Two-Step Random Access Feedback for 5G NR Reliability
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Solution Overview
Problem
In the two-step random access mechanism of 5G New Radio (NR), terminals cannot determine if their preamble and data messages are successfully received by the base station, leading to incomplete communication and reliability issues.
Innovation Solution
A method where the base station detects and feeds back the status of received preamble and data messages to the terminal, using various response formats to indicate successful or unsuccessful transmission, allowing the terminal to perform appropriate retransmissions or proceed with subsequent communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a two-step random access mechanism is used to reduce control plane processing latency, then processing speed is improved, but reliability of message receipt confirmation deteriorates
Solution Approach 1:
The base station sends a random access response message back to the terminal to provide feedback on whether the preamble and data were successfully received. This feedback mechanism allows the terminal to confirm message receipt and ensures reliable communication while maintaining the low-latency two-step random access structure.
2Productivity
If the terminal sends preamble and data simultaneously in Msg1, then communication efficiency is improved, but the ability to confirm successful reception deteriorates
Solution Approach 1:
The base station provides feedback in the random access response message indicating whether the preamble and data were successfully received. This feedback information compensates for the lack of separate acknowledgment messages, allowing the terminal to know whether retransmission is needed while maintaining the efficient two-step structure.
Solution Approach 2:
The random access response message acts as an intermediary that carries reception status information from the base station to the terminal. This intermediary message conveys the necessary confirmation information without requiring additional separate communication steps.
3Device complexity
If no feedback mechanism is implemented in the two-step random access, then device complexity is reduced, but communication reliability deteriorates
Solution Approach 1:
The random access response message serves multiple functions: it provides uplink grant information for resource allocation and simultaneously conveys reception status feedback. This multi-functionality allows the feedback mechanism to be integrated into existing message structures without significantly increasing system complexity.
Solution Approach 2:
The feedback information is merged with the random access response message that already contains uplink grant information. By combining multiple functions into a single message, the solution avoids creating separate feedback channels or procedures, thereby maintaining simplicity while ensuring reliability.
Data Source
AI summary
A random access feedback method, a random access processing method, a base station and a terminal are provided. The random access feedback method includes: receiving a first message sent by a terminal in performing a random access, wherein the first message comprises a preamble field and a data field; detecting the preamble field and the data field of the first message to obtain a detection result of whether or not a preamble exists in the first message and/or whether or not data is successfully obtained in the first message; and feeding back the detection result to the terminal.