Relay Node Grouping for Interference Mitigation in LTE-A Networks

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Relay-to-relay interference in LTE-A systems degrades access and relay link qualities due to the time multiplexing of relay and access links, leading to significant interference between neighboring relay nodes, especially in uncoordinated or imperfectly synchronized networks.

Innovation Solution

A divide-and-conquer strategy is employed to group relay nodes with similar sub-frame configurations to mitigate interference, using a 2-step scheme of interference detection and sub-frame configuration coordination, either centrally or distributively, to create interference-free groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If relay nodes are deployed to extend cell coverage and enhance capacity, then network coverage and data rates are improved, but relay-to-relay interference degrades link quality

Engineering Contradiction:

Improvecell coverage areaVSAvoidrelay-to-relay interference

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent segments relay nodes into different groups based on their sub-frame configurations. By dividing relay nodes into multiple groups with different time multiplexing patterns, the system reduces relay-to-relay interference while maintaining extended coverage. Each group operates with coordinated resource allocation, allowing coverage extension without the full interference burden.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the sub-frame configuration parameters of relay nodes to mitigate interference. By adjusting the time multiplexing parameters (different sub-frame patterns for different groups), the system transforms the interference problem into a manageable coordination task, allowing coverage extension with controlled interference levels.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If time multiplexing is applied to relay and access links, then relay functionality is enabled, but relay-to-relay interference occurs between neighboring relay nodes

Engineering Contradiction:

Improverelay functionalityVSAvoidrelay-to-relay interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different sub-frame configurations to different groups of relay nodes based on their local interference conditions. Instead of a uniform approach, each group receives tailored resource allocation suited to its specific interference environment, enabling relay functionality while minimizing local interference impacts.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically assigns relay nodes to different groups based on interference measurements and network conditions. The sub-frame configurations are not fixed but can be adjusted according to changing network states, allowing the system to maintain relay functionality while adapting to minimize interference.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If centralized coordination is used to manage relay nodes, then interference mitigation is improved, but system complexity increases

Engineering Contradiction:

Improverelay-to-relay interferenceVSAvoidcoordination system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the coordination task by dividing relay nodes into groups that can be managed semi-independently. This segmentation reduces the complexity of centralized coordination, as the coordinator can handle groups separately rather than managing all relay nodes as a single complex system.

Inventive Principle:

Principle #1Segmentation

4Reliability

If all relay nodes are coordinated to mitigate interference, then link quality is improved, but coordination overhead increases

Engineering Contradiction:

Improvelink qualityVSAvoidcoordination overhead

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments relay nodes into groups for coordinated interference mitigation. By coordinating only within groups rather than across all relay nodes, the system maintains link quality while significantly reducing coordination overhead and signaling requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial coordination to subsets of relay nodes (groups) rather than implementing full network-wide coordination. This partial action approach achieves sufficient interference mitigation for critical links while avoiding the excessive overhead of coordinating every relay node with every other node.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS9503174B2Divide-and-conquer approach to mitigating relay-to-relay interference

Publication Date: 2016.11.22 WSOU INVESTMENTS LLC

AI summary

An apparatus and a method are described, by which interference related detection results of a plurality of relay nodes are obtained, wherein each relay node to the radio access network, wherein a connection between the relay node and its serving access node is an access node—relay node connection. The relay nodes are grouped according to the obtained detection results such that the access node—relay node connection can be configured for each group in order to mitigate interference to mitigate interference between transmissions to and from different relay nodes in each group.