TVWS Narrowband Transceiver Filtering for Harmonic-Safe IoT Links
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Solution Overview
Problem
Existing TVWS communication technologies face limitations such as non-continuous spectrum, insufficient channel capacity for IoT devices, and sensitivity to interference, especially at low signal levels, which hinder effective communication.
Innovation Solution
A multi-narrowband transceiver system using a log periodic filter with periodically increasing filter elements suppresses second harmonics, enabling efficient communication in the TVWS spectrum by configuring a multi-narrowband transceiver with a log periodic filter to filter out second harmonics, allowing for long-range, low-power communication using the LoRa protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If single channel capacity is used in TVWS, then device simplicity is maintained, but communication capacity is insufficient for IoT devices
Solution Approach 1:
The TVWS spectrum is segmented into multiple narrowband channels (e.g., 1.25 MHz, 2.5 MHz, or 5 MHz bandwidths) within the broader TVWS band. The transceiver is configured to operate on these segmented channels, allowing sufficient communication capacity for IoT devices while maintaining relative simplicity through selective channel usage rather than processing the entire spectrum continuously.
2Reliability
If TVWS spectrum is used for communication, then broadband communication capability is achieved, but sensitivity to interference at low signal levels increases
Solution Approach 1:
Instead of treating the entire TVWS band uniformly, the system applies local quality by selecting specific narrowband channels with favorable interference characteristics. The transceiver can identify and prioritize channels with lower interference levels, adapting its operation to local spectral conditions. This allows reliable communication by focusing on quality channels rather than attempting to use the entire spectrum uniformly.
3Adaptability or versatility
If transceivers hop between different frequencies in TVWS, then spectrum availability variations are accommodated, but communication stability decreases
Solution Approach 1:
The system performs preliminary spectrum sensing and channel selection before establishing communication. By identifying suitable narrowband channels in advance and preparing the transceiver configuration beforehand, the system reduces the need for frequent frequency hopping during active communication. This preliminary action maintains spectrum adaptability while improving communication stability by establishing connections on pre-validated channels.
4Area of stationary object
If TVWS is used for communication, then wide spectrum coverage is achieved, but channel capacity for individual devices is insufficient
Solution Approach 1:
The system transitions from viewing TVWS as a single-dimensional continuous band to a multi-dimensional structure with multiple narrowband channels stacked within the broader spectrum. By operating in this channelized dimension, the system achieves wide spectrum coverage through selective channel access while providing sufficient capacity to individual IoT devices through dedicated narrowband channel allocation.
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
The system enables IoT devices to operate at lower frequencies for longer ranges with higher bandwidth, supporting large-scale IoT networks with reduced power consumption and compliance with FCC requirements, while minimizing interference.
Implementation Method 1
the log periodic filter comprises a plurality of filter elements each having a filter frequency increasing periodically in a same frequency increasing factor (K). Each filter of the plurality of filter elements is configured to filter out second harmonics in a defined frequency range.
Data Source
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AI summary
The disclosure described herein configures a multi-narrowband transceiver for communication within the television white space (TVWS) frequency spectrum using a log periodic filter, wherein the log periodic filter comprises a plurality of filter elements each having a filter frequency increasing periodically in a same frequency increasing factor (K). Each filter of the plurality of filter elements is configured to filter out second harmonics in a defined frequency range. The disclosure determines a TVWS channel for the communication and switches to a filter element of the plurality of filter elements corresponding to the determined TVWS channel. Data is transmitted and/or received over the TVWS channel using the filter element, thereby allowing narrowband communication over the TVWS channel.