Research Topics

Physical and MAC Layers Security

Physical layer security (PLS) has emerged as a new concept and powerful alternative that can complement and may even replace encryption-based approaches, which entail many hurdles and practical problems for future wireless systems. The basic idea of PLS is to exploit the characteristics of the wireless channel and its impairments including noise, fading, interference, dispersion, diversity, etc. in order to ensure the ability of the intended user to successfully perform data decoding while preventing eavesdroppers from doing so. Thus, the main design goal of PLS is to increase the performance difference between the link of the legitimate receiver and that of the eavesdropper by using well-designed transmission schemes. In this domain, we develop and propose novel security designs to meet the requirements of future secure wireless systems

Advanced Secure & Optimized Waveforms

In this area, we are focused on developing novel waveform designs to fulfill the requirements of future wireless networks. Toward this ultimate point, our scope ranges from the fundamental properties of the waveforms (e.g., pulse shapes, orthogonality, nonorthogonality, time-frequency lattice) to the frame structures in the transmission. We investigate not only waveform itself in time-frequency in terms of channel adaptation and flexibility, but also cross relations between waveforms like signal separability regarding to the their suitability to next generation networks. Additionally, considering practical systems, we focus on their impacts on the other topics in physical layer (e.g. PAPR, equalization, channel estimation, out-of-band radiation) and MAC layer (e.g. scheduling), since they essentially affect the transmitter and receiver algorithms.

Current studies

  • Non-orthogonal/Orthogonal/Biorthogonal multicarrier systems
  • Time-frequency characteristics of waveforms, Gabor systems
  • User-based and heterogeneous network-bearing waveforms
  • Spectral shaping for OFDM-based waveforms
  • Separability of waveforms
  • Covert, secure OFDM/OTFS communication (Physical and MAC layer security enhancement techniques)

New Efficient Modulation Techniques

In this area, we develop novel multi-dimensional, advanced modulation schemes such as OFDM with subcarrier number modulation, OFDM with subcarrier power modulation, OFDM with subcarrier shape modulation, etc.

Multiple Access Schemes

In this area, we develop different types of NOMA or OMA for meeting the requirements of future 6G and beyond wireless systems

Massive MIMO mmWave Systems

In this flied, we develop novel multi-dimensional, advanced spatial modulation schemes such as MIMO with antenna number modulation, MIMO with antenna power modulation, MIMO with antenna pattern shape modulation, etc.

IoT & AI

In this domain, we are interested in developing real working applications by utilizing the power of IoT, AI, and BC for solving challenging, practical problems in various areas including industrial factories, agricultural firms, service businesses, drones/UAV, AR, VR, etc.

