Reference-Signal Beam Selection for Millimeter-Wave Initial Access
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Solution Overview
Problem
In millimeter wave frequency bands, the rapid changes in channel conditions lead to inappropriate uplink transmission beams during the initial access process, resulting in failed data transmissions and repeated re-initiation of the access process.
Innovation Solution
The user equipment receives and measures reference signals from the network device multiple times, adjusting its uplink transmission beam based on beam correspondence and measurement results to ensure appropriate beam selection, using synchronization signal blocks (SSB) and channel state information reference signals (CSI-RS) to fine-tune the beam parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the user equipment uses a fixed uplink transmission beam in the initial access process, then the device complexity is reduced, but the reliability deteriorates due to rapid channel changes in millimeter wave frequency bands
Solution Approach 1:
The network device sends reference signals (SSB/CSI-RS) before the user equipment needs to transmit uplink data, allowing the UE to perform measurements and determine appropriate uplink beams in advance. The UE measures reference signals at multiple time-domain locations (before msg1, after RAR, before msg3) and uses beam correspondence to pre-determine uplink transmission beams, ensuring reliable initial access despite rapid channel changes.
Solution Approach 2:
The system implements feedback mechanisms where the network device provides downlink reference signals that the user equipment measures and reports back through the random access process. The UE uses measurement results of reference signals to adjust its uplink transmission beam selection, creating a closed-loop feedback system that adapts to channel conditions and improves access reliability.
2Measurement precision
If the user equipment performs multiple measurements of reference signals, then the beam selection accuracy is improved, but the time consumption increases
Solution Approach 1:
The user equipment performs a limited number of measurements at strategically selected time-domain locations rather than continuous measurements. Specifically, the UE measures reference signals at key moments (before msg1, after RAR, before msg3) which provides sufficient measurement precision for beam selection without excessive time consumption, balancing accuracy and efficiency.
3Adaptability or versatility
If the user equipment adjusts beam parameters dynamically, then the adaptability to channel changes is improved, but the device complexity increases
Solution Approach 1:
The user equipment autonomously performs reference signal measurements, determines uplink beam parameters, and adjusts its transmission beam based on beam correspondence principles. The UE independently selects appropriate uplink beams by measuring downlink reference signals and applying beam correspondence, without requiring complex network-controlled beam management, thereby achieving adaptability while limiting complexity growth.
Data Source
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AI summary
The present disclosure provides a beam management method and apparatus, and a readable storage medium. The method comprises: at an initial access stage, receiving a reference signal transmitted by a network device at least once; and determining an uplink transmission beam according to at least one measurement result of the reference signal and the beam reciprocity. In the method of the present disclosure, at an initial access stage, a user equipment receives a reference signal transmitted by a network device, and performs measurement on the reference signal for multiple times. The user equipment can reasonably select or adjust an uplink transmission beam on the basis of the beam reciprocity in combination with every measurement result of the reference signal, so as to ensure that an appropriate uplink transmission beam is used to transmit information, thereby improving the success rate of the initial access process.