Physical Layer Analysis Research Articles

Performance Analysis of Wireless Adhoc Networks in Flat Fading and Frequency Selective Fading channels

This research article presents the probability of error analysis in flat fading and frequency selective fading channels for wireless adhoc networks which can aid mobile sustainable networks. Adhoc networks due to their network arrangement which is not fixed and can exhibit mobility its physical layer analysis metric of probability of error needs to be analysed. Information data transmitted from a source node into a wireless channel due to its multipath propagation can limit the performance determined by the metric of probability of error. Wireless channel experiencing flat fading can have Rayleigh distribution, Rician distribution and frequency selective fading channel can be obtained from the power delay profile (PDP). Simulation results are obtained for wireless adhoc networks in matrix laboratory (MATLAB) using binary phase shift keying (BPSK) modulation scheme in flat fading channel and frequency selective fading channels for assessing wireless adhoc networks which also can exhibit similar conditions in mobile networks. The obtained simulation results can provide significant information where 5G and 6G networks are to be deployed and can aid real time implementation.

Performance analysis of PHY layer for RIS-assisted wireless communication systems with retransmission protocols

Reconfigurable intelligent surface (RIS) is one of the most promising technologies for constructing sixth-generation (6G) wireless networks. It has the capability of controlling the electromagnetic response, thereby improving the communication performance. Current studies about physical (PHY) layer analysis of RIS assisted WLC systems neglect the influence of retransmission protocols. Furthermore, the impacts of traffic rate and limited transit buffer on packet transmission and energy consumption are not considered for RIS assisted WLC systems. Focusing on the above problems, we put forward an insightful model to analyze the PHY layer performance of RIS assisted WLC systems using retransmission protocols. In the modeling process, we firstly provide an E2E (end to end) transmission model for the RIS assisted WLC system. The influence of typical retransmission protocols, containing ARQ (automatic repeat request) and hybrid ARQ (HARQ), channel fading types, frame duration on data transmission are comprehensively taken into consideration. Then, we establish an accurate energy consumption model through analyzing the queueing state of the transmitter with finite buffer size and traffic rate. Based on the above two models, we derive the closed-form expressions of PHY layer metrics for RIS assisted WLC systems considering the impact of retransmission protocols. In addition, we also analyze the bound performance of coverage range and expected power efficiency of RIS assisted WLC system with retransmission protocols. Finally, we evaluate the performance of RIS assisted WLC systems under different retransmission protocols and system parameters, and verify the proposed theoretical model.

Physical (PHY) Layer Analysis of Data Transmission in MIMO Wireless Networks in Line- of-Sight (LoS) Environments

This research paper presents the Physical (PHY) layer analysis of multiple input multiple output (MIMO) systems in line-of-sight environments between a user equipment (UE) and a base station when an information data is transmitted. The data transmission in wireless networks often takes place in non-line-of-sight in urban environments and Line-of-Sight (LoS) in rural environments depending on the bandwidth, power constraints. Using MIMO technology, the data transmission takes place with increased number of transmit and receive antennas which results in reduced signal to noise ratio (SNR) requirement. In this research work, simulation for PHY layer metric of probability of error, mean square error (MSE) for data transmission in MIMO wireless networks is obtained Matrix Laboratory (MATLAB) for LoS environment which follows Rician distribution. Probability of error reduces to a significant extent when the Rician factor increases as the line-of-sight component prevails which also takes lesser power in the lower SNR limits. Further, in MIMO systems also the probability of error and MSE reduces in concatenation with single antenna terminals thereby exploring power control a significant possibility for implementation in massive MIMO and millimeter wave communication systems for 5G and 6G systems.

