User Terminal Two-Step Random Access Control
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Solution Overview
Problem
Future radio communication systems, such as 5G and New Radio, face challenges in performing a random access procedure with fewer steps than the traditional four-step process, which can degrade communication quality if not properly controlled.
Innovation Solution
A user terminal is designed with a transmitting section for sending UL signals, a receiving section for DL signals, and a control section that applies common behaviors to both transmission and reception procedures, either with or without network indications, to manage the reduced-step random access process effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a random access procedure with fewer steps than the traditional four-step process is implemented, then the access speed and efficiency are improved, but the communication quality and reliability may be degraded
Solution Approach 1:
The patent combines the traditional four-step random access procedure into a two-step process by merging Message 1 and Message 3 into a single uplink transmission (Message A), and merging Message 2 and Message 4 into a single downlink transmission (Message B). This merging reduces the number of interaction steps while maintaining essential functionality through unified message structures that carry multiple information elements.
Solution Approach 2:
Message A in the two-step random access procedure serves multiple functions simultaneously: it acts as a random access preamble for synchronization, carries uplink data, and includes uplink control information. Similarly, Message B provides random access response, contention resolution, and downlink data delivery. This multi-functionality allows the reduced-step procedure to maintain comprehensive communication capabilities while improving access speed.
2Loss of time
If a two-step random access procedure is used instead of the four-step procedure, then the latency is reduced, but the complexity of controlling the procedure increases
Solution Approach 1:
The patent merges multiple control functions into unified message structures. Message A combines random access preamble, uplink data, and uplink control information into a single transmission unit. Message B combines random access response, contention resolution, and downlink data into a single response unit. This merging reduces the number of control interactions while maintaining comprehensive control capabilities.
Solution Approach 2:
The two-step random access procedure enables the user equipment to autonomously complete the random access process with minimal network intervention. The UE transmits Message A containing all necessary uplink information, and the network responds with Message B containing all necessary downlink information and contention resolution, allowing the procedure to self-complete in two steps without requiring additional control signaling exchanges.
Data Source
AI summary
To appropriately perform communications even when a random access procedure with less steps than existing steps is performed, an aspect of a user terminal according to the present disclosure includes a transmitting section that transmits a UL signal including a random access preamble and a certain message, a receiving section that receives a DL signal transmitted in response to the UL signal, and a control section that controls at least one of transmission of the UL signal and reception of the DL signal by applying a common behavior to a first procedure for transmitting the UL signal in accordance with an indication from a network and a second procedure for transmitting the UL signal without any indication from the network.