Heterogeneous Network Downlink Hearability Probe Method

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Solution Overview

Problem

In wireless communication networks, determining downlink hearability in shared cell heterogeneous deployments is challenging due to the lack of direct correlation between uplink and downlink signal conditions, especially in FDD systems, leading to inefficiencies in spectral reuse and interference management.

Innovation Solution

A method and device that transmit a probe message to user equipment to assess downlink hearability by monitoring the uplink channel response, using a processor to determine hearability based on signal criteria, and employing HARQ states to verify communication channel viability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a shared cell heterogeneous deployment is implemented to decrease signaling complexity, then the number of cell IDs is reduced and interference is minimized, but the ability to determine downlink hearability becomes difficult due to lack of correlation between uplink and downlink signal conditions

Engineering Contradiction:
Improvesignaling complexityVSAvoiddownlink hearability determination
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by transmitting probe messages from the radio unit to the UE before actual data transmission. These probe messages allow the network to assess downlink hearability in advance, establishing channel viability information that can be used for subsequent resource allocation and spectral reuse decisions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms by monitoring uplink channel responses from the UE to the radio unit. The UE's response to probe messages provides feedback about downlink signal reception quality, enabling the network to determine hearability status and adjust resource allocation accordingly.

Inventive Principle:
Principle #23Feedback

2Productivity

If spectral reuse is implemented within the shared cell to improve resource efficiency, then network throughput increases, but interference management becomes more complex due to uncertain downlink hearability status

Engineering Contradiction:
Improvenetwork throughputVSAvoidinterference management
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system applies dynamics by making spectral reuse and interference management strategies adaptive rather than static. Hearability information obtained through probe messages enables dynamic adjustment of resource allocation, allowing the network to reuse spectrum in regions where UEs are confirmed unhearable while avoiding interference in regions where UEs can receive signals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements local quality by applying different resource allocation and interference management strategies to different spatial regions within the shared cell. Based on hearability assessment results, the network can allow spectral reuse in specific locations where UEs cannot receive signals while maintaining strict interference control in locations where UEs are hearable.

Inventive Principle:
Principle #3Local quality

3Use of energy by stationary object

If power saving modes are activated to reduce energy consumption, then operational costs decrease, but the ability to maintain reliable communication channels is compromised due to insufficient hearability information

Engineering Contradiction:
Improvepower consumptionVSAvoidcommunication channel reliability
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The system performs preliminary hearability assessment through probe messages before activating power saving modes or transitioning UEs to dormant states. This advance evaluation ensures that power saving actions do not compromise communication reliability by confirming that UEs will remain reachable or can be quickly re-established.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3376791B1Determining hearability in a heterogenous communication network
Publication Date: 2019.12.18 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3376791B1 patent drawingFigure 1
  • EP3376791B1 patent drawingFigure 2
  • EP3376791B1 patent drawingFigure 3

AI summary

A method for determining downlink hearability of a plurality of radio units (14) by a plurality of user equipments (16) is provided. A radio unit (14) from the plurality of radio units (14) is selected (S100). A list of user equipments (16) that are uplink unhearable by the selected radio unit (14) is generated (S102) and a first user equipment (16) from the list of user equipments (16) is selected (S104). It is determined (S108) whether a downlink channel has available resources to transmit a probe message to the first user equipment (16) if downlink hearability of the first user equipment (16) has not been previously determined within a predefined time period. The probe message is transmitted to the first user equipment (16) provided downlink channel resources are available. The probe message is arranged to invoke a probe response from the first user equipment (16) if the selected radio unit (14) is hearable by the first user equipment (16) on the downlink channel.