Ambient IoT Backscattered Waveform Interference Handling
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Solution Overview
Problem
Ambient IoT devices face interference issues due to backscattering of signals on the same frequency and time symbol as the carrier wave used for energy, leading to potential interference at the reader and intermediate nodes.
Innovation Solution
Implement sequence-based and delay-based interference handling methods, including pre-configuring ambient IoT devices with preamble, midamble, and postamble sequences, and using intermittent blanking or artificially induced delays to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If ambient IoT devices backscatter signals on the same frequency and time symbol as the carrier wave, then energy efficiency is improved, but interference at the reader and intermediate nodes increases
Solution Approach 1:
The patent segments the time-frequency resources by introducing different cyclic shifts to different devices. Each device applies a unique cyclic shift to the base sequence, effectively dividing the same time-frequency resource into multiple orthogonal sub-channels. This segmentation allows multiple devices to backscatter simultaneously without interfering with each other, resolving the contradiction between energy efficiency and interference.
Solution Approach 2:
The patent changes the phase parameter of the backscattered signal by applying cyclic shifts. By modifying the phase parameter (cyclic shift value) while keeping the frequency and time symbol the same, the system enables multiple devices to transmit on the same resource without interference. This parameter change approach maintains energy efficiency while eliminating the harmful interference effect.
2Productivity
If multiple ambient IoT devices backscatter on the same time-frequency resource, then communication efficiency is improved, but signal detection accuracy deteriorates
Solution Approach 1:
The patent segments the signal space by applying different cyclic shifts to different devices' backscattered signals. This segmentation creates orthogonal signal subspaces that can be independently detected, allowing the reader to accurately distinguish and detect multiple simultaneous backscatter signals without mutual interference, thus maintaining both communication efficiency and detection accuracy.
Solution Approach 2:
The cyclic shift acts as an intermediary parameter that enables multiple devices to share the same time-frequency resource while maintaining detectability. By introducing this intermediate parameter (cyclic shift value), the system mediates between the need for high communication efficiency (multiple devices transmitting simultaneously) and accurate signal detection (distinguishing individual signals).
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
Effectively measures and cancels interference, enabling clear reception of backscattered signals by readers and intermediate nodes, thus enhancing communication efficiency and reliability for ambient IoT devices.
Implementation Method 1
an ambient IoT device receives a carrier wave and sends a backscattered signal comprising the carrier wave modulated with a sequence
Data Source
AI summary
Systems, methods and apparatuses herein provides ways to handle interference to a backscattered signal carrying information from an ambient internet of things (IoT) device. The interference may be from the carrier wave that is used for providing energy to the device. In some embodiments, sequence-based interference handling may be used to minimize the carrier wave interference. In some embodiments delay-based Interference handling may be used to minimize the carrier wave interference.