Physical layer security against eavesdropping in the internet of drones (IoD) based communication systems

rones or unmanned aerial vehicles (UAVs) communication technology, which has recently been thoroughly studied and adopted by 3GPP standard (Release 15) due to its dynamic, flexible, and flying nature, is expected to be an integral part of future wireless communications and Internet of drones (IoD) applications. However, due to the unique transmission characteristics and nature of UAV systems including broadcasting, dominant line of site and poor scattering, providing confidentiality for legitimate receivers against unintended ones (eavesdroppers) appears to be a challenging goal to achieve in such scenarios. Besides, the special features of UAVs represented by having limited power (battery-operated) and precessing (light RAM and CPU capabilities), makes applying complex cryptography approaches very challenging and inefficient for such systems. This motives the utilization of alternative approaches enabled by physical layer security (PLS) concept for securing UAV-based systems. Techniques based on PLS are deemed to be promising due to their ability to provide inherent secrecy that is complexity independent, where no matter what computational processing power the eavesdropper may have, there is no way to decrypt the PLS algorithms. This work is dedicated to highlight and overview the latest advances and state of art researches on the field of applying PLS to UAV systems in a unified and structured manner. Particularity, it discusses and explains the different, possible PLS scenarios and use cases of UAVs, which are categorized based on how the drone is utilized and employed in the communication system setup. The main classified categories include the deployment of the flying, mobile UAV as a 1) base station (BS), 2) user equipment (UE), 2) relay, or 4) jammer. Then, recommendations and future open research issues are stated and discussed.No sponso

Signal space diversity for improving the reliability performance of OFDM with subcarrier power modulation

As the demand for higher data rates continues to increase exponentially, there is a shift towards exploring contemporary techniques that are likely to offer higher spectral efficiency. A new modulation technique termed as orthogonal frequency division multiplexing with sub‐carrier power modulation (OFDM‐SPM) has recently been introduced. It is an original technique that is still largely under-explored and aims at transmitting more bits per sub‐carrier by manipulating the power of the sub‐carriers in an OFDM block, in addition to those bits that are usually transmitted by conventional modulation schemes such as M-PSK. During the investigation and theoretical testing stages, it was found that the additional data stream conveyed by subcarriers' power has higher bit error rate (BER) performance compared to the data stream conveyed by conventional modulation schemes. To overcome this shortfall, signal space diversity (SSD) along with coordinate interleaving is proposed in this work to be integrated with OFDM‐SPM to help improve the overall BER performance. By doing so, it is shown that a BER performance of 10-3 can be obtained at SNR of 15 dB, which means achieving an improvement of more than 5 dB compared to the case of using OFDM‐SPM without SSD. Furthermore, the performance results of OFDM‐SPM‐SSD is compared with those of OFDM‐SPM with maximal ratio combining (MRC) and the obtained results show that OFDM‐SPM‐SSD offers superior performance. Additionally, a study of the effect of the constellation rotation on OFDM‐SPM is provided and an in‐depth analysis is also carried out for different power polices of sub‐carrier power modulation with regards to two main performance metrics; namely BER and the throughput. Simulation results show that SSD provides a considerable improvement in the BER over both plain OFDM‐SPM and OFDM‐SPM‐MRC. The analysis also reveal that when considering the different power policies of SPM, the BER results are optimum in the case of using power‐reassignment policy.No sponso

The generalization of orthogonal frequency division multiplexing with subcarrier power modulation to quadrature signal constellations

A novel modulation technique termed as orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM) has been proposed for achieving spectral-efficient data transmission in wireless communication systems. OFDM-SPM utilizes the power of each subcarrier in an OFDM block as an extra degree of freedom to convey extra information bits besides the bits transmitted by conventional signal modulation. OFDM-SPM has originally been introduced with binary phase shift keying (BPSK) symbol modulation, and was shown to provide great gains and various merits such as doubling the spectral efficiency, reducing transmission power and transmission times by half. Displaying its capabilities as a scheme to be adopted for future wireless communication systems, a question detrimental to the adoption of OFDM-SPM has yet to be answered. This is whether the gains that OFDM-SPM brings persist when paired with higher order modulation schemes, especially two dimensional signal constellation schemes such as M-ary PSK. In this paper, OFDM-SPM is paired with quadrature phase shift keying (QPSK) symbol modulation as an example of a higher order two dimensional modulation scheme. The performance analysis of this scheme along with its numerical simulations are carried out where the bit error rate (BER) and throughput performances of the scheme are given in both an additive white Gaussian noise (AWGN), and multipath Rayleigh fading channels. These simulations are done for different power allocation policies. Unlike other 3D modulation methods, the results show that OFDM-SPM can be used with higher order modulation schemes while maintaining all the gains exhibited in OFDM-SPM with BPSK. This gives OFDM-SPM a unique advantage when compared to other 3D modulation schemes such as OFDM-IM and OFDM-SNM, which lose the gain in spectral efficiency as the modulation order becomes higher. Furthermore, the results of OFDM-SPM with QPSK were compared to that of conventional OFDM with 16-QAM symbol modulation. OFDM-SPM displayed superiority both in terms of BER and throughput achieving a gain of approximately 2.5-3 dB. These findings clearly point out that OFDM-SPM is a promising modulation scheme, which should be investigated more vigorously and considered as a strong candidate for adoption in future 6G and beyond wireless communication systems.This research was partly funded by TUBITAK under Grant/Award Number: 119E408

