SSB Beam Groupcast Timing for Efficient V2X Transmission
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Solution Overview
Problem
Existing groupcast transmission methods in V2X communication are inefficient due to the need to transmit the same data to multiple UEs using narrow beams, leading to resource wastage and time consumption.
Innovation Solution
A method and apparatus for groupcast transmission using a synchronization signal block (SSB) beam to align multiple UEs, determining groupcast timing, and transmitting data simultaneously to these UEs using the SSB beam, with retransmissions handled via unicast beams for UEs that send NACK feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If narrow beams are used for groupcast transmission to multiple UEs, then transmission precision and reliability are improved, but resource efficiency deteriorates due to repeated transmissions
Solution Approach 1:
The patent segments the transmission process into two distinct phases: (1) initial groupcast transmission using wide SSB beams to reach multiple UEs simultaneously, and (2) targeted retransmission using narrow unicast beams only for UEs that failed to decode successfully. This segmentation allows the system to benefit from both wide beam coverage and narrow beam precision without the drawbacks of either approach being applied throughout the entire transmission process.
Solution Approach 2:
The patent applies partial action by using narrow unicast beams only partially - specifically, only for the subset of UEs that require retransmission, rather than applying narrow beams to all UEs. This partial application of narrow beam technology reduces overall resource consumption while maintaining reliability for those who need it.
2Measurement precision
If narrow beams are used for groupcast transmission to multiple UES, then transmission precision is improved, but transmission time increases due to repeated transmissions
Solution Approach 1:
The transmission process is divided into an initial wide beam phase for rapid groupcast to multiple UEs, followed by a targeted narrow beam phase only for UEs requiring retransmission. This segmentation enables the system to achieve both fast initial transmission and precise retransmission, optimizing overall transmission time.
Solution Approach 2:
The patent performs preliminary action by using wide SSB beams to establish initial contact and transmit data to all potential target UEs simultaneously before determining which specific UEs require retransmission. This preliminary wide beam transmission prevents the need for sequential narrow beam transmissions to multiple UEs, significantly reducing overall transmission time.
3Loss of energy
If wide SSB beams are used for groupcast transmission, then resource efficiency is improved by simultaneous transmission to multiple UES, but transmission precision may be compromised
Solution Approach 1:
The patent segments the beam transmission approach into two stages: wide SSB beams for the initial groupcast transmission to maximize resource efficiency, followed by narrow unicast beams for targeted retransmissions to ensure precision for specific UEs. This segmentation allows each beam type to be used where it provides the most benefit.
Solution Approach 2:
The patent merges two different beam transmission approaches - wide SSB beams and narrow unicast beams - into a unified transmission strategy. The wide beams handle the initial groupcast to multiple UEs simultaneously, while narrow beams handle subsequent targeted retransmissions, combining the advantages of both beam types.
Data Source
AI summary
Provided are a method by which a transmission terminal performs groupcast transmission in a wireless communication system, and a device. The method transmits a synchronization signal block (SSB) through an SSB beam, receives, from each of a plurality of terminals, a discovery message as a response to the SSB, determines a groupcast transmission timing for specific terminals from among the plurality of terminals on the basis of the discovery message, transmits, to the specific terminals, a group transmission/reception timing message indicating the groupcast transmission timing, and performs groupcast transmission for the specific terminals by using the SSB beam at the groupcast transmission timing.