Multi-hop Communication System Research Articles

Challenges of the Promise of Internet of Things (IoT) in Multi-Hop Communication Systems

Challenges of the Promise of Internet of Things (IoT) in Multi-Hop Communication Systems

Multihop DF Relaying in NB-PLC System Over Rayleigh Fading and Bernoulli–Laplacian Noise

In this paper, we consider a decode-and-forward relay-assisted multihop power-line communication (PLC) system. The statistics of the end-to-end signal-to-noise ratio (SNR) in the destination are studied considering the Gaussian-distributed background and Laplacian-distributed impulsive noises. Using the statistics of the instantaneous SNR, the performance of the considered narrowband (NB) PLC system is analyzed. Particularly, new expressions are derived for the outage probability and end-to-end average bit-error-rate. Moreover, the average channel capacity is also obtained. The analytical results are corroborated through Monte Carlo simulations.

Multi-Hop D2D Communications With Network Coding: From a Performance Perspective

Multi-hop device-to-device (D2D) communications play an important role in expanding D2D coverage. In this paper, we study a relay-based and network-coding-assisted (in particular, XOR coding) multi-hop D2D communication system. In the system, toward jointly considering the impact of interference and network traffic conditions on the quality of D2D communications, various channel fading models and traffic models are investigated, and the packet loss probability of D2D links is meticulously computed using these models. With the packet loss probability of D2D links, the general closed-form expressions of end-to-end packet loss probability (E2EPLP) of the system with the presence (or absence) of XOR coding are subsequently derived. Our experiments reveal that both the number of relays and the mechanism of XOR coding can affect the system performance. Specifically, the increase in the number of relays will lower the overall system performance (e.g., an increase in the E2EPLP and end-to-end completion time, and a decrease of the end-to-end rate may follow as a result). On the other hand, although the presence of XOR coding unfortunately raises the system E2EPLP, it can effectively improve the end-to-end completion time and end-to-end rate. It is our belief that the analytical approach proposed in this paper and the results found in our work can be useful to peer studies in the context of applying network coding in multi-hop D2D networks.

Application of Bluetooth in Mine Gas Information Transmission

In order to solve the problem of information transmission, such as underground gas concentration, etc. Using Bluetooth Multi-hop Communication Technology based on VoWPAN, the feasibility of using Bluetooth multi-hop communication system to transmit data on aircraft is analyzed from three aspects: the transmission characteristics of radio in mine roadway, the construction of Bluetooth communication system and the Bluetooth multi-hop communication system mounted on aircraft. The most advanced detection vehicle is responsible for collecting data, and Bluetooth in the middle of the vehicle acts as a relay system. Theoretical research shows that this communication system has a good guiding effect on the downhole detection and rescue of aircraft.

Performance Analysis of Relay Assisted Multihop Coherant OFDM System over Malaga Distribution with Pointing Errors

Abstract This paper presents a multi-hop coherent orthogonal frequency division multiplexing free space optical communication system (OFDM-FSO) model which includes a relay transmission mode of decode and forward (DF) over Malaga disrubution (M) and we analyse the results by deriving mathematical expressions for average bit error rate (BER) and outage probability. And the FSO link is characterized by path loss, pointing errors and atmospheric turbulence and also weather conditions like clear air, haze, light fog have been considered in the channel model. The BER and outage probability of the proposed system are examined including the effects of pointing errors and weather conditions. From this work, we can justify that with multi-hop configuration coverage area and signal power improves which bolsters the usage of relay in FSO communication for efficient and reliable system design.

Performance analysis of multi-hop wireless communication systems over [formula omitted] channel

In this paper, expressions of tth-Moment and Moment Generating Function for instantaneous Signal to Noise Ratio of α−η−κ−μ fading channel have been derived. The derived expressions have been used to obtain Amount of Fading, Average Bit Error Rate (ABER) and Average Channel capacity for wireless communication system. Moreover, for multi-hop communication, Source to Sink Average Bit Error Rate (S2S-ABER) has been obtained for two special cases, (i) links with independent and identical distributions and (ii) links with independent and non-identical distributions.

