Low Probability Of Detection Communication Research Articles

A Time-Varying Chaotic Multitone Communication Method Based on OFDM for Low Detection Probability of Eavesdroppers

Due to the rapid development of modern communication technology and the substantial improvement of the processing capacity of communication equipment, it has become a challenging and meaningful research direction to realize the covert transmission of information by ensuring the low probability of detection (LPD) performance of the communication signals. The disadvantage of traditional fixed-parameter signal in LPD gradually appears. The paper proposes a time-varying chaotic multitone communication method to accomplish the LPD for the eavesdroppers. The method gets rid of the conventional LPD communication method whose performance improvement is exchanged at the expense of its reliability loss or sacrificing more resources. Based on the original chaotic multitone (CMT) communication method, the time-varying parameter is introduced to improve the randomness of the waveform and thus reduce the detection probability of eavesdroppers to the single tones in the multitone group (MTG). Meanwhile, to improve spectrum efficiency and reduce system complexity, the corresponding communication system model is designed based on orthogonal frequency division multiplexing (OFDM) technology. After given the corresponding detection and demodulation scheme based on the diversity and combination, the influence of time-varying parameters on the reliability for the cooperative receiver is analyzed. The LPD contribution of this method is evaluated by analyzing the detection probability of the eavesdropper. The experimental results show that the proposed method not only maintains the original reliability but also reduces the detection probability of eavesdroppers under the constant false alarm probability detection scheme.

LPD Communication: A Sequential Change-Point Detection Perspective

In this paper, we establish a framework for low probability of detection (LPD) communication from a sequential change-point detection (SCPD) perspective, where a transmitter, Alice, wants to hide her signal transmission to a receiver, Bob, under the surveillance of an adversary, Willie. The new framework facilitates to model LPD communication and further evaluate its performance under the condition that Willie has no prior knowledge on when the transmission from Alice starts and that Willie wants to detect the existence of the communication as quickly as possible in real-time manner. We consider three different sequential tests for Willie, i.e., the Shewhart test, the cumulative sum (CUSUM) test, and the Shiryaev-Roberts (SR) test, to model the detection procedure. Communication is said to be covert if it stops before detection by Willie with high probability. Covert probability defined as the probability that Willie is not alerted during the communication procedure is investigated. We formulate an optimization problem aimed at finding the transmit power and transmission duration such that the total amount of information that can be transmitted is maximized subject to a high covert probability. Under Shewhart test, closed-form approximations of the optimal transmit power and transmission duration are derived, which well approximate the solutions obtained from exhaustive search. As for CUSUM and SR tests, we provide an effective algorithm to search the optimal solution. Numeric results are presented to show the performance of LPD communication.

Low Probability of Detection Communication: Opportunities and Challenges

LPD communication has recently emerged as a new transmission technology to address privacy and security in wireless networks. Recent studies have established the fundamental limits of LPD communication in terms of the amount of information that can be conveyed from a transmitter to a receiver subject to a constraint on a warden's detection error probability. The established information- theoretic metric enables analytical studies on the design and performance of LPD communication under various channel conditions. In this article, we present the key features of LPD communication and discuss various important design considerations. First, we clarify the differences between LPD communication and well-known physical-layer security. Then, from an information-theoretic point of view, we discuss the optimal signaling strategies for transmitting the message-carrying signal and artificial noise signal for LPD communication. Finally, we identify the key challenges in the design of practical LPD communication systems and point out future research directions in this context. This article provides guidelines for designing practical LPD communication strategies in wireless systems and networks.

Bounds for Low Probability of Detection for Underwater Acoustic Communication

Most military underwater activities require stealth operations, and hydroacoustic transmissions might temper the mission. For this reason, military underwater acoustic transmission aims for low probability of detection (LPD). LPD communication systems are characterized by low transmission power and reception at low signal-to-noise power ratio (SNPR). As a side effect, LPD decreases acoustic noise pollution. In this paper, we study the LPD capability of underwater acoustic communication (UWAC) systems. We consider an interceptor with target false alarm and detection probabilities and a legitimate receiver with required detection and packet error probabilities. For the interceptor, we focus on an energy detector and calculate the minimal SNPR which satisfies its required performance. For the legitimate communication link, we consider spread-spectrum signaling with several modulation techniques, and calculate the minimal required SNPR to allow reliable detection and decoding of a data packet. Based on these minimal SNPR terms and using bounds on power attenuation in the channel, we quantify the LPD capability of the system and analyze the effect of channel and communication parameters. We also present results from a sea trial conducted in the Saanich Inlet off the coast of Vancouver Island, where we conducted LPD experiments for different transmission powers and carrier frequencies. We provide bounds for the minimal bandwidth and maximal transmission rate for LPD communication. Our results also show that LPD UWAC performs better in shallow and warm water, and for transmission at low carrier frequencies.