Hybrid buffer and AWG based add-drop optical packet switch

Abstract Optical packet switching (OPS) exhibits the ability to be utilized as a data transmission technique for next-generation. The core router/switch plays a significant role in packet routing and buffering in OPS. Arrayed waveguide grating (AWG) is realized as a promising core element for fast optical switching, with its intrinsic capacity to achieve wavelength routing of different wavelengths in parallel. This paper proposes an AWG-based add-drop optical packet switch, including a hybrid buffer, to resolve contention among packets. In a hybrid buffer, both optical and electronic buffers are used for the buffering of contending packets. AWGs are affected by crosstalk that can significantly impair system operation. The physical layer analysis is discussed in the presence of crosstalk, and the performance of the switch is evaluated in terms of bit error rate. The desired minimum input power is calculated for the switch’s correct operation for both optical buffer and electronic buffer. Finally, the packet loss probability (PLP) of the hybrid buffer is examined under various buffering conditions. Results reveal that with the increase in the optical power of the input signal, crosstalk power increases linearly for optical and electronic buffers. The increased crosstalk power is higher for electronic buffers than the optical buffer. The use of electronic memory in the hybrid buffer allows the hybrid buffer to increase its buffer size thus, reducing the PLP.

Security Model of Authentication at the Physical Layer and Performance Analysis over Fading Channels

Compared with conventional authentication schemes, which utilize cryptographic mechanisms and operate at an upper layer, authentication at the physical (PHY) layer possesses many advantages, such as, higher information-theoretic security by introducing uncertainty to an adversary, better efficiency, and better compatibility by avoiding any operations at the upper layer. An effective PHY-layer authentication scheme should consider covertness, security, and robustness together. However, in published literature, these three properties have been separately analyzed. This paper proposes a generic security model for PHY-layer authentication, and we design a new systematic metric, which is referred to as the probability of security authentication (PSA). According to the proposed generic security model, we can not only systematically analyze the effect of the parameter of a certain PHY-layer authentication scheme on the final performance, but also fairly compare the performance of different PHY-layer authentication schemes under the same channel conditions at the legitimate and adversary receivers. For performance analysis, the probability of detection (PD) and the probability of false alarm (PFA) of two PHY-layer authentication schemes over fading channels are defined, and their closed-form expressions are well derived. On the basis of the proposed generic security model, a systematic performance comparison between different PHY-layer schemes is provided.

Cascadability analysis of WDM recirculating loop buffer-based switch in optical data networks

Abstract In recent years the development of cloud computing, big data, cell phone application increases day by day and this will increase the work load on the server centers. Once the network traffic increases the power consumption also increases. In recent past, for reducing this power consumption arrayed waveguide grating (AWG) based optical packet switches are proposed. In these switches the physical and network layer analysis has been presented in isolated switch. In the core network to achieve low packet loss probability an effective buffering technique is required into the design of switch. In this paper a recirculating loop buffer based switch is presented, in this switch design for sharing the recirculating buffer, WDM technology is used by the packets. The main advantage of recirculating buffer is that it allows packet priority routing and by using this technique longer duration buffering of packet is achieved. This feature provides the quality of service in optical networks. In this paper, switch is deployed in the network and the performance of switch is measured when multiple switches are cascaded in the network simultaneously. The power analysis of switch is also performed for isolated and cascaded switches. For fixing the size of the switch into the network the concept of graph theory and random graph model is used.

Scheduling and Power Allocation Dampens the Negative Effect of Channel Misreporting in Massive MIMO

We study the sensitivity of multi-user scheduling performance to channel magnitude misreporting in systems with massive antennas. We consider the round-robin scheduler combined with max-min and waterfilling power controls, respectively. We show that user scheduling combined with power allocation, in general, dampens the negative effect of channel misreporting compared to the purely physical layer analysis of channel misreporting without scheduling. We discover several interesting results. First, we observe a periodicity in rate-loss behavior as the number of misreporting users increases. Second, we find that the waterfilling power control is more robust to channel misreporting compared with max-min power control. Third, for homogeneous users with equal average signal-to-noise ratios (SNRs), channel underreporting is harmful but overreporting is beneficial for max-min power control; the opposite impact is found for waterfilling power control. For heterogeneous users with various average SNRs, however, both underreporting and overreporting harm the system for both power control policies, demonstrating the complex interactions across network layers due to channel misreporting.

