Quantum Backscatter Communication: A New Paradigm

Abstract

In this paper, we propose a novel quantum backscatter communications (QBC) protocol, inspired by the quantum illumination (QI) concept. In the QBC paradigm, the transmitter generates entangled photon pair. The signal photon is transmitted and the idler photon is kept at the receiver. The tag antenna communicates by performing the pulse amplitude modulation (PAM), binary phase shift keying (BPSK) or quadratic phase shift keying (QPSK) on the signal impinging at the antenna. Using the sum-frequency-generation receiver, our QBC protocol achieves a 6 dB error exponent gain for PAM and BPSK, and 3 dB gain for QPSK over its classical counterpart. Finally, we discuss the QI-enhanced secure backscatter communication.

Retrieving Quantum Backscattered Signals in the Presence of Noise

“…We will assume that the retention process is carried out by a memory element that can be modelled accurately by a pure loss channel. This new treatment is a little bit different from earlier ones [15][16][17], where the idler mode was assumed to be retained losslessly at the receiver. The tag antenna can be modelled by a low reflectivity beamsplitter, where thermal noise enters from the beamsplitter's dark port.…”

“…Notable efforts have been made in the field of microwave quantum communication, the most renowned among them are microwave quantum teleportation [12] and quantum illumination enhanced sensing [13,14]. In this paper we will focus on a new application in which quantum approaches can be used for improved sensitivities and resolutions, namely, quantum backscatter communication (QBC) [15][16][17]. Quantum backscattering is a branch of quantum communication, which exploits quantum entanglement in order to distil backscattered signals propagating through a noisy thermal channel.…”

“…Alongside microwave beamsplitters, low power backscatter devices employed as phase gates, could pave the way for scalable and efficient linear microwave quantum computing. Recently, a few prototypes have been proposed for realizing quantum backscattering with both continuous variables and photon number states [15][16][17]. The main theme of these approaches was the lossless possession of the idler mode throughout the duration of the whole protocol.…”

Quantum Backscatter Communication with Photon Number States

“…Hence, we can conclude that the HOM receiver is a unitary linear receiver that preserves the total number of photons. On the other hand, the interaction Hamiltonian describing the sum frequency receiver is expressed as [2], [3] :…”

“…Quantum entanglement, whereby distant systems exhibit non-local measurement correlations, holds the keys to realizing precision measurements that go beyond the classical shot noise limit. By harnessing these non-classical correlations recent protocols had been developed to detect targets submersed in noisy and lossy environment [6], while recently the same concept was deployed to detect backscattered communication signals in the microwave regime [1], [2]. Moreover, it had been shown that target detection using entangled photon pairs is optimal under the same environmental assumptions [6]- [8].…”