Null Pilots for Interference Estimation in Wireless Networks

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Solution Overview

Problem

Existing wireless communication networks face challenges in accurately estimating out-of-cluster interference, which affects data transmission performance and quality.

Innovation Solution

The use of null pilots transmitted by cells and clusters on designated time-frequency resources allows user equipment (UEs) to estimate out-of-cluster interference by measuring received power, enabling more accurate interference estimation and improved data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional interference estimation methods are used in wireless communication networks, then the system can operate with existing infrastructure, but the accuracy of out-of-cluster interference estimation is insufficient

Engineering Contradiction:
Improveinterference estimation accuracyVSAvoiddata transmission performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces null pilots as an intermediary signal element that enables accurate interference estimation. These null pilots are specifically designed reference signals transmitted by serving cells that allow UEs to measure and estimate out-of-cluster interference without being affected by serving cell transmissions, thus resolving the contradiction between measurement precision and transmission reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary interference estimation by having UEs measure out-of-cluster interference on null pilot resources before actual data transmission occurs. This preliminary measurement allows the system to compensate for interference effects in advance, improving both estimation accuracy and transmission performance

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If null pilots are transmitted on designated time-frequency resources, then out-of-cluster interference estimation accuracy is improved, but the system complexity increases

Engineering Contradiction:
Improveout-of-cluster interference estimation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the null pilot mechanism universal by defining standardized procedures for null pilot transmission, resource allocation, and interference estimation that can be applied across different wireless communication scenarios and network configurations. This universal approach reduces implementation complexity while maintaining estimation accuracy

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes parameter changes in time-frequency resource allocation for null pilots, where specific time-frequency resources are designated for null pilot transmission. By changing the parameters of resource allocation rather than introducing fundamentally new system components, the patent achieves improved estimation accuracy with minimal increase in system complexity

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2618506B1Null pilots for interference estimation in a wireless communication network
Publication Date: 2016.09.14 QUALCOMM INC
  • EP2618506B1 patent drawingFigure 1
  • EP2618506B1 patent drawingFigure 2
  • EP2618506B1 patent drawingFigure 3

AI summary

Techniques for transmitting null pilots to support interference estimation in a wireless network are described. A null pilot is non-transmission on designated time-frequency resources by a cell or a cluster of cells supporting cooperative transmission to a UE. The received power of the null pilot from the cell or cluster of cells may be indicative of interference from other cells. In one design, a cell in the cluster may determine resources for sending a null pilot by the cell. The cell may transmit the null pilot (i.e., send no transmissions) on the resources to allow UEs to estimate out-of-cluster interference. Some or all cells in the cluster may transmit null pilots on the same resources. The cell may receive interference and channel information from the UE and may send data transmission to the UE based on the interference and/or channel information. Remaining cells in the cluster may reduce interference to the UE.