Uplink Beam Management Using UE Beam Reciprocity Reporting
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Solution Overview
Problem
In millimeter wave (mmWave) wireless communication systems, the reliance on directional transmissions and vulnerability of propagation environments pose challenges for beamforming, necessitating efficient uplink beam management, which consumes additional resources and can be minimized with beam reciprocity determination.
Innovation Solution
User equipment (UE) determines its beam reciprocity state and reports it to the base station (BS) via RRC signaling, triggering proper uplink beam management, with options for auxiliary information on uncertainty levels and resource configurations to reduce overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uplink beam management is performed in mmWave beamforming systems, then beamforming performance is improved, but resource consumption increases
Solution Approach 1:
The UE autonomously determines its own beam reciprocity state by performing self-measurements and self-evaluation, eliminating the need for network-assisted beam management in reciprocal conditions. The UE serves itself by reporting beam reciprocity status and selecting beams independently when reciprocity holds, reducing signaling overhead and resource consumption while maintaining beamforming performance.
2Measurement precision
If additional uplink beam management resources are allocated, then beam management accuracy is improved, but system overhead increases
Solution Approach 1:
The system dynamically changes operational parameters based on beam reciprocity conditions. When beam reciprocity is determined to hold, the system switches to a simplified mode with reduced overhead by using UE-autonomous beam selection. When reciprocity does not hold, the system transitions to a more complex mode with additional measurement resources and network-assisted beam management, thereby adapting resource allocation to actual channel conditions.
Data Source
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AI summary
A method of beam reciprocity state reporting and uplink beam management in wireless communication systems with beamforming is proposed. In one novel aspect, a BS configures one or more resource sets to a UE for uplink beam management. The one or more resource sets are allocated for UE to transmit UL reference signals using a number of UE beams. The number of UE beams to be trained is reported by the UE, e.g., via a "UE beam reciprocity state (update)" message. The BS also indicates whether a fixed UE TX beam or which UE TX beam is used for transmission, or indicates whether different UE TX beams are used for transmission of different resources in a resource set. The BS then feedback measurement results for UE to choose a proper TX beam.