Backscattered Ambient IoT FDM/CDM Interference Mitigation
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Solution Overview
Problem
Existing wireless communication systems face challenges in harmonizing air interface designs for ambient Internet of Things (IoT) devices with varying power consumption and transmission capabilities, leading to interference and inefficiencies in data transmission.
Innovation Solution
Implementing a harmonized air interface design that includes separate resource pools for different categories of ambient IoT tags, using frequency division multiplexing (FDM) and code division multiplexing (CDM) to differentiate transmissions, and employing interference mitigation techniques such as orthogonal preamble designs for channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If separate resource pools are implemented for different categories of ambient IoT tags, then interference between tags is reduced, but device complexity increases
Solution Approach 1:
The patent divides the resource pool into separate segments for different categories of ambient IoT tags. First category tags use a first resource pool with specific time-frequency resources, while second category tags use a second resource pool with different resources. This segmentation reduces interference between tags with different power consumption and transmission capabilities by isolating their transmissions in separate resource domains.
2Productivity
If frequency division multiplexing and code division multiplexing are used to differentiate transmissions, then data transmission efficiency is enhanced, but device complexity increases
Solution Approach 1:
The patent combines frequency division multiplexing (FDM) and code division multiplexing (CDM) techniques to differentiate transmissions from multiple ambient IoT tags. FDM separates tags by assigning different frequency resources, while CDM uses orthogonal codes to further differentiate tags sharing the same time-frequency resources. This merged approach enhances data transmission efficiency by allowing simultaneous transmissions from multiple tags while maintaining distinguishability through orthogonal signaling.
3Object-affected harmful factors
If orthogonal preamble designs are employed for channel estimation, then interference mitigation is improved, but measurement precision requirements increase
Solution Approach 1:
The patent introduces orthogonal preambles as intermediary signaling elements for channel estimation. These preambles serve as mediators between the transmitted signal and the channel, allowing the receiver to estimate channel characteristics by correlating the received signal with the known orthogonal preamble sequences. The orthogonality of these preambles ensures that channel estimates from different tags do not interfere with each other, improving interference mitigation while maintaining reasonable measurement precision requirements.
Data Source
AI summary
Systems and methods for interference mitigation for backscattered ambient internet of things(IoT) transmissions are discussed herein. A base station sends, to a first user equipment (UE) and to a second UE, a downlink control information (DCI) instructing the first UE and the second UE to transmit a carrier wave on different subcarriers during a slot; receives, during the slot: a first compound transmission on a first subcarrier comprising the carrier wave as transmitted by the first UE and a first backscattering generated by a first ambient IoT tag from the carrier wave, and a second compound transmission on the second subcarrier comprising the carrier wave as transmitted by the second UE and a second backscattering generated by a second ambient IoT tag from the carrier wave; and decodes, from the first backscattering and the second backscattering, data of the first ambient IoT tag and the second ambient IoT tag.