Query: IET communication

title: Performance comparison of two novel relay assisted hybrid FSO/RF communication systems
abstract: In this manuscript, two novel multi hop relay assisted hybrid Free Space Optical Radio Frequency (FSO RF) communication systems are presented and compared. In these structures, RF and FSO links, at each hop, are parallel and send data simultaneously. This is the first time that in a multihop hybrid FSO RF structure, Detect and Forward protocol is used. In the first structure, at each hop, received signals with higher Signal to Noise Ratio (SNR) is selected. But in the second structure, at each hop, received FSO and RF signals are separately detected and forwarded and selection is done only at the last hop. Considering FSO link in Negative Exponential atmospheric turbulence and RF link in Rayleigh fading, for the first time, closed form expressions are derived for Outage Probability (P_out) and Bit Error Rate (BER) of the proposed structures. MATLAB simulations are provided to verify derived expressions. The main motivation of this work is to answer this question that how much is the difference of selection at each hop and selection at the last hop. Results indicate that the structure with selection at each hop has better performance than the structure with selection at the last hop. At different target Outage Probability, selection at the last hop consumes about two times ~3dB) more power than selection at each hop. Both structures are particularly suitable for long range communications. However, selection at each hop, in the cost of more complexity, is recommended for applications which have problem with supplying the required power for communication.

title: Performance Evaluation of Communication Technologies and Network Structure for Smart Grid Applications
abstract: The design of an effective and reliable communication network supporting smart grid applications requires the selection of appropriate communication technologies and protocols. The objective of this study is to study and quantify the capabilities of an advanced metring infrastructure (AMI) to support the simultaneous operation of major smart grid functions. These include smart metring, price induced controls, distribution automation, demand response, and electric vehicle charging/discharging applications in terms of throughput and latency. OPNET is used to simulate the performance of selected communication technologies and protocols. Research findings indicate that smart grid applications can operate simultaneously by piggybacking on an existing AMI infrastructure and still achieve their latency requirements.

title: Performance analysis for non orthogonal multiple access (NOMA) based two way relay communication
abstract: This study analyses the performance of a non orthogonal multiple access based two way relaying system. Analytical expressions are obtained to characterise the outage probability and outage floor of the system for end to end communication over Rayleigh fading channels. Furthermore, results are also presented for the resulting individual user and sum ergodic capacities. A user power allocation technique is proposed for sum rate maximisation with user quality of service constraints by transforming the original non convex problem into a difference of convex program that can be readily solved. Finally, simulation results are presented to authenticate the analytical expressions obtained for the various quantities and illustrate the efficacy of the proposed scheme.

title: Enhancing data rate of molecular communication system using Brownian motion.
abstract: Inter symbol and co channel interferences restrict the capacity of molecular communication (MC) systems. In this study, the effect of these interferences on the data rate of MC systems is investigated to design an efficient MC system. To this end, the authors propose an analytical model for a diffusion based MC system comprised of two nanomachines when they exploit On/Off keying modulation. They model the Brownian motion of molecules in a one dimensional environment as a wiener process and the life expectancy of diffused molecules as an exponential process. First, they consider the inter symbol interference to derive the data rate of the MC system as a function of the receiver decision threshold and the symbol time duration. Hence, they propose an algorithm to obtain the optimal values of MC system parameters. Then, the effect of co channel interference is considered by assuming parallel MC systems. They propose a minimum distance between adjacent MC systems that their co channel interferences effect to be negligible. Moreover, they verify the accuracy of the analytical results by Monte Carlo simulations. Results show a remarkable improvement in the data rate of MC systems. The derived results may find application in nanonetworks where nanomachines connect together to perform complex tasks.

title: Evaluation of next generation low power communication technology to replace GSM in IoT applications
abstract: The large demand for smart metering and control, asset tracking, remote monitoring, and other applications has resulted in the emergence of innovative new internet of things (IoT) low power wide area networks (LPWANs) featuring low power consumption, low cost, high scalability and low data rate transmissions. This article compares the performance of LoRaWAN, Sigfox, and NB IoT as emerging technologies, in terms of power consumption, throughput, scalability, and range. For practical reasons, the comparison also includes cellular GPRS. Although GPRS does not fit the description of LPWAN technologies, it is a legacy method for IoT communications and provides insight into application areas where LPWAN technology can be applied. The study gives a clear comparative overview of the advantages and shortcomings of the various communication networks and highlights the most suitable applications cases for each technology on the basis of the tested metrics.

