Channel State Feedback Computation With Interference Cancellation

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Solution Overview

Problem

Wireless communication networks face interference challenges due to increased demand for mobile broadband access, leading to degraded performance, and existing methods like time multiplexed transmission schemes are not sufficient to mitigate interference effectively.

Innovation Solution

User Equipment (UE) enabled with common reference signal interference cancellation determines whether neighboring cells are transmitting during specific time periods and adjusts channel state feedback values accordingly, considering canceled interfering signals to generate an adjusted feedback value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If common reference signal interference cancelation is used, then interference from neighboring cells is reduced, but channel state feedback accuracy deteriorates because canceled signals are not considered

Engineering Contradiction:
Improveinterference from neighboring cellsVSAvoidchannel state feedback accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the UE determines whether neighboring cells are transmitting during the time period for channel state feedback computation. Based on this determination, the UE adjusts the channel state feedback value to account for canceled interfering signals. This feedback loop ensures that the channel state feedback accurately reflects the actual interference conditions, resolving the contradiction between interference cancellation and feedback accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes the channel state feedback parameter based on the transmission status of neighboring cells. When neighboring cells are determined to be transmitting, the feedback value is adjusted to compensate for the canceled interfering signals. This parameter adjustment ensures that the feedback accurately represents the channel conditions despite the interference cancelation process.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If time multiplexed transmission scheme is used, then interference from other cells is reduced, but network capacity and throughput are limited due to restricted resource utilization

Engineering Contradiction:
Improveinterference from other cellsVSAvoidnetwork capacity and throughput
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent transitions from static time multiplexed transmission to a dynamic approach where channel state feedback is adaptively adjusted based on real-time neighboring cell transmission status. This dynamic adjustment allows the system to utilize resources more efficiently while managing interference, thereby improving network capacity and throughput without sacrificing interference mitigation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The UE autonomously determines the transmission status of neighboring cells and self-adjusts the channel state feedback value accordingly. This self-service capability eliminates the need for complex network coordination while optimizing resource utilization and maintaining interference reduction, thus enhancing network productivity.

Inventive Principle:
Principle #25Self-service

3Device complexity

If channel state feedback is computed without considering canceled interfering signals, then computation complexity is reduced, but communication quality deteriorates

Engineering Contradiction:
Improvecomputation complexityVSAvoidcommunication quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies partial action by selectively adjusting the channel state feedback value only when neighboring cells are determined to be transmitting. This approach avoids the complexity of continuously monitoring and adjusting feedback in all conditions, while still maintaining communication quality when interference is present. The selective adjustment strikes a balance between computation complexity and communication reliability.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2537276B1Computation of channel state feedback in systems using common reference signal interference cancelation
Publication Date: 2019.01.02 QUALCOMM INC
  • EP2537276B1 patent drawingFigure 1
  • EP2537276B1 patent drawingFigure 2
  • EP2537276B1 patent drawingFigure 3

AI summary

When enabled with common reference signal interference cancelation, a user equipment (UE) may still compute a channel state feedback value with consideration of any canceled interfering neighboring signals. When the neighboring cells are determined to be transmitting data during the time for which the channel state feedback value is being computed, the UE is able to derive the channel state feedback value considering those canceled interfering signals. The UE determines whether each neighboring cell is transmitting during the designated time either by obtaining signals that indicate the transmission schedule of the neighboring cells or by detecting the transmission schedule, such as based on the power class of the neighboring cells. If the UE determines that the neighboring cells are transmitting data during this time period, the UE will compute the channel state feedback value including consideration of the canceled interfering signals.