No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Two-Way Relaying Networks in Green Communications for 5G: Optimal Throughput and Tradeoff between Relay Distance on Power Splitting-based and Time Switching-based Relaying SWIPT
Abstract
In this paper, we systematically study the performance of two and three time slot transmission schemes (2TS and 3TS) for bidirectional amplify-and-forward (AF) relaying channels, which are deployed by simultaneous wireless information and power transfer (SWIPT). In particular, in SWIPT, there are two protocols, namely power time splitting-based two-slot (PTSTW) and power time splitting-based three-slot (PTSTH) relaying protocol. We also derive closed-form expressions of throughput for both delay-limited and delay-tolerant transmission mode. Moreover, the proposed protocols will be evaluated in terms of the large scale path loss and the distance allocation to achieve the optimal throughput. In addition, numerical results prove that the throughput of PTSTW outperforms PTSTH. Furthermore, the throughput of delay-tolerant transmission mode is greatly better than delay-limited transmission mode. Other numerical results are also provided to verify the validity of theoretical analysis.
... Rayleigh fading channels have been utilized for studies about the adaptive relaying protocol of twohop amplify-and-forward (AF) relaying networks with exceptional throughput performance [9], [10]. Besides, in [11] where the outage probability (OP) of decode-and-forward (DF) PSR system was analyzed, we can see that EH relaying network is more beneficial than conventional networks. Additionally, it is essential to deploy hybrid concepts to study and effectively improve system performance. ...
... Then, within the 2nd time slot (1 − 2 ) , the harvested energy we have at R is used up to decode and forward the signal via the BS-to-D link. Besides, we assume that the processing power of R is neglected because it is relatively small in comparison with the transmission power of R-to-D [11], [39]. ...
... We can obtain the OP at D for the AF hybrid PSR-TSR systems as (9) Proof: With (7) and (9), we can formulate the OP for the HD-AF hybrid PSR-TSR network as (11). h is always a positive value, we can re-express the probability as (12). ...
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.
... The literature on EH via RF signal for wireless communication is quite rich [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]26]. There are two major directions research in RF-EH based communication networks. ...
... Performance of various forms of cooperative wireless networks are reported in [9-16, 22-24, 26] to highlight the efficacy of RF-EH relay. Studies on the performances of various system parameters like ergodic capacity, outage capacity, outage probability etc. are evaluated in RF-EH based wireless networks considering the AF and DF relay aided [9][10][11][12][13][14][15][16] network models for both one-way and two-way communications. ...
... To enhance the system performance in terms of spectrum efficiency, bidirectional communications using relaying scheme is found to be more effective compared to two parallel one-way communications. Bidirectional communications using AF and DF relay aided networks are studied in [9,[14][15][16]. The expressions of outage probability and ergodic capacity are derived in [14] to study the system performance of AF relay aided PS architecture. ...
This paper explores an end-to-end outage probability experienced in a bidirectional relay assisted communication where the relay is assumed to be equipped with an RF energy harvesting circuit. First, the closed-form expression for the outage of the system is derived. This is followed by the formulation of an unconstrained optimization problem to achieve minimum outage probability
with respect to the relay placement and consequent time allocation for energy harvesting. The system model is further extended in an underlay cognitive radio framework to study the impact of a primary user outage constraint on the end-to-end outage performance of the two-way communications. The accuracy of analytical results is validated through simulation results. The impact of various system parameters like relay position, time allocation factor, target rate of transmission on the outage probability is also observed. In addition, it is also shown that spectral efficiency of the communication system using hybrid power-time switching relaying protocol is much superior to similar one-way and two-way relay assisted communication system with power splitting relaying protocol.
... Following the work in [8], these authors continued evaluating the throughput performance and ergodic capacity of a decode-and-forward (DF) relaying network for both TSR and PSR protocols in [9]. In [10], the performance of two and three time slot transmission schemes in amplify-and-forward (AF) two-way relaying networks was investigated, where the authors proposed two new protocols: so-called power time splitting-based twoslot and power time splitting-based three-slot . Meanwhile, the authors in [10] continued their study on the throughput performance for two, three and four time slot transmission schemes for AF two-way relaying networks [11]. ...
... In [10], the performance of two and three time slot transmission schemes in amplify-and-forward (AF) two-way relaying networks was investigated, where the authors proposed two new protocols: so-called power time splitting-based twoslot and power time splitting-based three-slot . Meanwhile, the authors in [10] continued their study on the throughput performance for two, three and four time slot transmission schemes for AF two-way relaying networks [11]. Regarding bit error rate (BER) performance, the sum BER performance of (AF) EH twoway relaying networks was evaluated deploying TSR protocol [12] while the work in [13] derived an exact closed-form expression for average BER of a selection combining scheme for a cooperative system using an AF relay with simultaneous wireless information and power transfer. ...
... The BS is located at (0, 0.5) The CE is located at (1, 0.5) The DUE1, RUE and DUE2 are located at (0, 0), (0.5, 0) and (1, 0), respectively The path loss for the D2D link, i ! j P L 0 = 148 + 40log 10 particular, Cases 1 and 2 are represented as V = 1 and V = 5, respectively. It is clear that when there is an increase in g 0 , the outage probability in the D2D communication falls. ...
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.
... Rights reserved. research on energy harvesting enabled topology so-called as wireless powered communication (WPC) systems [1][2][3], and relaying cooperative networks for high speed applications and extending coverage [4,5]. Interestingly, the wireless nodes can be equipped energy harvest ability from ambient RF signals. ...
... Wireless energy harvesting applied in wireless communication is often considered as innovative technology for green applications development. Simultaneous wireless information and power transfer (SWIPT) based networks rely on surrounding RF electromagnetic signals is recently introduced in several works [1][2][3][4][5]. There is considerable recent analyze the outage probability of two-way full-duplex relaying with energy harvesting and information transfer for DF mode. ...
... Numerical results and comparisons are presented in Sect. 4. Finally, summarizing remarks are given in Sect. 5. ...
In this paper, we consider two-way full-duplex relay with energy harvesting system, in which the relay node harvests transmitted power from the two source nodes to forward signals to destinations. We also analyze the relay network model with decode-and-forward protocol for information cooperation and time switching-based relaying protocol for power transfer. In particular, the outage probability, average throughput and optimal energy harvesting time of novel scheme in simultaneous wireless information and power transfer are presented. We obtain analytic closed-form expressions for both tight bounded and asymptotic of outage probability and average throughput of system. Using numerical and analytic simulations, the performances of different situations are presented and discussed more clearly. The results show that the better performance is achieved in case of worse self-interference. As important result, the better self interference cancellation leads to superior system performance.
... This imposes major limitations on the system performance at the end-to-end link. So, the efficient usage of RF-EH relay in various forms of cooperative wireless networks is studied in [8][9][10][11][12][13][14][15][16], [19]. Performances of these networks are evaluated in terms of outage probability and throughput in both one-way [8][9][10][11][12] and two-way [13][14][15] communications. ...
... So, the efficient usage of RF-EH relay in various forms of cooperative wireless networks is studied in [8][9][10][11][12][13][14][15][16], [19]. Performances of these networks are evaluated in terms of outage probability and throughput in both one-way [8][9][10][11][12] and two-way [13][14][15] communications. In [8], amplify-and-forward (AF) relay assisted and in [9], decode-and-forward (DF) relay assisted PS relaying (PSR) and TS relaying (TSR) schemes are studied for delay-limited and delay-tolerant traffic, respectively. ...
... To enhance the spectrum efficiency, two-way communication using relaying scheme is more useful than two parallel one-way communication. The relay placement is one of the important aspect of research in two-way communication for harvesting an useful amount of energy from both of the users [15]. Two-way communications using AF relay assisted architecture is discussed in [13], [15]. ...
