Biblio

Filters: Keyword is Demodulation  [Clear All Filters]
2021-04-09
Cui, H., Liu, C., Hong, X., Wu, J., Sun, D..  2020.  An Improved BICM-ID Receiver for the Time-Varying Underwater Acoustic Communications with DDPSK Modulation. 2020 IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC). :1—4.
Double differential phase shift keying(DDPSK) modulation is an efficient method to compensate the Doppler shifts, whereas the phase noise will be amplified which results in the signal-to-noise ratio (SNR) loss. In this paper, we propose a novel receiver architecture for underwater acoustic DSSS communications with Doppler shifts. The proposed method adopts not only the DDPSK modulation to compensate the Doppler shifts, but also the improved bit-interleaved coded modulation with iterative decoding (BICM-ID) algorithm for DDPSK to recover the SNR loss. The improved DDPSK demodulator adopts the multi-symbol estimation to track the channel variation, and an extended trellis diagram is constructed for DDPSK demodulator. Theoretical simulation shows that our system can obtain around 10.2 dB gain over the uncoded performance, and 7.4 dB gain over the hard-decision decoding performance. Besides, the experiment conducted in the Songhua Lake also shows that the proposed receiver can achieve lower BER performance when Doppler shifts exists.
2021-01-25
Guri, M..  2020.  CD-LEAK: Leaking Secrets from Audioless Air-Gapped Computers Using Covert Acoustic Signals from CD/DVD Drives. 2020 IEEE 44th Annual Computers, Software, and Applications Conference (COMPSAC). :808—816.

Air-gapped networks are isolated from the Internet, since they store and process sensitive information. It has been shown that attackers can exfiltrate data from air-gapped networks by sending acoustic signals generated by computer speakers, however this type of covert channel relies on the existence of loudspeakers in the air-gapped environment. In this paper, we present CD-LEAK - a novel acoustic covert channel that works in constrained environments where loudspeakers are not available to the attacker. Malware installed on a compromised computer can maliciously generate acoustic signals via the optical CD/DVD drives. Binary information can then be modulated over the acoustic signals and be picked up by a nearby Internet connected receiver (e.g., a workstation, hidden microphone, smartphone, laptop, etc.). We examine CD/DVD drives and discuss their acoustical characteristics. We also present signal generation and detection, and data modulation and demodulation algorithms. Based on our proposed method, we developed a transmitter and receiver for PCs and smartphones, and provide the design and implementation details. We examine the channel and evaluate it on various optical drives. We also provide a set of countermeasures against this threat - which has been overlooked.

2020-12-28
Khatod, V., Manolova, A..  2020.  Effects of Man in the Middle (MITM) Attack on Bit Error Rate of Bluetooth System. 2020 Joint International Conference on Digital Arts, Media and Technology with ECTI Northern Section Conference on Electrical, Electronics, Computer and Telecommunications Engineering (ECTI DAMT NCON). :153—157.
The ad-hoc network formed by Bluetooth works on radio frequency links. The security aspect of Bluetooth has to be handled more carefully. The radio frequency waves have a characteristic that the waves can pierce the obstructions in the communication path, get rid of the requirement of line of sight between the communicating devices. We propose a software model of man-in-the-middle attack along with unauthorized and authorized transmitter and receiver. Advanced White Gaussian Noise channel is simulated in the designed architecture. The transmitter uses Gaussian Frequency Shift Keying (GFSK) modulation like in Bluetooth. The receiver uses GFSK demodulation. In order to validate the performance of the designed system, bit error rate (BER) measurements are taken with respect to different time intervals. We found that BER drops roughly 18% if hopping duration of 150 seconds is chosen. We propose that a Bluetooth system with hopping rate of 0.006 Hz is used instead of 10Hz.
2018-11-19
Yildiz, O., Gulbahar, B..  2018.  FoVLC: Foveation Based Data Hiding in Display Transmitters for Visible Light Communications. 2018 14th International Wireless Communications Mobile Computing Conference (IWCMC). :629–635.

Visible light communications is an emerging architecture with unlicensed and huge bandwidth resources, security, and experimental implementations and standardization efforts. Display based transmitter and camera based receiver architectures are alternatives for device-to-device (D2D) and home area networking (HAN) systems by utilizing widely available TV, tablet and mobile phone screens as transmitters while commercially available cameras as receivers. Current architectures utilizing data hiding and unobtrusive steganography methods promise data transmission without user distraction on the screen. however, current architectures have challenges with the limited capability of data hiding in translucency or color shift based methods of hiding by uniformly distributing modulation throughout the screen and keeping eye discomfort at an acceptable level. In this article, foveation property of human visual system is utilized to define a novel modulation method denoted by FoVLC which adaptively improves data hiding capability throughout the screen based on the current eye focus point of viewer. Theoretical modeling of modulation and demodulation mechanisms hiding data in color shifts of pixel blocks is provided while experiments are performed for both FoVLC method and uniform data hiding denoted as conventional method. Experimental tests for the simple design as a proof of concept decreases average bit error rate (BER) to approximately half of the value obtained with the conventional method without user distraction while promising future efforts for optimizing block sizes and utilizing error correction codes.