Our publications related to the above mentioned areas

  • A. Hajar, J. M. Hamamreh, M. Abewa and Y. Belallou, "A Spectrally Efficient OFDM-Based Modulation Scheme for Future Wireless Systems," 2019 Scientific Meeting on Electrical-Electronics & Biomedical Engineering and Computer Science (EBBT), Istanbul, Turkey, 2019, pp. 1-4.
  • doi: 10.1109/EBBT.2019.8742049
  • Abstract: A novel modulation technique termed as orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM) for efficient data transmission in wireless communication systems is proposed. OFDM-SPM uses the power of each subcarrier in an OFDM block as a third dimension to carry data, where different power levels correspond to different bits. In this paper, the concept of OFDM-SPM is applied to conventional OFDM using binary phase shift keying (BPSK) symbol modulation over an additive white Gaussian noise channel (AWGN). The system and its validity as a future adopted modulation technique is investigated, where a general overview of the system is given. Simulation results regarding the bit error rate (BER) and the throughput of the system are displayed, and the merits of this scheme are discussed. Results show that compared to other proposed modulation techniques which add a third dimension to carry data, OFDM-SPM vastly improves spectral efficiency, where it is capable of doubling the spectral efficiency in addition to reducing the transmission power of the system by half. Although this results in a degradation in the system bit error rate performance, the scheme suggests that this can be overcome by reallocating the saved power to the transmitted OFDM subcarriers.
  • keywords: {AWGN channels;error statistics;OFDM modulation;phase shift keying;radio spectrum management;wireless communication systems;OFDM-SPM;OFDM block;additive white Gaussian noise channel;spectral efficiency;system bit error rate performance;transmitted OFDM subcarriers;future wireless systems;subcarrier power modulation;adopted modulation technique;BPSK symbol modulation},
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  • A. M. Jaradat, J. M. Hamamreh and H. Arslan, "Modulation Options for OFDM-Based Waveforms: Classification, Comparison, and Future Directions," in IEEE Access, vol. 7, pp. 17263-17278, 2019.
  • doi: 10.1109/ACCESS.2019.2895958
  • Abstract: This paper provides a comparative study on the performance of different modulation options for orthogonal frequency division multiplexing (OFDM) in terms of their spectral efficiency, reliability, peak-to-average power ratio, power efficiency, out-of-band emission, and computational complexity. The modulation candidates are classified into two main categories based on the signal plane dimension they exploit. These categories are: 1) 2-D signal plane category including conventional OFDM with classical fixed or adaptive QAM modulation and OFDM with differential modulation, where information is conveyed in changes between two successive symbols in the same subcarrier or between two consecutive subcarriers in the same OFDM symbol and 2) 3-D signal plane category encompassing: a) index-based OFDM modulation schemes which include: i) spatial modulation OFDM, where information is sent by the indices of antennas along with conventional modulated symbols and ii) OFDM with index modulation, where the subcarriers' indices are used to send additional information; b) number-based OFDM modulation schemes which include OFDM with subcarrier number modulation, in which number of subcarriers is exploited to convey additional information; and c) shape-based OFDM modulation schemes which include OFDM with pulse superposition modulation, where the shape of pulses is introduced as a third new dimension to convey additional information. Based on the provided comparative study, the relationship and interaction between these different modulation options and the requirements of future 5G networks are discussed and explained. This paper is then concluded with some recommendations and future research directions.
  • keywords: {adaptive modulation;antenna arrays;OFDM modulation;quadrature amplitude modulation;telecommunication network reliability;modulation options;orthogonal frequency division multiplexing;out-of-band emission;computational complexity;2D signal plane category;3D signal plane category encompassing;index-based OFDM modulation schemes;future 5G networks;pulse superposition modulation;shape-based OFDM;subcarrier number modulation;number-based OFDM;index modulation;conventional modulated symbols;OFDM symbol;consecutive subcarriers;differential modulation;adaptive QAM modulation;classical fixed QAM modulation;signal plane dimension;power efficiency;peak-to-average power ratio;spectral efficiency;OFDM-based waveforms;Modulation;OFDM modulation;Frequency-domain analysis;Indexes;Transmitting antennas;Noise measurement;OFDM;OFDM-SNM;index-based OFDM family;shape-based OFDM family;3-D signal plane;modulation options;PAPR;OOBE;5G;spatial domain;spectral efficiency;URLLC;mMTC;eMBB;complexity;differential modulation},
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  • J. M. Hamamreh, H. M. Furqan and H. Arslan, "Classifications and Applications of Physical Layer Security Techniques for Confidentiality: A Comprehensive Survey," in IEEE Communications Surveys & Tutorials, vol. 21, no. 2, pp. 1773-1828, Secondquarter 2019.
  • doi: 10.1109/COMST.2018.2878035