For More Energy-Efficient Dual-Hop DF Relaying Power-Line Communication Systems

Energy efficiency in multihop cooperative power-line communication (PLC) systems has recently received considerable attention in the literature. In order to make such systems more energy efficient, this paper proposes a relaying technique equipped with energy-harvesting capabilities. More specifically, we consider a dual-hop decode-and-forward (DF) broadband PLC relaying system in which the relay exploits the high noise inherent in PLC channels to further enhance energy efficiency; this system will be referred to as DF with energy harvesting (DF-EH). This study deploys, particularly, the time-switching relaying protocol for energy harvesting. An accurate analytical expression for the energy efficiency and a closed-form expression for the average outage probability of the proposed system are derived and then verified with Monte Carlo simulations. For the sake of comparison and to highlight the achievable gains, we also analyze the energy-efficiency performances and the average outage probabilities of the conventional DF relaying system, i.e., without energy harvesting, as well as that of the direct-link approach. Furthermore, various frequency selection and power allocation strategies, namely, optimal frequency selection, random frequency selection, and equal power allocation, exploiting the multiple power cables, are studied. Then, the impact of several system parameters such as the energy-harvesting time factor, various idle power consumption profiles, relay location, power allocation as well as different noise scenarios are examined. The results reveal that the proposed DF-EH system is able to provide energy efficiency improvements of more than 30% compared to the conventional DF relaying scheme. It is also shown that the proposed system with optimal frequency selection performs better at low SNR, whereas at high SNR the equal power allocation based system will have the best performance.

A Dual Ring Connectivity Model for VANET Under Heterogeneous Traffic Flow

Vehicular ad-hoc network (VANET) is characterized as a highly dynamic wireless network due to the dynamic connectivity of the network nodes. To achieve better connectivity under such dynamic conditions, an optimal transmission strategy is required to direct the information flow between the nodes. Earlier studies on VANET’s overlook the characteristics of heterogeneity in vehicle types, traffic structure, flow for density estimation, and connectivity observation. In this paper, we have proposed a heterogeneous traffic flow based dual ring connectivity model to enhance both the message disseminations and network connectivity. In our proposed model the availability of different types of vehicles on the road, such as, cars, buses, etc., are introduced in an attempt to propose a new communication structure for moving vehicles in VANETl under cooperative transmission in heterogeneous traffic flow. The model is based on the dual-ring structure that forms the primary and secondary rings of vehicular communication. During message disseminations, Slow speed vehicles (buses) on the secondary ring provide a backup path of communication for high speed vehicles (cars) moving on the primary ring. The Slow speed vehicles act as the intermediate nodes in the aforementioned connectivity model that helps improve the network coverage and end-to-end data delivery. For the evaluation and the implementation of dual-ring model a clustering routing scheme warning energy aware cluster-head is adopted that also caters for the energy optimization. The implemented dual-ring message delivery scheme under the cluster-head based routing technique does show improved network coverage and connectivity dynamics even under the multi-hop communication system.

Performance study of multi‐hop communication systems with decode‐and‐forward relays over fading channels

In this study, we investigate the performance of multi-hop systems with decode-and-forward relaying over fading channels. Specifically, the authors derive closed-form expressions for the probability density function, cumulative distribution function, and moment generating function of the end-to-end signal-to-noise ratio. In addition, they derive closed-form expressions for the end-to-end capacity (ergodic and outage) and average symbol error rate (coherent and non-coherent) of the system. The derived expressions can be transformed to study the performance of multi-hop communication systems over other well-known fading channel models by using the proper values for the and parameters. Finally, the performance of multi-hop scenario is analysed and investigated using numerical evaluation. Results are provided to illustrate the system's performance and the impact of number of hops and fading parameters on network performance. The derived expressions, in this study, are very important for the prediction of the performance metrics and statistics such that efficient designs of multi-hop wireless systems can be realised.

Outage probability analysis of multi-hop relayed wireless networks over $$\alpha -\mu $$ α - μ fading channels

In this paper, we study the end-to-end outage probability performance of Amplify and Forward (AF) and Decode and Forward (DF) multi-hop wireless communication systems operating over independent but not necessarily identical \(\alpha -\mu \) fading channels. To this end, we derive an expression for the moment generating function of the reciprocal of the end-to-end signal-to-noise ratio, and then use this expression to evaluate the end-to-end outage probability of the AF system by numerically inverting the Laplace transform. We also derive an expression for the end-to-end outage probability of the DF system.

