Conditional Range Expansion in Heterogeneous Networks

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Solution Overview

Problem

In heterogeneous telecommunications systems, range expansion often results in a loss of downlink bit-rate due to the degradation of downlink signal strength when user equipment connects to low-power base stations, especially in densely planned networks and for outdoor user equipment with line-of-sight to the macro base station, particularly at lower frequency bands like 800 MHz.

Innovation Solution

Implementing conditional range expansion by assessing the uplink transmission power of user equipment to determine if applying range expansion is beneficial, and only applying it when specific criteria such as maximum uplink transmission power, bit-rate, or signal-to-noise ratio thresholds are met, thereby avoiding unnecessary degradation of downlink bit-rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If range expansion is applied to extend low-power base station coverage, then the coverage area is improved, but the downlink bit-rate deteriorates due to degradation of downlink signal strength

Engineering Contradiction:
Improvecoverage areaVSAvoiddownlink bit-rate
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the range expansion offset based on uplink transmission power conditions. When uplink power exceeds a threshold, range expansion is applied with a specific offset to extend coverage. When uplink power is below the threshold, range expansion is reduced or removed to preserve downlink signal strength, thus maintaining downlink bit-rate while still providing coverage extension when needed.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If range expansion is applied unconditionally, then coverage is extended to serve more user equipment, but planning costs increase due to unnecessary network optimization

Engineering Contradiction:
Improvecoverage areaVSAvoidplanning costs
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent implements self-service through autonomous, conditional range expansion that automatically adjusts based on real-time uplink transmission power measurements. The system self-configures by applying range expansion only when uplink power conditions warrant it, eliminating the need for manual network planning and optimization interventions. This reduces planning costs while maintaining adequate coverage through on-demand, condition-based expansion.

Inventive Principle:
Principle #25Self-service

3Productivity

If range expansion is applied to improve uplink coverage, then uplink transmission capability is improved, but downlink signal strength deteriorates

Engineering Contradiction:
Improveuplink transmission capabilityVSAvoiddownlink signal strength
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent applies local quality by differentiating treatment based on local uplink power conditions. Instead of uniform range expansion across all areas, the system applies range expansion selectively only in locations where uplink transmission power exceeds a specific threshold. This localized application ensures uplink capability improvement where needed while preserving downlink signal strength in areas where it is already adequate.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2749091B1Conditional range expansion in a heterogeneous telecommunications system
Publication Date: 2016.10.26 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2749091B1 patent drawingFigure 1
  • EP2749091B1 patent drawingFigure 2A~2B
  • EP2749091B1 patent drawingFigure 3

AI summary

A method is disclosed for use in a heterogeneous telecommunications system of the kind comprising a macro base station and a low-power base station, the low-power base station having a coverage which is extendible by range expansion, RE, to serve a user equipment which would otherwise have been served by the macro base station. According to the method, which is performed in either of the macro base station or the low-power base station, information about radio conditions of the user equipment at least with respect to the macro base station is obtained (310). Based on the obtained information, it is determined (320) whether a criterion for conditional range expansion is satisfied, said criterion being related to the uplink transmission power of the user equipment to the macro base station. Accordingly, range expansion is applied (330) for the user equipment only when the criterion is satisfied. A corresponding base station, telecommunications system and computer readable storage medium are also disclosed.