  • Abstract: Physical layer security (PLS) has emerged as a new concept and powerful alternative that can complement and may even replace encryption-based approaches, which entail many hurdles and practical problems for future wireless systems. The basic idea of PLS is to exploit the characteristics of the wireless channel and its impairments including noise, fading, interference, dispersion, diversity, etc. in order to ensure the ability of the intended user to successfully perform data decoding while preventing eavesdroppers from doing so. Thus, the main design goal of PLS is to increase the performance difference between the link of the legitimate receiver and that of the eavesdropper by using well-designed transmission schemes. In this survey, we propose a conceptual, generic, and expandable framework for classifying the existing PLS techniques against wireless passive eavesdropping. In this flexible framework, the security techniques that we comprehensively review in this treatise are divided into two primary approaches: signal-to-interference-plus-noise ratio-based approach and complexity-based approach. The first approach is classified into three major categories: first, secrecy channel codes-based schemes; second, security techniques based on channel adaptation; third, schemes based on injecting interfering artificial (noise/jamming) signals along with the transmitted information signals. The second approach (complexity-based), which is associated with the mechanisms of extracting secret sequences from the shared channel, is classified into two main categories based on which layer the secret sequence obtained by channel quantization is applied on. The techniques belonging to each one of these categories are divided and classified into three main signal domains: time, frequency and space. For each one of these domains, several examples are given and illustrated along with the review of the state-of-the-art security advances in each domain. Moreover, the advantages and disadvantages of each approach alongside the lessons learned from existing research works are stated and discussed. The recent applications of PLS techniques to different emerging communication systems such as visible light communication, body area network, power line communication, Internet of Things, smart grid, mm-Wave, cognitive radio, vehicular ad-hoc network, unmanned aerial vehicle, ultra-wideband, device-to-device, radio-frequency identification, index modulation, and 5G non-orthogonal multiple access based-systems, are also reviewed and discussed. The paper is concluded with recommendations and future research directions for designing robust, efficient and strong security methods for current and future wireless systems.
  • keywords: {Security;Communication system security;Internet of Things;Physical layer security;OFDM;Cognitive radio;Physical layer security;cross-layer security;eavesdropping;channel secrecy codes;adaptation;interfering signals;artificial noise;jamming;secret keys;signal domains: time;frequency and space;VLC;BAN;PLC;IoT;smart grid;mm-Wave;cognitive radio;vehicular;UAV;UWB;D2D;RFID;index modulation;spatial modulation;5G systems;OFDM;MIMO;Relay;NOMA;full-duplex;TDD},
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  • J. M. Hamamreh, Z. E. Ankarali and H. Arslan, "CP-Less OFDM With Alignment Signals for Enhancing Spectral Efficiency, Reducing Latency, and Improving PHY Security of 5G Services," in IEEE Access, vol. 6, pp. 63649-63663, 2018.
  • doi: 10.1109/ACCESS.2018.2877321
  • Abstract: Although orthogonal frequency-division multiplexing (OFDM) is a widely accepted waveform in many standards and is expected to keep its dominance in future 5G systems with various types of parameterized waveforms, its performance in terms of spectral efficiency as well as transmission latency is usually degraded due to the excessive usage of cyclic prefix (CP). Particularly, in highly dispersive channels, CP rate might be very large in order to maintain the low-complex frequency-domain equalization. In this paper, we propose a novel method that can fit the low latency and high spectral efficiency requirements of future 5G wireless services by eliminating the need for inserting CP between successive OFDM symbols while keeping the whole detection process the same at the receiver side. In order to achieve that, we utilize specially designed alignment signals that can cancel the interference of one symbol on the other and add an additional signal component that makes the signal circularly convolved with the channel at the receiver side. Simulation results prove the superiority of the proposed scheme in terms of enhancing spectral and power efficiency, reducing latency, and improving physical-layer security against eavesdropping while using a low-complexity one-tap frequency-domain equalizer. These numerous, simultaneous, and desirable advantages have the potential to make the proposed technique a suitable fit for future 5G wireless services and applications including Internet of Things-based massive machine-type communication, ultra-reliable and low-latency communication, and enhanced mobile broadband.
  • keywords: {5G mobile communication;equalisers;frequency-domain analysis;OFDM modulation;telecommunication security;wireless channels;Internet of Things-based massive machine-type communication;PHY security;signal component;OFDM symbols;parameterized waveforms;future 5G systems;widely accepted waveform;orthogonal frequency-division multiplexing;enhanced mobile broadband;low-latency communication;one-tap frequency-domain equalizer;physical-layer security;spectral power efficiency;alignment signals;low-complex frequency-domain equalization;CP rate;highly dispersive channels;cyclic prefix;OFDM;Frequency-domain analysis;5G mobile communication;Receivers;Complexity theory;Equalizers;OFDM;cyclic prefix (CP);guard period;5G;spectral efficiency;latency;reliability;physical layer (PHY) security;IoT;mMTC;URLLC;eMBB;PAPR;OOBE;MIMO;complexity},
