Beam-Sweep Random Access Msg 2 for Reliable Low-Latency Access
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Solution Overview
Problem
Existing wireless communication systems, particularly 5G NR, face challenges in improving random access reliability and reducing latency, especially in unlicensed spectra and controlled environments, due to limited beam reciprocity and transmission reliability.
Innovation Solution
The use of multiple beams for transmitting and receiving random access messages, where the UE and base station select beams based on different beam measurements than the latest beam report, enhancing transmission opportunities in the time, frequency, and spatial domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single beam is used for random access message transmission, then the device complexity is reduced, but the reliability of random access procedure deteriorates
Solution Approach 1:
The random access message transmission is segmented into multiple beams instead of using a single beam. The base station transmits the same random access message through multiple different beams to reach the UE through diverse paths, thereby improving reliability without requiring the UE to perform complex beam selection
Solution Approach 2:
The base station performs preliminary beam sweeping to identify multiple suitable beams for message transmission before the actual random access procedure. This preliminary action ensures that when random access is needed, pre-validated beams are available for immediate use, reducing both complexity and improving reliability
2Reliability
If multiple beams are used for random access message transmission, then the reliability is improved, but the latency increases
Solution Approach 1:
The base station maintains continuous transmission of the random access message across multiple beams in a sequential manner rather than waiting for confirmation from one beam before proceeding. This continuous action ensures that if one beam fails, the message is already being transmitted through alternative beams, reducing latency while maintaining reliability
Solution Approach 2:
The patent employs periodic beam sweeping at the base station to systematically cycle through multiple beams in a predetermined sequence. This periodic action ensures comprehensive coverage with multiple beams while maintaining a regular, predictable timing pattern that minimizes random access latency
3Measurement precision
If beams are selected based on the latest beam report, then the beam selection accuracy is improved, but the adaptability to changing channel conditions deteriorates
Solution Approach 1:
The base station performs preliminary identification of multiple candidate beams using the latest beam report before actual transmission needs occur. This preliminary action stores multiple pre-validated beam options that can quickly adapt to changing channel conditions without requiring real-time beam report updates
Solution Approach 2:
The patent implements dynamic beam selection from a pre-identified set of multiple beams. The base station can dynamically switch between different beams in the candidate set based on real-time channel conditions, combining the accuracy of beam reports with the adaptability to changing conditions by selecting from multiple pre-validated options
Data Source
AI summary
A method, a computer-readable medium, and an apparatus are provided for wireless communication including random access between a base station and a user equipment (UE). The UE transmits a beam report comprising beam measurement information to the base station and transmits a first random access message to the base station for reception using one or more beams based on a random access measurement that is different than the beam measurement information comprised in the beam report. The UE monitors for a second random access message from the base station using multiple beams, the beams being selected based on the beam report.