SSB Beam Selection With Gain Compensation for SBFD Random Access

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Solution Overview

Problem

The difference in beam gain between subband full duplex (SBFD) and non-SBFD symbols during UE initial access leads to inaccurate selection of the optimal synchronization signal/physical broadcast channel block (SSB) beam due to varying numbers of transmit radio frequency chains used for downlink transmission.

Innovation Solution

A method for determining an optimal SSB beam by a user equipment (UE) that involves receiving gain difference information from a network device, measuring signal strengths of SSB signals in multiple directions, and adjusting these strengths based on the gain difference to select the optimal beam for random access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the UE measures SSB signal strength directly without compensation, then the measurement process is simple, but the beam selection becomes inaccurate due to gain difference between SBFD and non-SBFD symbols

Engineering Contradiction:
ImproveSSB beam selection accuracyVSAvoidbeam determination process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by introducing a gain difference compensation parameter that adjusts the measured signal strength based on the symbol type (SBFD or non-SBFD). The UE modifies the measurement parameter (signal strength) according to the transmission configuration, transforming the raw measurement into a compensated value that accurately reflects the true beam quality regardless of symbol type differences.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback mechanisms where the network device provides configuration information about SBFD symbol arrangements and gain differences to the UE. The UE uses this feedback information to adjust its measurement and selection process, ensuring accurate beam determination based on the actual transmission conditions.

Inventive Principle:
Principle #23Feedback

2Reliability

If the UE considers gain difference compensation, then the beam selection accuracy improves, but the measurement and determination process becomes more complex

Engineering Contradiction:
Improvebeam selection reliabilityVSAvoidsignal processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the signal strength parameter dynamically based on the symbol type. When measuring SSB signals on SBFD symbols, the UE applies a compensation factor to adjust the signal strength value, ensuring that the comparison between different beams remains accurate regardless of whether they were transmitted on SBFD or non-SBFD symbols.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary compensation calculations before beam selection. The UE pre-processes the signal strength measurements by applying the appropriate gain difference compensation based on the symbol type configuration, so that when beam selection occurs, the data is already prepared and ready for accurate comparison.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4704486A1Beam determining method and apparatus, and storage medium
Publication Date: 2026.03.04 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
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AI summary

The present disclosure relates to the technical field of communications, and provides a beam determining method and apparatus, and a storage medium. The method comprises: by means of interaction between a user equipment (UE) and a network device, the network device sends a plurality of synchronization signal/physical broadcast channel block (SSB) beams to the UE, and the UE determines a first SSB beam which is used for random access, wherein the plurality of SSB beams include the first SSB beam, and the first SSB beam is used for random access. According to the solution of the present disclosure, a UE can receive a gain difference value between an SBFD symbol and a non-SBFD symbol from a network side, so that an optimal SSB beam is determined on the basis of the gain difference value, and the accuracy of the optimal SSB is ensured. By limiting a time domain position sent by an SSB signal, the method can further avoid the effect of a beam gain difference between a non-SBFD symbol and an SBFD symbol on optimal SSB beam selection, thereby ensuring the accuracy of an optimal SSB.