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  • J. M. Hamamreh and H. Arslan, "Joint PHY/MAC Layer Security Design Using ARQ With MRC and Null-Space Independent PAPR-Aware Artificial Noise in SISO Systems," in IEEE Transactions on Wireless Communications, vol. 17, no. 9, pp. 6190-6204, Sept. 2018.
  • doi: 10.1109/TWC.2018.2855163
  • Abstract: 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.
  • keywords: {access protocols;automatic repeat request;diversity reception;MIMO communication;quality of service;telecommunication security;joint PHY/MAC layer security design;ARQ;SISO systems;automatic-repeat-request;MAC layer mechanism;physical layer mechanism;channel condition;data packet;legitimate receiver;AN-free packet;MRC process;peak-to-average power ratio;Security;Wireless communication;Peak to average power ratio;Quality of service;Throughput;Signal to noise ratio;Cross PHY/MAC layer security;automatic-repeat-request (ARQ);peak-to-average power ratio (PAPR);out-off-band emission (OOBE);artificial noise (AN);maximum ratio combining (MRC);quality of service (QoS);throughput;secure throughput;delay;perfect secrecy;packet error rate (PER)},
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  • A. M. Jaradat, J. M. Hamamreh and H. Arslan, "OFDM With Subcarrier Number Modulation," in IEEE Wireless Communications Letters, vol. 7, no. 6, pp. 914-917, Dec. 2018.
  • doi: 10.1109/LWC.2018.2839624
  • Abstract: A new modulation technique, named orthogonal frequency division multiplexing (OFDM) with subcarrier number modulation, is proposed for efficient data transmission. In this scheme, the information bits are conveyed by changing the number of active subcarriers in each OFDM subblock. The idea behind this scheme is inspired from the integration of OFDM with pulse width modulation, where the width of the pulse represents the number of active subcarriers corresponding to specific information bits. This is different from OFDM with index modulation (OFDM-IM), where the information bits are sent by the indices of the subcarriers instead of their number. The scheme is shown to provide better spectral efficiency than that of OFDM-IM at comparable bit error rate performances. Another key merit of the proposed scheme over OFDM-IM is that the active subcarriers can be located in any position within the subblock, thus enabling channel-dependent optimal subcarrier selection that can further enhance the system performance.
  • keywords: {error statistics;OFDM modulation;pulse width modulation;subcarrier number modulation;active subcarriers;OFDM subblock;specific information bits;index modulation;OFDM-IM;channel-dependent optimal subcarrier selection;orthogonal frequency division multiplexing;data transmission;bit error rate;pulse width modulation;OFDM;Modulation;Noise measurement;Receivers;Detectors;Transmitters;OFDM;subcarrier number modulation;index modulation;spectral efficiency;channel-dependent subcarrier selection},
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  • H. M. Furqan, J. M. Hamamreh and H. Arslan, "Enhancing physical layer security of OFDM systems using channel shortening," 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), Montreal, QC, 2017, pp. 1-5.
  • doi: 10.1109/PIMRC.2017.8292335
  • Abstract: This work presents a simple, spectral and power efficient scheme for providing secure OFDM communication system using channel shortening. The basic concept is to utilize a channel shortening technique, whose design is based on the channel of the legitimate user (Bob), in such a way that the length of the effective channel is made equal to or less than the cyclic prefix (CP) at Bob only, while the length of the effective channel at the illegitimate receiver (Eve) is greater than CP. Thus, this causes inter-symbol-interference (ISI), loss of orthogonality, and overall performance degradation at Eve. The simulation results show that the presented technique can provide a significant BER performance gap between Bob and Eve, and can provide Quality of Service (QoS) based security. The design is shown to be robust against channel imperfections and can provide spectral and power efficiency beside enhancing security.
  • keywords: {error statistics;intersymbol interference;OFDM modulation;quality of service;radio spectrum management;telecommunication power management;telecommunication security;OFDM systems;channel shortening technique;channel imperfections;power efficiency;physical layer security;OFDM communication system;quality of service;spectral efficient scheme;QoS;cyclic prefix;Security;OFDM;Transmitters;Wireless communication;Quality of service;Frequency-domain analysis;Receivers},
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  • J. M. Hamamreh and H. Arslan, "Time-frequency characteristics and PAPR reduction of OTDM waveform for 5G and beyond," 2017 10th International Conference on Electrical and Electronics Engineering (ELECO), Bursa, 2017, pp. 681-685.
