D2D communication with energy harvesting relays for disaster management

ABSTRACT

In this paper, we consider a multi-hop device-to-device (D2D) communication, which enables communication from functional area (FA), where the D2D users are placed near to base station (BS) under its coverage to non-functional area (NFA). In our proposed model, random deployment as well as certain distance-dependent deployment of D2D node is considered in NFA. In case of FA, BS is transmitting information with fixed transmit power in multi-hop D2D network. In case of NFA, a D2D node harvests energy from its preceding node, and forwards the information to the successive node. Parallel best path selection (PBPS) and immediate best path selection (IBPS) strategies are considered for FA while several cases of deployment strategies based on inter-node distance is considered for NFA to reach the final destination node. A framework has been proposed for evaluating throughput, ergodic capacity and outage probability. Energy consumption in the system has been estimated via simulation. The throughput performance, ergodic capacity and the outage probability of end-to-end link (i.e. from BS to NFA) under different system parameters are evaluated.     

能量收集认知多跳中继网络中断性能分析及优化

针对能量收集认知无线网络中的多跳中继传输问题,该文构建了一种新的具有主网络干扰的功率信标(PB)辅助能量收集认知多跳中继网络模型,并提出单向传输方案。在干扰链路统计信道状态信息场景下,推导了次网络精确和渐近总中断概率闭合式。针对精确总中断概率表达式的复杂性和非凸性,采用自适应混沌粒子群优化(ACPSO)算法对次网络总中断性能进行优化。仿真结果表明,PB功率、干扰约束、次网络跳数、能量收集比率、主接收端数目和信道容量阈值等参数对中断性能影响显著,所提算法能快速和有效地对网络中断性能进行优化。     

Energy harvesting assisted cognitive radio: random location-based transceivers scheme and performance analysis

We consider spectrum-sharing scenario where coexist two communication networks including primary network and secondary network using the same spectrum. While the primary network includes directional multi-transceivers, the secondary network consists of relaying-based transceiver forwarding signals by energy harvesting assisted relay node. In cognitive radio, signals transmitted from secondary network are sufficiently small so that all of primary network receivers have signal to noise ratio (SNR) greater than a given threshold. In contrast, the transmitted signals from primary network cause increasing noise which is difficult to demodulate at secondary network nodes and hence it leads to the peak power constraint. In this paper, we focus on the influence of random location of transceivers at primary network using decode-and-forward protocol. Specifically, we derive closed-form outage probability expression of the secondary network under random location of transceivers and peak power constraint of primary network. This investigation shows the relationship between the fraction of energy harvesting time \(\alpha \) of time switching-based relaying protocol on outage probability of secondary network and throughput. In addition, we analyse the influence of the number of primary network transceivers as well as primary network’s SNR threshold on secondary network. Furthermore, the trade-off between increasing energy harvesting and rate was investigated under the effect of energy conversion efficiency. The accuracy of the expressions is validated via Monte-Carlo simulations. Numerical results highlight the trade-offs associated with the various energy harvesting time allocations as a function of outage performance.     

Performance analysis of energy harvesting cognitive relay networks with primary interference

This paper investigates the outage performance of multihop energy harvesting cognitive relay network (EH-CRN), in which the secondary nodes are powered by dedicated power beacons based on the time splitting strategy. Assuming a multihop secondary network, we derive an analytical expression for the outage probability experienced by a secondary user by taking into account the effect of interference power from primary source. The developed outage probability model can be used to assess the impact of some key parameters on the reliability of the secondary user’s link in an EH-CRN. We then investigate the optimal location of the relay node in a one dimensional two-hop secondary network that minimizes the outage probability. Next, we study how the various system parameters such as energy harvesting efficiency, path loss exponent, harvest-to-transmit time duration ratio and transmit power from primary source affect the optimal relay location. The outage improvement achieved when the relay is placed at the optimum location is also investigated. Furthermore, the sensitivity of optimal relay location to the variations in position of the primary receiver is examined. Extensive simulation results are used to corroborate the analytical findings.     

Analysis of Network Path Selection Based on Outage Probability in Cognitive Relay Networks

This paper evaluates the outage performance of cognitive relay networks with mutual interference between secondary users and primary users under the underlay approach, while adhering to the interference constraint on the primary user. A network path selection criterion, suitable for cognitive relay networks, is provided, from which we derive the outage probability expression of cognitive relay networks. It is shown that the outage probability considering the interference to secondary user from primary user is higher than that without considering the interference to secondary user from primary user. In addition, the outage probability is affected by key network parameters. We analyze network path selection method based on outage probability and prove that the interference to secondary user from primary user has a significant effect on the network path selection and can not be ignored in practical wireless communication environments. Simulation investigation is also provided and used to verify the theoretical analysis.     