PCOI: Packet Classification‐Based Optical Interconnect for Data Centre Networks

To support cloud services, Data Centre Networks (DCNs) are constructed to have many servers and network devices, thus increasing the routing complexity and energy consumption of the DCN. The introduction of optical technology in DCNs gives several benefits related to routing control and energy efficiency. This paper presents a novel Packet Classification based Optical interconnect (PCOI) architecture for DCN which simplifies the routing process by classifying the packet at the sender rack and reduces energy consumption by utilizing the passive optical components. This architecture brings some key benefits to optical interconnects in DCNs which include (i) routing simplicity, (ii) reduced energy consumption, (iii) scalability to large port count, (iv) packet loss avoidance, and (v) all-to-one communication support. The packets are classified based on destination rack and are arranged in the input queues. This paper presents the input and output queuing analysis of the PCOI architecture in terms of mathematical analysis, the TCP simulation in NS2, and the physical layer analysis by conducting simulation in OptiSystem. The packet loss in the PCOI has been avoided by adopting the input and output queuing model. The output queue of PCOI architecture represents an M/D/32 queue. The simulation results show that PCOI achieved a significant improvement in terms of throughput and low end-to-end delay. The eye-diagram results show that a good quality optical signal is received at the output, showing a very low Bit Error Rate (BER).

Investigating the impact of P2P trading on power losses in grid-connected networks with prosumers

The extensive financial benefit that a prosumer can reap from participating in P2P trading has been shown to be unprecedented by many recent studies. However, since the actual transfer of electricity occurs over the physical network, a key question that yet to answer is: what is the repercussion of P2P trading on the power losses in grid-connected electricity networks? To this end, this paper presents a detailed physical layer analysis of P2P trading to investigate its impact on the network losses. In this paper, P2P transaction losses is defined as one part of network losses and a strategy is proposed to trace P2P transaction losses using effective nodes’ area concept. The other portion of network losses is labelled as grid contributed losses incurred due to the power supplied by the grid to satisfy other customers within and outside effective nodes’ area. Finally, this paper utilises IEEE 8500-node distribution test feeder to capture the large-scale performance of P2P trading in comparison with the existing case, in which there is no P2P trading. Several case studies are considered and the first category of simulation results demonstrate that the P2P transactions do not change the network losses, compared to the non-P2P scenario, if prosumers do not have power dispatch flexibility. Further, It is observed from the second category of simulation results that flexible power dispatch of P2P prosumers can change the network losses at some time instants of a typical day. However, the variation in 24 h network losses between P2P and non-P2P cases is found to be insignificant for a large-sized distribution network with notable residential customers for a typical sunny day.

Analysis of AWG-Based Optical Data Center Switches

Abstract Optical packet switching (OPS) is an emerging area of research in next-generation datacenter applications. There is an exponential growth in the internet traffic due to applications such as social networking, cloud computing, video streaming, etc. Fiber optical network plays a critical role in various data center (DC) operations. Large bandwidth of the optical fiber made OPS, a promising technology for DCs. Arrayed waveguide gratings (AWGs) are used more frequently in the core of optical packet switches due to its low insertion loss and wavelength dependent routing pattern. Optical switching function can be performed by AWG if each input port is properly equipped with Tunable wavelength converters (TWCs). This paper presents analysis of four optical packet switches namely AWG and Feedback Loop Buffer based switch, AWG and Electronic Memory based switch, Petabit Optical Switch, AWG and Feedback Loop Buffer Loss Compensated based Switch. Switches are analyzed for Bit Error Rate (BER) and energy consumption. The power and noise analysis is performed for calculating the total power required for correct operation of switch and to determine the BER using physical layer analysis. Minimum power level is determined so that received bits are decoded correctly. Energy consumption per bit is also evaluated to identify architecture consuming less energy in the considered architectures.