  • Abstract: This paper provides an in-depth investigation and analysis on the characteristics of channel-based transform waveforms and their differences from Fourier transform-based waveforms. Particularly, the basis functions of the recently proposed orthogonal transform division multiplexing (OTDM) waveform, which belongs to the category of channel-based transform waveforms, are comprehensively compared with the fixed exponential basis functions of orthogonal frequency division multiplexing (OFDM) waveform, which pertains to the class of Fourier transform-based waveforms. The obtained results show significant differences in the time and frequency characteristics of both classes of the waveforms. Also, the peak-to-average power ratio (PAPR) of OTDM is investigated and compared to OFDM. Then, a new effective technique, referred to as OTDM with edge subcarrier dedication (OTDM-ESD), is proposed for PAPR reduction by exploiting the special characteristics of the effective channel response in OTDM waveform. Simulation results show that the proposed OTDM-ESD technique not only reduces the PAPR, but also enhances the BER performance significantly.
  • keywords: {5G mobile communication;channel allocation;error statistics;multiplexing;transforms;orthogonal transform division multiplexing;channel-based transform waveforms;edge subcarrier dedication;OTDM-ESD technique;fixed exponential basis functions;OTDM waveform;PAPR reduction;time-frequency characteristics;Transforms;Peak to average power ratio;Time-frequency analysis;Shape;5G mobile communication},
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  • J. M. Hamamreh, H. M. Furqan, Z. Ali and G. A. S. Sidhu, "An Efficient Security Method Based on Exploiting Channel State Information (CSI)," 2017 International Conference on Frontiers of Information Technology (FIT), Islamabad, 2017, pp. 288-293.
  • doi: 10.1109/FIT.2017.00058
  • Abstract: A channel amplitude quantization method that can effectively quantize the channel response using just one single threshold value is proposed in order to extract a random manipulating sequence with good secrecy properties. Specifically, a Time Division Duplex (TDD) wireless system is considered over independent identical distributed (i.i.d.) Rayleigh fast fading channel, where potential passive eavesdroppers (Eves) can only estimate their own channel and have no knowledge about CSI between legitimate communication parties. The transmitter (Alice) is only aware of the CSI of the legitimate user (Bob). Particularly, the proposed security technique takes the bits of the transmitted data packets and manipulate them with a logical vector that characterizes the channel randomness based on the estimated CSI gain. The process of manipulation is implemented on a bit level basis using an XOR operation exactly before modulation process. The same XOR operation is implemented after demodulation process on the detected bits to extract the concealed bits. The obtained simulation results show that the employment of such mechanism can ensure data confidentiality. Furthermore, the simulation results are extended to include the effect of the selected quantization threshold on the BER performance of Eve as well as the amount of information leakage to its side. It is shown that security gap region between Bob and Eve is made very large over all expected Signal to Noise ratio (SNR) values despite the small degradation in the bit error rate (BER) performance of Bob because of the expected channel estimation errors due to noise.
  • keywords: {channel estimation;error statistics;fading channels;quantisation (signal);Rayleigh channels;telecommunication security;wireless channels;channel amplitude quantization method;channel response;single threshold value;random manipulating sequence;good secrecy properties;Time Division Duplex wireless system;Rayleigh fast fading channel;potential passive eavesdroppers;Eve;legitimate communication parties;Bob;security technique;transmitted data packets;logical vector;channel randomness;estimated CSI gain;bit level basis;XOR operation;modulation process;demodulation process;detected bits;data confidentiality;selected quantization threshold;information leakage;security gap region;Noise ratio values;bit error rate performance;expected channel estimation errors;exploiting channel state information;Security;Channel estimation;Fading channels;Wireless communication;Transmitters;Receivers;Communication system security;Security;Channel State Information},
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  • J. M. Hamamreh, H. M. Furqan, Z. Ali and G. A. S. Sidhu, "Enhancing the Security Performance of OSTBC Using Pre-Equalicodization," 2017 International Conference on Frontiers of Information Technology (FIT), Islamabad, 2017, pp. 294-298.
  • doi: 10.1109/FIT.2017.00059
  • Abstract: In this study, we first quantify the secrecy performance achieved by employing precoded orthogonal space time block coding (POSTBC) in order to use it as a benchmark for comparison purposes with a new proposed security scheme. In POSTBC, space time codewords are precoded before being transmitted with an optimum pre-coding matrix based on the main channel of the legitimate parties. The obtained results demonstrate a considerable secrecy gap region in the resulting bit error rate (BER) performance due to using POSTBC. Afterwards, a new method called pre-equlicodization (precoding along with semi pre-equalization) is proposed to further enhance the secrecy performance. In pre-equlicodization scheme, the transmitted symbols are precoded by a new modified matrix called pre-equalicodizing matrix. This matrix is built by manipulating each row element in the optimal selected precoding matrix by the corresponding amplitude square inverse of the estimated channel gain over each data stream. The comparative simulation results prove that the employment of the proposed method can provide robustness against eavesdropping while assuring confidentiality and reliability between the legitimate communication parties albeit Eve is considered to have full knowledge of the used method, but not the main channel since TDD is adopted.
