Sidelink TDD Indication via PSBCH to Avoid DL Interference
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Solution Overview
Problem
In the 5G NR system, sidelink (SL) transmission between UEs causes interference to downlink (DL) transmission due to the lack of uplink-downlink TDD configuration indication, leading to SL transmission occupying DL transmission duration.
Innovation Solution
A configuration information indication method and apparatus that provide uplink-downlink TDD configuration to UEs through simplified signaling, using the physical sidelink broadcast channel (PSBCH) of the sidelink synchronization signal block (S-SSB) to indicate periodicity and UL transmission duration, reducing signaling overheads and avoiding interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If no uplink-downlink TDD configuration is indicated to UEs, then SL transmission can be performed between UEs on the same carrier frequency, but SL transmission occupies the DL transmission duration and causes interference to DL transmission
Solution Approach 1:
The gNB performs preliminary action by indicating the uplink-downlink TDD configuration to the first UE before SL transmission occurs. This allows the first UE to proactively indicate the TDD configuration to the second UE, ensuring the second UE knows in advance which time durations are designated for UL transmission and should not be used for SL transmission, thereby preventing interference to DL transmission
Solution Approach 2:
The first UE acts as an intermediary between the gNB and the second UE. It receives the TDD configuration from the gNB and forwards this information to the second UE via indication information. This intermediary mechanism enables the second UE to obtain necessary TDD configuration information without direct signaling from the gNB, resolving the contradiction by enabling coordinated SL transmission that avoids DL interference
2Object-affected harmful factors
If full TDD configuration information is indicated from gNB to second UE through first UE, then DL transmission interference is avoided, but signaling overhead increases
Solution Approach 1:
The solution extracts only the essential elements of the TDD configuration needed for SL transmission coordination. Instead of transmitting complete TDD configuration information, the system extracts and transmits only the uplink transmission duration information that is critical for preventing SL interference to DL, thereby reducing signaling overhead while maintaining interference avoidance
Solution Approach 2:
The system applies partial action by providing only the necessary portion of TDD configuration information (uplink transmission duration) rather than the complete configuration. This partial information suffices for the second UE to avoid interfering with DL transmission, achieving the desired effect with reduced signaling overhead
Data Source
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AI summary
This application provides a configuration information indication method and an apparatus, which are applicable to fields such as vehicle to everything V2X, intelligent connected vehicles, assisted driving, and intelligent driving, to resolve an existing-technology problem that SL transmission causes interference to DL transmission, and effectively reduce signaling overheads. This method is applied to a first terminal device, and includes: receiving an uplink-downlink time division multiplex TDD configuration sent by a network device; and sending indication information to a second terminal device based on the uplink-downlink TDD configuration, where the indication information is carried on a physical sidelink broadcast channel PSBCH of a sidelink synchronization signal block S-SSB, and the indication information is used to indicate periodicity information included in the uplink-downlink TDD configuration.