Radio Network Node Frequency Spectrum Segmentation for LTE Relay

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Solution Overview

Problem

In LTE release 10 radio communications networks, the use of multiple relay nodes enhances performance for users with poor signal conditions but limits peak rates for users with high Signal to Interference plus Noise Ratios (SINR) by up to 50% due to equal resource allocation between access and backhaul links.

Innovation Solution

A radio network node configures separate frequency spectrum connections for backhaul and access links, allowing simultaneous UL and DL transmissions on carefully selected spectrum portions when a backhaul link is configured, enabling the radio network node to communicate with both the user equipment and the radio base station in the same time slot, thereby optimizing resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If equal resource allocation is used between access and backhaul links, then cell edge users with poor signal conditions gain performance improvement, but peak rates for users with high SINR are limited by up to 50%

Engineering Contradiction:
Improveperformance for cell edge usersVSAvoidpeak rates for users with high SINR
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The frequency spectrum is segmented into multiple parts, with a first part allocated to backhaul link communication and a second part allocated to access link communication. This segmentation allows independent resource allocation and simultaneous transmission on different frequency portions, resolving the contradiction between supporting cell edge users and maintaining peak rates for high SINR users.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from time-division multiplexing (single dimension) to frequency-division multiplexing (adding another dimension). By utilizing different frequency parts for backhaul and access links simultaneously, the system achieves both improved reliability for cell edge users and maintained productivity for high SINR users without the 50% peak rate limitation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If strict time division multiplexing is used to coordinate Un and Uu links, then interference is managed, but the relay node cannot simultaneously communicate with both radio base station and user equipment

Engineering Contradiction:
Improveinterference managementVSAvoidcommunication efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The frequency spectrum is divided into separate parts for backhaul and access links, allowing simultaneous transmission without interference. This segmentation enables the relay node to communicate with both the radio base station and user equipment at the same time, improving productivity while maintaining interference management through frequency separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces frequency division as an intermediary mechanism to coordinate between Un and Uu links. Instead of using time-division multiplexing which prevents simultaneous communication, frequency-division multiplexing acts as a mediator that allows both links to operate simultaneously on different frequency parts, resolving the contradiction between interference management and communication efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If relay nodes are deployed to enhance performance for users with low SINR, then coverage is improved, but resource allocation efficiency decreases due to equal division between access and backhaul links

Engineering Contradiction:
Improvecoverage for low SINR usersVSAvoidresource allocation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The frequency spectrum is segmented into dedicated parts for backhaul and access links, enabling independent and optimized resource allocation. This allows efficient resource utilization for both cell edge users requiring coverage enhancement and high SINR users requiring peak rate performance, resolving the contradiction between reliability improvement and resource allocation efficiency.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2676520B1A radio network node and a method therein
Publication Date: 2015.07.29 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2676520B1 patent drawingFigure 1
  • EP2676520B1 patent drawingFigure 2
  • EP2676520B1 patent drawingFigure 3

AI summary

Embodiments herein relate to a method in a radio network node (14) for communicating with a user equipment (10) during a communication between the radio network node (14) and a radio base station (12) in a radio communications network The radio network node (14), radio base station (12) and the user equipment (10) are comprised in the radio communications network The radio network node (14) serves the user equipment (10) within a cell (16) and is configured to communicate with the radio base station (12) and the user equipment (10) over a frequency spectrum in a time division duplexing configuration The radio network node sets up a first connection over a first part of the frequency spectrum to the radio base station (12), and a second connection to the user equipment (10) over the first or a second part of the frequency spectrum The second part of the frequency spectrum is solely used for communication with user equipments within the cell (16) The radio network node (14) then communicates simultaneously with the user equipment (10) and the radio base station (12) over respective connection in a time slot of a reference time configured by the radio communications network.