Wireless Transceiver Neighboring Channel Interference Reduction

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Solution Overview

Problem

Wireless transceivers experience packet collisions due to insufficient frequency differences and strong interference between adjacent channels in the 2.4 GHz frequency band, leading to signal interference despite existing collision avoidance protocols.

Innovation Solution

A wireless transceiver and communication method that transmit a first CTS-to-Self packet on the neighboring channel before data packet transmission on the target channel, with a duration field defining the time for data packet completion, using an RF transceiver, frequency synthesizer, and RF controller to manage carriers for both channels, and optionally transmitting additional CTS or RTS packets to ensure channel clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RTS and CTS packets are transmitted via the target channel to prevent packet collision, then packet collision is avoided, but signal interference from neighboring channels still occurs when transceivers cannot recognize the CTS packets

Engineering Contradiction:

Improvepacket collision avoidanceVSAvoidsignal interference from neighboring channel

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by transmitting a CTS-to-Self packet on the neighboring channel before actual data transmission on the target channel. This preliminary transmission reserves the neighboring channel in advance, preventing other transceivers from using it during the data transmission period, thus eliminating signal interference while maintaining packet collision avoidance.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the frequency difference between target channel and neighboring channel is small to allow concurrent transmission, then channel utilization is improved, but packet collision and signal interference increase

Engineering Contradiction:

Improvechannel utilizationVSAvoidpacket transmission success rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent reserves the neighboring channel in advance by transmitting a CTS-to-Self packet before data transmission. This preliminary reservation allows the system to safely use frequencies closer together, as the neighboring channel is pre-blocked from causing interference during the data transmission period, thus improving channel utilization without sacrificing reliability.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If CTS packets are transmitted on the target channel, then collision avoidance is achieved, but transceivers on neighboring channels cannot recognize these packets and continue transmitting causing interference

Engineering Contradiction:

Improvecollision avoidance mechanismVSAvoidinter-modulation signal recognition

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses the CTS-to-Self packet as an intermediary message that serves dual purposes: it maintains the collision avoidance function on the target channel while simultaneously acting as a recognizable reservation signal on the neighboring channel. This intermediary packet type ensures both collision avoidance and universal recognition across different modulation schemes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the transmission parameter by sending the CTS-to-Self packet on the neighboring channel instead of (or in addition to) the target channel. This parameter change ensures that transceivers on the neighboring channel can recognize the reservation signal and adjust their behavior accordingly, preventing interference while maintaining the original collision avoidance mechanism.

Inventive Principle:

Principle #35Parameter changes

4Power

If high energy signals are transmitted on the target channel, then transmission distance is extended, but interference with neighboring channels increases

Engineering Contradiction:

Improvesignal transmission energyVSAvoidinterference signal energy

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent transmits a CTS-to-Self packet on the neighboring channel before high-energy data transmission on the target channel. This preliminary action reserves the neighboring channel, preventing other transceivers from transmitting during the high-power transmission period, thus allowing extended transmission distance without proportionally increasing interference to neighboring channels.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10973054B2Wireless transceiver and wireless communication method

Publication Date: 2021.04.06 REALTEK SEMICON CORP

AI summary

Disclosed are a wireless transceiver and a wireless communication method capable of reducing signal interference originated from a neighboring channel, in which the difference between the central frequency of the neighboring channel and the central frequency of a target channel is less than a frequency difference threshold and/or the energy of an interference signal of the neighboring channel is greater than a signal energy threshold. The wireless transceiver includes: a radio-frequency transceiver transmitting a first CTS-to-Self packet via the neighboring channel before it transmits a data packet via the target channel, in which the duration defined by the duration field of the first CTS-to-Self packet includes time for the radio-frequency transceiver finishing transmitting the data packet; a frequency synthesizer providing the signal carriers of the neighboring channel and the target channel for the radio-frequency transceiver; and a radio-frequency controller controlling the frequency synthesizer to provide the signal carriers.