IoV Synchronization via Non-Starting Sequence Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current synchronization methods in internet-of-vehicles systems fail to meet the requirement for time synchronization between user equipment (UEs) due to limitations in cyclic prefix (CP) duration and subcarrier spacing (SCS), especially in scenarios with high Doppler shifts and delay spreads, leading to incorrect data reception and frequency offset estimation issues.
Innovation Solution
The proposed method involves sending a first sequence for user synchronization in a non-starting part of each data transmission, allowing for time and frequency synchronization using a frequency domain algorithm, even when the CP duration of the data sending symbol is insufficient, and utilizing a longer CP structure for enhanced frequency synchronization precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UEs use downlink synchronization signal for time and frequency synchronization, then synchronization can be performed based on base station signals, but time synchronization accuracy between UEs deteriorates due to insufficient CP duration and frequency offset estimation errors
Solution Approach 1:
The patent applies preliminary action by inserting a synchronization sequence before the data signal in each transmission. This synchronization sequence is processed first to establish accurate time and frequency synchronization parameters before the actual data is received, ensuring that the receiver is properly synchronized before data processing begins. This resolves the contradiction by preparing synchronization information in advance, improving both time synchronization accuracy and data reception reliability.
Solution Approach 2:
The patent uses a synchronization sequence as an intermediary element between the transmitter and receiver. This intermediate synchronization signal carries synchronization information that mediates the time and frequency alignment process, allowing UEs to achieve accurate synchronization without relying solely on the base station's downlink synchronization signal. The intermediary synchronization sequence enables direct UE-to-UE synchronization, resolving the contradiction between synchronization capability and accuracy.
2Adaptability or versatility
If CP duration is increased to accommodate larger delay spread, then time synchronization tolerance improves, but overhead and transmission time increase
Solution Approach 1:
The patent applies segmentation by separating the synchronization function from the data transmission function. The synchronization sequence is inserted as a distinct segment before the data signal, allowing the CP duration to be optimized for synchronization purposes without necessarily increasing the overall transmission time. This segmentation enables the system to handle larger delay spreads while maintaining efficient data transmission, resolving the contradiction between synchronization tolerance and transmission time.
3Productivity
If frequency offset estimation is performed with limited CP duration, then transmission efficiency is maintained, but frequency synchronization precision deteriorates
Solution Approach 1:
The patent applies preliminary action by performing frequency offset estimation using the synchronization sequence before data reception. The synchronization sequence is processed first to accurately estimate frequency offsets, establishing precise frequency synchronization parameters before the data signal is received. This ensures that frequency synchronization precision is maintained without requiring extended CP duration during data transmission, thus preserving transmission efficiency while improving frequency synchronization accuracy.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
This application provides a synchronization method and an apparatus. The method includes: mapping, by first UE, to-be-transmitted data and a first sequence to a symbol of a first time unit, to obtain a first signal, where the first sequence is mapped to at least one symbol at a non-starting location of the first time unit; and sending, by the first UE, the first signal to second UE. The second UE receives the first signal, obtains the first sequence, and performs synchronization on the first signal based on the first sequence. A first sequence used for synchronization is sent in a symbol on a non-starting part of each data transmission, so that when CP duration of a data sending symbol cannot satisfy a time synchronization requirement, a receive-end device can still implement time synchronization on currently received data by using the first sequence, and implement frequency synchronization by performing frequency offset estimation by using a CP structure.