Multiple MIMO with joint block antenna number modulation and adaptive antenna selection for future wireless systems

Multiple MIMO with joint block Antenna Number Modulation (M-MIMO-ANM) is proposed in this paper as a novel transmission method that exploits the features of both Massive Multiple Input Multiple Output (M-MIMO) and Antenna Number Modulation (ANM) concepts. In this scheme, the main purpose is to increase the number of additionally transmitted data bits, which are sent without any consumption in the bandwidth. To achieve this, the antenna elements of a large array are divided into blocks, whose numbers are utilized to convey additional data bits along with those bits sent by the number of antenna elements within each block as well as those sent by conventional modulation schemes (e.g., BPSK). The implementation of M-MIMO-ANM scheme relies on the idea of dividing the whole antenna array into blocks, where each block corresponds to a group of bits depending on the total number of available blocks, thus ANM concept is applied not only to the antennas within each block but also to the blocks forming the entire antenna array. This creates an opportunity to convey even more additional data bits, compared with the conventional ANM scheme, while there is a noticeable improvement in the reliability of data transmission. With all these dynamics, M-MIMO-ANM concept is a candidate to create a new perspective to the Internet of Things (IoT) applications, with its energy efficient, spectrum efficient, robust, and both data and channel dependent data transmission nature that comes from the properties of Massive MIMO and ANM. The introduced system is investigated, and its validity is proven, where analytical and simulation results in terms of the bit error rate (BER) and throughput of the system are given. The numerical computer simulations furthermore compare the performances of M-MIMO-ANM with MIMO-ANM to show its superiority, and the advantages of the concept are discussed. M-MIMO-ANM is promising a highly reliable and resilient system thanks to its cascaded simultaneous bit transmission by the different number of both antenna blocks and antenna elements within each block.This research was partly funded by TUBITAK under Grant/Award Number 119E39

Joint PHY/MAC layer security design using ARQ with MRC and null-space independent PAPR-aware artificial noise in SISO systems

Automatic-repeat-request (ARQ) as a MAC layer mechanism and artificial noise (AN) as a physical layer mechanism along with the help of maximal ratio combining (MRC), are jointly designed to achieve secrecy. Basically, a special AN, which does not require null-space in the channel, is designed based on the quality of service requirements and the channel condition between the legitimate parties and injected to the data packet. If the same packet is requested by the legitimate receiver (Bob), an AN canceling signal is properly designed and added to the next packet. Then, an AN-free packet is obtained by using MRC process at Bob, while deteriorating the eavesdropper's performance. Furthermore, two simple closed-form expressions of the achievable secure throughput are derived. The first one is given in a closed-form for the case of ARQ scheme without AN, while the second one is given in an upper-bound form for the case of ARQ with AN. Moreover, this paper addresses two critical security-associated problems: 1) the joint design of secrecy, reliability, throughput, delay and the tradeoff among them, and 2) the increase in the peak-to-average power ratio (PAPR) due to the added AN. Finally, the proposed design is extended to OFDM to demonstrate its capability in not only enhancing the secrecy due to the frequency selectivity of the channel, but also in reducing the PAPR and out-of-band emission of OFDM-based waveforms, while maintaining secrecy.No sponso

Autonomous first response drone-based smart rescue system for critical situation management in future wireless networks

Numerous problems have been experienced due to the current exponential rise in urban population. Such challenges include insecurity and disaster management. It is therefore critical that new and efficient ways of disaster management are realized. Drone technology has been used in many applications due to their flexibility and cost-effectiveness in executing tasks. Such applications include goods delivery, data collection, surveillance, and tracking. This paper proposes an autonomous first response drone-based (Auto-FRD) smart rescue system. Auto-FRD paradigm uses drones to provide quick response to critical situations in a smart city setting. The system comprises three main sections: sensor network, intelligent drones, and the command center. The Auto-FRD system is designed such that the drones automatically deploy to a specific location upon receiving an alert signal from the smart sensors, as opposed to people sending the signal. Moreover, the system is implemented using cheap LoRa technology. Experimental results show that the proposed system drastically reduces the response time compared to conventional critical situation response systems. Additionally, the data collected by the drones prove to be extra valuable when analyzing the critical situation.No sponso

