UE CSI Reporting with Interference Cancellation

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Solution Overview

Problem

In LTE networks, accurate channel state information (CSI) reporting by user equipment (UE) with network-assisted interference cancellation and suppression (NAICS) receivers is challenging, especially for inter-cell interference, due to limited resource elements (REs) available for parameter estimation, which affects spectral efficiency and network capacity.

Innovation Solution

The UE employs advanced receiver algorithms that utilize higher-layer signaling assistance to estimate interference parameters from neighboring cells, extending CSI-IM resources and modifying CSI reporting to include interference measurements during PDSCH demodulation, allowing for more accurate CSI reporting by considering the interfering signal parameters and effective channel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If NAICS receiver algorithms are used to estimate interference parameters, then interference cancellation capability is improved, but the number of available resource elements for parameter estimation is insufficient

Engineering Contradiction:

Improveinterference cancellation capabilityVSAvoidnumber of resource elements

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extends CSI-IM resources from traditional dimensions into the PDSCH allocation domain, utilizing previously unused resource elements for interference measurement. This dimensional extension provides additional measurement opportunities without requiring extra dedicated interference measurement resources.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The PDSCH resource elements serve dual purposes: data transmission and interference parameter estimation. By making the PDSCH allocation serve multiple functions, the system achieves interference cancellation capability enhancement without dedicating separate resources solely for measurement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If CSI-IM resources are extended to PDSCH allocation, then interference measurement accuracy is improved, but device complexity increases

Engineering Contradiction:

Improveinterference measurement accuracyVSAvoidreceiver processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs interference parameter estimation during the PDSCH reception process itself, rather than as a separate subsequent step. By integrating interference measurement with data reception timing, the patent reduces additional processing complexity while improving measurement accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent combines interference measurement functionality with the existing PDSCH reception and demodulation processes. By merging these functions, the system achieves accurate interference estimation without requiring completely separate measurement procedures, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9590713B2User equipment and methods for CSI enhancements using interference cancellation and suppression receivers

Publication Date: 2017.03.07 APPLE INC

AI summary

In providing feedback to an eNB in an LTE network for downlink scheduling and link adaptation, a UE issues a channel state information (CSI) report that includes a channel quality index (CQI). The reported CQI should include all UE receiver processing capabilities, including NAICS (network assisted interference cancellation and suppression) capability to cancel and suppress interference. Described are measures that may be taken to provide more accurate reporting of CSI by a terminal with NAICS capability.