Relay-to-Relay Interference Coordination via Neighbor Cell Measurements
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Solution Overview
Problem
Wireless communication networks with relay nodes experience significant interference due to uncoordinated resource partitioning and lack of inter-eNB time synchronization, leading to degraded relay link quality and increased latency, which existing solutions fail to adequately address.
Innovation Solution
A method and apparatus that utilize neighbor cell measurement results from mobile devices to estimate and report interference experienced by relay nodes, allowing network access nodes to coordinate resource allocation and mitigate RN-to-RN interference without requiring additional measurements or complex reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If relay nodes operate without coordinated resource partitioning, then device complexity and implementation overhead are reduced, but interference between relay nodes increases and relay link quality deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where relay nodes measure interference from neighbor cells and report these measurements to donor eNBs. The donor eNBs then coordinate resource partitioning decisions based on this feedback, adjusting MBSFN subframe configurations to reduce RN-to-RN interference while maintaining relatively simple relay node operation
Solution Approach 2:
The donor eNB acts as an intermediary between relay nodes, receiving interference measurements from victim relay nodes and coordinating with aggressor donor eNBs to adjust resource allocation. This intermediary approach allows centralized coordination without requiring complex peer-to-peer communication between relay nodes themselves
2Measurement precision
If additional interference measurement and reporting mechanisms are implemented, then interference coordination accuracy is improved, but device complexity and implementation overhead increase
Solution Approach 1:
The patent leverages existing UE measurements of neighbor cell signals that UEs already perform for mobility and scheduling purposes. These existing measurements are repurposed to estimate RN-to-RN interference, eliminating the need for additional dedicated measurement mechanisms at the UE or relay node level
Solution Approach 2:
Existing ICIC messages used for traditional eNB-to-eNB interference coordination are extended to carry RN-to-RN interference information. This multi-functional use of existing signaling infrastructure allows interference coordination without adding new message types or reporting channels
3Adaptability or versatility
If uncoordinated resource allocation is used between relay nodes, then resource utilization flexibility is improved, but relay link quality and access link quality deteriorate due to interference
Solution Approach 1:
The patent implements dynamic resource partitioning where MBSFN subframe configurations are adjusted based on measured interference conditions. Relay nodes and donor eNBs can adaptively change resource allocation in response to changing interference environments, maintaining both flexibility and link quality
Solution Approach 2:
The system changes the MBSFN subframe configuration parameter to coordinate resource allocation between relay nodes. By adjusting this parameter based on interference measurements, the system maintains resource flexibility while reducing RN-to-RN interference to acceptable levels
Data Source
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AI summary
A method includes receiving neighbor cell measurement results at a first relay node, the neighbor cell measurement results originating from at least one mobile device located in a communications coverage area of the first relay node and that is served by the first relay node; estimating from the received neighbor cell measurement results an amount of interference experienced by the first relay node due to operation of a second relay node; and sending an interference report that comprises an indication of the estimated amount of interference from the first relay node to a network access node that serves the second relay node. The network access node can be different from a network access node that serves the first relay node. The interference report is sent from the first relay node over a wireless link (e.g., Un interface) between the first relay node and the network access node that serves the first relay node, and from the network access node that serves the first relay node to the network access node that serves the second relay node over an X2 interface. The neighbor cell measurement results can include reference signal received power and reference signal received quality measurement results, and the interference report can be an intercell interference coordination (ICIC) type of message. In a further embodiment the interference report is also sent from the first relay node to the second relay node via a network access node that serves the first relay node and a network access node that serves the second relay node.