Dynamic PCell Frequency Selection for Carrier Aggregation

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Solution Overview

Problem

In communications networks, deploying multiple frequency carriers poses challenges in achieving reliable uplink performance due to differing performance characteristics of low and high frequency bands, especially at large distances or indoor locations, where high frequency bands offer poor throughput and low frequency bands suffer from increased interference.

Innovation Solution

A method for determining the frequency location of the primary serving cell (PCell) in a carrier aggregation supported communications network, which considers uplink load levels and pathloss levels to select between low and high frequency bands, optimizing PCell placement to balance performance and interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high frequency bands are used for PCell, then bandwidth and capacity are improved, but uplink throughput and coverage are degraded

Engineering Contradiction:
ImprovebandwidthVSAvoiduplink throughput
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent implements dynamic PCell frequency selection that adapts to changing network conditions. The network node determines uplink load levels and pathloss levels, then dynamically selects whether to place the PCell in low or high frequency bands based on current conditions, allowing the system to optimize between bandwidth and uplink throughput requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the frequency band parameter of the PCell based on network conditions. By monitoring uplink load levels and pathloss levels, the system adjusts the PCell frequency location between low and high bands, transforming a static configuration into a dynamic parameter that adapts to traffic demands and channel conditions

Inventive Principle:
Principle #35Parameter changes

2Reliability

If low frequency bands are used for PCell, then coverage and propagation are improved, but uplink interference increases

Engineering Contradiction:
ImprovecoverageVSAvoiduplink interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts PCell frequency selection based on uplink load level measurements. When uplink interference becomes excessive in low frequency bands, the system transitions the PCell to high frequency bands, and vice versa, creating a dynamic balance between coverage requirements and interference management

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements a feedback mechanism where the network node continuously monitors uplink load levels and pathloss levels. Based on this feedback, the system makes informed decisions about PCell frequency placement, adjusting the configuration to maintain optimal performance while managing interference

Inventive Principle:
Principle #23Feedback

3Quantity of substance

If multiple frequency carriers are deployed, then capacity is improved, but performance reliability deteriorates

Engineering Contradiction:
ImprovecapacityVSAvoiduplink performance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies different frequency band qualities to different network conditions and locations. By determining pathloss levels and uplink load levels, the system assigns appropriate frequency characteristics (low band for coverage, high band for capacity) to specific PCells based on local network conditions, ensuring optimal performance reliability in each context

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3348013B1Frequency location of a pcell
Publication Date: 2018.12.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3348013B1 patent drawingFigure 1~2b
  • EP3348013B1 patent drawingFigure 3~5
  • EP3348013B1 patent drawingFigure 6~7(c)

AI summary

There is provided mechanisms for determining frequency location of a primary cell (PCell) for a wireless device in a carrier aggregation supported communications network having access to a group of low frequency bands and a group of high frequency bands. A method is performed by a network node. The method comprises acquiring an uplink load level for the group of low frequency bands. The method comprises acquiring a pathloss level between a wireless device served by the communications network and the network node. The method comprises selecting, from the acquired uplink load level and pathloss level, which one of the group of low frequency bands and the group of high frequency bands to place the frequency location of the PCell for the wireless device.