V2X Reference Signal Design for Unicast Link Establishment
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Solution Overview
Problem
Current cellular vehicle-to-everything (V2X) communication systems, particularly in 3GPP Release 14, lack the capability to establish unicast links between vehicles for advanced use cases such as on-demand sharing of sensor data and see-through camera feeds, which are not supported by broadcast communication.
Innovation Solution
The proposed solution involves methods and apparatus for scheduling traffic between a transmitter and a receiver, where a transmitter negotiates to reserve a slot and determines its master or slave role, sending a transmission priority signal to initiate data transmission, and the receiver responds with a clear-to-send message, enabling efficient unicast and multicast link setup and long-term key establishment for secure communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If broadcast communication is used for V2V communication, then system simplicity is maintained, but unicast link establishment capability is lost
Solution Approach 1:
The communication protocol is segmented into distinct phases: broadcast phase for initial discovery, negotiation phase for unicast link setup, and data transmission phase for actual communication. This segmentation allows the system to maintain simple broadcast operation while adding unicast capability through structured protocol phases.
Solution Approach 2:
The negotiation phase performs preliminary actions to establish unicast links before actual data transmission. Vehicles exchange negotiation messages to agree on communication parameters, resource allocation, and security settings in advance, enabling seamless transition to unicast mode without disrupting ongoing broadcast operations.
2Adaptability or versatility
If unicast links are established for advanced use cases, then communication versatility is improved, but channel access efficiency deteriorates
Solution Approach 1:
The system dynamically switches between broadcast and unicast modes based on communication requirements. The negotiation mechanism allows vehicles to transition from broadcast to unicast links on-demand, optimizing channel usage by using simple broadcast for common information and efficient unicast for dedicated data streams.
Solution Approach 2:
The protocol implements periodic negotiation cycles where vehicles periodically assess their communication needs and re-negotiate unicast link parameters. This periodic action ensures that unicast links are established only when necessary, maintaining high channel access efficiency while providing versatility when needed.
3Reliability
If negotiation-based slot reservation is implemented, then unicast link reliability is improved, but communication latency increases
Solution Approach 1:
The negotiation phase performs all necessary link establishment actions in advance, including resource allocation, parameter agreement, and security setup. By completing these preliminary actions before data transmission, the system ensures reliable unicast links without incurring latency during actual communication.
Solution Approach 2:
Vehicles autonomously perform negotiation and link establishment without requiring network controller intervention. This self-service mechanism reduces signaling overhead and latency by enabling vehicles to independently establish reliable unicast links through direct peer-to-peer negotiation.
Data Source
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AI summary
Aspects of the disclosure relate to methods and apparatus for scheduling traffic between a transmitting device and a receiving device. A transmitting device negotiates with a receiving device to reserve a slot for communicating data with the receiving device and determines whether the transmitting device is a master or a slave with respect to the receiving device. If the transmitting device is the master, the transmitting device sends, at a beginning of the slot, a transmission priority (TxP) signal, wherein the TxP signal indicates that the transmitting device intends and has priority to transmit the data in the slot. The transmitting device then receives, from the receiving device, a clear-to-send (CTS) message in the slot based on the TxP signal, and transmits the data to the receiving device in the slot upon receiving the CTS message. Other aspects, embodiments, and features are also claimed and described.