  • keywords: {antenna arrays;block codes;channel coding;channel estimation;error statistics;matrix algebra;MIMO communication;OFDM modulation;orthogonal codes;precoding;radio networks;space-time block codes;space-time codes;telecommunication security;wireless channels;security performance;OSTBC using pre-equalicodization;secrecy performance;precoded orthogonal space time block coding;POSTBC;security scheme;space time codewords;optimum pre-coding matrix;legitimate parties;considerable secrecy gap region;resulting bit error rate performance;semipre-equalization;pre-equlicodization scheme;transmitted symbols;modified matrix;pre-equalicodizing matrix;corresponding amplitude square inverse;estimated channel gain;legitimate communication parties;Security;Precoding;Wireless communication;Communication system security;Receivers;Channel estimation;Wireless sensor networks;security;Pre Equalicodization},
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  • J. M. Hamamreh, E. Basar and H. Arslan, "OFDM-Subcarrier Index Selection for Enhancing Security and Reliability of 5G URLLC Services," in IEEE Access, vol. 5, pp. 25863-25875, 2017.
  • doi: 10.1109/ACCESS.2017.2768558
  • Abstract: An efficient physical layer security technique, referred to as OFDM with subcarrier index selection (OFDM-SIS), is proposed for safeguarding the transmission of OFDM-based waveforms against eavesdropping in 5G and beyond wireless networks. This is achieved by developing a joint optimal subcarrier index selection (SIS) and adaptive interleaving (AI) design, which enables providing two levels (sources) of security in time division duplexing (TDD) mode: one is generated by the optimal selection of the subcarrier indices that can maximize the signal-to-noise ratio at only the legitimate receiver, while the other is produced by the AI performed based on the legitimate user's channel that is different from that of the eavesdropper. The proposed scheme not only provides a remarkable secrecy gap, but also enhances the reliability performance of the legitimate user compared with the standard OFDM scheme. Particularly, a gain of 5-10 dB is observed at a bit error rate value of 10-3 compared with standard OFDM as a result of using the adaptive channel-based subcarrier selection mechanism. Moreover, the proposed technique saves power, considers no knowledge of the eavesdropper's channel, and provides secrecy even in the worst security scenario, where the eavesdropper can know the channel of the legitimate link when an explicit channel feedback is used as is the case in frequency division duplexing systems. This is achieved while maintaining low complexity and high reliability at the legitimate user, making the proposed scheme a harmonious candidate technique for secure 5G ultra reliable and low latency communications (URLLC) services.
  • keywords: {5G mobile communication;error statistics;OFDM modulation;radio receivers;telecommunication security;time division multiplexing;wireless channels;OFDM-subcarrier index selection;enhancing security;5G URLLC services;efficient physical layer security technique;OFDM-SIS;AI;time division duplexing mode;optimal selection;subcarrier indices;signal-to-noise ratio;legitimate receiver;legitimate user;eavesdropper;reliability performance;standard OFDM scheme;adaptive channel;subcarrier selection mechanism;worst security scenario;legitimate link;explicit channel feedback;frequency division duplexing systems;noise figure 5.0 dB to 10.0 dB;OFDM;Indexes;Security;5G mobile communication;Receivers;Physical layer;Bit error rate;OFDM with subcarrier index selection (OFDM-SIS);physical layer security;eavesdropping;interleaving;5G;adaptive subcarrier selection;URLLC;FDD;TDD},
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  • J. M. Hamamreh, H. M. Furqan and H. Arslan, "Secure pre-coding and post-coding for OFDM systems along with hardware implementation," 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), Valencia, 2017, pp. 1338-1343.
  • doi: 10.1109/IWCMC.2017.7986479
  • Abstract: An effective and hardware-friendly physical layer security design, composed of a channel-based frequency pre-coder and a post-coder for OFDM-based systems, is proposed. The design is achieved by decomposing the diagonal matrix of the channel frequency amplitude of the legitimate receiver in order to obtain two unitary orthonormal matrices. The first matrix is used as a pre-coder just before the IFFT process at the transmitter, while the second matrix is used as a post-coder just after the FFT process at the receiver. Besides security, the presented design is interestingly found out to work as a shuffler or inter-leaver, which does not only provide secrecy, but also enhances the performance against burst errors. Moreover, a new channel calibration technique is developed to overcome the effect of channel reciprocity mismatch on the proposed scheme. The provided simulations and USRP hardware testbed implementation results validate the effectiveness of the proposed design in achieving practical and reliable secrecy with just minor modifications on the OFDM structure.
