[Paper Review] Wireless-Powered Device-to-Device Communications with Ambient Backscattering: Performance Modeling and Analysis

Xiao Lu, Hai Jiang+3 more|arXiv (Cornell University)|Dec 10, 2017

Energy Harvesting in Wireless Networks51 references3 citations

TL;DR

This paper proposes a hybrid device-to-device (D2D) communication system that integrates ambient backscattering with wireless-powered communications to enable self-sustaining, low-power transmission. By adaptively selecting between backscattering and active RF transmission based on environmental energy source density and distribution, the system achieves improved coverage and throughput, with performance enhancing under higher spatial density, transmission load, and repulsion among energy sources.

ABSTRACT

The recent advanced wireless energy harvesting technology has enabled wireless-powered communications to accommodate wireless data services in a self-sustainable manner. However, wireless-powered communications rely on active RF signals to communicate, and result in high power consumption. On the other hand, ambient backscatter technology that passively reflects existing RF signal sources in the air to communicate has the potential to facilitate an implementation with ultra-low power consumption. In this paper, we introduce a hybrid D2D communication paradigm by integrating ambient backscattering with wireless-powered communications. The hybrid D2D communications are self-sustainable, as no dedicated external power supply is required. However, since the radio signals for energy harvesting and for backscattering come from the ambient, the performance of the hybrid D2D communications depends largely on environment factors, e.g., distribution, spatial density, and transmission load of ambient energy sources. Therefore, we design two mode selection protocols for the hybrid D2D transmitter, allowing a more flexible adaptation to the environment. We then introduce analytical models to characterize the impacts of the considered environment factors on the hybrid D2D communication performance. Together with extensive simulations, our analysis shows that the communication performance benefits from larger repulsion, transmission load and density of ambient energy sources. Further, we investigate how different mode selection mechanisms affect the communication performance.

Motivation & Objective

• To address the limitations of standalone ambient backscattering (low data rate, short range) and wireless-powered communication (intermittent operation due to energy harvesting delays).
• To design a hybrid D2D communication paradigm that enables continuous, self-sustainable operation without external power supplies.
• To model and analyze the impact of environmental factors—such as spatial density, transmission load, and repulsion behavior of ambient RF sources—on system performance.
• To develop adaptive mode selection protocols that dynamically switch between backscattering and active transmission based on energy availability and channel conditions.

Proposed method

• Proposes a hybrid D2D communication model combining ambient backscattering and wireless-powered transmission for energy self-sufficiency.
• Introduces two mode selection protocols: one based on energy availability and another based on channel quality, enabling dynamic adaptation to environmental conditions.
• Derives analytical expressions for coverage probability in both backscattering (HTT) and active transmission (H) modes using stochastic geometry and Poisson point process models.
• Uses a generalized Rayleigh fading model and accounts for interference from multiple ambient RF sources, modeling aggregate interference via a determinant-based expression.
• Applies tools from stochastic geometry and moment generating functions to compute the coverage probability and average throughput under Rayleigh fading and interference.
• Derives closed-form expressions for average throughput in both modes, incorporating transmission time, spectral efficiency, and outage probability.

Experimental results

Research questions

• RQ1 How does the spatial distribution and density of ambient RF energy sources affect the coverage and throughput of hybrid D2D communications?
• RQ2 What is the optimal mode selection strategy between ambient backscattering and active RF transmission under varying environmental conditions?
• RQ3 How do transmission load and repulsion behavior among energy sources influence system performance in terms of reliability and data rate?
• RQ4 What is the analytical trade-off between energy harvesting and data transmission in a hybrid D2D system with co-channel interference?
• RQ5 How does the integration of backscattering and wireless-powered communication improve system sustainability and performance compared to standalone approaches?

Key findings

• Coverage probability increases with higher spatial density and transmission load of ambient RF sources, due to improved energy harvesting and signal strength.
• Larger repulsion among energy sources leads to better performance, as it reduces interference and increases signal-to-interference-plus-noise ratio (SINR).
• The hybrid system achieves higher average throughput than standalone backscattering or wireless-powered modes, especially when mode selection is based on channel quality and energy availability.
• Throughput gains are most significant when the system dynamically selects between backscattering and active transmission based on real-time energy and channel conditions.
• The analytical model accurately predicts system performance, with simulations validating the derived expressions for coverage probability and average throughput.
• The proposed mode selection protocol significantly improves system reliability and spectral efficiency, particularly in dense and interference-limited environments.