TX Terminal Modulation Scheme Selection via Link Quality
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Solution Overview
Problem
Current V2X communication technologies are limited to low-order modulation schemes like QPSK and 16QAM, which restrict data rate, reliability, and latency in advanced V2X applications, necessitating a method to determine link quality for higher order modulation schemes like 32QAM or 64QAM without compromising reliability and latency.
Innovation Solution
A TX terminal device determines link quality based on its context and reference signal received qualities (RSRQs) from RX terminal devices, allowing it to dynamically select a modulation scheme higher than 16QAM, such as 64QAM, for transmission, and optionally confirms with a network device before applying the higher order modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low-order modulation schemes (QPSK, 16QAM) are used in V2X communication, then reliability and latency requirements are met, but data rate is restricted
Solution Approach 1:
The patent implements dynamic modulation scheme selection where the TX terminal device adapts the modulation order based on real-time link quality measurements. The system transitions from static low-order modulation to dynamic modulation adaptation, allowing switching between QPSK, 16QAM, 32QAM, 64QAM, and higher order schemes depending on channel conditions, thereby resolving the contradiction between data rate and reliability
Solution Approach 2:
The patent changes the modulation order parameter from fixed low-order (QPSK, 16QAM) to variable high-order schemes (32QAM, 64QAM, 256QAM) based on link quality. By adjusting this key parameter dynamically, the system achieves higher data rates when channel conditions permit while maintaining reliability through adaptive selection, directly addressing the technical contradiction
2Productivity
If higher order modulation schemes (32QAM, 64QAM) are used, then data rate increases, but link quality requirements become more stringent
Solution Approach 1:
The patent performs preliminary link quality measurement and evaluation before selecting the modulation scheme. The TX terminal device measures RSRQ from RX terminal devices and evaluates propagation conditions in advance to determine whether high-order modulation is feasible, preventing inappropriate modulation selection and ensuring reliable communication
Solution Approach 2:
The patent implements a feedback mechanism where RX terminal devices send RSRQ measurements back to the TX terminal device. This feedback loop enables the TX device to continuously monitor link quality and adjust modulation order accordingly, ensuring that high-order modulation schemes are only used when link quality supports them, thus resolving the contradiction between data rate and measurement precision requirements
3Productivity
If adaptive modulation scheme selection is implemented, then data rate and reliability are improved, but system complexity increases
Solution Approach 1:
The patent enables the TX terminal device to autonomously determine link quality and select appropriate modulation schemes without requiring complex network-side control. The system performs self-evaluation of propagation conditions and self-selection of modulation orders, reducing overall system complexity while maintaining adaptive performance
Solution Approach 2:
The patent designs a universal link quality measurement and modulation selection mechanism that works across different V2X scenarios (V2V, V2P, V2I). The same RSRQ-based evaluation and adaptive modulation framework applies to all direct link communication types, simplifying implementation while achieving improved communication efficiency across diverse applications
Data Source
AI summary
Method and apparatus for determining a modulation scheme in direct link-based communication. A method implemented in a transmitting (TX) terminal device is provided. According to the method, a link quality of a direct link for transmission of information from the TX terminal device to one or more receiving (RX) terminal devices is determined based on one or more of the following: a context of the TX terminal device, or one or more reference signal received qualities (RSRQs) from the one or more RX terminal devices. A modulation scheme for modulating the information is determined based on the link quality. The information is modulated with the determined modulation scheme and the modulated information is transmitted to the one or more RX terminal devices via the direct link.