LTE Uplink Power Control Group RNTI Segmentation

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Solution Overview

Problem

Current LTE specifications result in undesirable and inaccurate PUCCH power control when multiple terminals are addressed using a group RNTI, as all terminals update their power according to the PDCCH command, leading to interference and incorrect power adjustments.

Innovation Solution

A method where a user terminal in an LTE system disregards transmission power control commands intended for a group of users, identified by a group RNTI or specific formats, to prevent unnecessary power adjustments and interference, using the DCI format to differentiate between individual and group commands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all terminals update their PUCCH transmission power according to PDCCH commands, then the network can control uplink power centrally, but this results in inaccurate power control and interference when multiple terminals are addressed using a group RNTI

Engineering Contradiction:

ImprovePUCCH power control accuracyVSAvoidinterference

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the power control response behavior by terminal type: terminals receiving group RNTI addressed PDCCH commands do not update power, while terminals receiving C-RNTI addressed commands do update power. This segmentation resolves the contradiction by allowing selective power control updates based on the RNTI type, preventing group terminals from causing interference while maintaining centralized control for individual terminals.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different power control update rules to different terminal groups based on their RNTI assignments. Terminals with group RNTIs have the local quality of not updating power upon receiving PDCCH commands, while terminals with C-RNTIs have the local quality of updating power. This local differentiation resolves the contradiction by tailoring the power control behavior to the specific addressing scenario.

Inventive Principle:

Principle #3Local quality

2Productivity

If group RNTI is used to address multiple terminals simultaneously, then efficient group communication is achieved, but all terminals incorrectly update their power leading to system interference

Engineering Contradiction:

Improvegroup communication efficiencyVSAvoidsystem interference

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the terminal response behavior based on RNTI type. When group RNTI is used to address multiple terminals, the segmentation ensures that these terminals do not update their power, while maintaining the efficient group communication capability. This resolves the contradiction by allowing group addressing efficiency while preventing the harmful power updates that would cause interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses the RNTI type as an intermediary to mediate between group communication needs and individual power control needs. The RNTI format serves as a signal that tells terminals whether to update power or not, allowing the system to efficiently address groups while preventing interference from erroneous power updates.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If PDCCH commands are used for both individual and group addressing, then versatile control is achieved, but terminals cannot distinguish between individual and group commands leading to incorrect power adjustments

Engineering Contradiction:

Improvecontrol channel versatilityVSAvoidpower adjustment accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent uses the RNTI format as a distinguishing characteristic (analogous to color changes) to differentiate between individual and group addressed PDCCH commands. Terminals examine the RNTI format to determine whether the command is intended for them individually or for a group, and adjust their power update behavior accordingly. This resolves the contradiction by providing a clear distinction mechanism that maintains control versatility while ensuring accurate power adjustments.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent inverts the traditional approach by having terminals not update power when receiving group RNTI commands, rather than updating power for all commands and then adjusting. This inversion resolves the contradiction by making the default behavior context-dependent on the RNTI type, ensuring accurate power adjustments while maintaining versatile control capability.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP3223566B1Improved uplink scheduling in a cellular system

Publication Date: 2020.04.29 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

A method (200) for use in a wireless cellular access system (100), according to which users (120) in a cell (110) in the system (100) receive one or more transmission power control commands on a control channel (205), the transmission power control commands comprising (225) an identifier for the intended user or users, said identifier being either an identifier for a specific user (230) or for a group of users (235). A user disregards (240) one or more predefined control commands if the identifier of the control command is for a group of users in which said user is included.