C-V2X Modem OOB Interference Mitigation via MCS Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The C-V2X system is prone to out-of-band interference from unlicensed WiFi devices in the U-NII-4 and U-NII-5 bands, which increases noise in the V2X band and reduces communication range, affecting both self-vehicles and nearby vehicles.
Innovation Solution
A method and system that detect out-of-band interference and mitigate it by adjusting Modulation Coding Scheme (MCS) values and resource reservations, using a V2X modem, OOB energy detection unit, and enhanced resource reservation algorithm to configure transmissions and schedule one-time allocations, thereby minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If C-V2X transmissions are performed in the V2X band, then vehicle-to-everything communication is enabled, but out-of-band interference from WiFi devices increases noise and reduces communication range
Solution Approach 1:
The system dynamically adjusts MCS values based on detected interference conditions. When OOB interference is detected, the system transitions from using regular MCS values to using reduced MCS values, making the transmission parameters adaptive to changing environmental conditions rather than static
Solution Approach 2:
The system changes the MCS parameter in response to detected interference. By modifying the MCS value (a key transmission parameter), the system adapts the transmission robustness to match the current channel conditions, thereby maintaining reliable communication despite the presence of OOB interference
2Reliability
If regular MCS values are used for transmission, then transmission efficiency is maintained, but resilience to out-of-band interference is insufficient
Solution Approach 1:
The system applies a partial reduction in MCS values rather than complete adaptation. By using reduced MCS values only when interference is detected (rather than always using the lowest robust setting), the system achieves sufficient interference resilience while minimizing the impact on transmission efficiency during normal conditions
3Reliability
If transmissions are continuously performed without interference checking, then communication continuity is maintained, but interference impacts reception of distant vehicles
Solution Approach 1:
The system performs preliminary interference detection during LBT periods before actual transmissions occur. By checking for OOB interference in advance and adjusting MCS values beforehand, the system prevents interference-related reception failures rather than attempting to correct them afterward
Solution Approach 2:
The system uses feedback from OOB energy detection to adjust transmission parameters. The detected interference levels feed back into the MCS selection process, creating a closed-loop control system that continuously adapts transmissions based on current channel conditions
Data Source
AI summary
System and methods for mitigating out-of-band (OOB) interference in C-V2X transmissions. The system may comprise a V2X modem for transmitting and receiving messages, an OOB energy detection unit for detecting OOB energy transmitted by a nearby WiFi transmitter inside the C-V2X band, a one-time allocation identification unit for tracking a resources map to identify a one-time allocation, and an enhanced resource reservation algorithm and modulation coding scheme (MCS) setting unit for configuring the V2X modem for transmission based on detected OOB energy and the resources map. The methods may set a MCS value while accounting for OOB interference detection and mitigation or may enhance resource reservation while accounting for OOB interference detection and mitigation.