Physical Layer Network Research Articles

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.

Communication Technologies for Smart Grid: A Comprehensive Survey.

With the ongoing trends in the energy sector such as vehicular electrification and renewable energy, the Smart Grid (SG) is clearly playing a more and more important role in the electric power system industry. One essential feature of the SG is the information flow over high-speed, reliable, and secure data communication networks in order to manage the complex power systems effectively and intelligently. SGs utilize bidirectional communication to function whereas traditional power grids mainly only use one-way communication. The communication requirements and suitable techniques differ depending on the specific environment and scenario. In this paper, we provide a comprehensive and up-to-date survey on the communication technologies used in the SG, including the communication requirements, physical layer technologies, network architectures, and research challenges. This survey aims to help the readers identify the potential research problems in the continued research on the topic of SG communications.

Enhancing Wireless Sensor Networks Routing Protocols based on Cross Layer Interaction

Wireless sensor networks aim to develop a smart city based on sensing environment. The routing protocols of wireless sensor networks is important to transfer the data in smart cities since sensor nodes have limited power and transmission range. The aim of this research is to enhance wireless sensor networks routing protocols based on proposed cross-layer interaction between physical layer and network layer also a proposed routing table information of wireless sensor nodes is developed to consider the transmission power of neighbor’s nodes to determine the next hop. Cross-layer interaction provides a useful information and effective adaptation for WSN routing protocols. As a result, the proposed routing protocol shows an improvement in network performance when number of intermediate nodes are minimized.

Backscatter Assisted NOMA-PLNC Based Wireless Networks

In this paper, sum capacity maximization of the non-orthogonal multiple access (NOMA)-based wireless network is studied in the presence of ambient backscattering (ABS). Assuming that ABS is located next to far nodes, it improves the signal strength of far node cluster. By applying suitable successive interference cancellation (SIC) operation, far node cluster act as an internet of things (IoT) reader. Moreover, to improve the uplink performance of the nodes, a physical layer network coding (PLNC) scheme is applied in the proposed network. Power optimization is employed at the access point (AP) to enhance the downlink performance with total transmit power constraint and minimum data rate requirement per user constraint using Lagrangian’s function. In addition, end-to-end outage performance of the proposed wireless network is analyzed to enhance each wireless link capacity. Numerical results evident that the outage performance of the proposed network is significantly improved while using the ABS. Furthermore, the average bit error rate (BER) performance of the proposed wireless network is studied to improve the reliability. Simulation results are presented to validate the analytical expressions.

Closed-Form Differential Hierarchical Demodulator of 2-Source Hierarchical-MAC Channel

This letter addresses a problem of differential demodulation in a 2-source Hierarchical MAC (H-MAC) in the context of a Wireless Physical Layer Network Coded system with Hierarchical Decode and Forward strategy. We assume a parametric H-MAC with known attenuations but unknown phases. Component phases have generally strong impact on the resulting superposed constellation which poses high demands on the accuracy of their estimation. In this letter we propose multiple suboptimal closed-form differential demodulation methods which do not require explicit phase estimation and thus substantially simplify the receiver processing. We analyze and compare their performance. Particularly we measure the resulting hierarchical bit error rate for all proposed demodulation methods for different scenarios of a particular symbol alphabet and channel attenuation values. For comparison we include a reference scenario of a fully coherent demodulation.

Amplitude variation phenomenon in optical Physical-layer Network Coding with direct detection

This paper studies the amplitude variation phenomenon in optical physical-layer network coding (OPNC) with intensity modulation and direct detection (IM/DD). Although PNC has been studied thoroughly in wireless communications, the application of PNC to optical communication networks is still challenging. In OPNC, two optical signals are transmitted simultaneously, and the received signals are overlapped in the optical field and then detected by a photo-detector (PD). Previous works assumed the OPNC signal and its electrical signal converted by a PD are linearly related. We find that the relationship is not the case. To fill this gap, we theoretically analyze OPNC and discover that an interference signal is generated when an OPNC signal is converted to its corresponding electrical PNC signal in most conditions. Besides, we implement the simulation and experiment to validate the theoretical analysis. The results coincide with our analysis and indicate that the PNC system does not work when the signal is severely damaged by the interference signal. However, we can recover the PNC signal by filtering the interference signal when their frequency spectrums are not aliasing. We further evaluate the BER performance in the simulation and experiment and found that when the frequency spectrum of the PNC signal is not aliased with the interference signal, using a low-pass filter can improve the BER performance by approximately 12 dB.

