The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

This paper presents an overview of ultrawideband (UWB) propagation channels. It first demonstrates how the frequency selectivity of propagation processes causes fundamental differences between UWB channels and "conventional" (narrowband) channels. The concept of pathloss has to be modified, and the well-known WSSUS model is not applicable anymore. The paper also describes deterministic and stochastic models for UWB channels, identifies the key parameters for the description of delay dispersion, attenuation, and directional characterization, and surveys the typical parameter values that have been measured. Measurement techniques and methods for extracting model parameters are also different in UWB channels; for example, the concepts of narrowband channel parameter estimation (e.g., maximum-likelihood estimation) have to be modified. Finally, channel models also have an important impact on the performance evaluation of various UWB systems.

Ultrawideband propagation channels-theory, measurement, and modeling

This paper proposes a vehicle-to-vehicle communication protocol for cooperative collision warning Emerging wireless technologies for vehicle-to-vehicle (V2V) and vehicle-to-roadside (V2R) communications such as DSRC are promising to dramatically reduce the number of fatal roadway accidents by providing early warnings One major technical challenge addressed in this paper is to achieve low-latency in delivering emergency warnings in various road situations Based on a careful analysis of application requirements, we design an effective protocol, comprising congestion control policies, service differentiation mechanisms and methods for emergency warning dissemination Simulation results demonstrate that the proposed protocol achieves low latency in delivering emergency warnings and efficient bandwidth usage in stressful road scenarios

A vehicle-to-vehicle communication protocol for cooperative collision warning

Radio-frequency identification tokens, such as contactless smartcards, are vulnerable to relay attacks if they are used for proximity authentication. Attackers can circumvent the limited range of the radio channel using transponders that forward exchanged signals over larger distances. Cryptographic distance-bounding protocols that measure accurately the round-trip delay of the radio signal provide a possible countermeasure. They infer an upper bound for the distance between the reader and the token from the fact that no information can propagate faster than at the speed of light. We propose a new distance-bounding protocol based on ultra-wideband pulse communication. Aimed at being implementable using only simple, asynchronous, low-power hardware in the token, it is particularly well suited for use in passive low-cost tokens, noisy environments and high-speed applications.

/pdf/an-rfid-distance-bounding-protocol-jgrstp34n2.pdf

An RFID Distance Bounding Protocol

Inter-vehicle communication (IVC) systems (i.e., systems not relying on roadside infrastructure) have the potential to radically improve the safety, efficiency, and comfort of everyday road travel. Their main advantage is that they bypass the need for expensive infrastructure; their major drawback is the comparatively complex networking protocols and the need for significant penetration before their applications can become effective. In this article we present several major classes of applications and the types of services they require from an underlying network. We then proceed to analyze existing networking protocols in a bottom-up fashion, from the physical to the transport layers, as well as security aspects related to IVC systems. We conclude the article by presenting several projects related to IVC as well as a review of common performance evaluation techniques for IVC systems.

/pdf/inter-vehicle-communication-systems-a-survey-4dcec4ylxn.pdf

Inter-vehicle communication systems: a survey

Preface. Acknowledgments. List of Figures. List of Tables. Introduction. I.1 Ultra wideband overview. I.2 A note on terminology. I.3 Historical development of UWB. I.4 UWB regulation overview. I.5 Key benefits of UWB. I.6 UWB and Shannon's theory. I.7 Challenges for UWB. I.8 Summary. 1 Basic properties of UWB signals and systems. 1.1 Introduction. 1.2 Power spectral density. 1.3 Pulse shape. 1.4 Pulse trains. 1.5 Spectral masks. 1.6 Multipath. 1.7 Penetration characteristics. 1.8 Spatial and spectral capacities. 1.9 Speed of data transmission. 1.10 Cost. 1.11 Size. 1.12 Power consumption. 1.13 Summary. 2 Generation of UWB waveforms. 2.1 Introduction. 2.2 Gaussian waveforms. 2.3 Designing waveforms for specific spectral masks. 2.4 Practical constraints and effects of imperfections. 2.5 Summary. 3 Signal-processing techniques for UWB systems. 3.1 The effects of a lossy medium on a UWB transmitted signal. 3.2 Time domain analysis. 3.3 Frequency domain techniques. 3.4 UWB signal-processing issues and algorithms. 3.5 Detection and amplification. 3.6 Summary. 4 UWB channel modeling. 4.1 A simplified UWB multipath channel model. 4.2 Path loss model. 4.3 Two-ray UWB propagation model. 4.4 Frequency domain autoregressive model. 4.5 IEEE proposals for UWB channel models. 4.6 Summary. 5 UWB communications. 5.1 Introduction. 5.2 UWB modulation methods. 5.3 Other modulation methods. 5.4 Pulse trains. 5.5 UWB transmitter. 5.6 UWB receiver. 5.7 Multiple access techniques in UWB. 5.8 Capacity of UWB systems. 5.9 Comparison of UWB with other wideband communication systems. 5.10 Interference and coexistence of UWB with other systems. 5.11 Summary. 6 Advanced UWB pulse generation. 6.1 Hermite pulses. 6.2 Orthogonal prolate spheroidal wave functions. 6.3 Wavelet packets in UWB PSM. 6.4 Summary. 7 UWB antennas and arrays. 7.1 Antenna fundamentals. 7.2 Antenna radiation for UWB signals. 7.3 Suitability of conventional antennas for the UWB system. 7.4 Impulse antennas. 7.5 Beamforming for UWB signals. 7.6 Radar UWB array systems. 7.7 Summary. 8 Position and location with UWB signals. 8.1 Wireless positioning and location. 8.2 GPS techniques. 8.3 Positioning techniques. 8.4 Time resolution issues. 8.5 UWB positioning and communications. 8.6 Summary. 9 Applications using UWB systems. 9.1 Military applications. 9.2 Commercial applications. 9.3 UWB potentials in medicine. 9.4 Summary. 10 UWB communication standards. 10.1 UWB standardization in wireless personal area networks. 10.2 DS-UWB proposal. 10.3 MB-OFDM UWB proposal. 10.4 A short comment on the term 'impulse radio'. 10.5 Summary. 11 Advanced topics in UWB communication systems. 11.1 UWB ad-hoc networks. 11.2 UWB sensor networks. 11.3 Multiple inputs multiple outputs and space-time coding for UWB systems. 11.4 Self-interference in high-data-rate UWB communications. 11.5 Coexistence of DS-UWB with Wi-Max. 11.6 Vehicular radars in the 22-29 GHz band. 11.7 Summary. References. Index.

