V2X Collision Avoidance via Energy Detection and Dynamic Resource Allocation
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Solution Overview
Problem
In wireless communication systems, especially for V2X (Vehicle-to-Everything) transmissions, existing resource allocation methods, such as UE autonomous selection, often result in resource collisions due to random selection of resources, which can lead to high latency and fail to meet low latency requirements, particularly when the minimum time period for transmission is 40 ms, causing delays and potential collisions for both scheduling and data transmissions.
Innovation Solution
The proposed solution involves an apparatus and method that detects energy levels in specific frequency resources within defined time and frequency units (TRUs) to determine if they are below a predetermined threshold, allowing for the selection and reservation of these resources for transmission, thereby avoiding collisions by transmitting a signal only if the energy is below the threshold, ensuring the resource is not in use by other devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If UE autonomous resource selection is used, then signaling overhead is reduced and out-of-network coverage is supported, but resource collisions occur due to random selection
Solution Approach 1:
The patent applies preliminary action by performing Clear Channel Assessment (CCA) before transmitting V2X data. The UE checks whether the channel is idle or occupied in advance, and only proceeds with transmission if the channel is determined to be idle. This preliminary channel status check prevents resource collisions before they occur, resolving the contradiction between autonomous resource selection and collision avoidance.
2Device complexity
If minimum time period for transmission is set to 40 ms, then resource allocation is simplified, but latency requirements are not met due to long wait times
Solution Approach 1:
The patent applies dynamics by making the transmission time period adaptive rather than fixed. The UE determines the time period between SA transmission and associated data transmission based on actual channel conditions and latency requirements. This dynamic adjustment allows the system to reduce wait times when low latency is required, while maintaining simplified resource allocation when conditions permit.
3Ease of operation
If random resource selection is used for SA and data transmission, then resource allocation is simple, but collisions occur in both SA and data resources
Solution Approach 1:
The patent applies feedback by using the result of CCA channel assessment to determine whether transmission should proceed. The UE receives feedback about channel occupancy status, and this feedback directly controls the transmission decision. If the channel is occupied, transmission is avoided; if idle, transmission proceeds. This feedback mechanism ensures reliable collision-free transmission while maintaining operational simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces resource collisions and meets low latency requirements by ensuring that transmissions occur only when the selected resources are available, optimizing resource allocation and minimizing wait times in V2X communication systems.
Implementation Method 1
a processor that detects a first energy in a first detection slot within a first time period over a first frequency resource of a first transmission resource unit ('TRU')
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for collision avoidance. One apparatus includes a processor that detects energy in a detection slot within a first time period over a first frequency resource of a transmission resource unit (“TRU”). The TRU includes the first time period, a second time period contiguous in time with the first time period, a second frequency resource, and a third frequency resource contiguous in frequency with the second frequency resource. The energy is below a predetermined threshold. The apparatus also includes a transmitter that transmits a time-contiguous signal after the detection slot until an end of the first time period over the first frequency resource. The transmitter transmits data within the second time period over the third frequency resource. The transmitter transmits a scheduling assignment (“SA”) within the second time period over the second frequency resource. The SA includes information related to the data.