Beam Switching Acknowledgement via PDSCH
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Solution Overview
Problem
In millimeter wave (mmW) wireless communication systems, the existing beam switching procedure is inefficient as it relies on acknowledgments through the physical uplink control channel (PUCCH), which fails when the uplink beam is blocked or has insufficient coverage, preventing the base station (BS) from switching to the best available beam, thereby compromising system performance.
Innovation Solution
The proposed solution involves transmitting beam switch commands via the physical downlink shared channel (PDSCH) and allowing additional time for user equipment (UE) to parse these commands, enabling the UE to send a coverage-enhanced acknowledgment, ensuring the BS receives the acknowledgment and can switch to the best available beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam switching is performed using PUCCH acknowledgment, then the beam switching procedure can be completed, but the system fails when uplink beam is blocked or has insufficient coverage
Solution Approach 1:
The patent introduces PDSCH as an intermediary channel to transmit beam switch commands and coverage-enhanced acknowledgments. When PUCCH is blocked, the system uses PDSCH with downlink resources to carry the acknowledgment signal, effectively mediating the communication between UE and BS despite uplink beam blockage. This resolves the contradiction by providing an alternative pathway that bypasses the harmful uplink blockage condition.
Solution Approach 2:
The patent changes the transmission parameters by switching from standard PUCCH transmission to coverage-enhanced PDSCH transmission. This involves using repeated transmissions, different modulation schemes, and adjusted timing parameters to enhance the reliability of acknowledgment transmission. The parameter changes enable the system to overcome uplink beam blockage by transforming the transmission characteristics to be more robust against channel impairments.
2Measurement precision
If additional time is allocated for UE to parse beam switch commands, then parsing accuracy improves, but beam switching delay increases
Solution Approach 1:
The patent applies preliminary action by providing advance notification to the UE about upcoming beam switch commands through downlink control information (DCI). The UE is prepared in advance with timing indicators and resource allocations, allowing it to parse the beam switch commands more efficiently when they arrive. This preliminary preparation reduces the actual parsing time needed while maintaining high accuracy, thus resolving the contradiction between parsing precision and switching delay.
Data Source
AI summary
Certain aspects of the subject matter described in this disclosure can be implemented in a method for wireless communication by base station. The method generally includes transmitting, to a user-equipment (UE), a packet indicating a beam switch associated with communication with the UE, receiving an acknowledgment (ACK) message, detecting that the ACK message is configured to indicate whether parsing of contents of the packet was successful, determining a timing of the beam switch based on the detection, and performing the beam switch in accordance with the determination of the timing.