Radio Module Coexistence Control Using External Antenna Detection
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Solution Overview
Problem
The proximity of 4G LTE and ISM radio modules in a shared housing causes interference due to overlapping frequency bands, leading to desensitization of the ISM module, which conventional filtering techniques cannot effectively address.
Innovation Solution
A method and device that manage the coexistence of these modules by detecting the presence of an external antenna for the 4G LTE module, prohibiting transmission on interfering frequency bands when no external antenna is connected, and allowing transmission on all bands when an external antenna is present, using a switch and impedance detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the 4G LTE radio module transmits at maximum power (27dBm) in the same housing as the ISM radio module, then the transmission power and coverage of the 4G LTE module is improved, but the ISM module experiences up to 30 dB loss of sensitivity due to interference
Solution Approach 1:
The patent implements dynamic control of the 4G LTE radio module's transmission power and frequency band selection based on the operational state of the ISM radio module. The system dynamically adjusts the 4G LTE module to operate in non-interfering frequency bands (excluding 868-870 MHz) when the ISM module is active, thereby resolving the contradiction between maintaining high transmission power and preventing sensitivity loss in the cohabiting ISM module
Solution Approach 2:
The patent changes the operational parameters of the 4G LTE radio module by restricting its frequency band selection and adjusting transmission power levels based on the presence and activity of the ISM module. This parameter adjustment ensures that the 4G LTE module maintains effective communication capability while preventing harmful interference to the ISM module's reception sensitivity
2Object-affected harmful factors
If conventional filtering techniques are applied to block interfering signals, then the interference from the 4G LTE module to the ISM module is reduced, but the filtering is ineffective because the interfering frequency falls within the ISM reception band
Solution Approach 1:
The patent applies preliminary action by proactively preventing interference before it occurs. Instead of attempting to filter interfering signals after they are generated, the system pre-configures the 4G LTE module to avoid transmitting in the 868-870 MHz frequency band when the ISM module is operational, thereby eliminating the need for ineffective filtering and preserving reception quality
3Device complexity
If both radio modules are placed in the same housing to centralize equipment, then the device integration and space utilization are improved, but the proximity causes coupling between antennas and phase noise that disrupts the ISM signal
Solution Approach 1:
The patent applies segmentation by logically separating the operational frequency bands of the two radio modules. The 4G LTE module is restricted from using the 868-870 MHz band when the ISM module is active, effectively segmenting the frequency spectrum to eliminate interference. This allows both modules to coexist in the same housing without requiring physical separation, maintaining device integration while preventing phase noise and antenna coupling effects
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 approach eliminates interference-related sensitivity loss in the ISM module without requiring additional antennas, ensuring reliable operation of both modules.
Implementation Method 1
detection of the presence of an external antenna on the second radio module
Data Source
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AI summary
The present invention relates to a method and device for managing the coexistence of a first and a second radio module transmitting and/or receiving signals in frequency bands, the first and second radio modules being arranged in the same housing, the housing comprising an antenna associated with the first radio module and an antenna associated with the second radio module. According to the invention, one: - checks (E42) whether an antenna external to the housing is connected to the second radio module, - prohibits (E43) radio transmission by the second radio module in a portion of the frequency bands if an antenna external to the housing is not connected to the second radio module, - allows (E45) radio transmission by the second radio module in all the frequency bands of the second radio module if an antenna external to the housing is connected to the second radio module.