NR Uplink Beam Selection via PDCCH Spatial Filters
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G and NR technologies, face challenges in efficiently selecting uplink transmit beams for optimal communication, especially in millimeter-wave systems where high path-loss and susceptibility to blockages necessitate new techniques to maximize signal energy transmission and reception.
Innovation Solution
The method involves a UE selecting an uplink transmit beam based on the receive beam used for downlink signals, allowing for associated or linked beams to enhance communication efficiency, and the BS transmitting indications for beam selection to ensure effective uplink transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming is used to maximize signal energy transmission in millimeter-wave systems, then communication reliability is improved, but device complexity increases due to the need for beam selection mechanisms
Solution Approach 1:
The patent applies preliminary action by having the UE determine the uplink transmit beam in advance based on the downlink receive beam before actual uplink transmission occurs. The UE uses the spatial filter information from downlink signals (PDCCH/PDSCH) to pre-select the corresponding uplink beam, so when uplink transmission is needed, the beam is already determined and ready for use.
Solution Approach 2:
The patent implements self-service by enabling the UE to autonomously select its uplink transmit beam without requiring explicit beam indication from the base station. The UE uses its own downlink receive beam information to self-determine the corresponding uplink transmit beam, reducing the need for complex base station control and beam management signaling.
2Reliability
If multiple beamformed downlink signals are transmitted to support beam selection, then uplink transmission reliability is improved, but downlink resource consumption increases
Solution Approach 1:
The patent applies universality by making the downlink beamformed signals serve dual purposes: they simultaneously deliver downlink data/control information and provide spatial filter information for uplink beam selection. The same PDCCH and PDSCH signals used for downlink communication also contain the spatial characteristics that the UE needs to determine the uplink transmit beam, eliminating the need for separate reference signals or training sequences.
Solution Approach 2:
The patent merges the downlink communication function with the uplink beam training function. Instead of having separate procedures for downlink data transmission and uplink beam selection, the patent combines them so that the downlink beamformed signals perform both functions simultaneously, reducing overall resource consumption.
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for selecting an uplink (UL) transmit beam by a user equipment (UE). A UE may receive, from a base station (BS), one or more beamformed downlink signals using one or more receive beams. The UE may select an uplink transmit beam based, at least in part, on the one or more beamformed downlink signals. The UE may transmit an uplink signal using the selected uplink transmit beam.