Wireless powered D2D communications underlying cellular networks: design and performance of the extended coverage

Because of the short battery life of user equipments (UEs), and the requirements for better quality of service have been more demanding, energy efficiency (EE) has emerged to be important in device-to-device (D2D) communications. In this paper, we consider a scenario, in which D2D UEs in a half-duplex decode-and-forward cognitive D2D communication underlying a traditional cellular network harvest energy and communicate with each other by using the spectrum allocated by the base station (BS). In order to develop a practical design, we achieve the optimal time switching (TS) ratio for energy harvesting. Besides that, we derive closed-form expressions for outage probability, sum-bit error rate, average EE and instantaneous rate by considering the scenario when installing the BS near UEs or far from the UEs. Two communication types are enabled by TS-based protocol. Our numerical and simulation results prove that the data rate of the D2D communication can be significantly enhanced.Web of Science58439939

Performance analysis with wireless power transfer constraint policies in full-duplex relaying networks

In practice, full-duplex (FD) transmission mode not only helps extend the coverage but also lengthen network lifetime. In this paper, we develop wireless power supply policies, namely separated power (SP) and harvested power (HP) to propose a flexible architecture at the relay node in FD decode-and-forward (DF) relaying networks considering time switching-based relaying protocol (TSR) to achieve optimal time used for a communication process. This transmission mode requires more processing procedure at the relay, i.e. antenna installations and radio frequency (RF) self-interference cancellation. We evaluate the optimal power constraints in case of SP and HP to achieve better power consumption efficiency at the relay node. More importantly, closed-form expressions for outage probability and throughput are provided, and we also use numerical and simulation results to compare SP with HP.Web of Science234767

Outage performance analysis of non-orthogonal multiple access with time-switching energy harvesting

In recent years, although non-orthogonal multiple access (NOMA) has shown its potentials thanks to its ability to enhance the performance of future wireless communication networks, a number of issues emerge related to the improvement of NOMA systems. In this work, we consider a half-duplex (HD) relaying cooperative NOMA network using decode-and-forward (DF) transmission mode with energy harvesting (Ell) capacity, where we assume the NOMA destination (D) is able to receive two data symbols in two continuous time slots which leads to the higher transmission rate than traditional relaying networks. To analyse EH, we deploy time-switching (TS) architecture to comprehensively study the optimal transmission time and outage performance at D. In particular, we are going to obtain closed-form expressions for outage probability (OP) with optimal TS ratio for both data symbols with both exact and approximate forms. The given simulation results show that the placement of the relay (R) plays an important role in the system performance.Web of Science253918

Neutron star cooling - a challenge to the nuclear mean field

The two recent density-dependent versions of the finite-range M3Y interaction (CDM3Y$n$ and M3Y-P$n$) have been probed against the bulk properties of asymmetric nuclear matter (NM) in the nonrelativistic Hartree Fock (HF) formalism. The same HF study has also been done with the famous Skyrme (SLy4) and Gogny (D1S and D1N) interactions which were well tested in the nuclear structure calculations. Our HF results are compared with those given by other many-body calculations like the Dirac-Brueckner Hartree-Fock approach or ab-initio variational calculation using free nucleon-nucleon interaction, and by both the nonrelativistic and relativistic mean-field studies using different model parameters. Although the two considered density-dependent versions of the M3Y interaction were proven to be quite realistic in the nuclear structure or reaction studies, they give two distinct behaviors of the NM symmetry energy at high densities, like the Asy-soft and Asy-stiff scenarios found earlier with other mean-field interactions. As a consequence, we obtain two different behaviors of the proton fraction in the $\beta$-equilibrium which in turn can imply two drastically different mechanisms for the neutron star cooling. While some preference of the Asy-stiff scenario was found based on predictions of the latest microscopic many-body calculations or empirical NM pressure and isospin diffusion data deduced from heavy-ion collisions, a consistent mean-field description of nuclear structure database is more often given by some Asy-soft type interaction like the Gogny or M3Y-P$n$ ones. Such a dilemma poses an interesting challenge to the modern mean-field approaches.Comment: Version accepted for publication in Phys. Rev.

