Dual Relay Research Articles

Performance analysis of joint dual relay selection and physical layer network coding in two-way relay channels

Performance analysis of joint dual relay selection and physical layer network coding in two-way relay channels

Mitigating interference and reducing detection complexity in asynchronous cooperative relay network utilising new distributed space time block coding

The synchronisation in wireless cooperative relay networks is impossible to achieve in real environment utilising orthogonal space time block coding. There have been several approaches proposed to mitigate the effect of synchronisation among the relay nodes at the receiver. All have managed to reduce the inter-symbol interference at the expense of low data rate with high detection complexity. Others achieved full data rate and high cooperative diversity using high decoding complexity that requires a feedback link. In this paper, a new approach is presented that reduces inter-symbol interference, achieves full data rate and full cooperative diversity with low complexity. This uses a new efficient distributed orthogonal space time block coding design with a sub-optimum detection scheme utilising dual relay nodes. This reduces the number of timing misalignments among the relay nodes and minimises the detection complexity. Furthermore, the new proposed method uses linear decoding process to achieve full data rate and full cooperative diversity without the need for any a feedback link. The analytical analysis and simulation results confirmed that sub-optimum approach with the new efficient design are very effective at reducing the lack of synchronisation among the relay nodes at the destination node with low encoding and decoding complexities.

Cooperative Dual Relay Overlay CR NOMA Network with Outdated CSI

Cooperative Dual Relay Overlay CR NOMA Network with Outdated CSI

Secrecy Outage Analysis for Cooperative NOMA Systems With Relay Selection Schemes

This paper considers the secrecy outage performance of a multiple-relay assisted non-orthogonal multiple access (NOMA) network over Nakagami-m fading channels. Two time slots are utilized to transmit signals from the base station to destination. At the first time slot, the base station broadcasts the superposition signal of the two users to all decode-and-forward relays by message mapping strategy. Subsequently, the selected relay transmits superposition signal to the two users via power-domain NOMA technology. Three relay selection schemes, i.e., optimal single relay selection (OSRS) scheme, two-step single relay selection (TSRS) scheme, and optimal dual relay selection (ODRS) scheme are proposed and the secrecy outage performance is analyzed. As a benchmark, we also examine the secrecy outage performance of the NOMA systems with traditional multiple relay forwarding (TMRF) scheme in which all the relay that successfully decode signals from the source forward signals to the NOMA users with equal power. Considering the correlation between the secrecy capacity of two users and different secrecy requirement for two NOMA users, the analytical expressions for the security outage probability (SOP) of the proposed OSRS, TSRS, and ODRS schemes along with the TMRF scheme are derived and validated via simulations. To get more insights, we also derive the analytical expressions for the asymptotic SOP for all the schemes with fixed and dynamic power allocations. Furthermore, the secrecy diversity order (SDO) and secrecy array gain of cooperative NOMA systems are obtained. The results demonstrate that our proposed schemes can significantly enhance the secrecy performance compared to the TMRF scheme and that all the schemes with fixed power allocation obtain zero SDO and the OSRS scheme with dynamic power allocation obtains the same SDO as TMRF.

Relay based Coupling Scheme of High Speed Communication data, High voltage DC And High Power Pulsed AC for Coaxial Cable

Coaxial cable telemetry is most commonly used in the field of underwater applications like data logging in oil rigs, underwater wireless modem, underwater acoustic measurements, borehole measurements, deep sea telemetry for sediment analysis, airborne sonars, imaging sonars etc. In all the above applications coaxial multicore cables are used. The design and development of relay based coupling scheme which helps to replace the multi core cable with a single core coaxial cable for telemetry application is described. Single core cable is suitable for long distance data communication. Multi core cables are generally heavy and due to the size, may not meet space constraints in complex systems. They are not economical too. The relay based coupling scheme is used to mix or separate the high speed bi-directional communication data, high voltage DC and high power pulsed AC. In single relay scheme one relay is used to switch the centre core of single core coaxial cable. Here the ground is common for both high power AC transmission and high speed bi-directional data path. A dual relay scheme is discussed where two relays are used to switch both the centre core and ground of the single core coaxial cable. This provides more ground isolation and can avoid ground lifting issues while high power AC transmission occurs. The simulation of the coupling scheme was done using PSpice®. A prototype of the coupling scheme was also made for analysis. Filter responses were analysed for each coupling path. The DC coupling filter has 85 Hz cut-off frequency at -3 dB. The cut-off frequency of high speed data coupler is 500 KHz at -3 dB. A 4.3KV peak to peak of 3 KHz and 7 KHz AC signals were transmitted and measurements were taken to analyse the effect of high voltage over different coupling paths. The 3 KHz signal has a peak of 61.88 dB and that of 7 KHz signal, the peak is 62.50 dB. The signal components of 3 KHz signal in the DC path has a voltage level of 9.375 dB and that of 7 KHz signal is 25.63 dB.

