Grant-Free UL Power Control via Pre-Configured Parameters
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Solution Overview
Problem
In wireless communication systems, particularly in NR (New Radio) systems, there is a lack of specific UL power control techniques for UL signals transmitted without a UL grant, which can lead to inadequate power control and interference issues.
Innovation Solution
A user apparatus is equipped with a signal reception part to receive power control parameters from the base station, a transmission power determination part to select and determine the UL signal transmission power based on these parameters and pathloss estimation, and a signal transmission part to transmit the UL signal using the determined power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If Grant free UL transmission is used to enable UL data transmission without UL grant for low delay, then transmission delay is reduced, but UL power control accuracy deteriorates due to lack of specific power control parameters
Solution Approach 1:
The patent applies universality by making the power control parameters configured for scheduled UL transmissions also applicable to Grant free UL transmissions. The base station configures power control parameters (P0, alpha, pathloss reference signal) that can be universally used by the user apparatus for both scheduled and Grant free transmissions, eliminating the need for separate parameter sets while maintaining power control accuracy.
Solution Approach 2:
The patent applies preliminary action by having the base station pre-configure power control parameters to the user apparatus before the Grant free UL transmission occurs. The power control parameters are configured in advance through RRC signaling or other higher layer signaling, so that when the user apparatus needs to perform Grant free transmission, the power control parameters are already available, enabling accurate power control without real-time UL grant.
2Productivity
If multiple user apparatuses transmit UL signals simultaneously without UL grant, then resource allocation efficiency is improved, but interference between user apparatuses increases
Solution Approach 1:
The patent applies local quality by enabling each user apparatus to independently determine its transmission power based on its own measured pathloss and the configured power control parameters. Each user apparatus adjusts its power locally according to its channel conditions (pathloss to the base station), rather than using a uniform power level, which reduces interference while maintaining efficient resource utilization.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the transmission power parameter based on the pathloss condition. The user apparatus measures the pathloss (a changing parameter) and uses it to calculate the appropriate transmission power, allowing the system to adapt to varying channel conditions and reduce interference when multiple user apparatuses transmit simultaneously.
Data Source
AI summary
A user apparatus in a wireless communication system including a base station and a user apparatus, includes a signal reception part that receives, from the base station, a plurality of power control parameters that become candidates for power control parameters to be used by the user apparatus, a transmission power determination part that selects power control parameters to be used, from the plurality of power control parameters, and determines a transmission power of a UL signal, based on the selected power control parameters and a pathloss estimation value, and a signal transmission part that transmits the UL signal using the transmission power determined by the transmission power determination part.