The study of relays with the scope of energy-harvesting (EH) looks interesting as a means of enabling sustainable, wireless communication without the need to recharge or replace the battery driving the relays. However, reliability of such communication systems becomes an important design challenge when such relays scavenge energy from the information bearing RF signals received from the source, using the technique of simultaneous wireless information and power transfer (SWIPT). To this aim, this work studies bidirectional communication in a decode-and-forward (DF) relay assisted cooperative wireless network in presence of co-channel interference (CCI). In order to quantify the reliability of the bidirectional communication systems, a closed form expression for the outage probability of the system is derived for both power splitting (PS) and time switching (TS) mode of operation of the relay. Simulation results are used to validate the accuracy of our analytical results and illustrate the dependence of the outage probability on various system parameters, like PS factor, TS factor, and distance of the relay from both the users. Results of performance comparison between PS relaying (PSR) and TS relaying (TSR) schemes are also presented. Besides, simulation results are also used to illustrate the spectral-efficiency and the energy-efficiency of the proposed system. The results show that, both in terms of spectral efficiency and the energy-efficiency, the two-way communication system in presence of moderate CCI power, performs better than the similar system without CCI. Additionally, it is also found that PSR is superior to TSR protocol in terms of peak energy-efficiency.
... Besides, simultaneous wireless information and power transfer (SWIPT) systems, as the name suggests, exploit the radio frequency (RF) for EH and transferring data to power finitecapacity batteries in wireless relaying networks, [9]- [14]. Indeed, we can find a wide range of studies relating to EH relaying networks for outdoor scenarios in [15]- [24]. Specifically, in [15]- [17], the two relaying protocols namely power splitting-based (PS) and time switching-based (TS) and their hybrid version in cooperative relaying networks were studied. ...
... Indeed, we can find a wide range of studies relating to EH relaying networks for outdoor scenarios in [15]- [24]. Specifically, in [15]- [17], the two relaying protocols namely power splitting-based (PS) and time switching-based (TS) and their hybrid version in cooperative relaying networks were studied. Additionally, two relay operation modes so-called amplify-andforward (AF) and decode-forward (DF) were investigated in [18]. ...
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.
... Nevertheless, many actual problems have arisen such as load balancing, traffic management, operation and maintenance etc. BSs network scope also has issues like capacity with low power consumption; therefore, wireless energy har- vesting plays a very important role for green network for Fifth Generation (5G) world using infrastructures having sufficient and green energy in HetNet [1]. When using ambient Radio-Frequency (RF) signals with the new source for energy harvesting, one of the appropri- ate ways to harvest energy is parallel Wireless Infor- mation and Power Transfer (SWIPT) by collecting en- ergy from ambient RF signals [2] and [3]. Accordingly, SWIPT helps to make the wireless device which can be obtained higher bandwidth efficiency when considering full-duplex mode in relaying networks [4]. ...
... In Fig. 2, we present a parameter α 2 1 (0 ≤ α 2 1 ≤ 1) denoting the fraction of the block time allocated for Energy Harvesting (EH) in the block time T /2 with T denoted as block time for signal frame processing, node D 2 is assumed as energy harvesting relaying node which uses Power Splitting-based Relaying (PSR) pro- tocol [2], [3], [4] and [10]. We assume that all of the channels are quasi-static fading channels, follow- ing Rayleigh fading. ...
The concept of energy harvesting-assisted relay has been introduced to support the relaying transmission using Device-to-Device (D2D) communications for enhancing communication reliability. Motivated by the recent advance in Heterogeneous Network (HetNet) using relaying techniques, we consider the D2D communication provided by Energy Harvesting (EH) assisted relay where signal is forwarded from a Base Station (BS) to the conventional cellular user (non-D2D user) and D2D user. We first derive the outage probability by taking into account the SNR and power allocation parameters, and propose the transmission mode for D2D link as well as non-D2D link. After deriving the outage probability of the D2D-HetNet, we explore the effects of the network parameters on the outage probability and throughput.
... As another line of research trend, non-relay assisted and relay assisted networks are supported by wireless EH in [15][16][17][18][19][20]. In [15], the energy-efficient RA in OFDM CRNs was evaluated, where many practical limitations were addressed to guarantee the system energy efficiency (EE), including transmission power, interference threshold and traffic demands of secondary users. ...
... In [19], a point-to-point link over the flat-fading channel was evaluated, in which the transmitter helps the receiver collects energy from its intended signal. In [20], the authors proposed two protocols so-called power time splitting-based two-slot (PTSTW) and power time splitting-based three-slot (PTSTH) for a two-way amplify-and-forward (AF) relaying network. ...
In this paper, we consider a half-duplex decode-and-forward small cell cognitive relay network, in which the source and the relay node are allocated with spectrum shared by the macro cell primary transmitter (MPT). In order to develop a practical design, we propose two time switching-based policies to optimize the maximum transmit power at source and relay so-called Optimal Time for Transmit Power at Source and Optimal Time for Transmit Power at Relay related to wireless energy harvesting for the considered network, thanks to the advantages of MPT. Additionally, we provide closed-form expressions for outage probability for the proposed policies. Furthermore, to achieve more genuine understandings of the successful data transmission of the small cells, we also consider the delay-constraint throughput, the rate-energy trade-off and the average energy efficiency by giving numerical and simulation results. © 2018 Springer Science+Business Media, LLC, part of Springer Nature
... We next consider several system models regarding existing cooperative networks with capability of energy harvesting. Firstly, the employed relay in SWIPT networks [9,10] or the source terminal [11] can harvest energy from the radiated signal of the source terminal or the employed relay. Secondly, in multi-hop networks, energy is transferred to remote terminals via multi-hop [12,13]. ...
... Specifically, this time fraction is always less than one, i.e., α i < 1, which implies the allocated time which is required for simultaneous wireless information and power transfer. (9) and (12), to convenience in represent we use two characters α single i and α dual i to denote α i in (9) and (12) ...
In terms of modern applications of wireless sensor networks in smart cities, relay terminals can be employed to simultaneously deliver both information and energy to a designated receiver by harvesting power via radio frequency (RF). In this paper, we propose time switching aware channel (TSAC) protocol and consider a dual-hop full-duplex (FD) relaying system, where the energy constrained relay node is powered by RF signals from the source using decode-and-forward (DF) relaying protocols. In order to evaluate system performance, we provide an analytical expression of the achievable throughput of two different communication modes, including instantaneous transmission and delay-constrained transmission. In addition, the optimal harvested power allocation policies are studied for these transmission modes. Most importantly, we propose a novel energy harvesting (EH) policy based on FD relaying which can substantially boost the system throughput compared to the conventional half-duplex (HD) relaying architecture in other transmission modes. Numerical results illustrate that our proposed protocol outperforms the conventional protocol under the optimal received power for energy harvesting at relay. Our numerical findings verify the correctness of our derivations and also prove the importance of FD transmission mode.
... We can calculate the first probability in (16) (20) Subsequently, we substitute (19) and (20) into (18), then combine the product with (17) to obtain the ergodic outage probability at UF, which is given in (15). This is the end proof. ...
Due to the development of state-of-the-art fifth-generation communication (5G) and Internet-of-Things (IoT), the demands for capacity and throughput of wireless networks have increased significantly. As a promising solution for this, a radio access technique, namely, non-orthogonal multiple access (NOMA) has been investigated. Particularly, in this paper, we analyse the system performance of a joint time allocation and power splitting (JTAPS) protocol for NOMA-based energy harvesting (EH) wireless networks over indoor scenarios, which we modelled with log-normal fading channels. Accordingly, for the performance analysis of such networks, the analytical expression of a metric so-called “ergodic outage probability” was derived. Then, thanks to Monte Carlo simulations done in Matlab, we are able to see how different EH power splitting (PS) and EH time switching (TS) factors influence the ergodic outage probability. Last, but not least, we plot the simulation results along with the theoretical results for comparison studies.
