PRACH Configuration for Beam Guidance in 5G Random Access
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Solution Overview
Problem
In mobile communication systems, especially in 5G networks, there is no mechanism to guide user equipment (UE) to preferred beams when using common PRACH resources, leading to inefficient resource usage and potential load imbalances between beams and cells during handovers.
Innovation Solution
The proposed solution involves generating and transmitting configuration information from network devices to terminal devices, indicating preferred target beams or cells for random access channel procedures, using the same mechanism as for dedicated PRACH resources, to optimize resource allocation and load balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If common PRACH resources are used for random access, then UEs can access any suitable beam in the target node, but there is no mechanism to guide UEs to preferred beams leading to inefficient resource usage and load imbalances
Solution Approach 1:
The network device provides feedback to the UE by including indication information in configuration information, which guides the UE to select preferred beams for random access. This feedback mechanism resolves the contradiction by directing UE beam selection to achieve both flexibility and efficiency.
Solution Approach 2:
The network device performs preliminary action by pre-configuring indication information that identifies preferred beams before the UE initiates random access. This allows the UE to make informed beam selection decisions, improving resource efficiency while maintaining access flexibility.
2Adaptability or versatility
If common PRACH resources are used for random access, then UEs can access any suitable beam in the target node, but load balancing between beams and cells cannot be ensured
Solution Approach 1:
The indication information acts as feedback from the network to the UE, providing guidance on preferred beams to ensure reliable service levels. This resolves the contradiction by maintaining beam selection freedom while ensuring quality through network-directed beam preferences.
Solution Approach 2:
The network device changes the parameter of beam selection by introducing indication information that modifies the UE's beam choice behavior. This allows the system to transition from unguided to guided beam selection, ensuring service quality while preserving adaptability.
3Productivity
If dedicated PRACH resources are prioritized over common resources, then UEs can use dedicated resources when available, but UEs may not be able to access when dedicated resources are not suitable due to rapid radio condition changes
Solution Approach 1:
The system dynamically adapts between dedicated and common PRACH resources based on radio conditions. The indication information mechanism enables this dynamics by providing guidance for common resource usage, allowing UEs to switch to common resources with beam guidance when dedicated resources become unsuitable.
Solution Approach 2:
The indication information acts as an intermediary that bridges dedicated and common PRACH resource usage. It provides the same level of beam guidance for common resources that dedicated resources naturally provide, making common resources a viable alternative when dedicated resources are unavailable or unsuitable.
Data Source
AI summary
Disclosed are information indication methods and apparatuses, a network device, and a terminal device. In an information indication method, a network device generates first configuration information, and transmits the first configuration information to the terminal device. The first configuration information is adapted to configure a first physical random access channel (PRACH) resource, and includes first indication information indicative of at least one of a target beam or a target cell to be accessed by a terminal device during a random access channel (RACH) procedure initiated with a second PRACH resource.