Distributed Antenna RRH Positioning via ON/OFF Patterns

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Solution Overview

Problem

In distributed antenna wireless systems, the use of multiple Remote Radio Heads (RRHs) within a single cell leads to insufficient positioning accuracy for wireless devices, particularly in indoor environments, due to the large granularity of location determination, which fails to meet the increased precision requirements for services like E911 and other location-based services.

Innovation Solution

The system employs different simultaneous ON/OFF patterns for the RRHs' receivers to combine signals and determine the geographic location of wireless devices, using an Intermediate Radio Unit to process these signals and identify the closest RRH, with the ability to repeat the process for improved precision and triangulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple RRHs are deployed within a single cell to improve coverage and avoid handovers, then device connectivity and coverage are improved, but positioning accuracy deteriorates due to large granularity of location determination

Engineering Contradiction:
Improvedevice connectivityVSAvoidpositioning accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system segments the signal reception process by assigning different ON/OFF patterns to different RRH receivers, allowing the network to determine which specific RRH received the strongest signal from the UE. This segmentation enables precise location identification at the RRH level rather than cell level.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses periodic ON/OFF patterns where RRH receivers are activated and deactivated in specific sequences. By analyzing which receivers are active during signal reception, the system can triangulate the UE's precise location across the distributed RRH network.

Inventive Principle:
Principle #19Periodic action

2Productivity

If many small cells are deployed to improve capacity and throughput, then network capacity is improved, but coverage is reduced and handover overhead increases

Engineering Contradiction:
Improvenetwork capacityVSAvoidhandover overhead
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent combines multiple RRHs into a single logical cell, allowing UEs to move between physical RRH locations while maintaining the same cell identity. This merging eliminates handovers during movement between RRHs while still providing the capacity benefits of distributed antenna deployment.

Inventive Principle:
Principle #5Merging (Combining)

3Area of stationary object

If a single radio base station provides coverage in different parts of an indoor environment using RRHs, then coverage is improved and handovers are avoided, but positioning accuracy becomes insufficient for E911 requirements

Engineering Contradiction:
Improvecoverage areaVSAvoidpositioning accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The system uses feedback from the signal strength measurements at different RRHs to determine UE location. By analyzing which RRH receives the strongest signal and using the known geographic positions of RRHs, the system can calculate precise UE location for E911 compliance.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3345440B1Systems and methods for UE positioning in a distributed antenna wireless system
Publication Date: 2020.02.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3345440B1 patent drawingFigure 1A
  • EP3345440B1 patent drawingFigure 1B
  • EP3345440B1 patent drawingFigure 2

AI summary

In some embodiments, a node associated with a distributed antenna wireless system obtains one or more combined receive signals responsive to a transmission by the wireless device. The distributed antenna wireless system comprises multiple Remote Radio Heads (RRHs) each comprising one or more receivers. Each receive branch of one or more receive branches of the distributed antenna wireless system comprises a combination of one receiver from each of the RRHs. The one or more combined receive signals comprise, for each receive branch, a combined receive signal that is a combination of signals received by the receivers comprised in the receive branch in accordance with different simultaneous ON/OFF patterns assigned to the RRHs for the receive branches. The node analyzes the one or more combined receive signals to determine information indicative of a geographic location of the wireless device.