... Currently, the multi-hop transmission, i.e., relaying communication systems, represents a promising solution to meet the requirements of the next-generation broadband wireless services, including range extension, power saving, and connectivity. Therefore, both 5G and future Sixth Generation (6G) systems include relaying technology in their architectures [3,4]. Communication systems are equipped with relays to realize a long-distance propagation of signals from between transmitter and receiver. ...
... Furthermore, WPT and wireless information transmit are simultaneous proceeded in wireless communications systems since the radio frequency (RF) signals are able to send both information and energy. Because of this, time switching (TS) and power splitting (PS) scheme are introduced since information processing and energy harvesting (EH) were separated through the time and the power domain [32]. In the other context, Simultaneous Wireless Information and Power Transfer (SWIPT) was considered to implement in CR-NOMA [33], [34]. ...
With the rapid growth of vehicles, the vehicular networks meet main challenges such as dynamic, heterogeneous, and large scaled. In addition, the cellular-based vehicular networks must satisfy further strict requirements including ultra low latency, high reliability, high spectrum efficiency and massive connections of the next generation (6G) network. Recently, by exploiting vehicle clustering utilized for reducing the complexity of vehicle-to-everything (V2X) systems, it could ultimately improve road traffic efficiency. In some specific scenarios related to Internet of Things (IoT), a group of vehicles can be served effectively in term of spectrum efficiency when two key techniques are enabled, i.e. non-orthogonal multiple access (NOMA) and cognitive radio (CR) schemes are joint deployed. These techniques certainly benefit to 6G V2X services to reduce specific challenges such as traffic congestion and massive connections. Different from existing works, we propose wireless power transfer (WPT) applied to roadside unit (RSU) to improve the situation that energy shortening in small devices deployed in V2X communications. In particular, we derive expressions of throughput to exhibit performance of the two grouped vehicles. To further indicate advantages of spectrum efficiency, we compare two schemes of V2X systems with and without CR schemes. Numerical results demonstrate that the non-CR NOMA-V2X scheme outperforms the CR-based NOMA-V2X scheme with fixed power allocation, but the non-CR NOMA-V2X scheme costs higher spectrum resource compared with the counterpart. Besides, by comparing with orthogonal multiple access (OMA)-assisted V2X, NOMA-V2X schemes demonstrate superiority in term of throughput performance whilst achieving the benefits of both NOMA and CR schemes.
... The authors analysed both TR and PR protocols for the outage probability. In [52], the authors study the two and three slot power time splitting-based SWIPT protocols for bi-directional AF channels. The closed-form expressions for delay limited and delay tolerant transmission modes are derived for throughput performances. ...
In this work, a generalized approach is proposed to review the performance of relaying designs with energy harvesting capability. The unified modeling of generalized energy harvesting relaying (GEHR) design covers the non-energy harvesting designs and the well-known energy harvesting designs, i.e., time-based relaying (TR) and power-based relaying (PR). Moreover, the hybrid of both TR and PR designs is also catered. We find the mathematical representations for the outage probability, ergodic capacity and average throughput in Rayleigh fading channels for amplify-and-forward (AF) and decode-and-forward (DF) relaying modes. The closed-form expressions are derived for the outage probability. To validate that GEHR design is a generalization of TR and PR designs, we study the individual cases of GEHR design from the perspectives of schematic diagram, signal analysis and the performance evaluation parameters comparison. Furthermore, the GEHR design is studied for the mixed Rayleigh-Rician fading channels. We considered two sub-cases of mixed fading, i.e., in case 01, source to relay (SR) link is considered as Rayleigh channel and relay to destination (RD) link is considered as a Rician channel. Conversely, in case 02, SR link is taken as Rician channel and RD link is a Rayleigh channel. We find the mathematical expressions for the ergodic capacity, outage probability and average throughput for DF and AF relaying for both cases of mixed fading channels. The analytical results in both channel configurations are presented for throughput and verified using extensive Monte-Carlo simulations. The results show that the proposed GEHR design can be set to work as not only for the conventional TR and 2 PR designs but also for hybrid of them. Furthermore, with some slight modifications in the proposed design, it can work as a conventional non-energy harvesting cooperative relaying model. Index Terms Ergodic capacity, outage probability, average throughput, delay tolerant and delay limited communication , mixed Rayleigh-Rician fading channels.
... The dual role of RF signals to transfer information and energy has led to the emergence of the concept of simultaneous wireless information and power transfer (SWIPT). The tradeoff between achievable rate and harvested energy for a SWIPT system with Amplify-and-Forward (AF) relays was evaluated in [1]; Nguyen et al. proposed two protocols based on a power-splitting technique for delay tolerant and delay limited networks. The outage performance of dual-hop cooperative networks was also investigated by [2]. ...
This work investigates the secrecy performance for a simultaneous wireless information and power transfer system that operates in the presence of cooperating eavesdroppers. The multi-antenna access point's transmission is used for information-decoding by a multi-antenna node and for energy-harvesting (EH) by multiple single-antenna nodes. However, some of the nodes authorized for EH only attempt to eavesdrop on the ongoing information transmission by utilizing a generalized on-off power splitting architecture. We derive a closed-form expression for the secrecy outage probability of the considered Multiple-Input-Multiple-Output Multiple-Eavesdroppers system. Theoretical and simulation results are provided to validate the derived results.
... For scenarios of multiple pairs of D2D users in the network, since different D2D users may have the same optimal CU multiplexing partner, the D2D user's access control and CU multiplexing partner selection become more complicated. In [16], the authors propose a heuristic algorithm based on user distance and user channel state information to pair D2D users and CU multiplexing partners. Although these two algorithms are simple, they are not theoretically optimal. ...
Aiming at the problem of D2D communication mode selection and resource optimization under the joint resource allocation mode in 5G communication network, a probabilistic integrated resource allocation strategy and quasi-convex optimization algorithm based on channel probability statistical characteristics are proposed. This strategy and algorithm guarantee D2D. Communication maximizes total system throughput while maximizing access. The analysis results show that this algorithm can significantly optimize the total throughput of the system and reduce the communication interference between users, which proves the rationality and efficiency of the communication model. The research results obtained in Muwen can provide a theoretical basis for analyzing more complex D2D communication systems and provide numerical basis for designing heuristic algorithms.
... In recent years, the demand for energy for wireless networks has significantly increased, so a number of solutions have been proposed in terms of energy-aware radio access [1]- [2], where the reasonable use of energy is considered as the priority to design next generations of wireless networks [3]- [6]. Energy harvesting (EH) has attracted much research interest, so relay selection (RS) is a useful method to receive and forward the source signal to make efficient use of the harvested energy. ...
In this paper, an energy harvesting (EH) amplifyand-forward (AF) multi-relay network is studied, in which the
communication between the source node and the destination node
is assisted by a number of relays. Furthermore, we adopt a
hybrid relaying protocol so-called hybrid power splitting and
time switching (HPTS) to allow EH and information processing
at relays. To discuss relay selection (RS), we try to achieve the
average end-to-end signal-to-noise ratio (SNR). Then, expressions
for outage probability and delay-restricted throughput are obtained. It is observed that the system throughput is significantly
improved thanks to the change of number of relays.
... In addition, to extend the lifetime of NOMA users, some works have been discussed [7]- [11]. In practice, information and energy are extracted from radio frequency (RF) signals based on two receiver architectures, i.e., time-switching (TS) or power-splitting (PS) [7]. ...
In this paper, we evaluate an energy harvesting (EH)
relaying cooperative non-orthogonal multiple access (NOMA)
system operating in half-duplex (HD) fixed decode-and-forward
(DF), where two data symbols can be received in two time slots
at the receiver which leads to higher transmission rate. In addition, time-switching (TS) protocol is considered to understand
its impacts on the outage performance and the delay-limited
throughput. It is shown that due to the placement of relay, the
system performance is affected. We provide simulation results to
prove the robustness of the system.
