Sidelink Transmission Reliability at High UE Speed
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Solution Overview
Problem
The reliability of sidelink transmission reception in wireless communication systems, particularly at higher speeds, is compromised due to lower observed signal-to-noise ratio (SNR) and frequency shifts, affecting the reliability of safety-critical messages like V2X communications.
Innovation Solution
A method where a user equipment (UE) adjusts its power class (PC) and/or transmission scheme based on its speed state and the criticality of the message, such as switching to a higher power class or using transmit diversity schemes like TxD or CDD, to enhance the reliability of sidelink communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE transmits sidelink communications at higher speeds, then the coverage area and communication range are improved, but the reliability of transmission reception deteriorates due to lower observed SNR and frequency shifts
Solution Approach 1:
The patent applies dynamics by making the power class and transmission scheme adjustable based on UE speed state. The system dynamically switches between different power classes (PC1, PC2, PC3) and transmission schemes (TxD, CDD, normal) according to whether the UE is in high-speed or normal speed state, allowing the transmission parameters to adapt to changing speed conditions and maintain reliability.
Solution Approach 2:
The patent changes physical transmission parameters (power class and transmission scheme) based on speed state. When the UE enters high-speed state, it switches to higher power classes and specific transmission schemes designed to counteract the effects of high speed on signal quality, such as transmit diversity and cyclic delay diversity schemes that provide frequency diversity.
2Reliability
If the UE uses higher power class and transmit diversity schemes to improve reliability, then the transmission power and signal quality are improved, but the use of energy and device complexity increase
Solution Approach 1:
The system dynamically adjusts power class and transmission scheme based on speed state, using higher power and more complex schemes only when necessary (in high-speed state). This dynamic adaptation ensures that energy-consuming reliability enhancement measures are applied selectively rather than continuously, optimizing the trade-off between reliability and energy consumption.
Solution Approach 2:
The patent changes power class and transmission scheme parameters conditionally based on speed state. By switching to higher power classes (PC2, PC3) and diversity schemes only when the UE is in high-speed state, the system maintains reliability when needed while minimizing energy consumption during normal operation.
3Reliability
If the UE uses higher power class and transmit diversity schemes, then the transmission power and reliability are improved, but the device complexity increases
Solution Approach 1:
The system dynamically selects transmission schemes based on speed state, using complex schemes (TxD, CDD) only in high-speed state when reliability is compromised. This dynamic selection allows the device to maintain simple normal transmission during typical operation while activating complexity-only-when-needed approaches to maintain reliability during high-speed operation.
4Reliability
If the UE continuously monitors speed state and adjusts transmission parameters, then the reliability at high speeds is improved, but the processing time and computational resources increase
Solution Approach 1:
The system performs preliminary determination of speed state and pre-selects appropriate power classes and transmission schemes based on predefined speed thresholds. By having predetermined the mapping between speed states and transmission parameters, the system avoids complex real-time calculations during transmission, reducing processing time while maintaining reliability.
Data Source
AI summary
An apparatus for wireless communications at a first UE may include a memory and at least one processor couple to the memory. The memory and the at least one processor may be configured to select one or more of a PC or a transmission scheme in response to the first UE meeting a speed state threshold. The memory and the at least one processor may be further configured to transmit a sidelink transmission using the one or more of the PC or the transmission scheme based on the first UE meeting the speed state threshold.