Beam Quality Based Random Access in Wireless Systems
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Solution Overview
Problem
Current random access procedures in wireless communication systems, particularly in 3GPP LTE and NR, face challenges in efficiently managing beam quality and frequency band allocation for optimal data transmission, especially in scenarios requiring low latency and energy efficiency, such as eMBB, mMTC, and URLLC.
Innovation Solution
A method and apparatus that monitor paging information for beams associated with a contention-free random access procedure, selecting beams with quality above a threshold for contention-free access and performing contention-based access when no suitable beams are found, allowing for efficient UL frequency band allocation and data transmission even in idle or inactive states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contention-free random access procedure is performed based on beam quality, then the reliability of random access is improved, but the device complexity increases due to beam quality monitoring and selection
Solution Approach 1:
The network pre-configures multiple beams and their associated parameters (including quality thresholds) before the random access procedure. The UE receives this preliminary beam information through system information or RRC signaling, enabling it to perform quality-based selection without complex real-time analysis, thus improving reliability while controlling complexity.
Solution Approach 2:
The UE autonomously monitors beam quality metrics (such as RSRP) and independently selects the appropriate beam for random access based on pre-configured thresholds. This self-service mechanism eliminates the need for complex network-side beam management during the access procedure, improving reliability through quality-based selection while keeping device complexity manageable.
2Adaptability or versatility
If multiple UL frequency bands are allocated for DL transmission, then the adaptability of the system is improved, but the difficulty of detecting and measuring the appropriate frequency band increases
Solution Approach 1:
Different UL frequency bands are associated with specific DL transmission characteristics and beam qualities. The UE measures beam quality metrics (RSRP, RSRQ) locally for each beam and selects the corresponding UL frequency band based on these local measurements and pre-configured band-beam associations. This approach enables flexible multi-band operation while simplifying detection through localized quality assessment.
Solution Approach 2:
Beam quality metrics serve as an intermediary that links DL transmission characteristics with UL frequency band selection. The UE uses beam quality measurements as a proxy to determine the appropriate UL band without directly measuring complex multi-band parameters, thus improving adaptability while reducing measurement difficulty.
3Loss of time
If the UE performs random access from idle or inactive state, then the latency is reduced, but the energy consumption increases due to additional transmissions
Solution Approach 1:
The network pre-configures beam information and quality thresholds while the UE is in idle or inactive state. This preliminary configuration enables the UE to perform efficient beam-based random access when needed, reducing access latency by eliminating the need for extensive beam training at access time while managing energy consumption through optimized transmission parameters.
Solution Approach 2:
The system changes transmission parameters (such as power levels, message formats) based on the UE's state and beam quality conditions. When performing random access from idle/inactive state, the UE uses beam quality-guided parameter selection to minimize the number of transmissions required, thus reducing latency while controlling energy consumption through adaptive parameter adjustment.
Data Source
AI summary
A method and apparatus for random access procedure based on a beam quality in a wireless communication system is provided. A wireless device monitors a paging including information on one or more beams associated with a contention free random access procedure and selects at least one beam of which a quality is above a threshold among the one or more beams. The wireless device performs the contention free random access procedure via the at least one beam. When there is no beam of which the quality is above the threshold, the wireless device performs a contention based random access procedure.