Collaborative Message Retransmission for Low-Overhead V2X Broadcasts
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Solution Overview
Problem
Conventional message retransmission solutions in wireless communication systems, particularly in the Internet of Vehicles, suffer from high signaling overheads and low time-frequency resource utilization, especially in intra-group message retransmissions where additional resources are allocated for retransmissions.
Innovation Solution
Implementing a message transmission method where terminal devices in a multicast group collaboratively retransmit data without requiring additional resources, by utilizing linear combinations of data and feedback mechanisms to ensure reliability and efficient resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional resources are allocated for retransmission in conventional message retransmission solutions, then message reliability is improved, but signaling overhead increases and time-frequency resource utilization decreases
Solution Approach 1:
Terminal devices in the multicast group perform self-service by autonomously determining when to retransmit messages based on receiving NACK feedback, without requiring base station coordination or additional signaling. Any terminal that successfully receives the message can become a retransmission source, eliminating the need for dedicated retransmission resources from the base station.
Solution Approach 2:
Multiple terminal devices in the multicast group can serve as potential retransmission sources, making the system universal and flexible. Instead of designating a single retransmission device, any terminal that receives the message can fulfill the retransmission function, distributing the burden and improving resource utilization across the group.
2Reliability
If additional resources are allocated for retransmission in conventional message retransmission solutions, then message reliability is improved, but time-frequency resource utilization decreases
Solution Approach 1:
Terminal devices autonomously manage retransmissions using existing uplink resources, converting what would be downlink retransmission resources into uplink opportunities. This self-service approach allows efficient use of available time-frequency resources without requiring additional base station allocations.
Solution Approach 2:
The conventional approach has the base station performing retransmissions in downlink, but this invention inverts the direction by having terminal devices perform retransmissions in uplink. This inversion allows better utilization of uplink resources and reduces the burden on downlink time-frequency resources.
3Ease of operation
If the base station configures feedback time index tables using RRC messages and indicates specific indices using DCI, then feedback timing is controlled, but signaling overhead increases
Solution Approach 1:
Terminal devices autonomously determine feedback timing based on pre-agreed rules within the multicast group, eliminating the need for base station configuration of feedback time index tables. The terminals self-manage the feedback process by selecting appropriate uplink resources independently.
Solution Approach 2:
The feedback timing control function is extracted from the base station and transferred to the terminal devices themselves. Terminals take out the responsibility of determining when to provide feedback and when to perform retransmissions, removing the signaling overhead associated with base station control while maintaining coordinated operation.
Data Source
AI summary
The disclosure provides message transmission methods and apparatuses, which can be used in various communication systems, for example, a V2X communication system, an LTE-V communication system, a V2V communication system, an IoV communication system, an MTC system, an IoT communication system, an LTE-M communication system, and a M2M communication system. One example method includes that a second terminal device receives a first message, where the first message is a broadcast message from a first terminal device, and the first message includes first data. The second terminal device receives a reception failure message for the first message, where the reception failure message for the first message is a broadcast message from a third terminal device, and the second terminal device broadcasts a second message, where the second message includes the first data.