Repeater Beam Determination Using PDCCH Resource Mapping
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Solution Overview
Problem
In wireless communication systems, repeaters face challenges in determining reception and transmission beams for links between a base station and the repeater, as well as between the repeater and user equipment, due to the lack of beam indication information from the gNB during procedures like random access channel (RACH) and beam failure recovery (BFR).
Innovation Solution
A method and apparatus for beam determination in repeaters, involving a transceiver and processor configured to receive information on resource mapping in time and frequency domains for physical downlink control channels, and determine spatial domain filters based on this information to establish beams for links between the gNB and repeater, and between the repeater and UE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gNB does not provide beam indication information to the repeater during RACH and BFR procedures, then the system maintains legacy compatibility and simple signaling, but the repeater cannot determine the reception and transmission beams for links between gNB-repeater and repeater-UE
Solution Approach 1:
The patent introduces reference signals (SSBs, CSI-RS) as intermediary elements that carry beam information indirectly. The gNB transmits these reference signals with embedded spatial domain filter information, allowing the repeater to infer beam characteristics without direct beam indication signaling. This mediator approach resolves the contradiction by providing necessary beam determination capability while maintaining legacy signaling compatibility.
Solution Approach 2:
The repeater performs self-service beam determination by autonomously measuring reference signals and deriving spatial domain filters from the received signal characteristics. Instead of relying on explicit gNB beam indications, the repeater independently determines appropriate beams for both gNB-repeater and repeater-UE links through self-measurement and processing of reference signals.
2Ease of operation
If the repeater determines beams independently without gNB indication, then the repeater gains beam determination capability, but the system loses synchronization and coordination between gNB, repeater, and UE
Solution Approach 1:
The patent implements feedback mechanisms where the repeater measures reference signals, determines spatial domain filters, and this information is subsequently used to configure both downlink and uplink transmissions. The feedback loop ensures that beam decisions made autonomously by the repeater remain synchronized with gNB intentions and UE requirements, maintaining system coordination while enabling operational autonomy.
Solution Approach 2:
The patent utilizes changes in reference signal parameters (time, frequency, spatial domain) to convey beam information indirectly. By encoding beam characteristics in the parameters of SSBs and CSI-RS rather than explicit beam indication messages, the system allows the repeater to determine beams autonomously while maintaining coordination through the structured parameter relationships that reflect gNB's beam management decisions.
3Measurement precision
If explicit beam indication signaling is introduced from gNB to repeater, then the repeater can accurately determine beams, but the signaling complexity and overhead increase
Solution Approach 1:
The patent makes reference signals serve multiple functions: they act as both channel estimation references and beam indication carriers. The same SSBs and CSI-RS used for basic channel measurement also embed spatial domain filter information for beam determination. This multi-functionality approach provides accurate beam indication without introducing separate dedicated signaling, thereby avoiding increased signaling complexity.
Solution Approach 2:
The patent copies beam information from the spatial characteristics of reference signals rather than transmitting separate beam indication data. The spatial domain filters are derived by copying the angular and spatial properties already present in the reference signal transmissions, eliminating the need for additional explicit beam indication signaling while maintaining measurement precision.
4Device complexity
If the repeater uses the same spatial domain filter for both gNB-repeater and repeater-UE links, then the device complexity is reduced, but the communication performance deteriorates due to channel mismatch
Solution Approach 1:
The patent segments the beam determination process into separate spatial domain filters for different links. Instead of using a single unified filter, the repeater determines distinct spatial domain filters for the gNB-repeater link and the repeater-UE link based on separate reference signal measurements. This segmentation allows each filter to be optimized for its specific channel conditions, maintaining communication performance while managing complexity through structured separation.
Solution Approach 2:
The patent applies local quality by tailoring spatial domain filters to specific link characteristics. Each spatial domain filter is customized to match the local channel conditions of its respective link (gNB-repeater or repeater-UE) rather than using a generic unified filter. This localized optimization ensures that each filter is specifically adapted to its operating environment, maintaining high communication performance while the overall system manages complexity through this modular approach.
Data Source
AI summary
Embodiments of the present application are related to a method and apparatus of beam determination. According an embodiment of the present application, an exemplary method includes: receiving information indicating mapping between a set of resources in at least one of time and frequency domain for PDCCH and a set of spatial domain filters; and determining at least one of the following based on the information: a first spatial domain filter for a first resource for PDCCH between the RAN node and a second RAN node; or a second spatial domain filter for a second resource for PDCCH between the RAN node and a third node.