Bit Error Rate Analysis of Hybrid Buffer-Based Switch for Optical Data Centers

Abstract Data centers are very critical elements which store and distribute data over the Internet. current data centers heavily rely on electronics, and thus require vast amount of power and speed is limited. These limitations can be tackled using optical technology. In general optical devices consume lesser amount of power, and support very high data rates. In this paper, a hybrid buffer-based optical packet switch which can be used in data centers as aggregated or core switches is discussed. The physical layer analysis is presented and performance is measured in terms of bit error rate (BER) obtained at various power levels. The analysis is carried out in presence of crosstalk of various components and for acceptable BER≤10–9, minimum power required for all optical, all electronic and hybrid buffer is evaluated. Finally power penalty is also evaluated which is required to overcome the effect of amplified spontaneous noise (ASE) and components crosstalk.

An Energy Efficient Communication Protocol for Low Power, Energy Harvesting Sensor Modules

Energy consumption has become one of the main parameters in evaluating sensor systems in the IoT market. Long range sensor systems are not an exception. Their application in the outdoor environment makes them an ideal candidate to combine energy harvesting mechanisms with the low power features. Using just low power electric components is not enough to ensure energy efficiency. Techniques and mechanisms for harvesting and saving energy are presented in this paper and in its core, a low power, energy efficient communication protocol is described. The proposed protocol optimizes the way in which information is collected from the environment, packed and transmitted over long distances with minimum energy. It is specially designed for energy constrained sensor modules which rely on energy harvesting. The gathered information is transmitted in a form of two different packet types called Teach-in and Data telegrams, respectively. A detailed structure of these packets and the energy required for transmission is explained in this paper, along with a deeper protocol physical layer analysis. In addition, this paper demonstrates the huge potential for mass market, as a result of the many proposed solutions that have been tested and implemented in a fully developed functioning prototype.

Develop physical layer analysis algorithm for OFDMA signal based IEEE 802.16e

Develop physical layer analysis algorithm for OFDMA signal based IEEE 802.16e

Design of Arrayed Waveguide Grating based Optical Switch for High Speed Optical Networks

This paper demonstrates the design of an Arrayed Waveguide Gratings (AWG) based optical switch. In the design both physical and network layer analysis is performed. The physical layer power and noise analysis is done to obtain Bit Error Rate (BER). This has been found that at the higher bit rates, BER is not affected with number of buffer modules. Network layer analysis is done to obtain performance in terms of packet loss rate and average delay. Analysis presented in the paper clearly reveals that there is a minimum amount of power required, which is necessary for the satisfactory performance of switch both at physical and network layer.

Physical layer analysis of AWG based optical packet switch architecture

Optical packet switching is the next generation switching technique in conjunction with mature electronic switching. In optical packet switching, the core router plays an important role in the routing and buffering of packets. In recent past, AWG based optical router are proposed and heavily investigated due to its very low insertion loss and very simple wavelength dependent routing pattern. In this paper, a further modification in an AWG based optical packet switch is proposed. These modifications improve the signal reception quality at the output. Power budget analysis is presented to evaluate the buffer capacity. As a physical layer parameters, the minimum switch power is evaluated using the mathematical model and at the BER level of 10−9 the maximum buffering capacity is evaluated. Finally, simulation results are presented in terms of network layer parameters, packet loss probability and average delay. The packet loss probability is as low as 10−7 well under acceptable limits.

Heterogeneous Optical Space Switches for Scalable and Energy-Efficient Data Centers

