Vehicle Channel Occupation Message for Hidden Node Mitigation
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Solution Overview
Problem
In the context of 5G V2X communications, the hidden node problem arises due to the directional nature of beamformed communications at higher frequency bands, where neighboring vehicles may not be able to sense interferers, leading to inefficient resource selection and increased signal attenuation, which complicates reliable data transmission.
Innovation Solution
The method involves generating and transmitting a channel occupation message (COM) that provides information about the occupancy of radio channels, allowing vehicles to select suitable channels for communication and improve signal strength by determining available and unavailable resources, thereby reducing unnecessary retransmissions and channel load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming is used at higher frequency bands, then communication reliability is improved through directional signal transmission, but the hidden node problem worsens because neighboring vehicles cannot sense interferers
Solution Approach 1:
The patent introduces a receiving vehicle as an intermediary that senses interferers and communicates this information to transmitting vehicles via COM messages. This mediator role allows transmitting vehicles to obtain hidden node information without needing direct sensing capability, resolving the contradiction between beamforming reliability and interferer detection difficulty
Solution Approach 2:
The system implements feedback through COM messages where receiving vehicles provide information about channel occupancy and interferers back to transmitting vehicles. This feedback loop enables transmitting vehicles to make informed resource selection decisions, addressing the hidden node problem while maintaining beamforming benefits
2Difficulty of detecting and measuring
If omnidirectional antennas are used at sub-6GHz bands, then interferer sensing is improved allowing better resource selection, but signal attenuation worsens in harsh mmWave environments
Solution Approach 1:
The patent segments the sensing function from the transmission function. Omnidirectional antennas are used only for sensing interferers and selecting resources, while separate beamforming is applied during actual data transmission. This segmentation allows the system to enjoy both the interferer detection capability of omnidirectional antennas and the low attenuation of beamformed transmission
Solution Approach 2:
The system performs preliminary interferer sensing and resource selection using omnidirectional antennas before switching to beamformed transmission. This preliminary action ensures that the transmitting vehicle selects resources that are free from hidden node interference, and then uses beamforming to transmit data with minimal signal attenuation
3Ease of operation
If random subchannel selection is used during sensing window, then resource selection simplicity is improved, but communication efficiency worsens due to hidden node collisions
Solution Approach 1:
The patent applies preliminary action by having receiving vehicles sense interferers and communicate channel occupancy information via COM messages before transmitting vehicles make resource selections. This preliminary information exchange enables transmitting vehicles to avoid hidden node collisions while maintaining relatively simple resource selection procedures
Solution Approach 2:
The system uses feedback through COM messages to inform transmitting vehicles about channel occupancy and potential hidden node interferers. This feedback mechanism allows transmitting vehicles to make more efficient resource selections without significantly complicating the resource selection process, thereby improving communication efficiency
Data Source
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AI summary
Embodiments relate to a method 100 for a vehicle for improving communication via a radio channel. The method 100 comprises generating 110 a channel occupation message, COM, which comprises information about an occupancy of one or more radio channels and transmitting 120 the COM to a further vehicle.