  • keywords: {calibration;matrix decomposition;OFDM modulation;precoding;radio receivers;telecommunication security;wireless channels;secure precoding;secure post-coding;OFDM-based systems;hardware-friendly physical layer security design;channel-based frequency pre-coder;post-coder;diagonal matrix decomposition;channel frequency amplitude;legitimate receiver;unitary orthonormal matrices;IFFT process;channel calibration technique;reciprocity mismatch;USRP hardware testbed implementation results;OFDM;Matrix decomposition;Receivers;Physical layer;Hardware;Network security},
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  • H. M. Furqan, J. M. Hamamreh and H. Arslan, "Secure communication via untrusted switchable decode-and-forward relay," 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), Valencia, 2017, pp. 1333-1337.
  • doi: 10.1109/IWCMC.2017.7986478
  • Abstract: In this paper, a practical power efficient technique is proposed for an untrusted decode-and-forward (DAF) based cooperative communication system to provide secure communication between the source and the destination. More specifically, a DAF relay, called switchable DAF (sDAF), is designed in such a way that it can be switched to amplify-and-forward (AAF) in certain predefined situations. The algorithm is based on destination-assisted jamming and comprised of two phases. The first phase securely shares the random manipulating sequence (RMS) through an untrusted relay, while the second phase uses this RMS for secure communication through untrusted relay. This algorithm not only provides secrecy, but also enhances the power efficiency as compared to other destination-assisted jamming techniques.
  • keywords: {amplify and forward communication;cooperative communication;decode and forward communication;jamming;relay networks (telecommunication);secure communication;untrusted switchable decode-and-forward relay;amplify-and-forward;random manipulating sequence;RMS;power efficiency;destination-assisted jamming techniques;Relays;Jamming;Switches;Interference;Channel estimation;Security;Cooperative communication;Phy-security;jamming;untrusted relay;secure DAF},
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  • J. M. Hamamreh and H. Arslan, "Secure Orthogonal Transform Division Multiplexing (OTDM) Waveform for 5G and Beyond," in IEEE Communications Letters, vol. 21, no. 5, pp. 1191-1194, May 2017.
  • doi: 10.1109/LCOMM.2017.2651801
  • Abstract: In this letter, a secure waveform design for future 5G wireless system is proposed. The developed waveform referred to as secure orthogonal transform division multiplexing (OTDM) waveform, is designed to diagonalize the multi-path channel matrix of only the legitimate receiver (Bob), while degrading eavesdropper’s reception. In particular, instead of using fixed exponential basis functions, generated by IFFT and FFT as in OFDM, orthogonal transform basis functions, which are extracted from the Bob’s channel, are utilized to modulate and demodulate the data symbols securely. The simulation results prove that the proposed design provides a significant practical security gap between the Bob’s and Eve’s performance. The design is shown to be robust against channel imperfection, and it neither sacrifices communication resources nor considers any knowledge on the eavesdropper’s channel. Besides security, the scheme results in a higher SNR, leading to a 3-5-dB gain over OFDM at BER = ${10^{-3}}$ .
  • keywords: {Transforms;OFDM;Receivers;Security;Data mining;5G mobile communication;Channel-based transforms;orthogonal transform division multiplexing (OTDM);physical layer security;secure 5G waveforms},
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  • H. M. Furqan, J. M. Hamamreh and H. Arslan, "Secret key generation using channel quantization with SVD for reciprocal MIMO channels," 2016 International Symposium on Wireless Communication Systems (ISWCS), Poznan, 2016, pp. 597-602.
  • doi: 10.1109/ISWCS.2016.7600974
  • Abstract: The generation of secret keys from reciprocal wireless channel by exploiting their randomness nature, is an emerging area of interest to provide secure communication. One of the main challenges in this domain is to increase the secret key length, extracted from the shared channel coefficients between two legitimate communication parties, while maintaining its randomness and uniformity. In this work, we develop a practical key generation method, based on channel quantization with singular value decomposition (CQSVD), which is capable of significantly increasing the generated secret key in MIMO systems. This is achieved through quantizing the phases and amplitudes of the estimated MIMO channel coefficient's matrix by using an alternative form of SVD, where the key sequence is extracted from the orthogonal basis functions of the decomposed channel. In this method, it is shown that for an M ×M antenna system, with M2 independent channel fading coefficients, a secret key sequence of length 2M3 can be generated. The extracted key sequence is transformed to a random phase sequence, which is then used to manipulate the transmitted data on a symbol level basis rather than bit level-basis, to provide more secure communication. The comparative simulation results show that the proposed CQSVD method outperforms the state of the art secret key generation methods.