Energy Harvesting Enabled Relaying network: Design System and Performance Analysis

The thesis deals with the design of new protocols and the analysis of wireless-powered communications networks’ performance. In order to bring the contribution to the science in field of my topic, this thesis starts with the study of wireless power supply policies, namely the separated power (SP) and harvested power (HP) techniques at the relay node in the full-duplex (FD) decode-and-forward (DF) relaying networks (RNs). In the second emphasis, the thesis deals with the factors degrading the system performance, i.e., channel state information (CSI) and hardware impairments (HWIs) using Hybrid time switching-based and power splitting-based relaying (HTPSR) protocol. Besides that, an optimization problem regarding time switching (TS) and power splitting (PS) ratios are solved in this thesis, where a genetic algorithm was used. In the third emphasis of this thesis, a two-way simultaneous wireless information and power transfer (SWIPT) network is considered to be an important technique, in which two new proposed protocols, namely power time splitting-based two-slot (PTSTW) and power time splitting-based three-slot (PTSTH) are deployed and compared with each other. The throughput performance is analyzed for both developed protocols. The following emphasis is the study of relay selection (RS) schemes. The three optimal RS schemes are proposed to examine the system performance, namely: * Half-duplex (HD) deploying maximal ratio combine (HDMRC), * FD deploying joint decoding (FDJD), * and hybrid FD/HD relaying transmission scheme (HTS). All of them operate in two optimal power supply policies - optimal power under the individual power constraints (OPIPC) and optimal power with energy harvesting ability (OPEHA). The simulation results show that the HTS outperforms HDMRC and FDJD, and OPEHA is better than OPIPC. Finally, Optimal time for transmitting power at source (OTPS) and Optimal time for transmitting power at relay (OTPR) are proposed to optimize the transmit power in a cognitive relaying network (CRN). For performance analysis, the outage probability, the rate-energy trade-off and the average energy efficiency are studied to enhance the successful data transmission.Tato dizertační práce se věnuje návrhu nových protokolů pro bezdrátově napájené komunikační sítě, jejichž efektivita je následně podrobena analýze. V této práci jsou probrány přístupy k bezdrátovému napájení komunikačních zařízení, a sice SP (Separated Power) a HP (Harvested Power), kdy energie je získána z okolí. Tyto techniky jsou zkoumány z pohledu tzv. relay uzlu R (Relay node) v plně duplexních sítích RN (Relaying Networks) pracujících v režimu DF (Decode-and-Forward). Mimoto, jsou v práci rozebrány i faktory snižující výkonnost a efektivitu bezdrátově napájených komunikačních systémů využívajících navržený hybridní protokol HTPSR (Hybrid Time Switching-based and Power Splitting-based Relaying). Pro tyto účely je využita zejména informace o stavu kanálu CSI (Channel State Information), přičemž detekovány a vyhodnoceny jsou i vlivy jednotlivých zařízení HWIs (Hardware Impairments). Pro zmíněný protokol HTPSR je v práci taktéž řešen problém optimalizace poměru mezi intervaly časového přepínání TS (Time Switching) a děleného napájení PS (Power Splitting), kde byl využit genetický algoritmus. Další oblastí, která je v této práci zkoumána, je síť umožňující současný přenos informací i energie pro napájení, pro niž byly v rámci této práce navrženy, nasazeny a vyhodnoceny dva protokoly, a to PTSTW (Power Time Splitting-based Two-slot) a PTSTH (Power Time Splitting-based Three-slot). Následně jsou v dizertaci zkoumány tři navržená schémata, ve kterých může být provozován uzel R a je provedena jejich výkonnostní analýza, konkrétně jde o režim: * poloduplexní využívající techniku kombinování maximálních poměrů HDMRC (Half-duplex Deploying Maximal Ratio Combine), * plně duplexní využívající sdružené dekódování FDJD (Full-duplex Deploying Joint Decoding), * a hybridní kombinující oba výše zmíněné způsoby v režimu HTS (Hybrid Transmission Scheme). Všechna tato tři schémata jsou provozována v optimalizovaných režimech provozu, přičemž v práci jsou rozebrány dva – optimální napájení s individuálními limity OPIPC (Optimal Power Under the Individual Power Constraints) a optimální napájení s možností využití získávání energie OPEHA (Optimal Power with Energy Harvesting Ability). Z následných simulací pak bylo zjištěno, že HTS svou efektivitou předčí jak HDMRC, tak FDJD a že režim OPEHA je výhodnější než režim OPIPC. Posledním přínosem této práce jsou dva navržené způsoby určení časových poměrů OTPS (Optimal Time for transmitting Power at Source) a OTPR (Optimal Time for transmitting Power at Relay) s cílem optimalizovat přenos energie v CR (Cognitive Relaying) sítích. Rovněž byly pečlivě zkoumány výkonnostní parametry jako pravděpodobnost výpadku, poměr mezi přenosovou rychlostí systému a dodanou energií a průměrná efektivita systému při přenosu energie, a to za účelem zlepšení vlastností datových přenosů.440 - Katedra telekomunikační technikyvyhově