Dual Relay Selection for Cooperative NOMA With Distributed Space Time Coding

We consider a two-user multi-relay cooperative non-orthogonal multiple access (NOMA) network with distributed space–time coding. Two dual-relay selection strategies are proposed for cooperative NOMA, namely, two-stage dual relay selection with fixed power allocation (DRS-FPA) and two-stage dual relay selection with dynamic power allocation (DRS-DPA). Furthermore, lower and upper bounds on the outage probability for the DRS-FPA scheme and the exact outage probability for the DRS-DPA scheme are obtained in closed-form, respectively. Numerical results show that the proposed two-stage DRS schemes not only yield better outage performance than the existing single relay selection schemes without sacrificing spectral efficiency, but can also achieve full diversity gain.

Discussion on “Optimal Protection Coordination for Meshed Distribution Systems With DG Using Dual Setting Relays”

Recently, Zeineldin et al. proposed Dual Setting Over Current Relays (DSOCRs) application in looped distribution networks [1] . Application of DSOCRs separates primary and back up roles of relays and relieves protection coordination constraint. Authors reported a significant reduction in relays operating times.

Single and Dual Relay Selection in Two-Way Network-coded Relay Networks

In this paper, the relay selection problem for two-way relaying networks in single and dual relay selection schemes is addressed. In the single relay selection scheme, the problem is to find the best relay node which leads to the minimum bit error rate (BER) between the source nodes. We then derive the upper and lower bounds for the signal to noise ratio and the end-to-end BER of this scheme. In the dual relay selection scheme, the problem is to find the two best relay nodes. In this scheme, Alamouti space-time coding and physical layer network coding are utilized in order to achieve the higher performance. For improving the system performance, optimal power allocation between the sources and the relays is considered based on decreasing the BER. Finally, simulation results are provided to verify the correctness of analytical results.

Development of Automatic Geofencing and Accidental Monitoring System Based on GPS Technology

The main objective of this project is to design and develop an embedded system for vehicle to detect the road accident for immediate medical help as well as for security purpose in theft prevention using single shock sensor. In case of accidental mode the system should inform automatically via text message to medical rescue team indicating the position of vehicle location. When there is no car driver, vehicle should automatically go into security mode. When a person tries to steal the vehicle, this system should send an alert message to the owner. The system Geo fencing and accidental monitoring system based on AT89S52 as a central core. This includes various technologies: a shock sensor, Liquid crystal display (LCD), Dual relay and wireless communication. This system also includes Geo fencing technology. Geo fencing enables the remote monitoring of predefined set of boundaries and automatic detect when vehicle exit from these areas.

310-Helical Peptide Acting as a Dual Relay for Charge-Hopping Transfer in Proteins

We present a density functional calculational study to clarify that a 3(10)-helix peptide can serve as a novel dual-relay element to mediate long-range charge migrations via its C- and N-termini in proteins. The ionization potential of the 3(10)-helix C-terminus correlates inversely with the helix length, HOMO energy, and dipole moment. In particular, it decreases considerably with the increase in the number of peptide units, even to a smaller value than that of the easily oxidized amino acid residue, which implies the possibility of releasing an electron and forming a hole at the 3(10)-helical C-terminus. On the other hand, the electron affinity of the 3(10)-helical N-terminus correlates positively with the helix length and dipole moment but inversely with the LUMO energy. Clearly, the increasing positive electron-binding energy with the increase in the number of peptide units implies that the 3(10)-helical N-terminus can capture an excess electron and play an electron-relaying role. The relaying ability of the 3(10)-helical C-terminus and N-terminus not only depends on the helix length but also varies subject to the capping effect, the collaboration and competition of proximal groups, and solvent environments. In contrast to the known hole relays such as the side chains of Tyr and Trp and electron relays such as the side chains of protonated Lys and Arg, either the hole relay (the 3(10)-helix C-terminus) or the electron relay (the 3(10)-helix N-terminus) is property-tunable and could apply to different proteins in assisting or mediating long-range charge migrations.

N – R th dual best relays opportunistic cooperation schemes and performance analyses over Nakagami‐ m fading channels

To overcome the performance loss caused by the N th single best relay selection schemes, in this study, the authors present the N-R th dual best relays selection schemes. In the proposed schemes, there are two relays selected out of the available relays to forward the received signals to the destination by using the decode-and-forward protocol. The statistical descriptions of instantaneous end-to-end received signal-to-noise ratios (SNR) are investigated over independent and non-identically distributed Nakagami- m fading channels. By using the appropriate mathematical proof, the authors firstly obtain the closed-form expressions to the probability density function and cumulative distribution function of instantaneous end-to-end SNR. Then, based on the derived results, the outage probability and average symbol error rate (SER) of the proposed N-R th dual best relays selection schemes are investigated. The comparison analyses between the N th schemes and the N-R th schemes show that the proposed N-R th dual best relays selection schemes can improve greatly the performance of opportunistic relaying systems such as outage probability and average SER. Especially, the proposed dual best relays selection scheme can obtain more outstanding improvement on SER.

