Default Beam Configuration in 5G UE via TCI Information
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Solution Overview
Problem
In 5G communication systems, determining a default beam for user equipment (UE) when beam information is not indicated can lead to overhead in beam configuration and potential performance degradation due to beam switching times exceeding cyclic prefix lengths, especially with larger subcarrier spacings.
Innovation Solution
A method where the base station transmits a radio resource control (RRC) message with physical downlink shared channel (PDSCH) resource allocation and transmission configuration indication (TCI) information, and the UE receives this information to determine a default beam for data reception, avoiding search in overlapping regions with different TCI information, thus optimizing beam configuration and reducing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If beam information is not indicated for UE data reception, then overhead in beam configuration is reduced, but performance degradation occurs due to beam switching times exceeding cyclic prefix lengths
Solution Approach 1:
The base station transmits TCI information in advance through RRC messages to configure the default beam for PDSCH reception. This preliminary configuration allows the UE to have the beam ready before data transmission, avoiding last-minute beam switching that would exceed the cyclic prefix length and cause performance degradation.
Solution Approach 2:
TCI (Transmission Configuration Indication) information serves as an intermediary parameter that bridges the base station's beam intent and the UE's beam configuration. The TCI information carried in RRC messages provides the UE with the necessary beam configuration details without requiring continuous explicit beam indication, thus reducing overhead while maintaining reliability.
2Adaptability or versatility
If beam switching is performed between overlapping PDCCH and PDSCH with different TCI information, then beam flexibility is improved, but beam switching time causes reception failure when exceeding cyclic prefix length
Solution Approach 1:
The UE determines the default beam for PDSCH reception in advance based on TCI information received from the base station, before the actual data transmission occurs. This preliminary beam configuration ensures that the beam is ready and stable, preventing reception failures that would occur if beam switching happened during the transmission window.
Solution Approach 2:
Instead of dynamically switching beams between PDCCH and PDSCH based on real-time conditions, the system inverts the approach by pre-configuring the default beam through TCI information. This inversion from dynamic switching to static pre-configuration resolves the timing conflict with cyclic prefix constraints while maintaining beam adaptability through RRC-level configuration.
Data Source
AI summary
The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. In a method performed by a UE in the communication system, the UE receives, from a base station, an RRC message including PDSCH resource allocation information and TCI information; receives, from the base station, DCI for scheduling at least one PDSCH through a first PDCCH; and receives, from the base station, data through the at least one PDSCH. In case that TCI information related to the at least one PDSCH is different from TCI information related to a second PDCCH overlapping the at least one PDSCH in a time domain and a beam switching time is required between the at least one PDSCH and the second PDCCH, the UE does not expect the second PDCCH to be searched in a region overlapping with the at least one PDSCH.