Random Access BWP Configuration Mismatch in 5G Uplink
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Solution Overview
Problem
In 5G mobile communications, the random access procedure often results in wasted uplink grants due to mismatched configuration information between the uplink bandwidth parts (BWP) used for initial random access and subsequent data transmission, leading to inefficient resource utilization.
Innovation Solution
A method where user equipment receives control signaling with a BWP identifier to initiate a random access procedure on the specified BWP, ensuring that the BWP used for random access matches the one indicated in the uplink grant, thereby allowing effective uplink data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If user equipment sends random access message on the active uplink BWP, then the random access procedure can be completed, but the configuration information of the uplink BWP may not match the required configuration for subsequent uplink data transmission, causing the UL grant to be wasted
Solution Approach 1:
The network device includes BWP configuration information and UL grant in the random access response message in advance, before the user equipment needs to send uplink data. This allows the user equipment to have the correct configuration ready before actual data transmission, preventing the UL grant from being wasted due to configuration mismatch.
Solution Approach 2:
The random access response message provides feedback to the user equipment about the correct BWP configuration information that should be used for subsequent uplink data transmission. This feedback mechanism ensures the user equipment aligns its configuration with what the network device expects, preventing resource waste.
2Adaptability or versatility
If different BWPs have different configuration information, then each BWP can be optimized for specific purposes, but the user equipment cannot send uplink data using the UL grant because of configuration mismatch
Solution Approach 1:
The correct BWP configuration information is provided to the user equipment in advance through the random access response message, before the user equipment needs to transmit uplink data. This preliminary provision of configuration information maintains the flexibility of different BWP configurations while ensuring the user equipment can easily transmit data by following the pre-provided instructions.
Data Source
AI summary
A random access method and device. The method includes receiving, by user equipment, a radio resource control (RRC) connection reconfiguration message from a first network device, the RRC connection reconfiguration message indicating a primary serving cell of the second network device for a user equipment, an active uplink bandwidth part (BWP) in the primary serving cell, and an active downlink BWP in the primary serving cell, the RRC connection reconfiguration message includes an uplink BWP identifier indicating the active uplink BWP and a downlink BWP identifier indicating the active downlink BWP, the uplink BWP identifier corresponds to the active uplink BWP, the downlink BWP identifier corresponds to the active downlink BWP, and initiating, by the user equipment, a random access procedure to the second network device on the active uplink BWP and the active downlink BWP.