Performance Analyses of the N–Rth Dual Best Relays Opportunistic Cooperation with Amplify-and-Forward Protocols

To overcome the loss in the outage probability and symbol error ratio (SER) caused by the Nth single relay opportunistic relaying (OR), in this paper, we present the N---Rth dual best relays OR sch...

A full rate dual relay cooperative approach for wireless systems

Cooperative relaying methods have attracted a lot of interest in the past few years. A conventional cooperative relaying scheme has a source, a destination, and a single relay. This cooperative scheme can support one symbol transmission per time slot, and is called full rate transmission. However, existing full rate cooperative relay approaches provide asymmetrical gain for different transmitted symbols. In this paper, we propose a cooperative relaying scheme that is assisted with dual relays and provides full transmission rate with the same macro-diversity to each symbol. We also address equalization for the dual relay transmission system in addition to addressing the issues concerning the improvement of system performance in terms of optimal power allocations.

Friction Modeling and Compensation of Servomechanical Systems With Dual-Relay Feedback Approach

The application of a dual-relay feedback approach toward the identification of a model of servomechanical system will be presented in this paper. The model will capture the linear dynamics of the system, as well as the frictional forces affecting the system, through a comprehensive friction model that includes static friction, Coulomb friction, viscous friction, and the boundary lubrication velocity. This friction model is able to adequately describe the friction property when the servo system runs under both low- and high-velocity modes. Properties of the oscillations induced under the dual relay will be presented, based on which insights for the selection of relay parameters can be drawn. A systematic set of procedures to derive all the parameters of the model will be furnished. The model will be directly useful in the design of the feedback controller and feedforward friction compensator. Results from the simulation and experiment will be presented to illustrate the practical appeal of the proposed method.

A dwell position verification method for high dose rate brachytherapy

Misplacement of dwell positions is a potential source of misadministration in high dose rate (HDR) brachytherapy. In this work, we present a dwell position verification method using fluoroscopic images. A mobile C‐arm fluoroscopic machine is used to take a snapshot of the treatment machine's check cable as it reaches the most distal dwell position. This fluoroscopic image is displayed side‐by‐side with a treatment planning image on a dual monitor relay station at the HDR treatment console. Any discrepancy between the check cable's position on the verification image and the intended dwell position on the planning image can be identified, immediately, thus avoiding the possibility of treating the wrong target volume.PACS numbers: 87.53.Jw, 87.53.Xd, 87.59.Ci

Automatic Friction Identification and Compensation with a Self-Adapting Dual Relay

Abstract The application of a dual relay feedback approach towards the identification of frictional effects in servo-mechanisms will be presented in this paper. The friction model, thus identified, will consist of Coulomb (including possibly directional Coulomb or load bias) and viscous friction components, both of which can be automatically extracted from suitably designed relay experiments. At the same time, from the same experiments, the dynamical model of the servomechanical system can be obtained from the experiments. These models will be directly useful in the design of the feedback controller and the friction compensator. Results from simulation and experiments are presented to illustrate the practical appeal of the proposed method.

Friction Modeling using a Relay Feedback Approach

In this paper, the application of a dual relay feedback approach towards modeling of frictional effects in servo-mechanisms is addressed. The friction model consists of Coulomb and viscous friction components, both of which can be automatically extracted from suitably designed relay experiments. At the same time, the dynamical model of the servo-mechanical system can be obtained from the experiments. Thus, a PID feedback motion controller and a feedforward friction compensator can be automatically tuned in this manner. The friction model obtained is also directly applicable to initialisation of an adaptive control scheme proposed. Results from simulation and experiments are presented to illustrate the practical appeal of the proposed method.

Text-To-Speech Technology for Dual Party Relay Services

We evaluated several human factors issues involved in applying AT&T Text-to-Speech (TTS) technology to Dual Party Relay (DPR) services for hearing- or speech-impaired end-users. Covered in this paper are: 1) lexical studies that were conducted to gather abbreviations and typographical errors generated by users of the Telecommunications Device for the Deaf (TDD); and 2) a laboratory trial that was performed to evaluate the feasibility of the TTS application and to examine associated user interface issues. Information gathered from the lexical studies was used for the laboratory trial and for constructing the field trial system. The laboratory trial consisted of several studies, including a comparison between the comprehension of TTS and human voices, identification of a desirable TTS presentation rate, examination of the effects of pauses, and observation of the difficulties related to TTS relay calls. Recommendations were made based on the lab trial results. We concluded that applying TTS to DPR service is feasible. That is, hearing and hearing-impaired subjects can carry on DPR conversations with the use of TTS technology. A field trial was subsequently conducted in California.

Small dual electronic relays with grid contact

Small dual electronic relays with grid contact