Physical Layer Protocol Research Articles

Jamming Attacks Detection Based on IGWO for Optimization of Fast Correlation-Based Feature extraction in Wireless Communication

Background: Wireless networks are essential communication technologies that prevent cable installation prices and burdens. Because of this technology's pervasive usage, wireless network safety is a significant problem. Owing to distributed and open wireless medium aspects, attackers might use different jamming methods to exploit physical and MAC layer protocol vulnerabilities. In addition, jamming attacks require to be accurately grouped so that suitable countermeasures can be considered. Given the potential severity of such attacks, precisely identifying and classifying them is critical for implementing effective responses. The motivation for this paper is the need to improve the detection and categorization of jamming signals using modern machine learning algorithms, consequently enhancing wireless network security and reliability. Objective: In this paper, we compare some machine learning models' efficiency for diagnosing jamming signals. Methods: Such algorithms refer to support vector machine (SVM) and k-nearest neighbors (KNN). We checked the signal features that recognize jamming signals. After the jamming attack model, the developed grey wolf optimizer version known as IGWO (improved grey wolf optimizer) has been discussed for feature extraction of software usability. Four separate metrics were employed as features to detect jamming attacks in order to evaluate the machine learning models. This novel feature extraction method is crucial for improving the accuracy of jamming detection. Results: The measurements of these parameters were gathered through a simulation of a real setting. And generated a large dataset using these parameters. Conclusion: The simulation results illustrate that the KNN algorithm based on jamming detection could diagnose jammers having a minimal likelihood of false alarms and a high level of accuracy.

Cooperative Communication Based Protocols for Underwater Wireless Sensors Networks: A Review.

Underwater wireless sensor networks are gaining popularity since supporting a broad range of applications, both military and civilian. Wireless acoustics is the most widespread technology adopted in underwater networks, the realization of which must face several challenges induced by channel propagation like signal attenuation, multipath and latency. In order to address such issues, the attention of researchers has recently focused on the concept of cooperative communication and networking, borrowed from terrestrial systems and to be conveniently recast in the underwater scenario. In this paper, we present a comprehensive literature review about cooperative underwater wireless sensor networks, investigating how nodes cooperation can be exploited at the different levels of the network protocol stack. Specifically, we review the diversity techniques employable at the physical layer, error and medium access control link layer protocols, and routing strategies defined at the network layer. We also provide numerical results and performance comparisons among the most widespread approaches. Finally, we present the current and future trends in cooperative underwater networks, considering the use of machine learning algorithms to efficiently manage the different aspects of nodes cooperation.

FPGA implementation of joint synchronization algorithm based on short training sequence

Synchronization processing is a vital component of the Orthogonal Frequency Division Multiplexing (OFDM) receiver, playing a decisive role in determining the performance of the OFDM receiver. Based on the repetitive structure of the Short Training Sequence (STS) in the IEEE 802.11 physical layer protocol data unit, this paper proposes and implements a joint synchronization algorithm to address issues related to data packet detection and coarse frequency offset correction during the synchronization process. Through software simulation and Field-Programmable Gate Array (FPGA) board-level validation, it is concluded that the algorithm ensures performance while, to some extent, conserving FPGA resources.

A study on optimization of polling schedule to minimize the number of frames for in-vehicle UWB wireless network

This paper discusses a polling and scheduling method for UWB-based in-vehicle networks. In IEEE 802.15.4a/z, conveying as much sensor data as possible in a Physical layer Protocol Data Unit (PPDU) is more efficient. Therefore, this paper proposes a scheduling scheme that minimizes the number of frames to be transmitted by adjusting the readout phase of periodic sensor data. Compared to existing methods, our proposed method can aggregate sensor data into fewer frames, resulting in a decreased loss rate in our experiment.

