Dynamic RF Front-End Filter Bypass for Coexistence

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Solution Overview

Problem

The simultaneous operation of WAN and WLAN transceivers in wireless communication devices often results in significant signal-to-noise ratio degradation due to interference from wideband noise, leading to reduced range and throughput, and existing solutions like sharp bandpass filters incur significant insertion loss.

Innovation Solution

A front end module with a filter that passes the carrier frequency of the WAN transceiver while substantially attenuating the WLAN transceiver's frequency, and a bypass path to reduce insertion loss by connecting the WAN transceiver directly to the antenna when the WLAN transceiver is not operating, using electronically controlled switches controlled by a circuitry to manage the connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sharp bandpass filter is placed at the output of the power amplifier to attenuate WLAN frequency components, then the signal-to-noise ratio degradation is reduced, but the insertion loss increases significantly

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidinsertion loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements a dynamic switching architecture where the filter is selectively connected to the antenna only when the WLAN transceiver is inactive. The system transitions between two states: (1) filter connected during WAN transmission to block WLAN frequencies, and (2) filter disconnected when WLAN is active to minimize insertion loss. This dynamic reconfiguration resolves the contradiction by applying filtering only when necessary.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs periodic monitoring of WLAN transceiver status to determine when to activate or deactivate the filter in the signal path. By periodically checking the operational state and adjusting the filter connection accordingly, the system ensures optimal performance for both WAN transmission (with filter active) and WLAN reception (with filter inactive).

Inventive Principle:

Principle #19Periodic action

2Object-affected harmful factors

If a filter is continuously connected in the WAN transmit path to protect WLAN reception, then interference is reduced, but transmit power is lost due to insertion loss

Engineering Contradiction:

Improveinterference to WLANVSAvoidtransmit power

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The patent employs a dynamic switching mechanism that adjusts the filter's presence in the transmit path based on WLAN operational status. When WLAN is inactive, the filter is connected to suppress interference. When WLAN becomes active, the switch dynamically reconnects the transmit path to bypass the filter, preserving transmit power. This resolves the contradiction by making filter application conditional rather than continuous.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If the WAN and WLAN transceivers operate simultaneously without filtering, then device functionality is maximized, but signal degradation occurs due to wideband noise

Engineering Contradiction:

Improvesimultaneous operation capabilityVSAvoidsignal quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system implements periodic status checking of the WLAN transceiver to dynamically adjust the filtering state. By continuously monitoring WLAN activity and switching the filter connection accordingly, the system enables simultaneous operation of WAN and WLAN transceivers while maintaining signal quality. The periodic action ensures that filtering is applied only during WAN transmission when WLAN is inactive, allowing both functions to operate reliably.

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution allows for simultaneous operation of WAN and WLAN transceivers without substantial signal degradation and minimizes overall power loss, maintaining effective range and throughput while reducing battery drain.

Implementation Method 1

a filter arranged to pass the carrier frequency of the WAN transceiver and substantially attenuate the carrier frequency of the WLAN transceiver

Methodology Applied

Scientific EffectFrequency filtering: Filter (electronic)

Implementation Method 2

a plurality of electronically controlled switches, each responsive to the control circuitry

Methodology Applied

Scientific EffectElectrical switching: Valve

Data Source

PatentUS8670726B2Architecture for coexistence of multiple band radios

Publication Date: 2014.03.11 MICROSEMI CORP

AI summary

A front end module for use with a first and a second radio frequency transceiver, constituted of: a control circuitry; a first antenna connection port; a second antenna connection port; a filter arranged to substantially attenuate the carrier frequency bandwidth of the second radio frequency transceiver; and a plurality of electronically controlled switches, wherein the control circuitry is arranged to: in the event that the first and second radio frequency transceivers are simultaneously operative, set the plurality of electronically controlled switches to connect the first radio frequency transceiver to one of the first and second antenna connection ports via the filter; and in the event that the first and second radio frequency transceivers are not simultaneously operative, set the plurality of electronically controlled switches to bypass the filter and connect the first radio frequency transceiver to one of the first and second antenna connection ports.