Performance Analysis of Multi-Hop Underwater Wireless Optical Communication Systems

In this letter, we analytically evaluate the end-to-end bit error rate (BER) of point-to-point multi-hop underwater wireless optical communication (UWOC) systems with respect to all degrading effects of the UWOC channel, namely absorption, scattering, and turbulence-induced fading. To do so, we first derive the BER expression of a single-hop UWOC link as the building block for end-to-end BER evaluation. We also apply Gauss–Hermite quadrature formula to obtain the closed-form solution for the system BER in the case of lognormal underwater fading channel. Numerical results demonstrate that multi-hop transmission, by alleviating channel impairments, can significantly improve the system performance and extend the viable end-to-end communication distance.

A Novel Equivalent Definition of Modified Bessel Functions for Performance Analysis of Multi-Hop Wireless Communication Systems

A statistical model is derived for the equivalent signal-to-noise ratio of the Source-to-Relay-to-Destination (S-R-D) link for Amplify-and-Forward (AF) relaying systems that are subject to block Rayleigh-fading. The probability density function and the cumulated density function of the S-R-D link SNR involve modified Bessel functions of the second kind. Using fractional-calculus mathematics, a novel approach is introduced to rewrite those Bessel functions (and the statistical model of the S-R-D link SNR) in series form using simple elementary functions. Moreover, a statistical characterization of the total receive-SNR at the destination, corresponding to the S-R-D and the S-D link SNR, is provided for a more general relaying scenario in which the destination receives signals from both the relay and the source and processes them using maximum ratio combining (MRC). Using the novel statistical model for the total receive SNR at the destination, accurate and simple analytical expressions for the outage probability, the bit error probability, and the ergodic capacity are obtained. The analytical results presented in this paper provide a theoretical framework to analyze the performance of the AF cooperative systems with an MRC receiver.

Outage performance of multihop free-space optical communication system over exponentiated Weibull fading channels with nonzero boresight pointing errors

The outage performance of the multihop free-space optical (FSO) communication system with decode-and-forward (DF) protocol is studied by considering the joint effects of nonzero boresight pointing errors and atmospheric turbulence modeled by exponentiated Weibull (EW) distribution. The closed-form analytical expression of outage probability is derived, and the results are validated through Monte Carlo simulation. Furthermore, the detailed analysis is provided to evaluate the impacts of turbulence strength, receiver aperture size, boresight displacement, beamwidth and number of relays on the outage performance for the studied system.

Multihop FSO Over Exponentiated Weibull Fading Channels With Nonzero Boresight Pointing Errors

The end-to-end (EE) average bit error rate (ABER) performance of a decode-and-forward-based multihop free-space optical communication system is investigated over composite exponentiated Weibull fading channels with nonzero boresight pointing errors considered. In particular, the cumulative distribution function of the aggregated fading channel for non-identically and independently distributed multihop system is derived. Then, the analytical expression of EE ABER with $M$ -ary phase shift keying subcarrier intensity modulation is achieved in terms of Gauss–Laguerre quadrature rule considering aperture averaging effect. The results show that the ABER performance is mainly limited by nonzero boresight pointing errors for larger receiver aperture size. The comparison with Monte Carlo simulation verifies the validity of the proposed ABER model.

Identifying and Averting the MAC Layer Misbehavior in AD-HOC Networks

The all-encompassing nature of the adhoc network and its design architecture in the multi-hop communication system, where trust value of the participant nodes cannot be necessarily taken for granted, is prone to selfish misbehavior by participant nodes. Therefore, the compliance of the MAC layer protocol has become pertinent to the proper functioning of the network. The optimal performance of the network and the judicious and fare usage of network resources can only be achieved by reliable and timely detection of illegitimate protocol operation. In this paper, it is envisaged that the determination factor quantifies the probability of the misbehavior whereas the trust value quantifies the probability of the well-behaved nodes. Thus, these values provide fair insight into the behavioral pattern of any ad-hoc network. The robust detection framework is, therefore implemented to timely notification of the selfish node. Here, the inherent defense mechanism is also incorporated which enhances efficiency, efficacy of the network and provides fare utilization of resources among the nodes. Proposed scheme is validated through simulation results using NS2.