... The benefits of directional antennas can be exploited also in vehicular environments (Fazio et al., 2012), (Fazio et al., 2011). Therefore, using high efficency antenna systems combined with scalable routing protocol could favourite the improvement of the overall network performance (Zhou et al., 2006), , (De Rango et al., 2008), and can positively impact on the energy consumption encouraging e better exploitation of the power resources with respect to the omnidirectional case (Nguyen et al., 2016a), (Nguyen et al., 2016b). However, these solutions are unlikely to fulfil the requirements for the the 5G next generation wireless communication systems technology. ...
... Wireless sensor networks (WSNs) are subject to the constraint of energy storage at each mobile node [1,2]. Saving on energy consumption or extending the battery life for sensor nodes has become an important research issue in wireless sensor networks. ...
In this paper, a rigorous analysis of the performance of time-switching energy harvesting strategy that is applied for a half-duplex bidirectional wireless sensor network with intermediate relay over a Rician fading channel is presented to provide the exact-form expressions of the outage probability, achievable throughput and the symbol-error-rate (SER) of the system under the hardware impairment condition. Using the proposed probabilistic models for wireless channels between mobile nodes as well as for the hardware noises, we derive the outage probability of the system, and then the throughput and SER can be obtained as a result. Both exact analysis and asymptotic analysis at high signal-power-to-noise-ratio regime are provided. Monte Carlo simulation is also conducted to verify the analysis. This work confirms the effectiveness of energy harvesting applied in wireless sensor networks over a Rician fading channel, and can provide an insightful understanding about the effect of various parameters on the system performance.
... In simultaneous wireless information and power transfer (SWIPT) technique, a user at the receiving end utilizes the same received signal to decode information and also for harvesting energy. Besides, the SWIPT technique is divided in two modes, Time Switching (TS) mode and Power Splitting (PS) mode [4]. ...
Two vital challenges arise in the next generation 5G networks: scarcity of spectrum and the aspect of energy efficiency (EE). In this letter, we first formulate the prime issue, i.e., energy harvesting (EV) for 5G wireless networks, in which spectrum and energy resources are efficiently received and resourcefully managed. Thereafter, we introduce a medium access control (MAC) scheme for dual tier 5G networks; it also invokes the simultaneous wireless information and power transfer (SWIPT) technique with other data transmission schemes, i.e., cooperative transmission (CT) scheme and non-cooperative transmission (NCT) scheme with EV abilities. Illustrative results demonstrate significant improvement in aggregated throughput and EE.
... Meanwhile, a number of problems related to resource allocation in wireless networks with EH capacity was discussed in [8]. Furthermore, the performance of two and three time slot transmission schemes in amplify-and-forward (AF) two-way relaying networks was investigated in [9], where the authors proposed two new protocols so-called power time splittingbased two-slot (PTSTW) and power time splitting-based three-slot (PTSTH). ...
In this paper, we focus on the optimal relay selection (RS) and ergodic capacity of an energy harvesting (EH) amplify-and-forward (AF) multi-relay network, where multiple relays cooperate with the source node and the destination node. We begin the work with the optimization of a single relay. In the first step, after the average end-to-end signal-to-noise ratio (SNR) is obtained, the high end-to-end SNR is approximated to achieve the PDF and CDF, and we jointly optimize time switching (TS) and power splitting (PS) ratios by using Alternate Convex Search algorithm, second derivatives and Hessian matrices. Following that, closed-form expressions for the outage probability and throughput in both delay-restricted and delay-tolerant transmission mode in the high SNR regime are derived. Most importantly, we achieve not only ergodic capacity in the considered EH multi-relay network but also the trade-off between it and the average EH. Our theoretical results are proved by numerical simulations, in which delay-tolerant throughput outperforms delay-restricted throughput thanks to the change of number of relays. In addition, the data rate can be significantly enhanced thanks to the achievement of optimal TS and PS ratios.
... It is clear that in wireless communications, energy efficiency (EE) and spectral efficiency (SE) are among the two most important design metrics to cope with environmental problems and the requirements for better wireless communication service. In recent years, simultaneous information and power transfer (SWIPT) has become a promising technology, which allows a wireless equipment to perform energy harvesting (EH) and information processing at the same time by using the ambient radio frequency signals [1][2][3][4][5][6]. In particular, the work in [7] focused on the analysis of EE in multiple relay orthogonal frequency-division multiplexing (OFDM) systems, equipped with power supplies, so it needs energy harvested from signals transferred by transmitter. ...
This paper studies the cognitive wireless powered device-to-device (D2D) communication underlaying a cellular network, where there are two types of communications, including peer-to-peer (P2P) communication and a multi-hop D2D communication, which are assumed to be affected by hardware impairments (HWIs). We investigate the one-hop P2P communication and the multi-hop D2D communication, where the relay node helps other two user equipments (UEs) exchange information with a two-time-slot physical-layer network coding scheme. To examine the system performance, we derive closed-form expressions for the average energy efficiency (EE) and spectral efficiency (SE). Besides that, we also obtain the successful transmission probability (STP) for the two considered communications, and the optimal values of time switching (TS) and power splitting (PS) ratios are achieved with the help of a genetic algorithm (GA)-based optimization algorithm in our proposed energy harvesting (EH) protocol so-called Hybrid TS-PS (HTPS) relaying protocol. Comparisons between amplify-and-forward (AF) and decode-and-forward (DF) transmission schemes are provided. The simulation results give evidence that the STP is significantly improved regardless of the presence of HWIs thanks to the derived parameters, i.e., average EE, SE, and the optimal TS and PS ratios.
... On the other hand, with a single pair of transmission wires, the idea of cooperative communication can be adopted into the indoor PLC environment, usually by plugging relay devices into the outlets located between the transceivers. Many system based on this idea can be found in the literature, such as two-way relay scheme for PLC [9] and cognitive radio [10] under PLC environment. Due to the broadcasting nature of the power cables, these relay devices may receive and forward the source message to the destination. ...
The user experience of practical indoor power line communication (PLC) applications is greatly affected by the system quality-of-service (QoS) criteria. With a general broadcast-and-multi-access (BMA) relay scheme, in this work we investigate the joint source and relay power optimization of the amplify-and-forward (AF) relay systems used under indoor broadband PLC environments. To achieve both time diversity and spatial diversity from the relay-involved PLC channel, which is time-varying in nature, the source node has been configured to transmit an identical message twice in the first and second signalling phase, respectively. The QoS constrained power allocation problem is not convex, which makes the global optimal solution is computationally intractable. To solve this problem, an alternating optimization (AO) method has been adopted and decomposes this problem into three convex/quasi-convex sub-problems. Simulation results show the fast convergence and short delay of the proposed algorithm under realistic relay-involved PLC channels. Compared with the two-hop and broadcast-and- forward (BF) relay systems, the proposed general relay system meets the same QoS requirement with less network power assumption.
... The Device-To-Device (D2D) communications network or wireless powered relaying networks are a new application in 5th generation (5G) wireless networks. The existing researches allow D2D as an underlay to the cellular network can be combined with relaying scheme to increase the coverage percentage and spectral efficiency [1][2][3][4]. In contrast with femtocell where users communicate with the assistance of low-power base stations of cellular network, user equipment (UEs) of D2D communication transmit data signals to each other over a direct link using the cellular resources instead of management by the BS, in which. ...
This paper analyzes the effect of co-channel interference on device-to-device (D2D) communication using amplified-and-forward technique. This paper considered the outage probability of D2D communication using two-way amplify-and-forward relaying protocol over Rayleigh fading channels. For this purpose, this paper presents closed expressions for the cumulative distribution function (CDF) of the signal-to-noise ratio plus the co-channel noise (SINR), throughput of such network under impact of the co-channel interference. The results of this analysis will be verified by the Monte-Carlo simulation method and simulated on Matlab.