Ultra-wideband signals and systems in communication engineering

Ultra Wideband Signals and Systems in Communication Engineering: Ghavami/Ultra Wideband Signals and Systems in Communication Engineering

This paper provides an overview of the physical layer specification of Advanced Television Systems Committee (ATSC) 3.0, the next-generation digital terrestrial broadcasting standard. ATSC 3.0 does not have any backwards-compatibility constraint with existing ATSC standards, and it uses orthogonal frequency division multiplexing-based waveforms along with powerful low-density parity check (LDPC) forward error correction codes similar to existing state-of-the-art. However, it introduces many new technological features such as 2-D non-uniform constellations, improved and ultra-robust LDPC codes, power-based layered division multiplexing to efficiently provide mobile and fixed services in the same radio frequency (RF) channel, as well as a novel frequency pre-distortion multiple-input single-output antenna scheme. ATSC 3.0 also allows bonding of two RF channels to increase the service peak data rate and to exploit inter-RF channel frequency diversity, and to employ dual-polarized multiple-input multiple-output antenna system. Furthermore, ATSC 3.0 provides great flexibility in terms of configuration parameters (e.g., 12 coding rates, 6 modulation orders, 16 pilot patterns, 12 guard intervals, and 2 time interleavers), and also a very flexible data multiplexing scheme using time, frequency, and power dimensions. As a consequence, ATSC 3.0 not only improves the spectral efficiency and robustness well beyond the first generation ATSC broadcast television standard, but also it is positioned to become the reference terrestrial broadcasting technology worldwide due to its unprecedented performance and flexibility. Another key aspect of ATSC 3.0 is its extensible signaling, which will allow including new technologies in the future without disrupting ATSC 3.0 services. This paper provides an overview of the physical layer technologies of ATSC 3.0, covering the ATSC A/321 standard that describes the so-called bootstrap, which is the universal entry point to an ATSC 3.0 signal, and the ATSC A/322 standard that describes the physical layer downlink signals after the bootstrap. A summary comparison between ATSC 3.0 and DVB-T2 is also provided.

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An Overview of the ATSC 3.0 Physical Layer Specification

We propose a circuit for generation of modified Hermite polynomial functions for use in impulse radio communications. Simultaneous generation of pulses of differing order is developed, reducing circuit complexity. Pulses are produced by applying modifications to Hermite polynomials. Pulses have the properties of orthogonality and not changing their pulse width and pulse bandwidth significantly dependent on pulse order, or under the differentiation effect of the transmitter or receiver antenna. The usefulness of these pulses applied to a multi-user system by orthogonal pulse modulation is shown by comparison with conventional pulse position modulation by computer simulation.

Multiple pulse generator for ultra-wideband communication using Hermite polynomial based orthogonal pulses

The universal platform for the SDR of the present invention employs the direct conversion approach with the n-port MMIC followed by reconfigurable reprogrammable devices such as DSP's or FPGA's. The universal platform is based on the linear operation of the devices. Thus, the DC offset problem may be solved. It is also possible to support very wide bandwidths compared with conventional I/Q receivers. Therefore, the present universal platform is suitable for multimode and multiband communications.

Lachlan Bruce Michael

Papers

Ultra-wideband signals and systems in communication engineering

Ultra Wideband Signals and Systems in Communication Engineering: Ghavami/Ultra Wideband Signals and Systems in Communication Engineering

An Overview of the ATSC 3.0 Physical Layer Specification

Multiple pulse generator for ultra-wideband communication using Hermite polynomial based orthogonal pulses

Universal platform for software defined radio