Random Access Msg3 Resource Matching for Bandwidth-Limited Terminals
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Solution Overview
Problem
Terminal devices with limited bandwidth, such as NR light devices or REDCAP devices, face challenges in sending the Msg3 message during the random access procedure due to the bandwidth of the initial BWP exceeding their channel bandwidth, leading to failed access attempts.
Innovation Solution
The method involves determining and utilizing resources with bandwidths that match or are less than the terminal device's channel bandwidth for sending the Msg3 message, and adjusting subcarrier spacing to accommodate these devices, thereby improving the random access success rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bandwidth of the resource for carrying Msg3 is configured to reach the bandwidth of the initial BWP (20 Mbps), then the network device can achieve high data transmission capacity, but terminal devices with limited bandwidth (5-10 Mbps) cannot send Msg3, leading to failed random access
Solution Approach 1:
The initial BWP is divided into multiple sub-BWPs with different bandwidth configurations. The network device configures a first sub-BWP with a first bandwidth and a second sub-BWP with a second bandwidth, where the second bandwidth is less than the first bandwidth. This segmentation allows bandwidth-limited terminal devices to select the second sub-BWP that matches their capabilities, while full-capability devices can use the first sub-BWP for higher data transmission capacity.
Solution Approach 2:
Different sub-BWPs are assigned different bandwidth qualities to match different terminal device capabilities. The first sub-BWP provides high bandwidth quality for devices with full capabilities, while the second sub-BWP provides reduced bandwidth quality suitable for bandwidth-limited devices. This local quality differentiation resolves the contradiction between high productivity and adaptability.
2Productivity
If the network device uses a large initial BWP bandwidth for random access, then resource utilization is improved, but bandwidth-limited terminal devices cannot complete the random access procedure
Solution Approach 1:
The network device dynamically configures multiple sub-BWPs with different bandwidths based on terminal device capabilities. Terminal devices can dynamically select the appropriate sub-BWP that matches their bandwidth capabilities. This dynamic approach ensures that bandwidth-limited devices can successfully access the network while full-capability devices can utilize larger bandwidths for higher productivity.
Solution Approach 2:
The network device changes the bandwidth parameter by configuring multiple sub-BWPs with different bandwidth values. The first sub-BWP has a larger bandwidth for high productivity, while the second sub-BWP has a reduced bandwidth for compatibility. This parameter variation allows the system to maintain high resource utilization while ensuring reliable random access for all device types.
Data Source
AI summary
In a communication method, a first terminal device determines a first resource. The first terminal device sends a first random access message on the first resource. A bandwidth of the first resource is less than or equal to a channel bandwidth of the first terminal device. The channel bandwidth of the first terminal device is less than or equal to a channel bandwidth of a second terminal device. The channel bandwidth of the second terminal device is greater than or equal to a first bandwidth. The first bandwidth is configured by a network device. For example, the first random access message is a Msg3 or a MsgA.