Priority Access in NOMA-Based Slotted ALOHA for Overload 6G Massive IoT

This letter proposes a priority access (PA) in non-orthogonal multiple access (NOMA)-based slotted ALOHA (SA) (PA-NOMA-SA) for overload 6G massive Internet of Things (IoT). First, a NOMA-SA is considered, where devices in massive machine-type communication exploit uncoordinated uplink NOMA for packet transmissions in physical layer and SA protocol in medium access control layer. Second, PA is proposed to prioritize emergency devices over regular devices to keep stable throughput at an overload network condition. Each device estimates the traffic of the IoT network via traffic load estimation and adopts an adaptive traffic load scheme to send packets. The PA controls the load of the IoT network above critical traffic load, and it is demonstrated that by appropriately employing priority access, the normalized throughput is enhanced. Last, the lower-bound of normalized throughput is derived to demonstrate the superiority of PA-NOMA-SA over the existing random access protocol.

From Demodulation to Decoding: Toward Complete LoRa PHY Understanding and Implementation

LoRa, as a representative of Low Power Wide Area Network technology, has attracted significant attention from both academia and industry. However, the current understanding of LoRa is far from complete, and implementations have a large performance gap in SNR and packet reception rate. This article presents a comprehensive understanding of LoRa physical layer protocol (PHY) and reveals the fundamental reasons for the performance gap. We present the first full-stack LoRa PHY implementation with a provable performance guarantee. We enhance the demodulation to work under extremely low SNR (-20 dB) and analytically validate the performance, where many existing works require SNR > 0. We derive the order and parameters of decoding operations, including dewhitening, error correction, deinterleaving, and so on, by leveraging LoRa features and packet manipulation. We implement a complete real-time LoRa on the GNU Radio platform and conduct extensive experiments. Our method can achieve (1) a 100% decoding success rate while existing methods can support at most 66.7%, (2) -142 dBm sensitivity, which is the limiting sensitivity of the commodity LoRa, and (3) a 3,600-m communication range in the urban area, even better than commodity LoRa under the same setting.

Experimental demonstration of entanglement delivery using a quantum network stack

Scaling current quantum communication demonstrations to a large-scale quantum network will require not only advancements in quantum hardware capabilities, but also robust control of such devices to bridge the gap in user demand. Moreover, the abstraction of tasks and services offered by the quantum network should enable platform-independent applications to be executed without the knowledge of the underlying physical implementation. Here we experimentally demonstrate, using remote solid-state quantum network nodes, a link layer, and a physical layer protocol for entanglement-based quantum networks. The link layer abstracts the physical-layer entanglement attempts into a robust, platform-independent entanglement delivery service. The system is used to run full state tomography of the delivered entangled states, as well as preparation of a remote qubit state on a server by its client. Our results mark a clear transition from physics experiments to quantum communication systems, which will enable the development and testing of components of future quantum networks.

Drone Detection and Classification Using Physical-Layer Protocol Statistical Fingerprint

We propose a novel approach for drone detection and classification based on RF communication link analysis. Our approach analyses large signal record including several packets and can be decomposed of two successive steps: signal detection and drone classification. On one hand, the signal detection step is based on Power Spectral Entropy (PSE), a measure of the energy distribution uniformity in the frequency domain. It consists of detecting a structured signal such as a communication signal with a lower PSE than a noise one. On the other hand, the classification step is based on a so-called physical-layer protocol statistical fingerprint (PLSPF). This method extracts the packets at the physical layer using hysteresis thresholding, then computes statistical features for classification based on extracted packets. It consists of performing traffic analysis of communication link between the drone and its controller. Conversely to classic drone traffic analysis working at data link layer (or at upper layers), it performs traffic analysis directly from the corresponding I/Q signal, i.e., at the physical layer. The approach shows interesting properties such as scale invariance, frequency invariance, and noise robustness. Furthermore, the classification method allows us to distinguish WiFi drones from other WiFi devices due to underlying requirement of drone communications such as good reactivity in control. Finally, we propose different experiments to highlight theses properties and performances. The physical-layer protocol statistical fingerprint exploiting communication specificities could also be used in addition of RF fingerprinting method to perform authentication of devices at the physical-layer.

