NodeB Transmit Power Adjustment for UE Phase Discontinuity

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Solution Overview

Problem

Relative phase discontinuity (RPD) between SRS and PUSCH transmissions leads to non-optimal precoder selection, resulting in performance loss due to power-dependent and time-dependent phase variations in transmitter chains, especially during power mode and configuration switching, and AM-to-PM distortion in power amplifiers.

Innovation Solution

Adjusting the transmit power of User Equipment (UE) by configuring SRS and PUSCH transmit powers to minimize RPD, with the NodeB receiving UE-specific RP characteristics to select optimal power levels and instructing the UE to set these levels, thereby reducing phase discontinuity and maintaining precoder optimality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transmit power is adjusted to reduce RPD, then precoder selection accuracy is improved, but system complexity increases due to additional power control mechanisms

Engineering Contradiction:

Improveprecoder selection accuracyVSAvoidpower control complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by adjusting the transmit power level of SRS signals based on UE-specific RP characteristics. The NodeB modifies the power parameter dynamically to reduce RPD, thereby improving precoder selection accuracy without requiring complex additional control mechanisms.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by having the UE report its RP characteristics to the NodeB, which then uses this information to determine optimal power levels for SRS transmission. This closed-loop feedback mechanism enables precise RPD reduction while keeping the control system manageable.

Inventive Principle:

Principle #23Feedback

2Stability of the object's composition

If SRS and PUSCH transmit powers are aligned, then RPD is reduced, but throughput may be affected due to power adjustment constraints

Engineering Contradiction:

Improvephase continuityVSAvoidthroughput

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent applies partial action by adjusting SRS power to a level that partially aligns with PUSCH power, sufficient to reduce RPD to an acceptable threshold without requiring complete power alignment. This approach maintains phase continuity while preserving throughput performance.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent uses parameter changes to dynamically adjust SRS power levels based on the relationship between SRS and PUSCH power, thereby achieving adequate phase alignment without excessive power adjustment that would harm throughput.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If power mode switching is used to improve power efficiency, then energy consumption is reduced, but RPD increases due to non-uniform phase shifts

Engineering Contradiction:

Improvepower efficiencyVSAvoidphase stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary anti-action by having the UE report RP characteristics that capture the phase shift effects of power mode switching. The NodeB then pre-adjusts SRS power compensation for these expected phase variations, counteracting the RPD before it affects precoder selection.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent uses parameter changes by adjusting SRS transmit power based on the operating power mode and UE-specific RP characteristics. This dynamic power adjustment compensates for the non-uniform phase shifts introduced by power mode switching, maintaining phase stability while preserving power efficiency.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8909283B2Transmit power adjustment to reduce a relative phase discontinuity

Publication Date: 2014.12.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method and a serving NodeB for adjusting transmit power of a User Equipment (UE) having multiple transmitter chains to reduce relative phase discontinuity (RPD) between a Sounding Reference Signal (SRS) and a Physical Uplink Shared Channel (PUSCH). The NodeB receives from the UE, an RP characteristic of the UE and, based on the RP characteristic, selects an SRS or PUSCH transmit power level for the UE so as to reduce the RPD. The NodeB instructs the UE to set the SRS or PUSCH transmit power level to the level selected by the NodeB.