Scheduling Coordinator for Inter-Cell Interference Cancellation

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Solution Overview

Problem

Existing LTE systems face challenges in coordinating scheduling and rate control across cells to effectively mitigate inter-cell interference, particularly in heterogeneous networks, which affects spectral efficiency and user performance at the cell edge.

Innovation Solution

The proposed solution involves a scheduling coordinator that adjusts transmission data rates and schedules users to account for their interference cancellation capabilities, allowing IC-capable terminals to effectively cancel interference by coordinating scheduling decisions across neighboring cells and adjusting rates to minimize interference impact, thereby enhancing spectral efficiency and user data rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If transmission data rates are increased to improve spectral efficiency, then system capacity improves, but inter-cell interference increases affecting user performance at cell edge

Engineering Contradiction:

Improvespectral efficiencyVSAvoidinter-cell interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts harmful inter-cell interference into a beneficial signal by enabling interference cancellation at the UE. The UE uses the interfering signal from neighboring cells as a resource to cancel out interference and improve reception of desired signals, thereby converting what was previously a harmful factor into a useful component of the communication system.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent dynamically adjusts transmission data rates as a parameter to account for interference cancellation capabilities. By modifying the data rate parameter based on UE IC capability and channel conditions, the system optimizes the balance between spectral efficiency and interference mitigation, allowing higher rates when IC is available and lowering rates when interference would be detrimental.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If scheduling coordination across cells is implemented to mitigate interference, then user performance at cell edge improves, but system complexity increases

Engineering Contradiction:

Improveuser performanceVSAvoidscheduling coordination

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent enables UEs to perform interference cancellation autonomously using their own received signals and channel state information. Rather than requiring complex centralized coordination, each UE independently processes and cancels interference based on its local measurements, thereby improving reliability without proportionally increasing system complexity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent incorporates feedback mechanisms where UEs report channel quality indicators and interference characteristics back to the scheduler. This feedback enables the scheduler to make informed decisions about data rate selection and scheduling decisions, improving user performance through adaptive control while keeping the coordination mechanism manageable through information exchange rather than complex processing.

Inventive Principle:

Principle #23Feedback

3Power

If transmission power levels are maintained to ensure signal strength, then coverage area is preserved, but interference cancellation effectiveness decreases

Engineering Contradiction:

Improvetransmission powerVSAvoidinterference cancellation

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent dynamically adapts transmission data rates based on real-time channel conditions and interference characteristics. By making the data rate a variable parameter that responds to changing conditions, the system maintains optimal performance across varying power levels and interference environments, allowing high power transmission when IC can effectively handle the interference and lower power when IC would be insufficient.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9078276B2Scheduling and rate control coordination accounting for interference cancellation at a mobile terminal

Publication Date: 2015.07.07 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Devices and methods for scheduling and interference cancellation that consider the interference cancellation capability of user equipment (UEs) are disclosed. Using reduced-rate sub-frame (or resource block) strategies, the transmission data rate to a scheduled user in a given cell may be reduced to ensure effective interference cancellation performance at the receiver of a co-scheduled user in another cell. By taking advantage of interference mitigation at one or more terminals, a scheduler may improve network spectral efficiency compared to existing inter-cell interference cancellation schemes, including almost blank sub-frame (ABS), further enhanced inter-cell interference coordination (FeICIC), and other resource partitioning schemes, such as reduced power sub-frames or frequency domain resource partitioning.