RF Filter Arrangement for WiFi LTE Coexistence
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Solution Overview
Problem
The close proximity of WiFi and WiMAX transceivers often results in interference due to insufficient guard band, leading to performance degradation and reduced link throughput, as existing antenna isolation methods are insufficient to mitigate the interference effectively.
Innovation Solution
The implementation of tailored RF filtering techniques in WiFi and WiMAX transceivers, including band-pass filters and notch filters, to reject emissions between the two systems, eliminating the need for additional antenna isolation and optimizing performance by placing filters strategically to maintain desired output power levels and comply with spectrum masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If antenna isolation methods are used to mitigate interference between WiFi and WiMAX transceivers, then interference reduction is achieved, but the isolation level is insufficient to achieve the desired 81 dB isolation
Solution Approach 1:
The patent introduces RF filters as intermediary components between the WiFi and WiMAX transceiver systems. These filters act as mediators that selectively pass desired frequency bands while blocking interfering signals, achieving the required 81 dB isolation level that cannot be obtained through antenna isolation alone. The filters are strategically placed in the signal paths to intercept and reject out-of-band emissions before they can interfere with the other system.
2Productivity
If guard band between WiFi and WiMAX operating bands is reduced, then spectrum efficiency is improved, but interference between transceivers increases
Solution Approach 1:
RF filters serve as intermediaries that enable tight frequency packing by actively blocking out-of-band emissions. This allows the guard band to be minimized or eliminated while maintaining system isolation through the filter's frequency-selective properties, thereby improving spectrum efficiency without sacrificing interference protection.
Solution Approach 2:
The patent changes the frequency response parameters of the transceiver systems by introducing filters with specific passband and stopband characteristics. These parameter changes enable the system to operate with reduced guard bands while maintaining signal integrity and rejecting interference through the filter's tailored frequency response.
3Object-affected harmful factors
If RF filters are strategically placed in transceiver systems, then interference rejection is improved, but device complexity increases
Solution Approach 1:
The patent segments the RF signal path into distinct functional sections, placing filters at strategic points where they can most effectively block interference. This segmentation allows each filter to be optimized for its specific location and function, managing complexity through modular placement rather than requiring a monolithic complex filter system.
Solution Approach 2:
The filter arrangement applies local quality by tailoring the filter characteristics and placement to the specific interference conditions at each location in the signal path. Each filter is positioned and configured to address the local interference problem, achieving high overall rejection performance without requiring every component to be maximally complex.
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 enables effective coexistence of WiFi and WiMAX transceivers by reducing interference, improving performance, and extending WiFi range without violating FCC spectrum masks, achieving up to 81 dB of isolation which is practically unattainable with conventional methods.
Implementation Method 1
The implementation of tailored RF filtering techniques in WiFi and WiMAX transceivers, including band-pass filters and notch filters, to reject emissions between the two systems
Data Source
AI summary
Embodiments provide WiFi and LTE tailored transceiver radio frequency (RF) filtering techniques and configurations to enable coexistence between WiFi and LTE transceivers operating in close proximity. In particular, embodiments provide filtering techniques to reject emissions from LTE into WiFi, and vice versa. The filtering techniques eliminate the need for additional isolation between LTE and WiFi antennas (approximately 50 dB), which is beyond what is achievable in practice. Embodiments can be tailored according to different use cases of the WiFi and LTE transceivers (e.g., fixed CPE, portable router, smart phone with tethering).