Sparse Signal Processing Concepts for Efficient 5G System Design

As it becomes increasingly apparent that 4G will not be able to meet the emerging demands of future mobile communication systems, the question what could make up a 5G system, what are the crucial challenges and what are the key drivers is part of intensive, ongoing discussions. Partly due to the advent of compressive sensing, methods that can optimally exploit sparsity in signals have received tremendous attention in recent years. In this paper we will describe a variety of scenarios in which signal sparsity arises naturally in 5G wireless systems. Signal sparsity and the associated rich collection of tools and algorithms will thus be a viable source for innovation in 5G wireless system design. We will discribe applications of this sparse signal processing paradigm in MIMO random access, cloud radio access networks, compressive channel-source network coding, and embedded security. We will also emphasize important open problem that may arise in 5G system design, for which sparsity will potentially play a key role in their solution.Comment: 18 pages, 5 figures, accepted for publication in IEEE Acces

A Survey of Physical Layer Security Techniques for 5G Wireless Networks and Challenges Ahead

Physical layer security which safeguards data confidentiality based on the information-theoretic approaches has received significant research interest recently. The key idea behind physical layer security is to utilize the intrinsic randomness of the transmission channel to guarantee the security in physical layer. The evolution towards 5G wireless communications poses new challenges for physical layer security research. This paper provides a latest survey of the physical layer security research on various promising 5G technologies, including physical layer security coding, massive multiple-input multiple-output, millimeter wave communications, heterogeneous networks, non-orthogonal multiple access, full duplex technology, etc. Technical challenges which remain unresolved at the time of writing are summarized and the future trends of physical layer security in 5G and beyond are discussed.Comment: To appear in IEEE Journal on Selected Areas in Communication

Practical security considerations for IoT systems over satellite

Currently, the forecast for the European market for IoT is a yearly 19.8% increase up to reach $241 billion in 2025. Thisstrong growing will be concentrated in verticals from manufacturing, utilities, retail and transportation [1], [2]. However, in orderto monetize the potential services over IoT it is necessary to guarantee the security of the communications [3]. In this regardphysical-layer security methods may complement higher-layer encryption techniques by exploiting the characteristics of wirelesschannels. For this purpose, it is resorted to the secrecy-capacity metric to measure the security level. More specifically, it was shownin [4] that reliable information-theoretic security could be achieved, whenever the eavesdropper’s channel be a degraded versionof the legitimate user’s channel. In this case, if the secrecy rate is chosen below the secrecy-capacity, then reliable transmissionscan be achieved in perfect secrecy. However, the time-varying fading effect of wireless channels degrades the secrecy-capacity. Inthis situation, it is used the ergodic capacity to measure the secrecy-capacity [5]. In order to make the overhearing process of theeavesdroppers difficult, it is used the time-packing/faster than Nyquist strategy [6]- [7].Thus, the time-duration of the transmittedframes are reduced which: i) improves the interception probability of the packets, ii) augments the spectral efficiency of theM2M communications without increasing the transmission bandwidth, iii) diminishes the effect of Doppler spread in Non-GEOcommunications, and iv) permits to use the overlapping degree among the pulse shapes to boost the secrecy-capacity. On thecontrary, this overlapping degree introduces a multi-path channel that may difficult the synchronization process. However, thecoefficients of the multipath channel are known by the legitimate user but ignored by the eavesdropper. This strategy of securityis similar to that the Artificial Noise (AN) one pursues [5], [8]- [9], but without wasting energy for jamming the eavesdropper’schannel.Note that the satellite channel model has a large Line of Sight (LoS) component. So, it means that the channel of theeavesdropper and the legitimate user could be quite similar in the same beam of the satellite constellation. So it is necessary todistort the channel of the desired user in order to increase the security of the communications. The use of non-Nyquist pulses,permits to introduce an artificial multipath interference that degrades the eavesdropper’s channel. In this case, we have consideredtwo types of eavesdropper: i) without being able to estimate the time-packing multipath, and ii) equipped with an estimationblock of the time-packing interference. In the first case, all interference signals are considered as noise whereas in the secondone part of the interference is assumed as noise. In both cases, it is possible to obtain a secrecy-capacity. Finally, comment thatin satellite constellation there is a residual co-channel interference. This interference limits the resolution of the eavesdroppersalthough they be equipped with multiple antennas. We have considered that the eavesdropper does not have full knowledge of thetime-packed/faster than Nyquist multi-path interference. This pragmatic approach was also followed in [9]. However, there therain losses made difficult to obtain perfect channel estimations.Peer ReviewedPostprint (published version

The Role of Physical Layer Security in IoT: A Novel Perspective

This paper deals with the problem of securing the configuration phase of an Internet of Things (IoT) system. The main drawbacks of current approaches are the focus on specific techniques and methods, and the lack of a cross layer vision of the problem. In a smart environment, each IoT device has limited resources and is often battery operated with limited capabilities (e.g., no keyboard). As a consequence, network security must be carefully analyzed in order to prevent security and privacy issues. In this paper, we will analyze the IoT threats, we will propose a security framework for the device initialization and we will show how physical layer security can effectively boost the security of IoT systems

Securing Wireless Communications of the Internet of Things from the Physical Layer, An Overview

The security of the Internet of Things (IoT) is receiving considerable interest as the low power constraints and complexity features of many IoT devices are limiting the use of conventional cryptographic techniques. This article provides an overview of recent research efforts on alternative approaches for securing IoT wireless communications at the physical layer, specifically the key topics of key generation and physical layer encryption. These schemes can be implemented and are lightweight, and thus offer practical solutions for providing effective IoT wireless security. Future research to make IoT-based physical layer security more robust and pervasive is also covered

Quantifying Equivocation for Finite Blocklength Wiretap Codes

This paper presents a new technique for providing the analysis and comparison of wiretap codes in the small blocklength regime over the binary erasure wiretap channel. A major result is the development of Monte Carlo strategies for quantifying a code's equivocation, which mirrors techniques used to analyze normal error correcting codes. For this paper, we limit our analysis to coset-based wiretap codes, and make several comparisons of different code families at small and medium blocklengths. Our results indicate that there are security advantages to using specific codes when using small to medium blocklengths.Comment: Submitted to ICC 201

Achievable Secrecy Rates of an Energy Harvesting Device

The secrecy rate represents the amount of information per unit time that can be securely sent on a communication link. In this work, we investigate the achievable secrecy rates in an energy harvesting communication system composed of a transmitter, a receiver and a malicious eavesdropper. In particular, because of the energy constraints and the channel conditions, it is important to understand when a device should transmit and to optimize how much power should be used in order to improve security. Both full knowledge and partial knowledge of the channel are considered under a Nakagami fading scenario. We show that high secrecy rates can be obtained only with power and coding rate adaptation. Moreover, we highlight the importance of optimally dividing the transmission power in the frequency domain, and note that the optimal scheme provides high gains in secrecy rate over the uniform power splitting case. Analytically, we explain how to find the optimal policy and prove some of its properties. In our numerical evaluation, we discuss how the maximum achievable secrecy rate changes according to the various system parameters. Furthermore, we discuss the effects of a finite battery on the system performance and note that, in order to achieve high secrecy rates, it is not necessary to use very large batteries.Comment: Accepted for publication in IEEE Journal on Selected Areas in Communications (Mar. 2016