater than 1, and the PUSCH is configured to carry a message 3 (Msg3) in a random access process.