Inter-cell Interference Measurement in Flexible Duplex Systems
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Solution Overview
Problem
In flexible duplex systems, inter-cell interference due to UL-DL mismatch in 5G communication networks is not effectively measured, affecting transmission rates, as existing technologies lack methods for interference measurement in LTE-Advanced systems.
Innovation Solution
A method and device for measuring inter-cell interference in flexible duplex systems by determining UL grants and using uplink interference measurement resources, where UEs measure and report interference, and eNBs adjust downlink signals based on channel quality information and uplink rank indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flexible duplex system borrows UL band for DL transmission, then DL traffic demand is satisfied, but inter-cell interference occurs due to UL-DL mismatch between cells
Solution Approach 1:
The patent applies preliminary action by having UEs measure and report uplink interference in advance before actual downlink transmission occurs. The eNB uses these pre-measured interference values to make informed scheduling decisions, selecting UEs for downlink transmission based on predicted interference conditions rather than reacting to interference after it occurs. This proactive measurement and reporting mechanism enables the system to anticipate and mitigate inter-cell interference while maintaining flexible duplex operation.
2Adaptability or versatility
If UL-DL subframe allocation is made flexible to adapt to traffic demand, then resource allocation efficiency improves, but interference measurement becomes difficult with existing LTE-A technologies
Solution Approach 1:
The patent applies segmentation by dividing the interference measurement process into distinct components: separate uplink interference measurement resources (IMR) are defined, UEs measure interference on these dedicated resources, and results are reported separately for each measured interference condition. This segmented approach allows accurate measurement of interference under different flexible duplex configurations without requiring a single monolithic measurement mechanism, thereby maintaining both measurement precision and allocation flexibility.
Solution Approach 2:
The patent implements feedback by establishing a closed-loop mechanism where UEs continuously measure uplink interference on designated IMR resources and report these measurements back to the eNB. The eNB then uses this feedback information to adjust downlink scheduling decisions, creating a dynamic adaptation system that maintains accurate interference awareness despite flexible and changing UL-DL allocations across different cells.
3Productivity
If eNB schedules UL transmission dynamically, then UL resource utilization improves, but interference measurement timing becomes complex due to variable subframe relationships
Solution Approach 1:
The patent resolves the scheduling complexity by applying preliminary action: the eNB configures and signals uplink interference measurement resources (IMR) to UEs in advance, establishing predetermined measurement opportunities independent of dynamic UL grant timing. UEs perform interference measurements on these pre-configured resources regardless of when UL transmissions are actually scheduled. This decouples the interference measurement timing from the dynamic UL scheduling, maintaining high UL resource utilization while simplifying the measurement process.
Data Source
AI summary
The present disclosure relates to a 5G or pre-5G communication system that will be provided to support a higher data transmission rate beyond a 4G communication system such as LTE. Disclosed is an interference measurement method and device in a flexible duplex system. The method comprises the steps of: determining whether uplink (UL) grant for allocating UL transmission has been received from a base station in a first subframe; when the UL grant has not been received, measuring inter-cell interference for an uplink interference measurement resource (IMR) in at least one second subframe determined by the first subframe; and when the UL grant has been received, measuring inter-cell interference for the uplink interference measurement resource (IMR) in at least one third subframe before a subframe that is indicated by the UL grant.