  • keywords: {channel estimation;cryptography;fading channels;MIMO communication;quantisation (signal);random sequences;singular value decomposition;telecommunication security;wireless channels;secret key generation method;channel quantization;reciprocal MIMO channels;reciprocal wireless channel;communication security;secret key length;shared channel coefficients;legitimate communication party;singular value decomposition;phase quantization;estimated MIMO channel coefficient matrix;orthogonal basis functions;decomposed channel;antenna system;independent channel fading coefficients;secret key sequence;extracted key sequence;random phase sequence;symbol level basis;bit level-basis;CQSVD method;Matrix decomposition;Channel estimation;MIMO;Encryption;Antennas;Quantization (signal);Fading channels},
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  • J. M. Hamamreh, M. Yusuf, T. Baykas and H. Arslan, "Cross MAC/PHY layer security design using ARQ with MRC and adaptive modulation," 2016 IEEE Wireless Communications and Networking Conference, Doha, 2016, pp. 1-7.
  • doi: 10.1109/WCNC.2016.7564987
  • Abstract: In this work, Automatic-Repeat-Request (ARQ) and Maximal Ratio Combination (MRC), have been jointly exploited to enhance the confidentiality of wireless services requested by a legitimate user (Bob) against an eavesdropper (Eve). The obtained security performance is analyzed using Packet Error Rate (PER), where the exact PER gap between Bob and Eve is determined. PER is proposed as a new practical security metric in cross layers (Physical/MAC) security design since it reflects the influence of upper layers mechanisms, and it can be linked with Quality of Service (QoS) requirements for various digital services such as voice and video. Exact PER formulas for both Eve and Bob in i.i.d Rayleigh fading channel are derived. The simulation and theoretical results show that the employment of ARQ mechanism and MRC on a signal level basis before demodulation can significantly enhance data security for certain services at specific SNRs. However, to increase and ensure the security of a specific service at any SNR, adaptive modulation is proposed to be used along with the aforementioned scheme. Analytical and simulation studies demonstrate orders of magnitude difference in PER performance between eavesdroppers and intended receivers.
  • keywords: {adaptive modulation;automatic repeat request;diversity reception;quality of service;Rayleigh channels;telecommunication security;cross MAC-PHY layer security design;ARQ;MRC;adaptive modulation;automatic repeat request;maximal ratio combination;wireless service confidentiality;security performance;packet error rate formula;PER formula;physical-MAC layer security design;quality of service;Rayleigh fading channel;Security;Measurement;Receivers;Modulation;Wireless communication;Fading channels;Decoding},
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  • J. M. Hamamreh, E. Guvenkaya, T. Baykas and H. Arslan, "A practical physical-layer security method for precoded OSTBC-based systems," 2016 IEEE Wireless Communications and Networking Conference, Doha, 2016, pp. 1-6.
  • doi: 10.1109/WCNC.2016.7564990
  • Abstract: In this work, we investigate the security performance obtained by employing a practical precoded orthogonal space time block coding method (POSTBC) in MISO wireless networks. In particular, space time codewords are precoded with an optimum matrix that minimizes the error rate at only the legitimate user (Bob). The acquired results depict that there exists a security gap region in the resulting BER performance as a consequence of using POSTBC. Moreover, we enhance the performance more by developing a new hybrid and green security method called precoding along with partial pre-equalizing (PCPPE). In this method, the transmitted symbols are precoded by a new precoder composed of both the original precoder and a new designed unitary matrix that maps Bob's channel amplitudes or phases estimated over the transmitting antennas into 2D orthonormal matrix. Additionally, three issues associated with the proposed security method have been tackled. Including: the slight increase in the transmit power, the appropriate selection process of the optimal precoding matrix, and the effect of imperfect channel estimation and reciprocity. The comparative simulation results prove that PCPPE method provides a secure link among the legitimate parties without sacrificing Bob's reliability although an eavesdropper is assumed to be fully aware of the used method and the original selected precoding matrix indicator (PMI).
  • keywords: {channel estimation;equalisers;matrix algebra;optimisation;orthogonal codes;precoding;radio networks;space-time block codes;telecommunication network reliability;telecommunication security;transmitting antennas;practical physical-layer security method;precoded OSTBC-based systems;precoded orthogonal space time block coding method;MISO wireless networks;space time codewords;error rate minimization;legitimate user;security gap region;BER performance;green security method;precoding-partial pre-equalizing method;PCPPE method;transmitted symbol precoding;unitary matrix;channel amplitude estimation;channel phase estimation;transmitting antennas;2D orthonormal matrix;transmit power;optimal precoding matrix;imperfect channel estimation;secure link;reliability;precoding matrix indicator;PMI;Security;Precoding;Wireless communication;Channel estimation;Receivers;MIMO;Communication system security},
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