Relay Node Timeslot Type Change for LTE Interference Reduction

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Solution Overview

Problem

Current mobile networks, particularly LTE networks, face challenges with noise amplification and interference due to simultaneous transmissions on the same frequency resource, leading to inefficient resource allocation and reduced access throughput, as relay nodes cannot receive and transmit data simultaneously on the same frequency.

Innovation Solution

A relay node that can dynamically change timeslot types based on received information, allowing for flexible resource sharing between backhaul and access links by converting pre-configured MBSFN subframes into downlink access subframes, thereby optimizing resource utilization and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If pre-configured MBSFN subframes are used for backhaul transmissions, then interference between backhaul and access links is reduced, but access throughput decreases due to redundant subframes when backhaul traffic volume is low

Engineering Contradiction:
ImproveinterferenceVSAvoidaccess throughput
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies dynamics by enabling the relay node to dynamically change timeslot types between MBSFN and non-MBSFN based on real-time backhaul traffic conditions. When backhaul traffic volume is low, the relay node receives indication information from the eNB to change specific MBSFN subframes to non-MBSFN subframes, allowing these resources to be reused for access link transmissions. This dynamic adaptation resolves the contradiction by adjusting the system state according to actual traffic demands, reducing redundant MBSFN subframes and improving access throughput while maintaining interference avoidance when needed.

Inventive Principle:
Principle #15Dynamics

2Productivity

If relay node transmits to user equipment simultaneously with receiving from eNB on the same frequency, then resource utilization increases, but noise amplification and feedback isolation problems occur

Engineering Contradiction:
Improveresource utilizationVSAvoidnoise amplification
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies segmentation by dividing the transmission time into distinct timeslots with different types. MBSFN subframes are segmented specifically for backhaul transmissions where the relay receives from eNB without transmitting to UEs, while non-MBSFN subframes are used for access link transmissions. This temporal segmentation prevents simultaneous transmission and reception on the same frequency, avoiding noise amplification and feedback isolation problems while still achieving high resource utilization through efficient use of both subframe types.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2446552B1Relay node and method for changing the timeslot type according to the received information
Publication Date: 2016.08.10 NOKIA SOLUTIONS & NETWORKS OY
  • EP2446552B1 patent drawingFigure 1~2
  • EP2446552B1 patent drawingFigure 3A~3B
  • EP2446552B1 patent drawingFigure 4A~4C

AI summary

It is described a mobile network, in particular an LTE network, comprising a relay node and a base station. The relay node is adapted for receiving signals from the base station during timeslots of a first type and for transmitting signals to a connected user equipment during timeslots of a second type differing from the first type of timeslots. The base station is adapted for transmitting signals to the relay node during timeslots of the first type and for sending informa- tion to the relay node indicating a change of the timeslot type. The relay node is further adapted for changing the timeslot type according to the received information.