Uplink Carrier Selection in Wireless Random Access
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Solution Overview
Problem
In wireless communication systems, the existing methods for selecting uplink carriers during random access procedures in cells configured with supplementary uplink carriers face inefficiencies due to RSRP-based selection, which can lead to high load situations and inadequate carrier reselection, particularly when downlink signal quality is poor or fluctuates.
Innovation Solution
A method where a user equipment (UE) selects a uplink carrier based on downlink signal quality thresholds, randomly choosing between normal and supplementary uplink carriers when the signal quality is good, and reselects carriers under specific failure conditions or signal quality changes, ensuring efficient distribution of congestion and maintaining communication reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If RSRP-based carrier selection is used, then carrier selection simplicity is improved, but load distribution efficiency deteriorates
Solution Approach 1:
The patent implements dynamic carrier selection where the UE switches between RSRP-based selection and random selection based on the downlink signal quality threshold. When DL signal quality is above the threshold, random selection is used to distribute load; when below the threshold, RSRP-based selection ensures reliable connection. This dynamic adaptation resolves the contradiction by using the appropriate strategy for current channel conditions.
2Reliability
If RSRP-based carrier selection is used, then connection reliability is improved, but adaptability to fluctuating signal quality deteriorates
Solution Approach 1:
The system dynamically adapts the carrier selection strategy based on real-time downlink signal quality measurements. When signal quality fluctuates above the threshold, random selection provides adaptability; when it drops below the threshold, RSRP-based selection ensures reliability. This dynamic switching mechanism simultaneously achieves both reliability and adaptability.
Solution Approach 2:
The patent changes the selection parameter based on signal quality conditions. The selection criterion transitions from random (when quality is good) to RSRP-based (when quality is poor), allowing the system to maintain reliability while adapting to varying signal conditions through parameter adjustment.
3Productivity
If random carrier selection is used, then load distribution is improved, but connection reliability in poor signal conditions deteriorates
Solution Approach 1:
The system dynamically switches between random selection (for load distribution) and RSRP-based selection (for reliability) based on downlink signal quality. When signal quality is above the threshold, random selection distributes load; when below the threshold, RSRP-based selection ensures reliable connection, thus resolving the contradiction between load distribution and reliability.
Data Source
AI summary
A method for performing a random access (RA) procedure by a user equipment (UE) in a wireless communication system is provided. The method comprises: selecting a uplink carrier for the RA procedure between a first uplink carrier for a serving cell and a second uplink carrier for the serving cell; and performing a first random access preamble (RAP) transmission for the RA procedure through the selected uplink carrier. Selecting the uplink carrier comprises: selecting the first uplink carrier when a downlink signal quality of the serving cell is less than a first threshold, and selecting one of the first and second uplink carriers randomly when the downlink signal quality of the serving cell is equal to or above the first threshold.