Performance study of terrestrial multi-hop OFDM FSO communication systems with pointing errors over turbulence channels

The free-space optical communication systems attract significant research and commercial interest the last few years, due to their high performance and reliability characteristics along with their, relatively, low installation and operational cost. Moreover, due to the fact that these systems are using the atmosphere as propagation path, their performance is varying according to its characteristics. Here, we present the performance analysis of a serially relayed radio-on-free-space-optical (RoFSO) communication system which employs the orthogonal frequency division multiplexing technique, with a quadrature amplitude modulation scheme, over atmospheric turbulence channels modelled by either the Gamma–Gamma or the Gamma distribution model. For this RoFSO communication link, we derive closed-form mathematical expressions for the estimation of its average bit error rate and outage probability, taking into account the relays’ number, the atmospheric turbulence and the pointing errors effect. Furthermore, for realistic parameter values, numerical results are presented using the derived mathematical expressions, which are verified through the corresponding numerical simulations.

Performance analysis of multihop coherent OFDM free-space optical communication systems

This paper proposes a multihop coherent orthogonal frequency division multiplexing free space optical (OFDM-FSO) communication system model based on a relay transmission mode of decode and forward (DF) with the Gamma-Gamma channel. In the study of atmospheric statistical model, mainly considering the combined action by the following three aspects, they are the light intensity scintillation caused by the atmospheric turbulence, the pointing error caused the transmitter and the receiver without aiming at each other and the path loss. We derived closed-form expressions of outage probability and symbol error rate of the multihop coherent OFDM-FSO system with serial DF relay transmission. We simulated and analyzed the influence of the atmospheric turbulence, the modulation order, the beam width and the jitter factor on the communication interruption performance and bit error performance of the multihop coherent OFDM-FSO system with different number of hops. ©2015 Optical Society of America

Performance of Multihop Wireless Networks in Fading Channels Perturbed by an Additive Generalized Gaussian Noise

In the literature, the performance of multihop wireless networks is extensively analyzed over various fading channels subject to an additive white Gaussian noise (AWGN). However, and to the best of authors’ knowledge, the generalized Gaussian noise case has not been considered before. Motivated by this, we therefore analyze the system performance—in terms of the average bit error rate—of a multihop wireless communication system that operates over the $\alpha$ - $\mu$ fading channels perturbed by an additive white generalized Gaussian noise (AWGGN). To this end, we obtain an exact closed-form expression for the average bit error rate (BER) for $M$ -ary quadrature amplitude modulation ( $M$ -QAM) over the $\alpha$ - $\mu$ fading channels with AWGGN. Some representative numerical results are presented to study the influence of the fading parameters, as well as the influence of the shaping noise parameter. These results are supported with Monte-Carlo simulations to validate our analysis.

Relay Multi-hop Communications for Next Generation Mobile Networks: Investigation of Path-Loss Models

In next generation communication systems, a multi-hop scheme, in which stations between a mobile terminal and a base station relay signal transmissions, seems a promising ap-proach for wide-area coverage and system capacity enhancement. Another prospective benefit for multi-hop scheme is the reduction of transmission power for a link. This reduction is expected by splitting the transmission into a series of hops using the other mobile stations as repeaters which provide a gain from receiver (Rx) to transmitter (Tx). In this way, the transmission power is expected to become less due to the non-linear nature of the path loss. In this work, different path loss models are examined for multi-hop communication systems. Direct communication and the multi-hop communication cases are compared according to different path loss models. The question of how path loss changes by splitting the transmission into a series of sub-paths is also investigated. The investigations show that it is not possible to reduce the path losses except for some cases thus the transmit power. On the other hand using the multi-hop scheme makes possible to increase the coverage area of the network and also reduce the dead spots in the cell.

Multi-hop relay-based maritime visible light communication

This Letter presents a multi-hop relay visible light communication (VLC) system for maritime applications. Maritime VLC systems suffer from limited coverage distance due inherently to the usage of light-emitting diodes and photodetectors. The proposed system employs a multiple of decode-and-forward relays to extend coverage distance in maritime environments. The multi-hop relay based maritime VLC is analyzed under a maritime channel modeled by the JONSWAP spectrum and gamma–gamma distribution. It is found that the use of relays in maritime environments can extend the coverage distance significantly and also improve the performance. In addition, the performance of the system is analyzed using various combining techniques at the receiver to enhance the performance. The maximal ratio combining technique is found to provide superior link quality in maritime environments.