Iterative Equalization of STSK-Aided Single-Carrier Systems: Design and Analysis With Non-Ideal Power Amplifiers

A plethora of new applications will be enabled by next generation wireless networks. These demand sophisticated medium access control and physical layer protocols in order to fulfill the requirements in terms of spectral efficiency, bit error rate (BER), energy efficiency, reliability, and security, among others. This paper develops an advanced space-time multiple-input, multiple-output (MIMO) solution that builds on the concept of space-time shift keying (STSK) for single-carrier frequency domain equalization (SC-FDE). STSK-aided SC-FDE, or SSF, ensures space-time and frequency diversity in dispersive channels, but can only support suboptimal linear receiver schemes. We therefore introduce a turbo equalizer for SSF in frequency-selective multipath channels. It enables inter-symbol-interference cancellation by means of iterative space-time processing. We coin it the iterative space-time block equalizer (SSF-ISTBE). We provide the mathematical formulation for the proposed SSF-ISTBE framework in non-linear channel conditions. We demonstrate that the SSF-ISTBE achieves a substantial 4 dB gain in terms of BER over the linear minimum mean square error equalizer while significantly reducing the computational complexity of the optimal maximum likelihood SSF. When considering practical transceivers, in particular non-linear power amplifiers, the gain of the SSF-ISTBE becomes more prominent over state-of-the-art approaches, demonstrating its robustness against non-linear distortion.

Построение и анализ модели передачи в соте 5G в виде двухфазной системы массового обслуживания с учетом механизма предсказания повторной передачи

The mechanism of early channel adaptation based on e-HARQ (early Hybrid Automatic Repeat reQuest) prediction for the downlink of a mobile network, which solves the problem of improving information transmission characteristics, is studied. The model is a two-phase queuing system (QS). In the QS, at the first phase, the prediction process with the possibility of relaying is modeled, and at the second phase, the process of message processing by the user terminal based on the HARQ physical layer protocol is considered. The HARQ protocol in the 5G network provides the transmitter with an acknowledgment message ACK in case of successful decoding of the packet, and NACK in case of error. Its main disadvantage is the limitation on RTT (Round Trip Time) - the time interval between the initial and retransmission processes. Numerical analysis of the obtained probabilistic-temporal characteristics (PTCR) is carried out. At the first stage, the transition probabilities were found by modeling the link layer of the 5G network. Obtaining realistic values for the transition probabilities allows using this analytical model to analyze and optimize existing e-HARQ prediction schemes. Next, a simulation complex was developed to check the correctness of the analytical model.

Conformal Load-Bearing Antenna Structures-Mechanical Loading Considerations.

One of the important functions of antennas is to facilitate wireless communication. The IEEE 802.11 is part of the IEEE802 set of local area network technical standards, and specifies the media access control and physical layer protocols for implementing wireless local area network computer communication. The network physical layer protocol with a centre frequency of 2.4 GHz has a bandwidth of 22 MHz. A conformal load-bearing antenna structure (CLAS) facilitating this communication band that is tuned to 2.4 GHz must remain within this bandwidth. The aim of this paper is to investigate the effects of mechanical loading imposed on a load-bearing patch antenna with respect to its ability to remain within the specified bandwidth. The mechanical loading configurations considered include tensile, biaxial, and twisting. This paper will also report on the response of the antenna patch to the presence of a disbond between the metallised antenna and its substrate, which can arise due to fabrication anomalies and operational usage. This numerical work will assist in the design of experimental testing of the mechanical and electromagnetic properties of an embedded CLAS, which will ultimately be used to inform selection of appropriate regions to place patch antennas on load-bearing deformable surfaces.

An Implementation Design of Unified Protocol Architecture for Physical Layer of LoRaWAN End-Nodes

LoRa Wide Area Networks (LoRaWAN) can provide a connectivity service to Internet of Things (IoT) for an extremely long run-time and with low power consumption. As the LoRaWAN is extensively applied to various IoT scenarios, LoRaWAN solutions face a flexibility issue in terms of inter-operating with various kinds of LoRa modem hardware and protocol scenarios. In this regard, we design a unified protocol architecture for LoRaWAN physical layer, which can flexibly correspond to various deployment and operational cases. The new protocol architecture includes a hardware abstraction sub-layer, which contains generalized handlers for configuring various kinds of the LoRa modem, and a physical procedure sub-layer that structurally models the physical layer procedures of the LoRaWAN based on Finite State Machine(FSM). We illustrate the flexibility of the new protocol architecture by implementing an extensive feature that enhances the packet reception ratio based on the status of preamble detection. For evaluating the new protocol architecture, we implement the LoRaWAN physical layer protocol on real-time embedded systems and conduct experiments. The experimental results show that the proposed protocol robustly transmits and receives packets and generates little amount of additional burden compared with the conventional open source protocol provided by SemTech.

