Dynamic Uplink Carrier Selection for 5G Random Access
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Solution Overview
Problem
In a 5G mobile communication system, when a serving cell is configured with both a normal uplink (NUL) carrier and a supplement uplink (SUL) carrier, terminals face challenges in determining the appropriate carrier for random access, especially when multiple uplink carriers with different band types are involved, leading to potential failures in the random access process.
Innovation Solution
The proposed solution involves a random access method where a terminal selects or changes the target carrier based on threshold information and channel measurement information. This method allows the terminal to choose between a first type of uplink carrier and a second type of uplink carrier, improving the flexibility in selecting random access resources and ensuring successful random access by adapting to changing channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal uses a fixed uplink carrier for random access, then the carrier selection process is simple, but the random access success rate decreases when channel conditions change
Solution Approach 1:
The patent implements dynamic carrier selection by enabling terminals to switch between different uplink carriers (NUL and SUL) based on real-time channel conditions. The terminal determines channel quality metrics and dynamically selects the most appropriate carrier for random access, transforming the static carrier selection into a dynamic adaptive process that responds to changing radio conditions.
Solution Approach 2:
The patent changes the selection parameter from a fixed carrier configuration to a variable selection based on channel quality parameters. The terminal evaluates channel conditions using measurable parameters (such as signal strength, interference levels) and adjusts carrier selection accordingly, allowing the system to adapt to varying channel states while maintaining reliable random access.
2Reliability
If a terminal dynamically selects carrier based on channel conditions, then the random access success rate improves, but the processing time and complexity increase
Solution Approach 1:
The patent applies preliminary action by having the network pre-configure multiple uplink carriers (NUL and SUL) with different characteristics before the terminal needs to perform random access. The terminal also performs preliminary channel quality assessments and has carrier selection criteria pre-established, enabling faster decision-making when random access is actually needed, thus reducing the time penalty of dynamic selection.
3Adaptability or versatility
If multiple uplink carriers are configured for a serving cell, then the flexibility in random access resource selection improves, but the difficulty in determining the appropriate carrier increases
Solution Approach 1:
The patent applies local quality by assigning different characteristics and optimization goals to different uplink carriers. The NUL carrier may be optimized for certain conditions while the SUL carrier for others. The terminal evaluates channel quality locally for each carrier type and selects based on which carrier's characteristics best match the current channel conditions, making the determination process more manageable despite multiple options.
Data Source
AI summary
A random access method includes: sending a random access request message through a target carrier. The target carrier is one of a first type of uplink carrier and a second type of uplink carrier.