Asymmetric Full Duplex Wi-Fi Synchronization via AP Timing

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Solution Overview

Problem

Asymmetric full-duplex communications in Wi-Fi networks face challenges in synchronizing downlink and uplink transmissions between different nodes, leading to potential interference and synchronization issues.

Innovation Solution

An access point provides information about uplink transmission opportunities in the header of downlink frames and transmits a block acknowledgement request frame to synchronize acknowledgments, ensuring coordinated timing between downlink and uplink transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If asymmetric full-duplex communications are implemented between different node pairs, then communication capacity is improved, but synchronization difficulty increases leading to interference

Engineering Contradiction:

Improvecommunication capacityVSAvoidsynchronization complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The access point acts as an intermediary that coordinates timing between downlink and uplink transmissions. It provides timing information in DL frame headers and sends BAR frames to synchronize ACK transmissions, mediating the interaction between unsynchronized node pairs to prevent interference while maintaining high communication capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses feedback mechanisms where the access point monitors transmission timing and sends block acknowledgement requests to adjust and synchronize uplink acknowledgments. This feedback loop enables dynamic timing coordination between asymmetric node pairs, resolving synchronization issues while preserving full-duplex communication benefits

Inventive Principle:

Principle #23Feedback

2Productivity

If downlink and uplink transmissions occur simultaneously between different nodes, then spectral efficiency is improved, but interference between transmissions increases

Engineering Contradiction:

Improvespectral efficiencyVSAvoidtransmission interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The access point performs preliminary actions by embedding timing information in downlink frame headers before uplink transmissions occur. This advance timing coordination allows stations to prepare their uplink transmissions to avoid interfering with ongoing downlink transmissions, enabling simultaneous operations without interference

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system converts the potential harmful effect of simultaneous transmissions into a benefit by using the downlink transmission itself as a timing reference. The DL frame headers provide synchronization information that turns what could be interference into coordinated simultaneous operation, improving spectral efficiency while preventing harmful interference

Inventive Principle:

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

Data Source

PatentEP3689070B1A media access control for full duplex communications

Publication Date: 2022.08.24 HUAWEI TECH CO LTD

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AI summary

Methods and apparatuses for asymmetric full duplex (FD) communications. Information about an uplink (UL) transmission opportunity (TXOP), including an indication of the TXOP, is sent by an access point (AP). The AP sends a downlink (DL) transmission to a receiving station. During the TXOP, an UL transmission is received from a transmitting station. The UL transmission at least partially overlaps in time with the DL transmission. Acknowledgement of the UL transmission is sent to the transmitting station, and acknowledgement of the DL transmission is received from the receiving station, at a synchronized time.