Phase Sweeping for Ambient IoT Coherent Signal Reception
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Solution Overview
Problem
Ambient IoT devices, such as cell-edge devices, struggle to receive sufficient energy for communication due to the lack of channel phase information, leading to ineffective signal combination and inability to backscatter or actively transmit channel estimation information.
Innovation Solution
Implement a phase sweeping procedure where a first network node transmits a signal at a first phase, while one or more second network nodes transmit signals at multiple second phases, allowing for coherent signal combination and enabling the ambient IoT device to identify phases with the highest received signal power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If network nodes transmit signals without channel phase information, then device complexity is reduced, but signal combination effectiveness deteriorates leading to random phases instead of coherent combining
Solution Approach 1:
The patent implements a phase sweeping procedure where network nodes pre-sweep through multiple candidate phases before actual data transmission. This preliminary phase identification enables subsequent coherent combining without requiring complex real-time channel estimation at the ambient IoT device, thus maintaining low device complexity while improving signal combination effectiveness
Solution Approach 2:
The patent introduces a phase indication mechanism as an intermediary between network nodes and ambient IoT devices. The network node transmits phase information through backscatter signals or uplink transmissions, serving as a mediator that conveys channel phase characteristics without requiring the ambient IoT device to perform complex channel estimation, thereby resolving the contradiction between device simplicity and signal combining reliability
2Use of energy by moving object
If ambient IoT devices lack channel phase information, then device power consumption is reduced, but the ability to backscatter or actively transmit channel estimation information is lost
Solution Approach 1:
The network node performs preliminary phase sweeping and identifies optimal phases before data transmission. This advance preparation eliminates the need for ambient IoT devices to consume power for channel estimation or active transmission of such information, while still enabling coherent combining through the pre-identified phase relationships
Solution Approach 2:
The patent implements a feedback mechanism where ambient IoT devices provide phase indications to network nodes through backscatter or uplink transmissions. This feedback loop allows the network to adaptively adjust transmission phases based on actual channel conditions without requiring the ambient IoT device to continuously estimate or transmit detailed channel information, thus maintaining low power consumption while preserving necessary information exchange
3Device complexity
If multiple network nodes transmit signals simultaneously without phase coordination, then system simplicity is maintained, but interference increases and power transfer efficiency decreases
Solution Approach 1:
The patent implements a phase sweeping procedure where network nodes pre-coordinate their transmission phases by sweeping through candidate phase combinations before actual data transmission. This preliminary coordination identifies optimal phase relationships that enable constructive interference, thereby improving power transfer efficiency without requiring complex real-time phase adjustment mechanisms during data transmission
Solution Approach 2:
The patent employs periodic phase sweeping where network nodes systematically cycle through different phase combinations at regular intervals. This periodic approach allows the system to adapt to changing channel conditions while maintaining relatively simple transmission mechanisms, balancing the trade-off between coordination complexity and energy efficiency by updating phases only when necessary
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 enhances coverage for ambient IoT devices by enabling coherent signal reception and improving power transfer efficiency, reducing interference, and supporting cell-edge devices effectively.
Implementation Method 1
a first network node transmits a first signal at a first phase and one or more second network nodes transmit a plurality of second signals at a plurality of second phases
Implementation Method 2
Coherently combining signals transmitted from network nodes may involve estimating channel phase information from each of the network nodes to an ambient IoT device
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a phase sweeping procedure involves a first network node transmitting a first signal at a first phase while one or more second network nodes transmit a plurality of second signals at a plurality of second phases. In some aspects, the phase sweeping procedure may produce a plurality of combined signals, each combined signal a combination of the first signal and at least one of the plurality of second signals. For example, the first signal and the one or more second signals may constructively interfere with each other to produce a signal of sufficient energy to be received by an ambient internet of things (IoT) device. The ambient IoT device may transmit, to a network node, an indication of a received signal power associated with the combined signal.