Control PHY Mode for Interference Management in Dense Wireless Networks

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Solution Overview

Problem

In dense wireless communication environments, battery-powered mobile devices face challenges in collecting up-to-date virtual carrier sense information due to power limitations and interference from hidden nodes, leading to communication failures due to interference from other transmissions.

Innovation Solution

Implementing a Control PHY mode with enabled Control PHY modulation and coding schemes and disabled Single Carrier PHY schemes, allowing devices to set NAV timers and manage interference by sending Denial-to-Send messages, enabling communication despite interference and switching between modes to optimize power usage and thermal design parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If battery-powered mobile devices implement CSMA/CA with full channel information collection, then collision avoidance is improved, but power consumption increases and hidden node interference cannot be detected

Engineering Contradiction:

Improvecollision avoidanceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by having mobile devices perform only essential channel sensing (physical carrier sense) rather than complete channel information collection. Devices listen for ongoing transmissions but do not continuously monitor virtual carrier sense information from hidden nodes, accepting partial information to conserve battery power while maintaining adequate collision avoidance capability.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent introduces an intermediary mechanism where fixed dock stations act as intermediaries to detect hidden node transmissions and alert mobile devices. The dock's enhanced sensing capability compensates for the mobile device's limited sensing, allowing the mobile device to save power while still receiving warning about hidden node activity through the dock's intermediary observation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of information

If mobile devices continuously monitor channel for virtual carrier sense information, then hidden node detection is improved, but battery life decreases

Engineering Contradiction:

Improvehidden node detectionVSAvoidbattery life

Core Design Contradiction:

Loss of informationVSDuration of action of moving object

Solution Approach 1:

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent applies self-service by having dock stations, which have unlimited power supply, perform the energy-intensive task of continuous channel monitoring and hidden node detection. The mobile devices rely on the dock's self-performed monitoring function, allowing the mobile device to extend battery life while the dock handles the continuous surveillance in its capacity as a permanently powered infrastructure element.

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If beamforming is used to reduce transmission distance, then interference to other stations is reduced, but ability to detect hidden nodes decreases

Engineering Contradiction:

Improveinterference to other stationsVSAvoidhidden node detection

Core Design Contradiction:

Object-affected harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies merging by combining the beamforming capability of mobile devices with the omnidirectional sensing capability of dock stations. The mobile device transmits directionally to reduce interference, while the dock station provides complementary full-direction monitoring to detect hidden nodes that the mobile device's directional beam cannot sense, creating a merged sensing system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If stations transmit with high power to overcome interference, then communication reliability is improved, but thermal issues and power consumption increase

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidthermal issues

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent applies preliminary action by having dock stations perform preliminary channel assessment and hidden node detection before mobile devices attempt transmission. The dock evaluates the channel conditions and alerts the mobile device of upcoming hidden node transmissions, allowing the mobile device to postpone or cancel high-power transmission attempts, thereby avoiding thermal issues while maintaining communication reliability through selective transmission.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9923663B2Methods and arrangements for time-sharing in a dense environment

Publication Date: 2018.03.20 INTEL CORP

AI summary

Logic may enable communication between stations in the presence of interference. Logic may communicate with the station in the presence of interference, the interference from a communication between other stations comprising a first network allocation vector (NAV) reminder, by entering a mode in which a Control Physical layer (PHY) modulation and coding scheme (MCS) is enabled and a Single Carrier PHY MCS is disabled. Logic may enable the Single Carrier PHY MCS in response to receipt of a clear-to-send (CTS) or an expiration of a CTS timeout. Logic may determine an active time remainder during a Contention-based access period. Logic may determine a time to access a channel in response to receipt of the Denial to Send and based upon a predefined, maximum inactivity time. Logic may remain beamformed while the apparatus is in the Control PHY mode.