Interference Suppression Time-Frequency Zone for Cellular Networks

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Solution Overview

Problem

Current interference suppression methods in cellular networks, such as the Almost Blank Subframe (ABS) and Reduced Power ABS, degrade downlink throughput for UEs served by interfering base stations, as they either halt or reduce data transmission to mitigate interference.

Innovation Solution

Implementing an Interference Suppression (IS) time/frequency zone, where transmission parameters are coordinated between serving and interfering base stations to align reference signals, allowing UEs to estimate and cancel interference without degrading receiver performance, and enabling higher power and modulation orders for improved data throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If Almost Blank Subframe or Reduced Power ABS is used to suppress interference, then interference at UE is reduced, but downlink throughput for UEs served by interfering base stations deteriorates

Engineering Contradiction:

Improveinterference at UEVSAvoiddownlink throughput

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent changes the temporal and spectral parameters of reference signals by aligning them in specific time-frequency zones. This allows the UE to estimate and cancel interference from interfering base stations without requiring those base stations to reduce or halt data transmission, thus resolving the contradiction between interference suppression and throughput maintenance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the time-frequency resource into specific zones where reference signal alignment occurs. By confining interference suppression activities to these segmented zones rather than applying them system-wide, the interfering base stations can maintain normal data transmission in other resources, preserving overall throughput while achieving interference suppression where needed

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If reference signals are aligned in time and frequency between serving and interfering base stations, then UE can estimate and cancel interference effectively, but system complexity increases due to coordination requirements

Engineering Contradiction:

Improveinterference estimation accuracyVSAvoidcoordination complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary coordination between base stations to align reference signal parameters before actual data transmission begins. This preliminary action establishes the time-frequency alignment in advance, enabling the UE to effectively estimate and cancel interference without requiring complex real-time coordination during data transmission

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a coordination mechanism that acts as an intermediary between serving and interfering base stations. This intermediary facilitates the exchange of reference signal parameter information, enabling alignment without requiring direct complex interactions between all base stations, thus reducing overall system complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If interfering base station maintains high power transmission, then data throughput is improved, but interference at served UEs increases

Engineering Contradiction:

Improvedata throughputVSAvoidinterference at served UEs

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful interference from high-power transmission at interfering base stations into a beneficial effect by enabling the UE to estimate and cancel this interference through aligned reference signals. The interference that would normally degrade performance is transformed into a measurable and cancellable component, allowing the interfering base station to maintain high power transmission for improved throughput without adversely affecting served UEs

Inventive Principle:

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

Data Source

PatentUS9780843B2Interference suppression and alignment for cellular networks

Publication Date: 2017.10.03 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

An interference suppression (IS) time/frequency zone for improved interference suppression at the user equipment (UE) is provided. The IS time/frequency zone can be scheduled and set up using existing signaling of the Almost Blank Subframe (ABS) framework. This includes using the existing signaling of the ABS framework to schedule the IS time/frequency zone, coordinate transmission parameters among base stations for the IS time/frequency zone, and signal the IS time/frequency zone to the UE. In another aspect, interfering base stations align respective reference signals during the IS time/frequency zone, which allows the UE to measure the channels from its serving base station and/or the interfering base stations(s). With channel state information knowledge at the UE, interference alignment can be achieved at the UE during the IS time/frequency zone.