5G NR TDD Configuration Indication for Accurate Sidelink Timing
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Solution Overview
Problem
In 5G NR systems, sidelink (SL) transmission on the PC5 interface causes interference to downlink (DL) transmission due to inaccurate indication of uplink (UL) transmission time, which is not adequately considered in conventional uplink-downlink TDD configurations.
Innovation Solution
A method and apparatus that determine a first subcarrier spacing (SCS) based on periodicity information to accurately indicate UL transmission time, using a function relationship formula to ensure precise UL slot quantities, thereby allowing SL transmission without interfering with DL transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional uplink-downlink TDD configuration is used to indicate UL transmission time, then the configuration can be transferred between UEs, but the indication accuracy is poor and SL transmission causes interference to DL transmission
Solution Approach 1:
The patent introduces a new parameter - SL reference SCS (subcarrier spacing) - to accurately indicate UL transmission time for SL transmission. By determining the SL reference SCS based on the TDD configuration's periodicity information and using it to calculate the UL slot quantity, the system achieves precise time indication that prevents SL interference to DL transmission.
2Productivity
If SL transmission is performed without accurate UL transmission time indication, then SL communication can proceed, but interference to DL transmission occurs
Solution Approach 1:
The patent establishes a feedback mechanism where the first UE determines the SL reference SCS based on received TDD configuration information and periodically indicates the UL transmission time to the second UE. This continuous time synchronization and indication process ensures SL transmission occurs only in appropriate time slots, preventing interference to DL transmission while maintaining SL communication productivity.
Data Source
AI summary
A configuration information indication method and apparatus, applicable to systems such as a vehicle to everything V2X communication system and a vehicle-to-vehicle V2V communication system, to resolve a problem that SL transmission causes interference to DL transmission due to relatively poor indication accuracy of UL transmission time in the conventional technology. The method includes: receiving an uplink-downlink time division duplex TDD configuration from a network device; determining, based on first periodicity information included in the uplink-downlink TDD configuration, a first subcarrier spacing SCS corresponding to the first periodicity information, where the first SCS is used to indicate a sidelink SL reference SCS; and sending indication information to a second terminal device based on the uplink-downlink TDD configuration and the first SCS, where the indication information is used to indicate uplink UL transmission time corresponding to the first periodicity information.