Terminal PRACH Control Without RAR Monitoring in Inter-Cell Mobility
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Solution Overview
Problem
In future radio communication systems, controlling uplink transmission timing advance during inter-cell mobility, particularly in scenarios involving non-serving cells or multiple transmission/reception points, is challenging, especially when random access procedures without a response signal are employed, leading to potential degradation in communication quality.
Innovation Solution
A terminal equipped with a receiving section for a first downlink control channel order, a transmitting section for a random access channel based on the order, and a control section to manage PRACH success or failure and retransmission based on reception of a second PDCCH order or transmission confirmation, enabling appropriate communication control during inter-cell mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inter-cell mobility with candidate cells is implemented, then communication capacity and flexibility are improved, but timing advance acquisition control becomes uncertain and communication quality may degrade
Solution Approach 1:
The invention introduces a feedback mechanism where the base station monitors whether the terminal has successfully acquired timing advance and provides appropriate control signals. The base station determines whether to transmit timing advance based on whether the random access procedure succeeded, creating a closed-loop feedback system that ensures reliable timing advance acquisition while maintaining inter-cell mobility flexibility
Solution Approach 2:
The base station performs preliminary control by determining in advance whether to transmit timing advance before the terminal attempts random access. This preliminary action allows the system to prepare timing advance transmission conditions, ensuring that timing advance is available when needed for inter-cell mobility operations
2Ease of operation
If random access procedure without RAR monitoring is used, then procedure simplicity is improved, but PRACH success determination becomes uncertain
Solution Approach 1:
The invention resolves the detection difficulty by introducing feedback from the base station. The base station monitors the random access procedure and provides control signals indicating whether the PRACH transmission was successful, allowing the terminal to determine success without complex self-detection mechanisms while maintaining procedure simplicity
Solution Approach 2:
The base station acts as an intermediary that mediates the success determination. Instead of the terminal attempting to self-detect PRACH success (which is difficult without RAR), the base station observes the actual reception status and communicates this information back to the terminal, simplifying the terminal's operation while ensuring accurate success detection
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A terminal according to one aspect of the present disclosure includes a receiving section that receives a first downlink control channel (PDCCH) order, a transmitting section that transmits a random access channel (PRACH), based on the first PDCCH order, and a control section that controls, when a random access procedure without monitoring of a response signal (RAR) of the PRACH is configured, at least one of determination of a success or a failure of the PRACH and retransmission of the PRACH, based on whether or not a second PDCCH order or transmission confirmation information is received in certain duration.