Anytime‐wireless‐everywhere (AWE) aspirations for Internet‐of‐things (IoT) applications to be enabled through current 5G and evolving 6G and beyond ecosystems necessitate the development of innovative electrically small antennas (ESAs). While a variety of ESA systems are reviewed, those realized from the near‐field resonant parasitic (NFRP) antenna paradigm are emphasized. Efficiency, bandwidth, and directivity issues are highlighted. Multifunctional, reconfigurable, passive and active systems that have been achieved are discussed and illustrated; their performance characteristics and advantages described. This overview finalizes by going back to the future and considers enterprising research areas of current and forward‐looking interest.
In this paper, we improve the uplink energy efficiency (EE) of the multi-band machine-to-machine (M2M) communications underlaying cellular networks. In particular, based on the theory of stochastic geometry, we derive the closed-form expressions of the outage probability (OP), and the average energy efficiency of cellular and Machine-to-Machine users in two-way cooperative relaying networks with three-time-slot setting. We ensure the quality of service (QoS) by considering the OP and the average energy efficiency of all links. It is concluded that the three-time-slot relay-aided Machine-to-Machine communication can offer considerably high QoS and low transmission power for fairly distant machine-to-machine networks.
The continuous development of fifth generation (5G) communication and Internet of Thing (IoT) inevitably necessitates more advanced systems that can satisfy the growing wireless data rate demand of future equipment. Device-to-Device (D2D) communication, whose performance is evaluated in terms of the overall throughput, energy efficiency (EE) and spectral efficiency (SE), is considered a promising solution for the aforementioned problem. Thereby, this paper aims at improving the performance of the D2D communication underlaying cellular networks operating on multiple bands by maximizing the EE in its uplink. Thanks to the stochastic geometry theory, it is possible to derive the closed-form expressions for the successful transmission probability (STP), the total average transmission rate (TATR), and the total average energy efficiency (TAEE) of cellular and D2D users in different time slot setting. Particularly investigated and compared in this study, there are one-hop, direct, D2D communication in two time slots (2TS), and multi-hop, indirect, D2D communication in three time slots (3TS) with an additional D2D user acting as a two-way relay to assist the communication. Moreover, an optimization problem is formulated to calculate the maximum TAEE of D2D users and the optimum transmission power of both the cellular and D2D users. Herein this optimization study, which is proven to be non-convex, the Quality of Service (QoS) is ensured as the STP on every link is considered. The herein approach is referred to as relay-assisted D2D communication which is capable of delivering a notably better QoS and lower transmission power for communication among distant D2D users.
In relay-based cooperative communications (RBCC) system, the energy problem of relays is a significant issue needs to be addressed. In the last few years, the simultaneous wireless information and power transfer (SWIPT) technique has been introduced to solve that matter. SWIPT technique aims to carry data and power over the wireless signals from the source node to the destination for the relays system. The SWIPT technique can be implemented utilizing two protocols. The first one has been introduced as time switch relay (TSR) protocol, which is time division between energy harvesting and data transmission. The second one has been introduced as power switch relay (PSR) protocol based on power division between two mentioned processes. The time or power fraction directly affects the quality of service (QoS) parameters in SWIPT-based cooperative communication systems. This paper aims to maximize effective capacity by implementing an optimization to find the optimum time or power fraction of energy harvesting in relays system utilizing TSR or PSR protocols. The optimization is applied using Lagrange multipliers while simulation results are used to verify the theoretical results obtained from the optimization process. In addition, outage probability of the source-relay-destination link is analyzed in both TSR and PSR protocols.
In this paper, cooperative non-orthogonal multiple access (NOMA) network is investigated to aid device-to-device (D2D) communication. In such D2D NOMA, Amplify and Forward (AF) and Decode and Forward (DF) mode are deployed to signal processing at relay who intends to serve NOMA far user. To ensure the quality of service (QoS) for the NOMA devices, a minimum rate requirement is pre-defined for each device. Two main schemes are considered insightfully: i) The first scenario is that the first device intends to communicate with the second device through the assistance of AF/DF-assisted base station (BS), where equips individual power; and ii) The second scenario is that the wireless powered device is able to communicate with non-energy harvesting device. Because of the QoS requirement, it is first necessary to determine performance gap in two folds: relay and direct mode; non-wireless power transfer (NWPT) scenario and wireless power transfer (WPT) scenario, by comparing the outage performance with the required power for satisfying the QoS of the devices. To further evaluation, we extend our analysis on non-linear energy harvesting policy and multiple NOMA far users which are deployed in such D2D transmission. If feasible, a closed-form solution is provided for system performance evaluation. Numerical results are presented to validate the effectiveness of the proposed D2D transmission strategies.
The fast progress of mobile devices and modern wireless networks result in the explosive demand for wireless data transfer. Such wireless communications have to meet numerous challenges such as spectrum sharing, energy scarcity, and security to deal with the dramatic growth in wireless data which shift the focus of research directions to fifth-generation (5G) networks. To address these challenges in wireless design, researchers need to come up with energy and spectrum management solutions in 5G networks. The key technologies for 5G considering reliable cooperative networks such as full-duplex networks, energy-efficient communications so-called energy harvesting, and secure networks with physical layer considerations. In general, to guarantee quality-of-service (QoS) it is required high-speed data rate and reliable transmission in design of new paradigms in 5G networks. This chapter focuses on cooperative networks applied in several emerging wireless technology. In addition, these cooperative networks have been well-known models for improving the coverage of wireless systems. The key principle of cooperative network is that one or some relay nodes are installed to forward messages from the source node to its destinations in case of the direct transmission is inaccessible. As popular schemes, we introduce dual-hop scheme and multi-hop scheme with one or many relaying links from the source node to the destination node in this section. In each hop, the relaying node first process received signal of the signal from the previous hop and then used to relay the signal to the next hop. To examine the performance of relay networks, various relay selection protocols and key fundamental relaying schemes including amplify-and-forward (AF) and decode-and-forward (DF) are investigated. In recent applications of Internet of things (IoT) or wireless sensor networks (WSNs), the source and relay are usually energy-constrained nodes which result in limitation of operation time and the network performance. To overcome the challenge of replacing or recharging batteries in such wireless nodes, energy harvesting has been proposed architecture in relaying networks to prolonging the lifetime of these mobile nodes. Motivated by the recent benefits of self-interference elimination procedures of possible full-duplex (FD) transceivers. As an important model, this chapter further explores the reliable cooperative networks to enhance system performance. In such networks, FD entities and energy harvesting-assisted relay node can be examined to confirm advantages of FD transmission architecture. Furthermore, with the aim to deal with high traffic volume and optimize spectral efficiency, two-way relaying scheme is widely considered. In particular, this chapter presents system model of relaying networks to improve the spectral efficiency of the network, and the outage performance for the network is analyzed. Finally, due to the broadcast nature of wireless transmission, secure communication is compulsorily required in emerging network design, especially in scenarios of increasing number of the unintended receivers which is very challenging mission. Through this secure model, the physical layer without cryptography is investigated to examine positive secrecy capacity. In particular, the secrecy performance of an energy harvesting relay system is studied, in which a legitimate source transfers data to a legitimate destination via the support of unreliable relays.