Optical space switches are key elements for the next generation of switching fabrics in backbone routers, high performance computing systems, and large data processing and storage systems. A number of architectures and alternative options for gating elements have been proposed, assessed, and implemented for a limited port count. The challenge is to further enhance the scalability and energy efficiency of space switches to support future traffic loads. This paper proposes a heterogeneous implementation of the space switches based on two different types of gating elements, namely semiconductor optical amplifiers (SOA) and Mach-Zehnder Interferometers (MZI). With respect to the existing homogeneous implementations, a higher energy efficiency can be achieved by minimizing the number of SOAs, but crosstalk is introduced by MZI. To reduce the power consumption while still guaranteeing adequate physical layer performance, the design of both Spanke and multi-stage architectures is optimized by strategically placing the different gating and amplification elements, and a physical layer analysis is carried out to validate the performance. The proposed heterogeneous implementation is able to achieve power savings up to 10% and 50% in the Spanke and multi-stage Benes architectures, respectively, with respect to SOA-based space-switch implementations. Moreover, an improvement of the physical layer performance is achievable in the Spanke architecture thanks to the different placement of the SOAs.

Performance Evaluation of the Loop Buffer Switch under Prioritized Traffic

In this paper, optical loop buffer based architecture is discussed; with its advantages over other architectures. In general the performance of the switch is measured at physical and network layer. The physical layer analysis deals with power budget analysis, however, at the network layer; the performance is measured in terms of packet loss probability and average delay. To obtain more realistic performance at the network layer the QoS parameters need to be included. In this paper, a QoS parameter which is known as priority of the incoming packets is included and corresponding results are presented, and it has been found that even at the load of 0.7, packet loss probabilities on the order of 10 -5 can be achieved.

Towards a Traceability System Based on RFID Technology to Check the Content of Pallets within Electronic Devices Supply Chain

In the last few years there has been a growing interest in smart solutions capable of dealing with the traceability of products and materials to improve logistical processes. Most of the existing solutions have been designed without considering the difficulties of deploying traceability systems in the storehouses currently working, not dealing with specific needs, such as environment characteristics or time required to be handled by workers. In this paper, in order to test the viability of its application, a first prototype of a traceability system capable of checking the content of pallets loaded with electronic devices is presented. It is based on ultra-high frequency (UHF) radio frequency identification (RFID) technology using passive tags. A holistic approach has been adopted to design the system: it begins with a radioelectrical characterization of the environment where the check points will be implemented, continues with the integration of a set of data acquisition and wireless communication devices, and ends with a logistics information system able to provide final user services. The combination of physical layer analysis with a top layer system view can aid the planning as well as operational phase of this type of RFID system within a logistic chain.

Protocol Conversion between PCI-Express and 1553B Bus

1553B bus is designed for aircraft developed an information transmission device bus standard, which is an agreement between devices. PCI Express is built on the PCI standard technology. It has the advantages of fast transmissions and strong reliability, so it can serve as a 1553B bus data transmission interface. The 1553B bus protocol includes data link layer, physical layer, and functional analysis. In the system, large scaled FPGA chip is used as the core. In its internal hardware, there are integrated PCI Express physical layer, while the PCI Express and 1553B bus protocol layer all in the internal FPGA implementation, carried out through the DMA the exchange of data in order to improve system integration. System testing includes f real-time, reliability and fault tolerance. Test results show that the whole system is well suitable for 1553B in the PCI Express environment applications.

Power and scalability analysis of multi-plane optical interconnection networks

The scalability of current electrical interconnection networks will be soon limited by their power consumption and dissipation. To overcome such an issue, multi-plane optical interconnection networks have been proposed. Multi-plane networks are composed of a number of cards, each of them supporting a number of ports, interconnected through a passive optical backplane. Two switching domains are envisioned to be exploited allowing for flexible switching of data packets across all ports and cards. This study considers three different implementations that are representative of the multi-plane optical interconnection networks based on space and wavelength switching. The implementations differ from each other in the switching domain used. The aim of the work is to investigate the power consumption and scalability of the three implementations, based on state-of-the-art 40 Gb/s technology. The physical layer analysis and the power consumption assessment including both electronic and optical components indicate that the implementation can impact on the scalability as well as the power consumption. The arrayed waveguide gratings (AWG)-based implementation is found to suffer from scalability and power consumption issues. On the other hand, an implementation based on active switches shows an energy efficiency similar to the coupler-based implementation, but a four-fold scalability increase.