Enhanced packet reordering procedure to improve TCP communication

PurposeThe research work is attained by Spurious Transmission–based Enhanced Packet Reordering Method (ST-EPRM). The packet reordering necessity is evaded by presenting random linear network coding process on wireless network physical layer which function on basis of sequence numbers. The spurious retransmission happening over wireless network is obtained by presenting monitoring concept for reducing number of spurious retransmissions because it might need more than three DUPACKs for triggering fast retransmit. This monitoring node performs as centralized node as well variation amid buffer length and number of packets being sent can be predicted. This information helps in differentiating spurious retransmission from the packet loss.Design/methodology/approachBased on transmission detection, action is accomplished whether to retransmit or evade transmission. Monitoring node selection is achieved by presenting improved cuckoo search algorithm. The modified support vector machine algorithm is greatly used for variation-based spurious transmission.FindingsThe research work which is attained by ST-EPRM. The packet reordering necessity is evaded by presenting random linear network coding process on wireless network physical layer which function on basis of sequence numbers. The spurious retransmission happening over wireless network is obtained by presenting monitoring concept for reducing number of spurious retransmissions because it might need more than three DUPACKs for triggering fast retransmit. This monitoring node performs as centralized node as well variation amid buffer length and number of packets being sent can be predicted. This information helps in differentiating spurious retransmission from the packet loss.Originality/valueBased on transmission detection, action is accomplished whether to retransmit or evade transmission. Monitoring node selection is achieved by presenting improved cuckoo search algorithm. The modified support vector machine algorithm is greatly used for variation-based spurious transmission.

Semi-Stochastic Aircraft Mobility Modelling for Aeronautical Networks: An Australian Case-Study Based on Real Flight Data

Terrestrial Internet access is gradually becoming the norm across the globe. However, there is a growing demand for Internet access of passenger airplanes. Hence, it is essential to develop aeronautical networks above the clouds. Therefore, the conception of an aircraft mobility model is one of the prerequisite for aeronautical network design and optimization. However, there is a paucity of realistic aircraft mobility models capable of generating large-scale flight data. To fill this knowledge-gap, we develop a semi-stochastic aircraft mobility model based on large-scale real historical Australian flights acquired both on June 29th, 2018 and December 25th, 2018, which represent the busiest day and the quietest day of 2018, respectively. The semi-stochastic aircraft mobility model is capable of generating an arbitrary number of flights, which can emulate the specific features of aircraft mobility. The semi-stochastic aircraft mobility model was then analysed and validated both by the physical layer performance and network layer performance in the case study of Australian aeronautical networks, demonstrating that it is capable of reflecting the statistical characteristics of the real historical flights.

Wireless Network Coding With Intelligent Reflecting Surfaces

Conventional wireless techniques are becoming inadequate for beyond-5G networks due to latency and bandwidth considerations. To improve the error performance of wireless communication systems, we propose physical layer network coding (PNC) in an intelligent reflecting surface (IRS)-assisted environment. We consider an IRS-aided butterfly network, where we propose an algorithm for obtaining the optimal IRS phases. Analytic expressions for the bit error rate (BER) are derived. Numerical results demonstrate that the proposed scheme significantly improves the BER performance. For instance, the BER at the relay in the presence of a 32-element IRS is three orders of magnitudes less than that without an IRS.

PERFORMANCE OF NETWORK CODING SCHEMES FOR 5G SYSTEM

Huge data rates have been provided by 5G wireless communication systems using millimeter wave (mmWave) band that have frequencies ranging from 30 to 300 GHz. mmWave provides much wider bandwidth than the existing 4G band. The 5G network deals with massive number of devices. This presents many challenges including capacity, end to end delay, data rate, and very large number of connections. In this paper, the main task is to apply network coding to 5G mmWave communication system to increase the throughput of the communication links. Simple packet-based network coding schemes using butterfly network topology are simulated. The two network coding schemes considered here are Physical Layer Network Coding (PLNC) and Network Layer Network Coding (NLNC). Models of Additive White Gaussian Noise (AWGN) and mmWave indoor fading channels are considered in the work using Quadrature Phase Shift Keying (QPSK) modulation. The results of the tests showed that the use of both NLNC and PLNC improved throughput in comparison to uncoded system. Using PLNC increased the Bit Error Rate (BER) and the Packet Error Rate (PER), while NLNC scheme showed almost identical error performance to uncoded system over mmWave fading channel. The results show that network coding improved throughput when compared.

