mmWave Beam Switching Gap for Short Cyclic Prefix Timing
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Solution Overview
Problem
5G mmWave systems face challenges in beam switching due to reduced cyclic prefix duration, leading to insufficient time for beam switching and resulting in poor performance and user experience.
Innovation Solution
Implementing a beam switching gap (BSG) and modifying beam switching parameters to accommodate shorter symbol durations, allowing for symbol-level beam switching, including additional symbols and configuring slot formats to support beam switching at higher subcarrier spacings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If beam switching is performed during cyclic prefix (CP) duration, then beam switching can be completed quickly, but the reduced CP duration in mmWave systems is insufficient to complete the beam switching operation
Solution Approach 1:
The beam switching operation is segmented into two parts: (1) fast switching during the reduced CP duration in mmWave systems, and (2) completion of the switching operation during the extended BSG period. This segmentation allows the system to utilize the short CP for initial switching while having additional time resources in the BSG to ensure complete switching without losing critical information.
Solution Approach 2:
The system performs preliminary beam switching action during the CP duration, initiating the switching process before the BSG. This preliminary action allows the beam switching to start early, and the remaining switching completion occurs during the BSG, ensuring that the switching is substantially completed before critical information reception begins.
2Loss of time
If beam switching is completed within the reduced CP duration, then timing is efficient, but critical information may not be received resulting in poor performance
Solution Approach 1:
The BSG acts as an intermediary time resource between the reduced CP duration and the critical information reception. It provides an intermediate period where the beam switching operation can complete without interfering with the reception of critical information, thus mediating between the need for fast switching and reliable information reception.
Solution Approach 2:
The system provides beforehand cushioning by extending the BSG duration beyond the minimum CP length. This additional time cushion ensures that even if the beam switching takes longer than the CP duration, the switching will still be substantially completed before critical information reception begins, preventing information loss and ensuring reliable operation.
3Device complexity
If standard beam switching parameters are used, then system operation is simple, but symbol-level beam switching cannot accommodate higher subcarrier spacings
Solution Approach 1:
The system changes the beam switching parameters specifically for mmWave operations with higher subcarrier spacings. The BSG duration is adjusted based on the subcarrier spacing configuration, allowing the system to adapt to different frequency ranges and spacing requirements. This parameter adaptation enables symbol-level beam switching to work effectively at higher subcarrier spacings while maintaining simple operation at standard configurations.
Data Source
AI summary
Some embodiments include a system, method, and computer program product for managing beam switching at a higher subcarrier spacing (SCS) at millimeter wavelength (mmWave) frequencies in a 5G wireless communications system. A user equipment (UE) transmits a beam switching gap (BSG) capability to a 5G Node B (gNB). The UE receives a transmission configuration indicator (TCI) state from the gNB, and performs a beam switch to the TCI state corresponding to a first beam. The UE can receive a first control resource set (CORESET) on the first beam and a second CORESET on a second beam where the BSG occurs between the first CORESET and a second CORESET. The UE can perform beam switching within the BSG from the first beam to a second beam, and receive the second CORESET on the second beam. The UE can determine and transmit modified candidate values of beam switching parameters to the gNB.