Wideband Control Frame for Cell-Edge Downlink Throughput

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Solution Overview

Problem

In IEEE 802.11 wireless communications systems, cell-edge stations (CE STAs) experience lower physical data rates due to propagation losses, limiting their ability to transmit and receive wideband signals, which restricts downlink data throughput and requires increased transmit power from access points (APs), leading to inefficiencies in high-density environments.

Innovation Solution

The implementation of a new wideband control frame structure that includes a legacy preamble for decoding over a 20 MHz channel and a new preamble indicating the total signal bandwidth, allowing APs to decode and transmit data over the indicated bandwidth, even if the CE STA cannot send a wideband signal, thereby enhancing data throughput without increasing device transmit power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the AP transmits data over wide bandwidth (80 MHz) to the CE STA, then the downlink data throughput is improved, but the CE STA cannot receive the wideband signal due to propagation loss and limited transmit power

Engineering Contradiction:

Improvedownlink data throughputVSAvoidsignal reception reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the control frame transmission into two parts: a legacy narrowband preamble (20 MHz) that the CE STA can reliably decode, and a new wideband preamble (80 MHz) that indicates the total signal bandwidth. This segmentation allows the control information to be delivered reliably to the CE STA while still enabling wideband downlink data transmission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The legacy preamble acts as an intermediary that bridges the gap between the CE STA's limited receive capability and the wideband downlink transmission. The CE STA can decode the legacy preamble to obtain basic control information, while the new preamble provides additional bandwidth indication that enables the AP to transmit wideband data that the CE STA can still receive despite its power limitations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the CE STA increases transmit power to send wideband CTS signals, then the uplink signal reach is improved, but the device power consumption increases

Engineering Contradiction:

Improveuplink signal reachVSAvoiddevice power consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by having the CE STA transmit the CTS signal only on the narrowband primary channel (20 MHz) rather than attempting to transmit on the full wideband channel (80 MHz). This partial transmission is sufficient to convey the CTS acknowledgment to the AP while significantly reducing the power consumption compared to full wideband transmission.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If the AP transmits duplicate RTS/CTS frames over multiple channels, then collision protection is improved, but the CE STA cannot send wideband CTS and the AP cannot send wideband DL data

Engineering Contradiction:

Improvecollision protectionVSAvoidwideband data transmission

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by having the CE STA transmit the CTS frame with different properties on different channels: on the narrowband primary channel, the CTS includes a legacy preamble for reliable decoding, while on wideband secondary channels, the CTS includes a new preamble that indicates the total signal bandwidth. This allows collision protection through duplicate transmissions while enabling the AP to identify and transmit wideband downlink data.

Inventive Principle:

Principle #3Local quality

4Reliability

If the system uses narrowband (20 MHz) transmission, then the CE STA can reliably communicate, but the data throughput is limited compared to wideband transmission

Engineering Contradiction:

Improvecommunication reliabilityVSAvoiddata throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent makes the control frame universal by incorporating both legacy and new preambles that serve different functions. The legacy preamble ensures reliable decoding by CE STAs with limited capabilities, while the new preamble enables wideband transmission for systems that support it. This multi-functionality allows the same control frame structure to serve both reliability and throughput requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11229052B2Processes and methods to enable downlink data transmission over wide bandwidth for the cell edge station

Publication Date: 2022.01.18 INTEL CORP

AI summary

Methods and systems herein provide better downlink (DL) data throughput for cell-edge stations (CE STAs). The systems enable protection from a third-party collision during a wideband DL data transmission to the cell edge STA, when the wideband control frame, such as clear-to-send (CTS) or acknowledge (ACK), transmission from a cell edge STA cannot reach the AP. This process can be achieved by designing a new wideband control frame comprising: a legacy preamble sent over the primary 20 MHz channel that can be decoded by the legacy STAs, a new preamble sent over the primary 20 MHz channel that can be used to identify the new wideband control frame (this new preamble has the total signal bandwidth information for the rest of the packet following the new preamble); and duplicate legacy control packets set over the total bandwidth indicated in the new preamble (the legacy control packets can be decoded by the legacy STAs).