Terminal PRACH Power Ramping Control During Inter-Cell Mobility

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Solution Overview

Problem

In future radio communication systems, the control of power ramping during inter-cell mobility is unclear, leading to potential degradation of communication throughput due to inappropriate random access procedures.

Innovation Solution

A terminal equipped with a receiving section for higher layer signaling to determine power ramping values for candidate cells and a control section to manage PRACH transmissions based on this signaling, ensuring appropriate power ramping control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple RACH procedures are performed in parallel without clear power ramping control, then random access capability is maintained, but communication throughput degrades due to inappropriate power ramping

Engineering Contradiction:

Improvecommunication throughputVSAvoidrandom access procedure appropriateness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the power ramping control by dividing candidate cells into different groups (first group and second group) with distinct power ramping behaviors. Cells in the first group perform power ramping while cells in the second group do not, allowing differentiated control strategies for different candidate cells during parallel RACH procedures

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic control of power ramping by using higher layer signaling to indicate whether power ramping should be performed for each candidate cell. The power ramping counter is dynamically adjusted based on PDCCH orders and RAR reception status, enabling adaptive power management during mobility scenarios

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If power ramping is not controlled clearly in parallel RACH transmissions, then implementation simplicity is maintained, but power ramping maintenance becomes undefined

Engineering Contradiction:

Improvepower ramping control clarityVSAvoidpower ramping maintenance status

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

The patent implements feedback mechanisms where the UE monitors RAR reception and reports back to the network. The power ramping counter is incremented based on feedback from PDCCH orders and RAR reception status. This feedback loop ensures that power ramping maintenance status is clearly defined and tracked across parallel RACH procedures

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the power ramping parameter (powerRampingCounter) dynamically based on higher layer signaling and RACH procedure outcomes. The parameter is incremented when power ramping is indicated and RAR is not received, and reset when RAR is successfully received, providing clear operational rules for power ramping maintenance

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4712667A1Terminal, wireless communication method, and base station

Publication Date: 2026.03.18 NTT DOCOMO INC

Figure 1A~1B
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Figure 3A~3B

AI summary

A terminal according to one aspect of the present disclosure includes: a receiving section that receives higher layer signaling including information regarding power ramping for a given candidate cell; and a control section that decides to perform power ramping for a random access channel (PRACH) transmission, based on the higher layer signaling. The higher layer signaling includes one or more power ramping values.