Advances and Open Problems in Backscatter Networking

Despite significant research in backscatter communication over the past decade, key technical open problems remain underexplored. Here, we first systematically lay out the design space for backscatter networking and identify applications that make backscatter an attractive communication primitive. We then identify 10 research problems that remain to be solved in backscatter networking. These open problems span across the network stack to include circuits, embedded systems, physical layer, MAC and network protocols as well as applications. We believe that addressing these problems can help deliver on backscatter's promise of low-power ubiquitous connectivity.

Internet of Things (IoT) for MC-CDMA-Based Cognitive Radio Network (CRN) in 5G: Performance Results

Both the internet-connected devices, i.e. IoT and Cognitive Radio Network (CRN) are considered to be the future technologies for the fifth generation of cellular wireless standards (5G). On the one hand, Internet of Things (IoT) focuses primarily on how to allow general objects to see, hear, and smell their own physical environment and make them connected to share the observations. On the other hand, a CRN is based on a complex spectrum allocation system, and licenced primary users (PUs) or unlicenced secondary users (SUs) are allowed to share the spectrum, provided they do not cause significant interference. The IoTs are meaningless if IoT objects are not equipped with cognitive radio capability. In cognitive radio, it is important to control the transmission power of SUs so that the interference should not be harmful to the quality of service of PUs. In this paper, the authors addressed the effects of imperfect power control between primary users (PUs) and the secondary users (SUs) of an IoT-based CRN. The effect of the co-channel interference (CCI) and adjacent channel interferences (ACIs) occurring in CRN using MC-CDMA system is also analysed. A new expression of the signal-to-interference-noise ratio (SINR) for CRN-based MC-CDMA system over a Nakagami-[Formula: see text] fading channel with imperfect power control condition is derived and investigated. The performance of IoT-based CRN using MC-CDMA system over the frequency selective multipath fading channel is examined with varying the number of users, the SINR per bit, number of fading path and number of sub-carriers. From the simulation results, we have seen that the SINR performance is affected by these parameters. The result of the analysis will provide relevant information to design the physical layer protocol for high-speed IoT-based CRN system for 5G.

Mobile Performance Evaluation for ATSC 3.0 Physical Layer Modulation and Code Combinations Under TU-6 Channel

This paper presents performance analysis of the Advanced Television Systems Committee (ATSC) 3.0 physical layer protocol in mobile multipath channels. Given the recommended configurations for ATSC 3.0 mobile services, intensive computer simulations as well as laboratory tests are conducted to verify the performance of various modulation and code combinations in ATSC 3.0 physical layer protocol. The results demonstrate that the ATSC 3.0 physical layer can reliably deliver intended mobile services in high-mobility scenarios.

Connectivity probability analysis for freeway vehicle scenarios in vehicular networks

The connectivity probability analysis of vehicular networks can be employed for providing theoretical guidance for both obtaining an accurate real-time traffic information and reducing hazardous traffic situations. Most previous studies focused on analyzing the connectivity probability of vehicular networks in physical (PHY) layer protocol. However, the effects of packet collision in media access control (MAC) layer on the connectivity probability of vehicular networks have been rarely studied, where MAC and PHY layers actually interact on each other. In this paper, some parameters are dynamically set and analyzed under consideration of the influence of MAC and PHY layers on the connectivity probability of vehicular networks. Numerical results are shown to be consistent with the proposed theoretical analysis.