Research on 5G Security Technology for Industrial Internet

5G network has great application potential in the field of industrial Internet. However, the current lack of development of 5G network in the field of security technology restricts its application on the Industrial Internet. In this article, the author combines the industry’s needs for Industrial Internet security, and summarizes the research status of 5G network security technology, gives the development direction of three 5G network security technologies with development potential. This paper found that due to the three end-to-end characteristics of the Industrial Internet: physical security, information security, and system self-healing, there are security requirements; the other three 5G network security technologies, namely lightweight encryption mechanism, physical layer security technology and network slicing security technology will help 5G network be more widely used in the Industrial Internet field.

Performance Analysis of Two-Way Satellite-Terrestrial Relay Network with SWIPT.

In this paper, we investigated the performance of a two-way satellite-terrestrial DF relay network with asymmetric simultaneous wireless information and power transfer (SWIPT). In particular, selective physical-layer network coding (SPNC) was employed in the proposed network, improving the throughput performance. We derived the expressions of system average end-to-end throughput and single node detection (SND) occurrence probability. Furthermore, to observe the effects of the power splitting (PS) coefficient on the energy efficiency performance, the expressions of energy harvested in the physical-layer network coding (PNC) and SPNC protocol were also derived. Finally, theoretical analyses and Monte Carlo simulation results are presented to show: (i) SPNC protocol outperforms the conventional PNC protocol in the two-way satellite-terrestrial relay network with SWIPT in infrequent light shadowing (ILS), average shadowing (AS), and frequent heavy shadowing (FHS) Shadowed-Rician fading channels; (ii) as the channel state gets worse, SPNC protocol can achieve more performance improvement than PNC protocol; (iii) as the PS coefficient increases, the average end-to-end throughput performance increases progressively, and the average energy efficiency performance increases progressively within a certain range, while decreasing in the others.

A Novel Joint Index Modulation and Physical Layer Network Coding Mechanism for Beyond 5G

In beyond 5G communications, besides energy efficiency (EE) and spectral efficiency (SE), latency and reliability are among the main metrics that extreme ultra-reliable low-latency communications (URLLC) applications must fulfill. Although new techniques are sought after to meet the crunching requirements of URLLC, combining existing phys-ical-layer techniques have become a compelling, attractive, and cost saving approach to achieving the same goal. In this article, we describe a novel mechanism combining physical layer network coding (PNC) and index modulation (IM) to achieve a balance between SE and EE for URLLC applications beyond 5G. PNC has the potential to increase SE because it leverages on interference from many transmissions occurring at the same time. Although fewer resources are required for IM the capacity gain is the same as if all transmission resources are used, and as a result, both EE and SE can increase simultaneously. Our simulation results show the feasibility of combining these two key physical-lay-er techniques, affirming the complementary role this approach will play in meeting the performance KPIs of URLLC beyond 5G.

Research on the robustness of interdependent supply networks with tunable parameters

A supply network is considered robust when it can maintain operations and connectedness despite disruptions, and building robust supply networks is one of the challenges in supply chain management. Typically, a supply network is an interdependent supply network (ISN) which consists of an undirected cyber-layer network and a directed physical-layer network. The cascading failure in an ISN can be caused by over-load and loss-dependency failures simultaneously, called hybrid cascading failure (HCF), which is limitedly studied in previous studies. In addition, ISNs are usually characterized by some tunable parameters such as the number of nodes, the number of inter-links, interconnecting patterns, and scaling exponents. However, a generic model that can generate ISNs with all of the aforementioned parameters is not proposed, and hence how these parameters affect the robustness of ISNs when considering HCF is still not clear. Therefore, in this paper, we first propose an ISN model to generate ISNs with the aforementioned tunable parameters, and then study how these parameters affect the robustness of the generated ISNs against random and targeted disruptions when considering HCF. The simulation results mainly show that: (i) an ISN is very vulnerable to disruptions in most cases, and removing a small number of nodes can make it collapse; (ii) the behavior of an ISN is very complex when considering HCF; and (iii) the robustness of an ISN can undergo first- and second-order phase transitions under proper parameters. Our work may be helpful for developing HCF-mitigating strategies and building robust supply networks.

Inter-ONU-communication for future PON based on PAM4 physical-layer network coding

A physical-layer network coding (PNC) based inter-ONU-communication (IOC) scheme is proposed for next generation high-speed PONs which apply four-level pulse amplitude modulation (PAM4). A 25 Gb/s full-duplex and private communication is demonstrated.

