User Equipment Acknowledgement for Two-Step Random Access
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Solution Overview
Problem
The two-step random access procedure in wireless communication technologies faces challenges in generating and transmitting acknowledgement information effectively, as the base station cannot determine if the user equipment (UE) has correctly received a message without explicit acknowledgement, leading to potential retransmissions.
Innovation Solution
The UE generates and transmits media access control layer control information (MAC CE), MAC PDU, or hybrid automatic repeat request acknowledgement (HARQ-ACK) information to indicate acknowledgement of the message, using a UL grant or PUCCH-related information, depending on the presence of a contention resolution ID in the response message from the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the two-step random access procedure is used to shorten access time, then the random access time is reduced, but the base station cannot determine whether the UE has correctly received the message B
Solution Approach 1:
The patent implements a feedback mechanism where the UE sends acknowledgement information (MAC CE, MAC PDU, or HARQ-ACK) to the base station after receiving message B. This feedback allows the base station to determine whether the UE has correctly received the message, resolving the information loss problem while maintaining the fast two-step access procedure.
Solution Approach 2:
The patent introduces an intermediary acknowledgement mechanism that mediates between the UE and base station. The acknowledgement information acts as an intermediary signal that carries the reception status of message B, enabling the base station to infer receipt status without extending the basic two-step procedure structure.
2Device complexity
If acknowledgement information is not transmitted, then the procedure remains simple, but the base station cannot determine correct message reception leading to unnecessary retransmissions
Solution Approach 1:
The patent adds a lightweight feedback element (acknowledgement information) that provides essential reception status without significantly complicating the procedure. This single feedback signal prevents unnecessary retransmissions and improves overall access efficiency while maintaining procedural simplicity.
Solution Approach 2:
The UE autonomously generates and transmits the acknowledgement information based on its own reception status of message B. This self-service approach allows the UE to independently inform the base station of its reception status without requiring complex coordination protocols, thereby improving efficiency with minimal added complexity.
Data Source
AI summary
The present invention provides a random access method and user equipment. The random access method includes: user equipment (UE) transmitting a message A to a base station, wherein the message A includes a preamble and a payload of the message A; the user equipment (UE) receiving a message B transmitted by the base station and serving as a response message to the message A; determining whether the message B includes a contention resolution ID of the UE; and upon determining that the message B includes the contention resolution ID of the UE, generating a media access control layer control information (MAC CE), or a media access control layer protocol data unit (MAC PDU), or hybrid automatic repeat request acknowledgement (HARQ-ACK) information to indicate acknowledgement information related to the message B.