Almost Blank Subframe Signaling for Interference Coordination

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Solution Overview

Problem

Existing wireless communication networks face challenges in efficiently measuring and mitigating interference between heterogeneous cells, leading to inaccurate RRM, RLM, and CSI measurements, which result in erratic behaviors, failed connections, and suboptimal spectral resource utilization in heterogeneous networks.

Innovation Solution

Implementing Almost Blank Subframes (ABS) patterns in wireless communication systems, where cells configure specific subframes for critical information transmission only, allowing UEs to perform measurements during interference-free periods, and using interference rejection or cancellation techniques to mitigate interference from neighboring cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If cells transmit continuously to maintain coverage, then network coverage is improved, but interference between heterogeneous cells increases

Engineering Contradiction:

Improvenetwork coverageVSAvoidinterference between heterogeneous cells

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent segments the transmission timeline into different types of subframes: regular subframes for normal data transmission and Almost Blank Subframes (ABS) for interference-free periods. This segmentation allows the network to maintain continuous coverage while creating dedicated measurement windows where interference is minimized, resolving the contradiction between continuous transmission and interference reduction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic ABS patterns where cells alternately transmit regular subframes and ABS. This periodic action creates predictable interference-free windows for measurements while maintaining overall network coverage, allowing UEs to perform accurate RRM, RLM, and CSI measurements during ABS periods without sacrificing continuous network availability.

Inventive Principle:

Principle #19Periodic action

2Loss of time

If UEs perform measurements during active subframes, then measurement opportunities increase, but measurement accuracy decreases due to interference

Engineering Contradiction:

Improvemeasurement opportunitiesVSAvoidmeasurement accuracy

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The patent prepares ABS patterns and signals them to UEs in advance through higher layer signaling. This preliminary action allows UEs to know when interference-free measurement opportunities will occur, enabling them to schedule their measurements accordingly. The network configures ABS patterns before measurement, ensuring UEs have accurate measurement opportunities without interference.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If cells use all subframes for data transmission, then spectral efficiency is improved, but measurement accuracy for RRM, RLM, and CSI deteriorates

Engineering Contradiction:

Improvespectral efficiencyVSAvoidmeasurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies partial action by using ABS for measurements rather than all subframes. Although some subframes are dedicated to measurements rather than data transmission, the overall system achieves better performance because accurate measurements enable optimal scheduling and resource allocation. The sacrifice of some data transmission capacity in ABS is compensated by improved network-wide efficiency through better measurement accuracy.

Inventive Principle:

Principle #16Partial or excessive action

4Measurement precision

If ABS patterns are implemented for interference coordination, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvemeasurement accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses the network infrastructure (eNB) as an intermediary to manage ABS patterns and signal them to UEs through existing higher layer signaling mechanisms. This intermediary approach allows complex interference coordination to be implemented without requiring complex processing at the UE side. The eNB handles the complexity of pattern generation and signaling, while UEs simply follow the signaled patterns for measurements, minimizing device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9344248B2Positioning reference signal assistance data signaling for enhanced interference coordination in a wireless communication network

Publication Date: 2016.05.17 GOOGLE TECHNOLOGY HOLDINGS LLC

AI summary

A method in a wireless communication terminal is disclosed. The method includes receiving a first signal including a desired second signal and an interference component, wherein the interference component includes at least a third signal transmitted in an Almost Blank Subframe (ABS) by a neighbor cell, and configuring the wireless communication terminal to employ interference reduction to process the first signal based on a configuration of the interference component.