In practice, full-duplex (FD) transmission achieves better system outage performance than that of half-duplex (HD) transmission but suffers from strong self-interference (SI). In this paper, we provide performance analysis of relay selection (RS) schemes in multi-relay wireless networks, where we obtain the exact and approximate closed-form expressions for outage probability (OP) in the high signal-to-noise ratio (SNR) regime over independent and identically distributed (i.i.d.) Rayleigh fading channels in three proposed optimal RS schemes, i.e., HD deploying maximal ratio combine (HDMRC) and FD deploying joint decoding (FDJD) and hybrid FD/HD relaying transmission scheme (HTS). Most importantly, these schemes operate in two proposed optimal power supply policies so-called optimal power under the individual power constraints (OPIPC) and optimal power with energy harvesting ability (OPEHA). Additionally, asymptotic expressions in high SNR regime are given to help gain better insights on the system performance. It is also shown that the proposed HTS scheme outperforms HDMRC and FDJD schemes in terms of outage performance, where OPEHA is better than OPIPC under the impact of SI. Besides that, HTS RS scheme significantly decreases the power consumption which helps enhance energy efficiency. The validity of the proposed analyses is proven by simulations.
The emergence of Simultaneous Wireless Information and Power Transfer (SWIPT) has opened new avenues to address the issue of energy shortage in wireless networks. The ability to transfer power and information across the network can not only help the edge devices to communicate efficiently but also prolong the lifetime of devices near the base station. In cooperative networks it can provide the much needed flexibility at relays to harvest the energy from a distant source. Aforementioned reasons are some of the key motivations to review the advances in SWIPT. Therefore, this paper provides a review of recent studies in SWIPT from a technical point of view. In particular we discuss the fundamentals of separated and integrated receiver architectures in SWIPT. We then provide the tradeoff between rate and energy in SWIPT by using data outage and energy shortage probabilities. This review also act as a corner stone to understand the significance of green communication in future 5G technologies.
The cognitive radio (CR) with energy harvesting is a potential technology to improve both the spectrum efficiency (SE) and the energy efficiency (EE). In this letter, we consider that the secondary users can harvest radio frequency (RF) energy from primary signal and its own signal. The goal is to maximize the energy efficiency of the CR system subject to sufficient protection to the primary user and the power constraint. An efficient algorithm is proposed to optimize the sensing time and the power of the secondary transmitter. Simulation results show that the EE is further improved by using the proposed mechanism.
In this paper, we consider a cognitive cooperative wireless system consisting of two primary users, a cognitive base station (CBS) and a secondary user. A cognitive two-way relaying (CTWR) scheme is proposed, where the secondary user tries to assist the primary users to meet their target quality of service (QoS) by acting as a cognitive two-way relay, when the direct link of the two primary users cannot meet the target QoS. As a return, the primary network shares its transmission time-slot with the secondary user. First, the system outage probabilities of traditional direct transmission and CTWR scheme are analyzed, giving both the exact and approximated expressions. Second, a transmission time-slot splitting algorithm between the primary and secondary users is proposed. Third, the ergodic capacity of the secondary user under the CTWR scheme is examined. Finally, simulation results show that the proposed scheme cannot only help the primary users to meet their target QoS, but also improve the communication opportunities of the secondary user.
This paper aims at energy-efficient transmission of packets with individual deadlines. In order to reduce the transmission energy of a packet, a lower data rate should be adopted, while the deadline restraint leads to a rate lower limit. It is derived theoretically that the energy-optimal transmission, i.e., the transmission consuming the minimal energy, follows three theorems: (1) the rate is invariable except for the deadlines of the packets; (2) the rate is non-increasing over the whole transmission time; (3) if the rate decreases at a deadline, only the terminated packets have been transmitted. Then, a scheduling algorithm based on backward unidirectional valve (BUV) is proposed, where the packets are divided into multiple groups and each group corresponds to a fixed rate. Specifically, the packets are handled one by one, and any packet is taken as a new group in the initial. If the transmission rate of the new group is not lower than that of its preceding neighboring group, the two groups are amalgamated into one, and this procedure is implemented constantly before the rate decreases in stairs. The BUV scheduling not only achieves the energy-optimal transmission, but also has a low computational complexity.
This work investigates the secrecy performance for a simultaneous wireless information and power transfer system that operates in the presence of cooperating eavesdroppers. The multi-antenna access point’s transmission is used for information-decoding by a multi-antenna node and for energy-harvesting (EH) by multiple single-antenna nodes. However, some of the nodes authorized for EH only attempt to eavesdrop on the ongoing information transmission by utilizing a generalized on-off power splitting architecture. We derive a closed-form expression for the secrecy outage probability of the considered Multiple-Input-Multiple-Output Multiple-Eavesdroppers system. Theoretical and simulation results are provided to validate the derived results.
We consider a multi-input-single-output (MISO) system where a wireless power transmitter sends wireless power to a receiver via beamforming using the estimated channel, and the power receiver uses the harvested energy to power some applications. We consider transmissions based on frames each of which consists of the channel estimation phase, the feedback phase, the wireless power transfer phase, as well as the energy utilization phase. The feedback time is assumed to be negligible. In this paper, we maximize the utility of the harvested energy, by jointly optimizing the time resource allocated for channel estimation, wireless power transfer, as well as the energy utilization. In particular, we consider two typical application scenarios in which the energy-harvesting receiver uses the harvested energy to perform wireless transmission or sensing. The optimal time allocation is derived to maximize the net average information rate or maximize the sensing accuracy. The analysis results are validated by numerical simulations.
This paper exploits an amplify-and-forward (AF) two-way relaying network (TWRN), where an energy constrained relay node harvests energy with wireless power transfer. Two bidirectional protocols, multiple access broadcast (MABC) protocol and time division broadcast (TDBC) protocol, are considered. Three wireless power transfer policies, namely, 1) dual-source (DS) power transfer; 2) single-fixed-source (SFS) power transfer; and 3) single-best-source (SBS) power transfer are proposed and well-designed based on time switching receiver architecture. We derive analytical expressions to determine the throughput both for delay-limited transmission and delay-tolerant transmission. Numerical results corroborate our analysis and show that MABC protocol achieves a higher throughput than TDBC protocol. An important observation is that SBS policy offers a good tradeoff between throughput and power.
Optimization of a point-to-point (p2p) multipleinput single-output (MISO)
communication system is considered when both the transmitter (TX) and the
receiver (RX) have energy harvesting (EH) capabilities. The RX is interested in
feeding back the channel state information (CSI) to the TX to help improve the
transmission rate. The objective is to maximize the throughput by a deadline,
subject to the EH constraints at the TX and the RX. The throughput metric
considered is an upper bound on the ergodic rate of the MISO channel with
beamforming and limited feedback. Feedback bit allocation and transmission
policies that maximize the upper bound on the ergodic rate are obtained. Tools
from majorization theory are used to simplify the formulated optimization
problems. Optimal policies obtained for the modified problem outperform the
naive scheme in which no intelligent management of energy is performed.
While cognitive radio enables spectrum-efficient wireless communication,
radio frequency (RF) energy harvesting from ambient interference is an enabler
for energy-efficient wireless communication. In this paper, we model and
analyze cognitive and energy harvesting-based D2D communication in cellular
networks. The cognitive D2D transmitters harvest energy from ambient
interference and use one of the channels allocated to cellular users (in uplink
or downlink), which is referred to as the D2D channel, to communicate with the
corresponding receivers. We investigate two spectrum access policies for
cellular communication in the uplink or downlink, namely, random spectrum
access (RSA) policy and prioritized spectrum access (PSA) policy. In RSA, any
of the available channels including the channel used by the D2D transmitters
can be selected randomly for cellular communication, while in PSA the D2D
channel is used only when all of the other channels are occupied. A D2D
transmitter can communicate successfully with its receiver only when it
harvests enough energy to perform channel inversion toward the receiver, the
D2D channel is free, and the $\mathsf{SINR}$ at the receiver is above the
required threshold; otherwise, an outage occurs for the D2D communication. We
use tools from stochastic geometry to evaluate the performance of the proposed
communication system model with general path-loss exponent in terms of outage
probability for D2D and cellular users. We show that energy harvesting can be a
reliable alternative to power cognitive D2D transmitters while achieving
acceptable performance. Under the same $\mathsf{SINR}$ outage requirements as
for the non-cognitive case, cognitive channel access improves the outage
probability for D2D users for both the spectrum access policies.
