A Review of Analog Audio Scrambling Methods for Residual Intelligibility

In this paper, a review of the techniques available in different categories of audio scrambling schemes is done with respect to Residual Intelligibility. According to Shannon's secure communication theory, for the residual intelligibility to be zero the scrambled signal must represent a white signal. Thus the scrambling scheme that has zero residual intelligibility is said to be highly secure. Many analog audio scrambling algorithms that aim to achieve lower levels of residual intelligibility are available. In this paper a review of all the existing analog audio scrambling algorithms proposed so far and their properties and limitations has been presented. The aim of this paper is to provide an insight for evaluating various analog audio scrambling schemes available up-to-date. The review shows that the algorithms have their strengths and weaknesses and there is no algorithm that satisfies all the factors to the maximum extent. Keywords: residual Intelligibility, audio scrambling, speech scramblin

MATHEMATICAL MODEL OF THE SYSTEM OF ACTIVE PROTECTION AGAINST EAVESDROPPING OF SPEECH INFORMATION ON THE SCRAMBLER GENERATOR

The development of reliable systems for protecting speech information that can protect it from being intercepted by cybercriminals is a fundamental task of the security service of organizations and firms. For these purposes, active jamming systems are used at the border of the controlled area. The main element of such systems is noise generators. However, in many cases, “white” noise and its clones are used as interference, which makes it possible for an attacker to gain unauthorized access. The structure and mathematical model of a speech information protection system based on a scrambler-type noise generator is proposed. The transition in such systems of protection of speech information to this structure allows to abandon the outdated, ineffective in modern conditions, energy noise of speech information and move on to a more productive method – information (linguistic) masking. An analysis of the destructive effect of this type of interference shows its high resistance to modern methods of mathematical processing of digital phonograms (wavelet transform, correlation-spectral analysis, etc.), filtering interference, and dividing the voices of speakers. Studies of the mathematical model in the environment of Matlab 15 R2015a/Simulink show the high efficiency of such a protection system and a decrease in the signal-to-noise ratio with a residual speech intelligibility of 0.1 by 6...9 dBA. This leads to a decrease in noise in the room and beyond, which positively affects the bioacoustic characteristics of the premises, improves working conditions and staff productivity, and also reduces the unmasking performance of the objec

Mapping DSP algorithms to a reconfigurable architecture Adaptive Wireless Networking (AWGN)

This report will discuss the Adaptive Wireless Networking project. The vision of the Adaptive Wireless Networking project will be given. The strategy of the project will be the implementation of multiple communication systems in dynamically reconfigurable heterogeneous hardware. An overview of a wireless LAN communication system, namely HiperLAN/2, and a Bluetooth communication system will be given. Possible implementations of these systems in a dynamically reconfigurable architecture are discussed. Suggestions for future activities in the Adaptive Wireless Networking project are also given

Performance of encoding/decoding of bit strings using coded sound signals.

Encryption of the data using coded sound signals and evaluation of the performance of the coded sound signal.Encryption of the data using coded sound signals and evaluation of the performance of the coded sound signal

Waveforms and channel coding for 5G

Abstract. The fifth generation (5G) communication systems are required to perform significantly better than the existing fourth generation (4G) systems in data rate, capacity, coverage, latency, energy consumption and cost. Hence, 5G needs to achieve considerable enhancements in the areas of bandwidth, spectral, energy, and signaling efficiencies and cost per bit. The new radio access technology (RAT) of 5G physical layer needs to utilize an efficient waveform to meet the demands of 5G. Orthogonal frequency division multiplexing (OFDM) is considered as a baseline for up to 30 GHz. However, a major drawback of OFDM systems is their large peak to average power ratio (PAPR). Here in this thesis, a simple selective-mapping (SLM) technique using scrambling is proposed to reduce the PAPR of OFDM signals. This technique selects symbol sequences with high PAPR and scrambles them until a PAPR sequence below a specific threshold is generated. The computational complexity of the proposed scheme is considerably lower than that of the traditional SLM. Also, performance of the system is investigated through simulations and more than 4.5 dB PAPR reduction is achieved. In addition, performance of single carrier waveforms is analyzed in multiple-input multiple-output (MIMO) systems as an alternative to OFDM. Performance of a single carrier massive MIMO system is presented for both uplink and downlink with single user and multiple user cases and the effect of pre-coding on the PAPR is studied. A variety of channel configurations were investigated such as correlated channels, practical channels and the channels with errors in channel estimate. Furthermore, the candidate coding schemes are investigated for the new RAT in the 5G standard corresponding the activities in the third generation partnership project (3GPP). The schemes are evaluated in terms of block error rate (BLER), bit error rate (BER), computational complexity, and flexibility. These parameters comprise a suitable set to assess the performance of different services and applications. Turbo, low density parity check (LDPC), and polar codes are considered as the candidate schemes. These are investigated in terms of obtaining suitable rates, block lengths by proper design for a fair comparison. The simulations have been carried out in order to obtain BLER / BER performance for various code rates and block lengths, in additive white Gaussian noise (AWGN) channel. Although polar codes perform well at short block lengths, LDPC has a relatively good performance at all the block lengths and code rates. In addition, complexity of the LDPC codes is relatively low. Furthermore, BLER/BER performances of the coding schemes in Rayleigh fading channels are investigated and found that the fading channel performance follows a similar trend as the performance in the AWGN channel

Microprocessor- Oriented Algorithms for Data Communications

Data modem design has attracted a lot of scientific and commercial interest for more than three decades now. The field is important from a scientific point of view, since reliable data communications require very sophisticated solutions to many associated problems. From a commercial point of view its importance arises from the ever- rising needs for Computer networking and distributed processing in general. Modem algorithms are real-time in nature, so adequate technological support is important for modem design development. Advances in VLSI are opening new possibilities in this area and current trends toward integration of computing and communications are placing new demands on its further development. One can say that data modem design is entering its renaissance and this fact was our motivation in preparing this text. The objective is to bridge the gap between the increasing number of published papers on modem design and implementation, and the rapidly growing interest in the field. Included in the text are topics to introduce and familiarize the reader with modem design. Topics covered include: microprocessor applications in communications, data modem types, microprocessor and VLSI types, and technological impacts on design. Finally, we address the hardware issues such as the processor elements and interfacing, and software issues like the digital filter implementation. A comprehensive bibliography on modem design and implementation is also provided. With this bibliography one can research VLSI/microprocessor-based data modem design easily and thoroughly

LTE implementation on CGRA based SiLago Platform

Abstract. This thesis implements long term evolution (LTE) transmission layer on a coarse grained reconfigurable called, dynamically reconfigurable resource array (DRRA). Specifically, we implement physical downlink shared channel baseband signal processing blocks (PDSCH) at high level. The overall implementation follows silicon large grain object (SiLago) design methodology. The methodology employs SiLago blocks instead of mainstream standard cells. The main ambition of this thesis was to prove that a standard as complex as LTE can be implemented using the in-house SiLago framework. The work aims to prove that customized design with efficiency close to application specific integrated circuit (ASIC) for LTE can be generated with the programming ease of MATLAB. During this thesis, we have generated a completely parametrizable LTE standard at high level