Sidelink Reference Signal Configuration for Beam Alignment
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently establishing and maintaining sidelink beams for unicast and groupcast transmissions, particularly in high-frequency bands like mm wave frequencies, due to issues such as lack of synchronization and beam alignment among user equipment.
Innovation Solution
The implementation of multiple sidelink reference signals, including SL CSI-RS, SL SSB, and SL PRS, with configurations for beam establishment and feedback mechanisms, such as beam correspondence and default reference signal configurations, to facilitate initial beam acquisition and synchronization in sidelink communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple reference signals are transmitted for beam acquisition, then beam alignment precision is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent segments the beam acquisition process into distinct phases: initial beam sweep using SSB signals for coarse alignment, followed by refined beam tracking using CSI-RS signals for precise alignment. This segmentation allows different reference signals to serve different purposes, improving overall beam alignment precision while managing signaling overhead through phased approach
Solution Approach 2:
The patent employs preliminary beam sweep using SSB (Synchronization Signal Block) signals before actual data transmission to establish initial beam alignment. This preliminary action enables the receiver to identify candidate beams in advance, so that subsequent CSI-RS (Channel State Information Reference Signal) transmissions can focus on refining alignment rather than searching from scratch, thereby reducing overall signaling overhead
2Area of stationary object
If beam sweeping is performed across multiple directions, then coverage area is improved, but transmission time and latency increase
Solution Approach 1:
The patent implements periodic beam sweeping where the transmitter systematically cycles through multiple beam directions in a predetermined sequence. Each beam direction is transmitted for a defined duration, allowing receivers to measure and report quality metrics. This periodic structure ensures comprehensive coverage area while controlling transmission time through efficient cycling patterns and time-division multiplexing
Solution Approach 2:
The patent employs dynamic beam adjustment where the beam sweeping pattern and duration are adapted based on channel conditions, mobility status, and traffic requirements. For example, in high-mobility scenarios, the beam sweep may be shortened or focused on likely directions, while in static scenarios, more comprehensive sweeping is performed. This dynamic approach optimizes the trade-off between coverage area and transmission time
3Reliability
If beam management procedures are implemented for unicast and groupcast, then communication reliability is improved, but protocol complexity increases
Solution Approach 1:
The patent designs a universal beam management framework that handles both unicast and groupcast communications through common procedures and signaling mechanisms. The same reference signal structures (SSB, CSI-RS) and feedback mechanisms are used for both transmission types, with adaptations only in specific parameters. This universality improves communication reliability through consistent beam management while reducing protocol complexity by avoiding separate procedures for different cast types
Solution Approach 2:
The patent implements feedback mechanisms where receivers report beam quality metrics (such as RSRP - Reference Signal Received Power) back to transmitters. This feedback enables transmitters to adjust beam directions and selections to maintain optimal links. For unicast, dedicated feedback is used, while for groupcast, feedback aggregation and representative reporting are employed. These feedback procedures enhance communication reliability by enabling adaptive beam management while managing protocol complexity through standardized feedback formats
Data Source
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AI summary
Apparatuses, methods, and systems are disclosed for multiple sidelink RSs. One method (1000) includes transmitting (1002), from a transmitter user equipment to a receiver user equipment, information indicating RSs. The information further indicates beams and/or panels transmitting first layer control signaling indicating target user information, resource configuration of a RS for receiver decoding or transmitting using a default reference signal configuration, and a time slot offset and time frequency resource. Transmitting the information indicating the RSs includes determining (1004) to transmit: the RSs as part of the initial beam acquisition together with a higher layer discovery request message and/or prior to higher layer signaling. The receiver user equipment determines (1006) the target user information, and generates and transmits: a beam measurement feedback using a beam correspondence; or a RS indicating the beams and/or the panels in the time slot offset if not supporting beam correspondence.