Beam Switching via PRACH Signaling for Low-Latency Handover
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Solution Overview
Problem
The existing beam switching methods in low-orbit satellite communication systems face challenges with long switching times and high signaling overhead due to frequent beam switching, irreversible nature, and constraints in using Bandwidth Part (BWP) switching mechanisms, particularly in 5G NR systems.
Innovation Solution
A method and apparatus for beam switching that involves determining a target beam and sending a PRACH signal on indicated time-frequency resources without RRC reconfiguration, using BWP or dynamic CA switching commands, and incorporating beam identifier and PRACH resource indications to reduce switching time and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beam switching is performed by calculating correlation values between pilot signals and data signals, then channel quality can be measured accurately, but measurement time increases and productivity decreases
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing correlation values between pilot signals and potential beam signals before actual beam switching is needed. This allows the system to quickly retrieve pre-computed correlation data during beam switching operations, avoiding time-consuming real-time calculations while maintaining measurement accuracy.
Solution Approach 2:
The beam switching process is segmented into distinct phases: pilot signal transmission, correlation value calculation and storage, and beam selection based on retrieved correlation data. By dividing the process into segments, the system can perform computationally intensive correlation calculations during idle periods and only execute the essential beam selection step during actual switching, thereby improving overall switching speed.
2Measurement precision
If multiple beams are transmitted for channel quality measurement, then measurement accuracy improves, but measurement time increases
Solution Approach 1:
The system implements periodic action by transmitting pilot signals at regular intervals using different beam directions. This periodic transmission pattern allows the system to gather channel quality information from multiple beams over time without requiring all measurements to be completed simultaneously, thereby reducing the immediate measurement time while maintaining comprehensive measurement coverage.
Solution Approach 2:
The system performs preliminary channel quality measurements using pilot signals before actual data transmission begins. By conducting these measurements in advance and storing the results, the system avoids the need to perform time-consuming measurements during critical data transmission periods, thus reducing overall measurement time while maintaining accuracy.
Data Source
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AI summary
Disclosed are a beam switching method and apparatus, relating to the technical field of wireless communications, and used for reducing beam switching time and reducing the signaling overhead of switching. The method comprises: determining a beam that needs to be switched, and obtaining the beam identifier of a switched beam and physical random access channel (PRACH) resource indication information; and after the switching of the beam is completed, transmitting, to a network device on the time frequency resource of the switched beam indicated by the PRACH resource indication information, a PRACH signal used for indicating that the switching of the beam is completed. By means of the beam switching method, a beam switching process does not need to transmit an RRC signaling to the network device, and does not need to wait to establish an RRC connection with the network device, thereby being capable of reducing the beam switching time and simultaneously reducing the signaling overhead of switching.