This paper studies a wireless-energy-transfer (WET) enabled massive
multiple-input-multiple-output (MIMO) system (MM) consisting of a hybrid
data-and-energy access point (H-AP) and multiple single-antenna users. In the
WET-MM system, the H-AP is equipped with a large number $M$ of antennas and
functions like a conventional AP in receiving data from users, but additionally
supplies wireless power to the users. We consider frame-based transmissions.
Each frame is divided into three phases: the uplink (UL) channel estimation
(CE) phase, the downlink (DL) WET phase, as well as the UL wireless information
transmission (WIT) phase. Firstly, users use a fraction of the previously
harvested energy to send pilots, while the H-AP estimates the UL channels and
obtains the DL channels by exploiting channel reciprocity. Secondly, the H-AP
broadcasts wireless energy to all users in the DL via energy beamforming.
Thirdly, the users use the rest of the harvested energy to send their
independent information to the H-AP simultaneously in the UL. To optimize the
throughput and ensure rate fairness, we consider the problem of maximizing the
minimum rate among all users. The variables are the time allocation for UL CE
and DL WET, the energy allocation weights in the DL WET phase, as well as the
fraction of energy used for CE. In the large-$M$ regime, we obtain the
asymptotically optimal solutions and some interesting insights. We define a
metric, namely, the massive MIMO degree-of-rate-gain (MM-DoRG), as the
asymptotic UL rate normalized by $\log(M)$. We show that the proposed WET-MM
system is optimal in terms of MM-DoRG, i.e., it achieves the same MM-DoRG as
the case with ideal CE. Moreover, in the proposed WET-MM system, the users
asymptotically achieve a common rate, ensuring the best possible rate fairness
among users.
The various wireless networks have made the ambient radio frequency signals
around the world. Wireless information and power transfer enables the devices
to recycle energy from these ambient radio frequency signals and process
information simultaneously. In this paper, we develop a wireless information
and power transfer protocol in two-way amplify-and-forward relaying channels,
where two sources exchange information via an energy harvesting relay node. The
relay node collects energy from the received signals and uses it to provide the
transmission power to forward the received signals. We analytically derive the
exact expressions of the outage probability, the ergodic capacity and the
finite-SNR diversity-multiplexing trade-off (DMT). Furthermore, the tight
closed-form upper and lower bounds of the outage probability and the ergodic
capacity are then developed. Moreover, the impact of the power splitting ratio
is also evaluated and analyzed. Finally, we show that compared to the
non-cooperative relaying scheme, the proposed protocol is a green solution to
offer higher transmission rate and more reliable communication without
consuming additional resource.
1. Introduction. 2. Events as Propositions. 3. Finitely Additive Probability. 4. Coherent probability. 5. Betting Interpretation of Coherence. 6. Coherent Extensions of Probability Assessments. 7. Random Quantities. 8. Probability Meaning and Assessment: a Reconciliation. 9. To Be or not To Be Compositional? 10. Conditional Events. 11. Coherent Conditional Probability. 12. Zero-Layers. 13. Coherent Extensions of Conditional Probability. 14. Exploiting Zero Probabilities. 15. Lower and Upper Conditional Probabilities. 16. Inference. 17. Stochastic Independence in a Coherent Setting. 18. A Random Walk in the Midst of Paradigmatic Examples. 19. Fuzzy Sets and Possibility as Coherent Conditional Probabilities. 20. Coherent Conditional Probability and Default Reasoning. 21. A Short Account of Decomposable Measures of Uncertainty. Bibliography. Index.
In this paper, we propose a new formula for achieving optimal throughput in energy-aware cooperative networks with generic time and power energy harvesting protocol, namely time power switching based relaying (TPSR). Especially, this investigation analyzes the impact of imperfect hardware at the relay node and the destination node in the two-way relaying networks (TWRN). This analysis enables us to derive the closed-form expressions of outage probabilities of signal-to-noise and distortion ratio (SNDR) at the destination nodes under the effect of hardware impairments. Interestingly, the optimal policy of joint wireless information and energy transfer is designed to maximize the system throughput by finding the optimal time switching and power splitting fractions in the proposed TPSR protocol. An important achievement is that the proposed optimal design offers the maximum throughput of system when we consider the trade-off between throughput and time-power factors in energy harvesting protocol by both numerical method and simulation. Numerical results provide practical insights into the performance of energy-aware TWRN under hardware impairments. Monte-Carlo method is also deployed to corroborate the accuracy of analytical derived expressions.
The concept of mobile user equipment (UE) relay (UER) has been introduced to support the relaying transmission using device-to-device (D2D) communications for enhancing communication reliability. However, as the UER needs to use its own power for the other UE's data transmission, the D2D communication can be unfair to the UER. To overcome this issue, motivated by the recent advance in energy harvesting (EH) techniques, we consider the D2D communication provided EH cellular network (D2D-EHCN) where the UERs harvest RF energy from a base station (BS) and use the harvested energy for D2D communications. We first derive the UER distribution by taking into account the EH parameters, and propose the transmission mode selection scheme including the UER selection method. After deriving the outage probability of the D2D-EHCN, we explore the effects of the network parameters on the outage probability. Particularly, we show that the outage probability of D2D-EHCN is smaller than that of the cellular network without D2D communication, and their difference becomes more significant when the density of BSs is small.
This paper studies the outage probability minimization problem for a multiple
relay network with energy harvesting constraints. The relays are hybrid nodes
used for simultaneous wireless information and power transfer from the source
radio frequency (RF) signals. There is a trade-off associated with the amount
of time a relay node is used for energy and information transfer. Large
intervals of information transfer implies little time for energy harvesting
from RF signals and thus, high probability of outage events. We propose relay
selection schemes for a cooperative system with a fixed number of RF powered
relays. We address both causal and non-causal channel state information cases
at the relay--destination link and evaluate the trade-off associated with
information/power transfer in the context of minimization of outage
probability.
Opportunistic forwarding assisted by mobile relays is an effective way of improving network capacity and packet delivery ratio in delay tolerant networks (DTNs). However, such performance gain comes at the price of increased energy consumption due to the duplicated transmissions at relays. In this paper, we investigate how energy harvesting, a promising technique of enabling sustainable communications, can be exploited to improve the performance of opportunistic forwarding in mobile DTNs. Specifically, we formulate the problem using a Markov Decision Process (MDP) framework in which each source should strike a balance between exploitation, by forwarding the packet to the relay currently in contact, and exploration, by waiting for possible better relays in the future, given the harvested energy constraint. The formulated MDP having exponential complexity, we devise a heuristic relay-assisted opportunistic forwarding scheme, termed as adaptive M-step lookahead scheme, to alleviate the computation complexity, where M can be adjusted adaptively according to both the current energy and the energy that might be harvested in the future. Simulation results show that our proposed algorithm can use the harvested energy more efficiently, especially for the circumstance where the energy harvesting rate is low.
In this paper, a half-duplex two-way relay channel with energy harvesting nodes is considered. In particular, short-term throughput maximization problems are solved using a decode-and-forward relay. Necessary properties of the optimal transmission policy are derived to gain insights into the optimal solution. Then, a subgradient descent algorithm is used to find the optimal policy. It is observed through simulations that energy-deficient nodes act as bottlenecks on the achieved throughput. The achieved average throughput is observed to be close to the upper bound when nodes have no energy intermittency, and significantly higher than the throughput achieved by naïve policies.