A novel small-scale nonorthogonal communication technique using auxiliary signal superposition with enhanced security for future wireless networks

In this work, an advanced novel small-scale non-orthogonal communication technique utilizing physical layer security (PLS) for enhanced security and reliability for two users is proposed. This work is motivated by current challenges faced by conventional non-orthogonal multiple access (NOMA) techniques, for instance, the recent exclusion of power-domain NOMA (PD-NOMA) from 3GPP release 17 due to its performance degradation resulting from channel estimation errors and the utilization of successive interference cancellation (SIC) algorithms at the receiver. The proposed model uses the wireless channel characteristics to eliminate user interference as well as completely degrade the received signal at the eavesdropper’s terminal. More specifically, auxiliary signals are precisely designed and superimposed on top of user signals from a dual-transmitter system to provide perfect secrecy against external and internal eavesdroppers, while providing low complexity at the receiver. The efficiency and novelty of the proposed system are presented via mathematical analysis and validated by Monte Carlo simulations. Results obtained indicate that the proposed model achieves less complex, secure, and more efficient communication, suitable for low power consumption and limited processing applications.This work is funded by the scientific and technological research council of Turkey (TÜBITAK) under grand 119E392

Hybrid MIMO: a new transmission method for simultaneously achieving spatial multiplexing and diversity gains in MIMO systems

Multiple input multiple output (MIMO) technology has evolved over the past few years into a technology with great potential to drive the direction of future wireless communications. MIMO technology has become a solid reality when massive MIMO systems (MIMO with large number of antennas and transceivers) were commercially deployed in several countries across the world in the recent past. Moreover, MIMO has been integrated into state-of-the-art paradigms such as fifth-generation (5G) networks as one of the main enabling technologies. MIMO possesses many attractive and highly desirable properties such as spatial multiplexing, diversity gains, and adaptive beamforming gains that leads to high data rates, enhanced reliability, and other enhancements. Nevertheless, beyond 5G technologies demand wireless communication systems with, among other properties, immensely higher data rates and better reliability simultaneously at the same time. In this work, a new, novel MIMO technique for simultaneously achieving multiplexing and diversity gains as well as completely eliminating any processing at the MIMO receiver, leading to advantages such as low complexity and low power consumption, is proposed. The proposed technique employs the design of interference-canceling matrices, which are calculated from the channels between the transceiver antennas, where the matrices are employed at the base station to help achieve multiplexing and diversity gains simultaneously. The novelty and efficiency of the introduced paradigm is demonstrated via mathematical models and validated by Monte Carlo simulations. Results indicate that the proposed system outperforms conventional MIMO models.No sponso

Massive MIMO channel prediction using recurrent neural networks

Massive MIMO has been classified as one of the high potential wireless communication technologies due to its unique abilities such as high user capacity, increased spectral density, and diversity among others. Due to the exponential increase of connected devices, these properties are of great importance for the current 5G-IoT era and future telecommunication networks. However, outdated channel state information (CSI) caused by the variations in the channel response due to the presence of highly mobile and rich scattering is a major problem facing massive MIMO systems. Outdated CSI occurs when the information obtained about the channel at the transmitter changes before transmission. This leads to performance degradation of the network. In this work, we demonstrate a low complexity channel prediction method using neural networks. Specifically, we explore the power of recurrent neural network utilizing long-short memory cells in analyzing time series data. We review various neural network-based channel prediction methods available in the literature and compare complexity and performance metrics. Results indicate that the proposed methods outperform conventional systems by tremendously lowering the complexity associated with channel prediction.This work is funded by the scientific and technological research council of Turkey (TÜBITAK) under grand 119E392

An advanced non-orthogonal multiple access security technique for future wireless communication networks

The future wireless communication systems demand much more enhanced security and reliability compared to currently deployed systems. In this work, we propose a much simpler yet more efficient physical layer security (PLS) technique for achieving reliable and secure communication in the multiple-input single-output non-orthogonal multiple access (MISO-NOMA) systems. This system is capable of providing enhanced confidential communication as well as inter-user interference cancellation without using the successive interference cancellation (SIC) method. The conventional NOMA was previously adopted under the name of multi-user superposition transmission (MUST) in release 13 of 3GPP but recently excluded from 3GPP-release 17 due to its performance degradation. In this work, we analyze the drawbacks in conventional NOMA and present a new kind of NOMA with more improved performance metrics. The proposed algorithm combines the benefit of pre-coder matrices with simultaneous transmission using antenna diversity to provide simple, reliable, and secure communication without complex processing at the receivers in downlink scenarios. The effectiveness of the proposed algorithm is verified and proven by extensive analysis and numerical simulations.This work was supported in part by the Scientific and Technological Research Council of Turkey (TÜBİTAK), under project grant No. 119E39