title: Secrecy performance of a two way communication network with two half duplex DF relays
abstract: In this paper, the authors evaluate the secrecy performance of a two way communication network via two half duplex decode and forward relays under an eavesdropper attacking. The sources (S1 and S2) communicate with each other via the relays in two phases. Due to the directional antennas at the relay, eavesdropper does not eavesdrop from the relay. The eavesdropper only eavesdrops the message from one of two sources at a time, which has higher strength. The total relay power is divided between two relays. An optimal value of power allocation, which minimises the secrecy outage probability (SOP) is derived under equal and different transmit power of both the sources. The optimal value of transmitting power of S1 is obtained for a fixed value of transmitting power of S2. Performance in terms of the SOP increases with increase in transmit power of the sources, supply power for relays while it may decrease with increase in transmit power of one source beyond its optimal value for a given transmit power of the other source and increase in the threshold of global secrecy rate. They derive a closed form expression of SOP of this proposed model. The analytical results are validated by our MATLAB based simulation results.

title: Weighted cooperative reinforcement learning based energy efficient autonomous resource selection strategy for underlay D2D communication
abstract: Underlay Device to Device (D2D) communication is a key technology responsible for high data rate, ultra low latency with high spectral and energy efficiency in 5G cellular networks. But to achieve its full potential, optimal channel allocation and effective co channel interference management must be accomplished. To address this challenge, we propose a multi agent reinforcement learning based autonomous channel selection scheme for D2D communication. The proposed scheme, Weighted Cooperative Q Learning based Resource Selection (WCopQLRS) allows a D2D pair to learn to select a channel from the available resources autonomously. Learning process of each D2D transmitter involves cooperation from neighboring D2D agents by exchanging their latest Q values. An additional parameter called cooperation range is used to determine the neighboring pairs whose Q values can be used for learning the optimal policy. The limited prior information prevents a linear increase in the dimensions of Q value matrix of each learning agent when the number of D2D pairs within the cell is huge. Though WCopQL RS involves additional information exchange among agents as compared to independent learning but also provides improved system throughput and convergence speed. It is shown through simulation results that WCopQL RS outperforms other existing schemes in terms of average D2D user throughput, energy consumption and fairness value.

title: New mobile communication system design for Rayleigh environments based on compressed sensing source coding
abstract: A new end to end communication system is proposed to increase transmission speed, robustness, and security in order to meet the requirements of mobile systems that know an exponentially increasing data amount over time. The design relies on the use of compressed sensing source coding instead of the supported speech coding standards in actual mobile communication systems. The proposed compressed sensing source coding method allows reducing the speech coding complexity by using simple quantisation and binary encoding, saving communication system resources, and encrypting communications without additional costs. The performance of the resulting communication system is evaluated for speech communication via 10 dB Rayleigh environment in terms of perceptual evaluation of speech quality (PESQ) scores and coherence speech intelligibility index (CSII) when convolutional coding, orthogonal frequency division multiplexing, and diversity schemes are used. Results report that for a bit rate of 12.8 kbit/s the proposed scheme achieves fair speech intelligibility justified by a CSII value of 0.5, and offers good output speech quality measure, providing a PESQ of 3.33 for the same bit rate.

title: Survey of cross technology communication for IoT heterogeneous devices
abstract: The ever developing Internet of Things (IoT) drives the prosperity of ubiquitous connections among heterogeneous wireless devices (e.g. WiFi, ZigBee and Bluetooth) that follow different standards. Wireless devices share unlicensed industrial, scientific and medical bands, offering an opportunity for cross technology communication (CTC) where coexistence and cooperation mechanisms of wireless technologies incur the problem of coexistence. This study is purposed to present a rounded state of the art survey on CTC from the hardware perspective, CTC techniques are roughly divided into two types: hardware based and hardware free. In hardware based strategies, a dedicated hardware is required to send information to wireless devices for enabling direct communication. The hardware free schemes, by contrast, enable heterogeneous wireless devices to communicate directly by exchanging information or data without the dedicated hardware. Recent advances in CTC are reviewed in both types by expatiating on how heterogeneous wireless devices are achieving direct communication. The authors compare some CTCs with respect to throughput, communication range, energy efficiency and cost, in addition, they present open research issues of two types.

title: Alleviation of LED nonlinearity impact in visible light communication using companding and predistortion
abstract: In order to suppress the nonlinearity impact of light emitting diodes (LEDs) on the performance of visible light communication (VLC) the combined method including companding and predistortion was proposed in this work. The modified companding and predistortion based on the LED characteristic analysis were used corresponding to the output current input voltage (I V) and light output injected current (L I) nonlinearity, respectively. Using the combined method, the performances of the DC biased optical orthogonal frequency division multiplexing (DCO OFDM) VLC system were analysed. It is demonstrated that the non linear distortion of OFDM transmitted signal is alleviated, thus the received signal quality is increased. As a result, the bit error rate (BER) performance of VLC system is improved obviously by using the combined method of companding and predistortion. Furthermore, the applicability of this combined method is also verified by analysing the nonlinearity suppression of the VLC system using different LED. The results reveal that both the impact from LED's I V and L I nonlinearity can be alleviated using the proposed method combining from companding and predistortion for DCO OFDM VLC system.