Backscatter-Based Cooperative Communication in Wireless-Powered Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The 'doubly near-far problem' in wireless-powered communication networks, where RF signals undergo double attenuations, leads to reduced service areas and performance fairness issues, particularly in battery-less IoT sensor networks, as existing cooperative communication techniques require high power consumption and are limited in supporting dense device distributions.
Innovation Solution
A backscatter-based cooperative communication system utilizing low-power access points and hybrid access points, where IoT devices harvest energy and transmit information through bistatic backscatter communication, enabling cooperative communication modes based on signal-to-noise ratio thresholds, and using dual-band energy harvesting for efficient energy reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If harvest-then-transmit technique is used for wireless-powered communication, then energy harvesting is achieved, but doubly near-far problem occurs due to double attenuations
Solution Approach 1:
The patent introduces a hybrid access point as an intermediary node that simultaneously performs energy harvesting and information transmission. This mediator node receives RF signals from the energy node, harvests energy, and then transmits information to the information access point, thereby solving the doubly near-far problem by breaking the direct transmission path into two separate functional stages.
Solution Approach 2:
The hybrid access point is designed with multi-functionality, serving both as an energy harvesting node and an information transmission node. This universal node can operate in different modes (energy harvesting mode, information transmission mode, or cooperative mode) depending on channel conditions and energy availability, thereby addressing both energy efficiency and service area coverage requirements.
2Reliability
If active RF communication technique is used for information exchange, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The patent dynamically changes communication parameters including transmission power, modulation schemes, and coding rates based on channel conditions and energy availability. The system adapts between active RF communication and backscatter communication modes, adjusting parameters to maintain communication reliability while minimizing power consumption according to real-time conditions.
Solution Approach 2:
The communication system operates dynamically, switching between different communication modes (active RF communication, backscatter communication, and cooperative modes) based on real-time channel conditions, energy harvesting status, and quality of service requirements. This dynamic operation allows the system to optimize the trade-off between reliability and power consumption.
3Use of energy by moving object
If backscatter communication is used for information transmission, then power consumption is reduced, but service area is limited
Solution Approach 1:
The patent merges backscatter communication with cooperative communication mechanisms, where multiple hybrid access points work together to extend the service area. Nodes that cannot directly communicate with the information access point can use intermediate hybrid access points as relays, combining the low-power advantage of backscatter with the extended reach of cooperative communication.
Solution Approach 2:
The system transitions from single-hop direct backscatter communication to multi-hop cooperative backscatter communication, adding a spatial dimension to the communication architecture. This dimensional change allows information to reach distant nodes through multiple intermediate relays, thereby extending the service area while maintaining low power consumption characteristics.
4Reliability
If cooperative communication is implemented to solve near-far problem, then fairness among nodes is improved, but device complexity increases
Solution Approach 1:
The patent implements periodic channel measurements and periodic mode selection between different communication protocols. Nodes perform channel state information acquisition at regular intervals and switch between active RF and backscatter modes based on periodic assessments of channel conditions and energy availability, simplifying the complexity by using periodic rather than continuous complex protocols.
Solution Approach 2:
Each node autonomously determines its communication mode and parameters based on locally measured channel conditions and energy harvesting status. The system uses distributed decision-making where nodes self-select between cooperative and non-cooperative modes, reducing the need for complex centralized control and simplifying overall system complexity while maintaining fairness.
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 increases energy efficiency, expands service areas, and alleviates fairness issues between nodes, supporting a battery-less IoT sensor network with dense device distributions by leveraging short-range ambient and long-range bistatic backscatter communications.
Implementation Method 1
IoT devices harvest energy of a signal from a hybrid access point and energy of an unmodulated carrier from a low-power access point
Implementation Method 2
each of the Internet of Things (IoT) devices sequentially transmits information to the hybrid access point through a bistatic backscatter communication-based cooperation mode or non-cooperation mode using the harvested energy
Data Source
AI summary
A system for backscatter-based cooperative communication in a wireless-powered heterogeneous network includes a low-power access point, a hybrid access point, and Internet of Things (IoT) devices. The low-power access point transmits an unmodulated carrier. The hybrid access point is in communication with a primary device using a signal. Internet of Things (IoT) devices harvest energy of the unmodulated carrier and the signal, and each of the IoT devices sequentially transmits information to the hybrid access point through a bistatic backscatter communication-based cooperation mode or non-cooperation mode using the harvested energy.