Full-Duplex Signaling with Cancelation Tones and Cyclic Extensions

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Solution Overview

Problem

In wireless communication systems, the timing advance used for synchronizing uplink and downlink communications can cause interference between uplink and downlink transmissions due to a timing mismatch at the user equipment (UE), leading to decreased throughput, increased latency, and reliability issues.

Innovation Solution

The UE employs cancelation tones and cyclic extensions to suppress interference, where cancelation tones are generated based on feedback control information and timing advance values, and cyclic extensions are used to align uplink symbols with downlink symbols, thereby restoring orthogonality between uplink and downlink communications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If timing advance is used to synchronize uplink and downlink communications at the network entity, then synchronization is improved, but interference between uplink and downlink transmissions occurs at the UE due to timing mismatch

Engineering Contradiction:

ImprovesynchronizationVSAvoidinterference

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent generates cancelation tones based on the uplink signal and timing advance value to convert the harmful self-interference caused by timing advance into a beneficial cancellation mechanism. The cancelation tones are designed to match the interference characteristics and subtract them from the received downlink signal, effectively eliminating the harmful effect while preserving the synchronization benefit.

Inventive Principle:

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

Solution Approach 2:

The patent introduces cancelation tones as an intermediary element between the uplink and downlink signals. These cancelation tones serve as a mediator that represents the interference component, allowing the UE to separate and remove the harmful interference from the desired downlink signal through signal processing operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If uplink resources puncture downlink resources to provide frequent feedback control information, then communication reliability is improved, but interference with downlink transmissions increases

Engineering Contradiction:

Improvefeedback control information transmissionVSAvoidinterference with downlink transmissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful interference caused by uplink transmissions puncturing downlink resources into a beneficial cancellation opportunity. By generating cancelation tones that match the uplink signal characteristics and applying them to the received signal, the UE can eliminate the interference while maintaining the frequent feedback control information transmission that improves reliability.

Inventive Principle:

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

3Object-generated harmful factors

If cancelation tones are generated based on feedback control information and timing advance values, then interference cancellation is improved, but device complexity increases

Engineering Contradiction:

Improveinterference cancellationVSAvoidsignal processing complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements a self-service mechanism where the UE uses its own transmitted uplink signal and known timing advance value to generate the cancelation tones. This self-generated reference signal approach eliminates the need for external interference measurement or complex joint estimation, reducing device complexity while maintaining effective interference cancellation performance.

Inventive Principle:

Principle #25Self-service

4Reliability

If cyclic extensions are used to align uplink symbols with downlink symbols, then orthogonality is restored, but additional processing overhead is introduced

Engineering Contradiction:

ImproveorthogonalityVSAvoidsignal processing overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies cyclic extensions as a preliminary action to the uplink signal before transmission. By pre-aligning the uplink and downlink symbols in the time domain through cyclic extensions, the system restores orthogonality at the source, preventing interference before it occurs and reducing the need for complex post-reception processing.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12177800B2Signaling for enabling full-duplex communications in the presence of a timing advance

Publication Date: 2024.12.24 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communication are described. In some wireless communications systems, a user equipment (UE) may receive a control signal allocating downlink resources and uplink resources, where the uplink resources puncture the downlink resources and are allocated for transmitting feedback control information. The UE may generate an uplink signal containing the feedback control information and one or more cancelation tones for canceling interference between a downlink signal and the uplink signal in accordance with a timing advance value. Additionally, or alternatively, the UE may generate an uplink signal including the feedback control information, where the uplink signal contains uplink symbols and cyclic extensions appended to the uplink symbols, and the cyclic extensions may be based on the timing advance value. The UE may transmit, while receiving downlink data on the downlink resources, the uplink signal including the feedback control information using the set of uplink resources.