System Imperfections on the Overall Performance of MC-CDMA-Based Cognitive Radio Network (CRN) System

Cognitive radio network (CRN) is considered to be the future technology for the fifth generation of cellular wireless standards (5G). CRN is based on a complex spectrum allocation system, and licensed primary users (PUs) or unlicensed secondary users (SUs) are allowed to share the spectrum, provided that they do not cause significant interference. In cognitive radio, it is important to control the transmission power of SUs so that the interference should not be harmful to the quality of service of PUs. In this paper, the authors addressed the impact of system imperfections on the overall performance of multi-carrier code division multiple access (MC-CDMA)-based CRN system. A new expression of the signal-to-interference-noise ratio (SINR) for MC-CDMA-based CRN system over a Rayleigh fading channel without any power control condition among the PUs and SUs is derived and investigated. The performance of MC-CDMA-based CRN system over the frequency selective multi-path fading channel is examined by varying the number of users, the signal-to-noise-ratio (SNR) per bit, number of fading path and number of subcarriers, respectively. From the simulation results, we have seen that the SINR performance is affected by these parameters. The analysis presented in this paper shows the impact of lack of a controlling mechanism on transmitted signal power affecting the between PUs and SUs ultimately system performance. The result of the analysis will provide relevant information to design the physical layer protocol for high speed CRN system for 5G.

Testing and fingerprinting the physical layer of wireless cards with software-defined radios

Many performance characteristics of wireless devices are fundamentally influenced by their vendor-specific physical layer implementation. Yet, characterizing the physical layer behavior of wireless devices usually requires complex testbeds with expensive equipment, making such behavior inaccessible and opaque to the end user, and complex to perform for wireless researchers. In this work, we propose and implement a new testbed architecture for software-defined radio-based wireless device performance benchmarking. The testbed allows tight control of timing events, at a microsecond time granularity, and is capable of accessing and measuring physical layer protocol features of real wireless devices, which allows to fingerprint the device type with high accuracy. Using the testbed, we measure the receiver sensitivity and signal capture behavior of Wi-Fi devices from different vendors. We identify marked differences in their performance, including a variation of as much as 20 dB in their receiver sensitivity. We further assess the response of the devices to truncated packets and show that this procedure can be employed to fingerprint device types with high consistency in both wired and wireless lab setups using only commodity SDR equipment.

Improving IEEE 802.15.4 performance with a switched Gold sequence chip formation

Low power, low data rate, low complexity wireless networks are among the most preferred ones in the data communication between wireless sensors, IoT devices, and control applications. IEEE 802.15.4 is a well-known standard for low rate wireless personal area networks which specifies only physical layer and media access control layer. However, IEEE 802.15.4 suffers from several limitations that play a role in deteriorating its performance such as using a standard PN sequence for every channel types. Noise level and interference are significant factors that should be taken into consideration for the achievement of successful communication in different channel characteristics. Utilization of a standard PN sequence would not give optimum performance results for every channel types. In this study, we design a IEEE 802.15.4 peer to peer network simulator to compare the performance of standard IEEE 802.15.4 PN chip sequences and generated Gold sequences in terms of data throughput. The results from Monte Carlo simulations show that Gold sequences give better throughputs compared to standard PN sequence of IEEE 802.15.4. However, both chip sequences could not achieve any data transfer for the noisier channels that show a chip error rate greater than 0.18. To overcome this problem, each symbol of the physical layer protocol data unit is matched with a Gold set with greater spreading factors. Obtained results show that, using variable length Gold sets according to operation environment increases the data throughput in IEEE 802.15.4 networks.

Backward Compatible Physical Layer Protocol Evolution for ADS-B Message Authentication

The automatic dependent surveillance-broadcast system is a pillar of the future air traffic control system. It is a surveillance system in which air planes transmit their information (identity, position, velocity, etc.) in broadcast to any listener equipped with a receiver. Networks of ADS-B receivers have been installed all over the world, producing a clear traffic awareness for air traffic controllers. For historical reasons, this protocol does not have any authentication/encryption mechanism. The aim of this article is to improve the ADS-B system security by introducing a physical layer protocol modification for the introduction of an authentication scheme. The proposed evolution fully complies with the current standard and exploits the phase modulation to increase the number of bits that can be transmitted with a single packet of data. These additional bits can be used to carry authentication information, making the overall system more secure (and safe). The proposed protocol evolution is developed ensuring backward compatibility and respecting the ICAO and RTCA recommendations; it can be introduced and used together with the present standard in a mixed scenario, allowing a smooth transition from the present protocol to the new one. Protocol performances were evaluated by simulations and, moreover, its feasibility and compliance with recommendations were tested using a software-defined radio (as transmitter) and a laboratory ADS-B receiver.