Joint timing‐offset and channel estimation for physical layer network coding in frequency selective environments

Joint timing‐offset and channel estimation for physical layer network coding in frequency selective environments

User Selection for NOMA-Based MIMO With Physical-Layer Network Coding in Internet of Things Applications

Nonorthogonal multiple access (NOMA)-based multiple-input-multiple-output (MIMO), which has the potential to provide both massive connectivity and high spectrum efficiency, is considered as one of the efficient techniques for sixth-generation (6G) wireless systems. In massive Internet of Things (IoT) networks, the user-set selection is crucial for enhancing the overall performance of NOMA-based systems when compared with orthogonal multiple access (OMA) techniques. In this article, we propose a user-set selection algorithm for IoT uplink transmission to improve the sum data rate of the NOMA-based MIMO systems. In order to exchange data between the selected IoT pairs, we propose to employ wireless physical-layer network coding (PNC) to further improve the spectral efficiency and reduce the delay to fulfill the requirements of future IoT applications. Performance evaluations are provided based on both the sum data rate and bit error rate for the proposed NOMA-based MIMO with PNC in the considered massive IoT scenarios.

Implementation of Short-Packet Physical-Layer Network Coding

This paper presents the implementation and experimental evaluation of a short-packet physical-layer network coding (PNC) system. Implementation of short-packet PNC systems is challenging. First, short packets may have only a few pilot symbols for synchronization and channel estimation purposes. Increasing the number of pilots increases the overhead; decreasing the number of pilots, on the other hand, degrades the packet error rate performance. Second, many short-packet systems are meant for applications with very stringent delay requirements. Employing advanced but complex PNC channel decoding may result in unacceptable delay due to the processing delay. This work presents a low-complexity and low-overhead physical-layer design of OFDM-based short-packet PNC systems, implemented over the software-defined radio platform. Our design makes use of only a small number of pilots (without separate OFDM preamble symbols) to address issues such as slot synchronization, packet detection, carrier frequency offsets, and mismatched channel state information. Our design employs reduced-complexity XOR channel decoding based code-aided parameter estimation (that includes synchronization and channel estimation) to compensate for the limitations imposed by having a small number of pilots. This is the first demonstration that provides a practical framework for applying PNC to short-packet communications.

Performance Analysis of Physical Layer Network Coding in Massive MIMO Systems With M-QAM Modulations

In this paper, we develop a practical approach for deploying Physical Layer Network Coding (PNC) in multi-user M-Ary Quadrature Amplitude Modulation (M-QAM) Massive Multiple-Input Multiple-Output (MIMO) systems. We formulate a PNC mapping scheme as a function of clusters of estimated summation and difference (SD) of the transmitted symbols from user pairs. Utilizing existing linear detection schemes, such as Zero Forcing (ZF) and Minimum Mean Square Error (MMSE), a cluster of SD symbols are detected using an SD linearly transformed channel matrix. Furthermore, utilizing Maximum a Posteriori (MAP) soft decoding, the SD symbols are mapped to the PNC symbols, leveraging on the PNC symbol that maximizes the likelihood function. For each variant of M-QAM, we derive and simplify a specialization of the generalized PNC mapping function. The error performance results, through simulation, reveal that the proposed PNC scheme achieves twice the spectral efficiency in Massive MIMO, without changing the latter's underlying framework and without any degradation in the bit-error-rate (BER). In fact, our investigation has proved that the BER of the proposed Massive MIMO and PNC is slightly better than that of the conventional Massive MIMO. The feasibility of deploying our proposed PNC scheme in Massive MIMO systems paves way for NC applications to be realized in cellular systems.

Utilizing Interference by Network Coding for Simultaneous Wireless Information and Power Transfer

This letter puts forth a novel way to manage interference in simultaneous wireless information and power transfer (SWIPT) systems by utilizing physical-layer network coding (PNC). We consider multi-user multiple-input single-output (MU-MISO) broadcast channels. Unlike the conventional zero-forcing scheme, the PNC-SWIPT scheme introduced in this letter does not eliminate the interfering signals at the receivers. The PNC-SWIPT scheme cancels out the undesired messages over a finite field during PNC demodulation for information decoding (ID). It preserves the interfering signals which are beneficial energy sources for energy harvesting (EH). Simulation results show that the PNC-SWIPT scheme achieves superior EH performance than conventional interference mitigation schemes, such as zero-forcing (ZF) and maximizing EH precoding (Max EH), while maintaining the same ID performance. The performance improvement of the PNC-SWIPT scheme mainly comes from canceling out the interference at the receivers from the aspect of data by PNC, without eliminating the interfering signals which are beneficial energy sources.