V2X Terminal TTI Selection via Distinct RNTIs
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Solution Overview
Problem
The introduction of a short transmission time interval (S-TTI) in V2X communication systems poses challenges in packet data latency reduction, leading to issues in PSCCH interpretation methods, field configuration, and payload size setting, which existing technologies struggle to address effectively.
Innovation Solution
A V2X communication method that efficiently controls and interprets PSSCH by distinguishing between first and second TTIs, using different radio network temporary identifiers, and dynamically scheduling transmissions based on predefined subchannel groups, allowing for seamless coexistence of S-TTI and L-TTI-based V2X communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If S-TTI is introduced to reduce packet data latency, then transmission speed is improved, but device complexity increases due to multiple TTI configurations
Solution Approach 1:
The system dynamically switches between S-TTI and L-TTI configurations based on service requirements. The base station can flexibly configure different TTI lengths for different V2X services, allowing the system to adapt transmission time intervals to specific application needs while maintaining operational simplicity through standardized handling procedures
Solution Approach 2:
The V2X service is segmented into different TTI types (S-TTI and L-TTI) with distinct RNTI configurations. First DCI with first RNTI handles S-TTI services, while second DCI with second RNTI handles L-TTI services. This segmentation allows independent optimization of each TTI type without increasing overall system complexity
2Adaptability or versatility
If multiple DCI formats with different RNTIs are used to support both S-TTI and L-TTI, then adaptability is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
Different RNTI types serve as intermediaries to distinguish between S-TTI and L-TTI DCI formats. The first RNTI and second RNTI act as identifiers that enable the UE to correctly interpret DCI content without requiring complex detection mechanisms. This intermediary approach simplifies the detection process by providing clear differentiation signals
Solution Approach 2:
Different RNTI configurations are applied locally to specific DCI formats based on their TTI type. First DCI uses first RNTI for S-TTI services, while second DCI uses second RNTI for L-TTI services. This localized differentiation allows the system to maintain high adaptability while keeping detection rules simple and context-specific
3Manufacturing precision
If PSCCH payload size is adjusted for S-TTI, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The PSCCH payload size parameter is changed based on TTI type. For S-TTI services, the payload size is optimized to match the shorter transmission interval, while L-TTI services use the conventional payload size. This parameter adjustment enables precise configuration for each service type without requiring complex structural changes to the PSCCH format
Data Source
AI summary
Provided are a V2X communication method of a terminal in a wireless communication system and a terminal using the method. The method is characterized by: receiving at least one DCI of a first DCI based on a first TTI and a second DCI based on a second TTI, from a base station through a PDCCH; and, based on the at least one DCI, performing V2X communication by using one of the methods of transmission based on the first TTI and transmission based on the second TTI, wherein the first TTI is shorter than the second TTI, a first RNTI configured for the first DCI is different from a second RNTI configured for the second DCI, and which one between the first TTI-based transmission and the second TTI-based transmission is accepted is determined based on one of the first RNTI and the second RNTI.