Outage probability analysis for hybrid TSR-PSR based SWIPT systems over log-normal fading channels

Employing simultaneous information and power transfer (SWIPT) technology in cooperative relaying networks has drawn considerable attention from the research community. We can find several studies that focus on Rayleigh and Nakagami-m fading channels, which are used to model outdoor scenarios. Differing itself from several existing studies, this study is conducted in the context of indoor scenario modelled by log-normal fading channels. Specifically, we investigate a so-called hybrid time switching relaying (TSR)-power splitting relaying (PSR) protocol in an energy-constrained cooperative amplify-and-forward (AF) relaying network. We evaluate the system performance with outage probability (OP) by analytically expressing and simulating it with Monte Carlo method. The impact of power-splitting (PS), time-switching (TS) and signal-to-noise ratio (SNR) on the OP was as well investigated. Subsequently, the system performance of TSR, PSR and hybrid TSR-PSR schemes were compared. The simulation results are relatively accurate because they align well with the theory

A High-Throughput Hardware Implementation of NAT Traversal For IPSEC VPN

In this paper, we present a high-throughput FPGA implementation of IPSec core. The core supports both NAT and non-NAT mode and can be used in high speed security gateway devices. Although IPSec ESP is very computing intensive for its cryptography process, our implementation shows that it can achieve high throughput and low lantency. The system is realized on the Zynq XC7Z045 from Xilinx and was verified and tested in practice. Results show that the design can gives a peak throughput of 5.721 Gbps for the IPSec ESP tunnel mode in NAT mode and 7.753 Gbps in non-NAT mode using one single AES encrypt core. We also compare the performance of the core when running in other mode of encryption

Outage performance analysis of non-orthogonal multiple access systems with RF energy harvesting

Non-orthogonal multiple access (NOMA) has drawn enormous attention from the research community as a promising technology for future wireless communications with increasing demands of capacity and throughput. Especially, in the light of fifth-generation (5G) communication where multiple internet-of-things (IoT) devices are connected, the application of NOMA to indoor wireless networks has become more interesting to study. In view of this, we investigate the NOMA technique in energy harvesting (EH) half-duplex (HD) decode-and-forward (DF) power-splitting relaying (PSR) networks over indoor scenarios which are characterized by log-normal fading channels. The system performance of such networks is evaluated in terms of outage probability (OP) and total throughput for delay-limited transmission mode whose expressions are derived herein. In general, we can see in details how different system parameters affect such networks thanks to the results from Monte Carlo simulations. For illustrating the accuracy of our analytical results, we plot them along with the theoretical ones for comparison

Frequency entrainment in a self-oscillatory system under parametric excitation

In the present paper, the frequencies for appearing the entrained oscillations in a self-oscillatory system under the parametric excitation, have been determined. The almost periodic oscillation which develops from the entrained oscillation when the driving frequency is given just outside the region of entrainment also have been investigated by the method of the phase plane