2019-01-31
Bak, D., Mazurek, P..  2018.  Air-Gap Data Transmission Using Screen Brightness Modulation. 2018 International Interdisciplinary PhD Workshop (IIPhDW). :147–150.

Air-gap data is important for the security of computer systems. The injection of the computer virus is limited but possible, however data communication channel is necessary for the transmission of stolen data. This paper considers BFSK digital modulation applied to brightness changes of screen for unidirectional transmission of valuable data. Experimental validation and limitations of the proposed technique are provided.

2018-01-10
Zhang, Z. G., Wen, H., Song, H. H., Jiang, Yixin, Zhang, J. L., Zhu, Xiping.  2016.  A MIMO cross-layer secure communication scheme based on spatial modulation. 2016 IEEE Conference on Communications and Network Security (CNS). :350–351.

A cross-layer secure communication scheme for multiple input multiple output (MIMO) system based on spatial modulation (SM) is proposed in this paper. The proposed scheme combined the upper layer stream cipher with the distorted signal design of the MIMO spatial modulation system in the physical layer to realize the security information transmission, which is called cross-layer secure communication system. Simulation results indicate that the novel scheme not only further ensure the legitimate user an ideal reception demodulation performance as the original system, but also make the eavesdropper' error rate stable at 0.5. The novel system do not suffer from a significant increasing complexity.

2017-02-21
M. Clark, L. Lampe.  2015.  "Single-channel compressive sampling of electrical data for non-intrusive load monitoring". 2015 IEEE Global Conference on Signal and Information Processing (GlobalSIP). :790-794.

Non-intrusive load monitoring (NILM) extracts information about how energy is being used in a building from electricity measurements collected at a single location. Obtaining measurements at only one location is attractive because it is inexpensive and convenient, but it can result in large amounts of data from high frequency electrical measurements. Different ways to compress or selectively measure this data are therefore required for practical implementations of NILM. We explore the use of random filtering and random demodulation, techniques that are closely related to compressed sensing, to offer a computationally simple way of compressing the electrical data. We show how these techniques can allow one to reduce the sampling rate of the electricity measurements, while requiring only one sampling channel and allowing accurate NILM performance. Our tests are performed using real measurements of electrical signals from a public data set, thus demonstrating their effectiveness on real appliances and allowing for reproducibility and comparison with other data management strategies for NILM.

A. Dutta, R. K. Mangang.  2015.  "Analog to information converter based on random demodulation". 2015 International Conference on Electronic Design, Computer Networks Automated Verification (EDCAV). :105-109.

With the increase in signal's bandwidth, the conventional analog to digital converters (ADCs), operating on the basis of Shannon/Nyquist theorem, are forced to work at very high rates leading to low dynamic range and high power consumptions. This paper here tells about one Analog to Information converter developed based on compressive sensing techniques. The high sampling rates, which is the main drawback for ADCs, is being successfully reduced to 4 times lower than the conventional rates. The system is also accompanied with the advantage of low power dissipation.

S. Chen, F. Xi, Z. Liu, B. Bao.  2015.  "Quadrature compressive sampling of multiband radar signals at sub-Landau rate". 2015 IEEE International Conference on Digital Signal Processing (DSP). :234-238.

Sampling multiband radar signals is an essential issue of multiband/multifunction radar. This paper proposes a multiband quadrature compressive sampling (MQCS) system to perform the sampling at sub-Landau rate. The MQCS system randomly projects the multiband signal into a compressive multiband one by modulating each subband signal with a low-pass signal and then samples the compressive multiband signal at Landau-rate with output of compressive measurements. The compressive inphase and quadrature (I/Q) components of each subband are extracted from the compressive measurements respectively and are exploited to recover the baseband I/Q components. As effective bandwidth of the compressive multiband signal is much less than that of the received multiband one, the sampling rate is much less than Landau rate of the received signal. Simulation results validate that the proposed MQCS system can effectively acquire and reconstruct the baseband I/Q components of the multiband signals.

2015-05-01
Soderi, S., Dainelli, G., Iinatti, J., Hamalainen, M..  2014.  Signal fingerprinting in cognitive wireless networks. Cognitive Radio Oriented Wireless Networks and Communications (CROWNCOM), 2014 9th International Conference on. :266-270.

Future wireless communications are made up of different wireless technologies. In such a scenario, cognitive and cooperative principles create a promising framework for the interaction of these systems. The opportunistic behavior of cognitive radio (CR) provides an efficient use of radio spectrum and makes wireless network setup easier. However more and more frequently, CR features are exploited by malicious attacks, e.g., denial-of-service (DoS). This paper introduces active radio frequency fingerprinting (RFF) with double application scenario. CRs could encapsulate common-control-channel (CCC) information in an existing channel using active RFF and avoiding any additional or dedicated link. On the other hand, a node inside a network could use the same technique to exchange a public key during the setup of secure communication. Results indicate how the active RFF aims to a valuable technique for cognitive radio manager (CRM) framework facilitating data exchange between CRs without any dedicated channel or additional radio resource.