Interference Control in Cellular Networks via Base Station Cooperation
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Solution Overview
Problem
Cellular communications networks face significant interference issues, particularly in frequency reuse-1 systems, where uplink interference can lead to service degradation and unstable connections due to intra-cell and inter-cell interference, which existing techniques like soft handover and inter-cell interference control do not fully address, especially considering the limitations and costs associated with these methods.
Innovation Solution
A method where base stations cooperate by determining and notifying each other of uncontrolled uplink interference, calculating noise rise contributions from user equipment devices, and implementing corrective actions such as adjusting resource allocations or handovers to mitigate interference, using information exchanged over interfaces like the X2 interface in LTE networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If soft handover is implemented to reduce uplink interference, then interference levels are reduced, but system complexity and cost increase
Solution Approach 1:
The patent segments the interference control function by dividing base stations into victim base stations (detecting interference) and aggressor base stations (controlling UE transmissions). This segmentation allows interference mitigation without requiring all base stations to participate in soft handover, reducing overall system complexity while still achieving interference reduction through targeted control actions at the aggressor end.
2Reliability
If victim base station requires connected UEs to increase transmit power to overcome interference, then signal reception improves, but uplink interference increases further causing system instability
Solution Approach 1:
The patent implements a feedback mechanism where the victim base station measures uplink interference, identifies aggressor base stations, and communicates interference information back to them. The aggressor base stations then adjust UE transmit power or resource allocations based on this feedback, creating a closed-loop system that reduces interference without causing the instability that would result from simple power increases.
3Object-affected harmful factors
If blind inter-cell interference control techniques are applied, then interference mitigation is achieved, but system adaptability decreases due to blanket actions
Solution Approach 1:
The patent applies local quality by enabling victim base stations to specifically identify and communicate with only those aggressor base stations that are actually causing interference to their UEs. This targeted approach allows each base station to adapt its interference control actions to its specific local interference conditions, rather than applying blanket restrictions to all cells, thereby maintaining system adaptability while effectively mitigating interference.
Data Source
AI summary
A method of controlling interference in a cellular communications network comprises, in a first base station of the network: determining that the first base station is suffering from uncontrolled interference from at least one other base station of the network; based on information received from at least one other base station of the network regarding estimates of interference caused at the first base station by at least one user equipment device connected to the respective other base station, selecting a proposed action to mitigate said interference; and notifying the respective other base station of the selection of the proposed action.