Energy harvesting (EH) has recently emerged as a promising technique for green communications. To realize its potential, communication protocols need to be redesigned to combat the randomness of the harvested energy. In this paper, we investigate how to apply relaying to improve the short-term performance of EH communication systems. With an EH source and a non-EH half-duplex relay, we consider the problem of maximizing the achievable rate for a given time duration. The half-duplex constraint at the relay renders the design problem quite challenging, as the source and relay transmission periods should be carefully scheduled. Moreover, the adaptive power allocation is needed at the source to combat the random energy arrivals. A key finding is that the optimal power allocation algorithm, called directional water-filling (DWF), for the single-hop EH system can serve as guideline for the design of a two-hop communication system, as it not only provides an achievable performance upper bound, but also forms the basis to derive the optimal solution for our design problem. Based on a modified energy profile according to the DWF power allocation, we derive key properties of the optimal solution and thereafter propose an efficient algorithm to maximize the throughput. Simulation results show that both scheduling and power allocation optimizations are necessary in two-hop EH communication systems.
We consider energy harvesting cognitive radio networks in which a secondary transmitter harvests energy from ambient sources or wireless power transfer systems while opportunistically accessing the spectrum licensed to the primary network. The primary traffic is modeled as a time-homogeneous discrete Markov process, and the secondary transmitter may not be able to operate continuously due to sporadic and unstable energy sources. At the beginning of each time slot, the secondary transmitter thus needs to determine whether to remain idle so as to conserve energy, or to execute spectrum sensing to acquire knowledge of the current spectrum occupancy state. It also needs to configure the spectrum sensor detection threshold to achieve an effective tradeoff between false alarms and misdetections. This sequential decision-making, done to maximize the expected total throughput, requires the joint design of a spectrum sensing policy and a detection threshold under the energy causality and collision constraints. We formulate this stochastic optimization problem as a constrained partially observable Markov decision process (POMDP), and then convert it to a computationally tractable unconstrained POMDP. Numerical results show that the proposed approach enables efficient usage of the harvested energy by exploiting the temporal correlation of the primary traffic.
This paper studies optimal resource allocation in the wireless-powered
communication network (WPCN), where one hybrid access-point (H-AP) operating in
full-duplex (FD) broadcasts wireless energy to a set of distributed users in
the downlink (DL) and at the same time receives independent information from
the users via time-division-multiple-access (TDMA) in the uplink (UL). We
design a protocol to support simultaneous wireless energy transfer (WET) in the
DL and wireless information transmission (WIT) in the UL for the proposed
FD-WPCN. We jointly optimize the time allocations to the H-AP for DL WET and
different users for UL WIT as well as the transmit power allocations at the
H-AP to maximize the users' weighted sum-rate. We consider both the cases with
perfect and imperfect self-interference cancellation (SIC), for which we obtain
optimal and suboptimal time and power allocation solutions, respectively.
Furthermore, we consider the half-duplex (HD) WPCN as a baseline scheme and
derive its optimal resource allocation solution. Simulation results show that
the FD-WPCN outperforms HD-WPCN when effective SIC is implemented and/or more
stringent peak power constraint is applied at the H-AP.
We consider a cognitive radio network with an energy-harvesting secondary transmitter to improve both energy efficiency and spectral efficiency. The goal of this paper is to determine an optimal spectrum sensing policy that maximizes the expected total throughput subject to an energy causality constraint and a collision constraint. The energy causality constraint comes from the fact that the total consumed energy should be equal to or less than the total harvested energy, while the collision constraint is required to protect the primary user. We first show that the system can be divided into a spectrum-limited regime and an energy-limited regime depending on where the detection threshold for the spectrum sensor lies. Assuming infinite battery capacity, we derive the optimal detection threshold that maximizes the expected total throughput subject to the energy causality constraint and the collision constraint. Analytical and numerical results show that the system is energy-limited if the energy arrival rate is lower than the expected energy consumption for a single spectrum access. They also show that a decreasing probability of accessing the occupied spectrum does not always result in decreased probability of accessing the idle spectrum in the energy-limited regime.
An emerging solution for prolonging the lifetime of energy constrained relay
nodes in wireless networks is to avail the ambient radio-frequency (RF) signal
and to simultaneously harvest energy and process information. In this paper, an
amplify-and-forward (AF) relaying network is considered, where an energy
constrained relay node harvests energy from the received RF signal and uses
that harvested energy to forward the source information to the destination.
Based on the time switching and power splitting receiver architectures, two
relaying protocols, namely, i) time switching-based relaying (TSR) protocol and
ii) power splitting-based relaying (PSR) protocol are proposed to enable energy
harvesting and information processing at the relay. In order to determine the
throughput, analytical expressions for the outage probability and the ergodic
capacity are derived for delay-limited and delay-tolerant transmission modes,
respectively. The numerical analysis provides practical insights into the
effect of various system parameters, such as energy harvesting time, power
splitting ratio, source transmission rate, source to relay distance, noise
power, and energy harvesting efficiency, on the performance of wireless energy
harvesting and information processing using AF relay nodes. In particular, the
TSR protocol outperforms the PSR protocol in terms of throughput at relatively
low signal-to-noise-ratios and high transmission rate.
This paper considers a two-user Gaussian interference channel with energy
harvesting transmitters. Different than conventional battery powered wireless
nodes, energy harvesting transmitters have to adapt transmission to
availability of energy at a particular instant. In this setting, the optimal
power allocation problem to maximize the sum throughput with a given deadline
is formulated. The convergence of the proposed iterative coordinate descent
method for the problem is proved and the short-term throughput maximizing
offline power allocation policy is found. Examples for interference regions
with known sum capacities are given with directional water-filling
interpretations. Next, stochastic data arrivals are addressed. Finally online
and/or distributed near-optimal policies are proposed. Performance of the
proposed algorithms are demonstrated through simulations.
Optimal power control for source and relay in energy harvesting relay networks
- Y Xia
- H Chen
- L Fan
- F Dai
Xia Y, Chen H, Fan L, Dai F. Optimal power control for source and relay in
energy harvesting relay networks. In: Proc. of 8th International ICST
Conference on Communications and Networking in China (CHINACOM). p.
942-7. doi: http://dx.doi.org/10.1109/ChinaCom..6694730.
Optimal MIMO broadcasting for energy harvesting transmitter with non-ideal circuit power consumption
- X Wang
- Z Nan
- T Chen
Wang X, Nan Z, Chen T. Optimal MIMO broadcasting for energy harvesting
transmitter with non-ideal circuit power consumption. IEEE Trans. Wireless
Commun. 2015;14(5):2500-12. doi: http://dx.doi.org/10.1109/TWC.2014.
2387380.
His research interests include energy-efficient wireless communications, 5G wireless communication networks
- Hoang-Sy
Hoang-Sy Nguyen received the B.S. and MS.c degree from the Department of
Computer Science from Ho Chi Minh City University of Information Technology
(UIT-HCMC), Vietnam in 2007, 2013. He is currently pursuing the Ph.D. at School of
Electrical Engineering and Computer Science, Technical University of Ostrava, Czech
Republic. His research interests include energy-efficient wireless communications,
5G wireless communication networks, computer network, network security, lowpower networks, cloud and distributed networks.
Prior to joining Ton Duc Thang University, he was senior engineer at the VinaPhone Mobile Network from 2003 to 2009. Dr. Thuan was recipient of Golden Globe Award from Vietnam Ministry of Science and Technology in 2015
- Dinh-Thuan
Dinh-Thuan Do received the B.S. degree, M. Eng. degree, and Ph.D. degree from
Vietnam National University (VNU-HCMC) in 2003, 2007, and 2013 respectively, all
in Communications Engineering. He was a visiting Ph.D. student with Communications Engineering Institute, National Tsing Hua University, Taiwan from 2009 to
2010. Prior to joining Ton Duc Thang University, he was senior engineer at the
VinaPhone Mobile Network from 2003 to 2009. Dr. Thuan was recipient of Golden
Globe Award from Vietnam Ministry of Science and Technology in 2015. His
research interest includes signal processing in wireless communications network,
cooperative communications, full-duplex transmission and energy harvesting.