PRACH Power Allocation in Dual Connectivity User Terminals

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In dual connectivity scenarios of next-generation mobile communication systems, there is no established rule for allocating power to the Physical Random Access Channel (PRACH), which can lead to unpredictable power scaling and dropping, affecting the quality and throughput of uplink communication.

Innovation Solution

A user terminal with a power control section that preferentially allocates power to the retransmission of PRACH over other channels in the secondary cell group, ensuring adequate power allocation and maintaining communication quality by configuring the maximum transmission power of PRACH based on guaranteed transmission powers of cell groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power is allocated to PRACH retransmission in dual connectivity, then communication quality and reliability are improved, but available power for other channels in the second cell group is reduced

Engineering Contradiction:
Improvecommunication qualityVSAvoidpower allocation
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by differentiating power allocation rules between different cell groups. The first cell group (with the PRACH retransmission) receives preferential power allocation to ensure reliable random access, while the second cell group's power is adjusted accordingly. This localized differentiation of power quality resolves the contradiction by ensuring critical communications (PRACH) get sufficient power while managing overall power consumption.

Inventive Principle:
Principle #3Local quality

2Reliability

If power is preferentially allocated to PRACH retransmission, then the likelihood of radio link failures is reduced, but power available for transmission in the second cell group is reduced

Engineering Contradiction:
Improvelikelihood of radio link failuresVSAvoidtransmission power
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent changes the power allocation parameter dynamically based on the transmission type. When PRACH retransmission is detected, the power allocation parameters for the first cell group are adjusted to provide preferential allocation. This parameter change ensures reliable connection establishment while the system manages overall power levels by adjusting the second cell group's allocation accordingly.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If maximum transmission power of PRACH is configured based on guaranteed transmission powers, then coverage is maintained equivalent to non-dual connectivity scenarios, but power flexibility for other channels is reduced

Engineering Contradiction:
ImprovecoverageVSAvoidpower flexibility
Core Design Contradiction:
Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by pre-configuring the maximum transmission power of PRACH based on guaranteed transmission powers of cell groups. This advance configuration ensures that sufficient power is reserved for PRACH operations to maintain coverage equivalent to non-dual connectivity scenarios, while the system manages overall power flexibility by establishing these boundaries in advance.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3169117B1User terminal, wireless communication system, and wireless communication method
Publication Date: 2020.01.15 NTT DOCOMO INC
  • EP3169117B1 patent drawingFigure 1
  • EP3169117B1 patent drawingFigure 2A~2B
  • EP3169117B1 patent drawingFigure 3

AI summary

The present invention is designed to adequately allocate power to PRACHs in dual connectivity. A user terminal communicates by using a first cell group (CG) and a second CG, and has a power control section that controls UL transmission power for the first CG and the second CG, and a transmission section that transmits at least a physical random access channel (PRACH), and, when the transmission section retransmits the PRACH in a primary cell of the first CG, the power control section applies control so that power is preferentially allocated to the retransmission of the PRACH over transmission in the second CG.