Uplink Control Channel Power Management in Heterogeneous Networks

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Solution Overview

Problem

In wireless communication networks, especially during soft-handover scenarios, uplink control channels face reliability issues due to power imbalances between serving and non-serving cells, leading to potential failures in receiving critical control information, particularly in heterogeneous network deployments where conventional retransmission techniques are inadequate.

Innovation Solution

Implementing inner-loop power control (ILPC) mechanisms where only the serving cell dictates power control commands, and adjusting power offsets for uplink data channels to compensate for uplink-downlink power imbalances, ensuring that only the serving cell's ILPC commands affect the power of control channels transmitted to it, while reducing E-DPDCH power offsets to minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power control is dictated by the non-serving cell during soft handover, then the uplink data channel power can be optimized for that cell, but the serving cell cannot reliably receive the uplink control channel transmissions

Engineering Contradiction:

Improvereliability of control channel reception at serving cellVSAvoidpower control mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the power control mechanism into two independent parts: (1) control channel power controlled exclusively by serving cell ILPC commands, and (2) data channel power controlled by non-serving cell ILPC commands with adjusted power offsets. This segmentation allows each channel type to be optimized independently, resolving the contradiction between control channel reliability and power control flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making the power control behavior different for different channel types. Control channels use one power control regime (serving cell only) while data channels use another regime (non-serving cell with offsets). This localized differentiation ensures that control channel reception reliability is prioritized without compromising data channel performance.

Inventive Principle:

Principle #3Local quality

2Reliability

If conventional retransmission techniques are used to improve control channel reception, then some reliability improvement is achieved, but the technique is inadequate for heterogeneous network deployments with pronounced power imbalances

Engineering Contradiction:

Improvecontrol channel reception reliabilityVSAvoidadaptability to heterogeneous network scenarios

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements preliminary action by proactively preventing power control imbalances before they cause reception failures. Instead of relying on reactive retransmissions, the system pre-configures power control to exclusively use serving cell ILPC commands for control channels, ensuring reliable reception from the outset and adapting to heterogeneous network conditions.

Inventive Principle:

Principle #10Preliminary action

3Loss of energy

If power offsets for data channels are not adjusted, then data channel transmission power remains consistent, but uplink-downlink power imbalance causes interference and performance degradation

Engineering Contradiction:

Improveinterference and energy wasteVSAvoidpower offset adjustment mechanism

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent changes the power offset parameter dynamically based on network conditions and cell type. By adjusting power offsets for data channels transmitted to non-serving cells, the system compensates for uplink-downlink power imbalances, reducing interference while maintaining data transmission effectiveness. This parameter adjustment resolves the contradiction between energy efficiency and power control complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9930622B2Power control of uplink control channels in heterogeneous networks

Publication Date: 2018.03.27 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A network node of a wireless communication network serves a wireless device that is transmitting one or more uplink channels to each of a serving cell and at least one non-serving cell. Inner-loop power control, ILPC, commands are sent (420) to the wireless device in such a way that only ILPC commands transmitted by the serving cell affect the power of one or more control channels transmitted by the wireless device to the serving cell. In addition, a power offset for a data channel transmitted by the wireless device to the at least one non-serving cell is adjusted (430), so as to compensate for an uplink-downlink power imbalance among the serving cell and the at least one non-serving cell.