Performance Analysis of Two-Way Hybrid Decode-and-Amplify Relaying Scheme with Relay Selection for Secondary Spectrum Access

In this paper, we propose and analyze the outage probability of a two-way hybrid decode-and-amplify relaying scheme with relay selection for secondary spectrum access. In this scheme, a secondary network is co-located and uses the same spectrum as the primary network. The primary network is comprised of two primary terminals that attempt to transmit signals to one another; the secondary network is comprised of M secondary transmitter-receiver pairs (ST-SR). One of the secondary transmitters chosen to cooperate with the primary network uses a hybrid decode-and-amplify forward technique in order to relay primary and secondary signals. We derive expressions for the outage probability of the primary network as well as the secondary network over a Rayleigh fading channel. Simulation results are presented to verify theoretical analyses and to compare the performance of the proposed protocol to that of a two-way direct transmission protocol.     

Analysis and modeling of upstream throughput in multihop packet CDMA cellular networks

We consider the problem of throughput modeling of wireless multihop packet CDMA networks with cellular overlay using simple forwarding strategies in the upstream. Considering the effect of shadowing and distance-dependent path loss, we approximate the probability density of interference at each base station (BS) and compare numerical and simulation results for different path-loss parameters. We derive the probability density of the received power at each BS due to transmission of one packet from a random node, as well as the probability distribution of the number of packets received at each node per time slot. Subsequently, we use the above results to approximate the probability density of the total received power at each BS based on calculations of moments. We observe that the probability density of intercell interference due to transmissions from terminals and routers may be approximated by normal and log-normal densities, respectively. We quantify the network performance based on throughput, total consumed power, and outage probability for different system parameters. For homogeneous link efficiencies, introducing routers into the network while reducing the transmission power increases the mean and variance of interference to the desired signal, hence higher outage probability. However, there are ample opportunities inherent to multihop structure, applicable to any of the physical, data link, and network layers, which help increase the overall achievable network throughput.     

Energy aware power allocation strategies for multihop-cooperative transmission schemes

This paper is focused on the optimization of transmitted power in a cooperative decoded relaying scheme for nodes belonging to the single primary route towards. a destination. The proposed transmission protocol, referred to as Multihop Cooperative Transmission Chain (MCTC), is based on the linear combination of copies of the same message by multiple previous terminals along the route in order to maximize the multihop diversity. Power allocations among transmitting nodes in the route can be obtained according to the average (not instantaneous) node-to-node path attenuation using a recursive power assignment. The latter can be employed locally on each node with limited signalling exchange (for fixed or nomadic terminals) among nodes. In this paper the power assignments for the MCTC strategy employing conventional linear combining schemes at receivers (i.e., selection combining, maximal ratio combining and equal gain combining) have been derived analytically when the power optimization is constrained to guarantee the end-to-end outage probability. In particular, we show that the power assignment that minimize the maximum spread of received power (min-max strategy) can efficiently exploit the multihop diversity. In addition, for ad hoc networks where the energy of each node is an issue, the MCTC protocol with the min-max power assignment increases considerably the network lifetime when compared to non-cooperative multihop schemes     

Outage Performance of Hybrid Decode–Amplify–Forward Protocol with the nth Best Relay Selection

In this paper, we consider the Hybrid Decode–Amplify–Forward protocol with the \(n\) th best-relay selection scheme. In the best-relay selection scheme, the best relay only forwards the source signal to the destination, regardless of working in the Amplify-and-Forward mode or the Decode-and-Forward mode. However, the best relay might be unavailable due to some reasons; hence we might bring into play the second, third or generally the \(n\) th best relay. We derive closed-form expression for the outage probability using the probability density function and moment generating function of the signal-to-noise ratio of the relayed signal at the destination node. Results show that with the \(n\) th best relay the diversity order is equal to \((m-n+2)\) where \(m\) is the number of relays. Simulation results are also given to verify the analytical results.     

A Relay-Aided Media Access (RAMA) Protocol in Multirate Wireless Networks

The IEEE 802.11 standard inherently supports multiple data rates at the physical layer. Various rate adaptation mechanisms have been proposed to exploit this multirate capability by automatically adapting the transmission rate to best utilize the wireless spectrum. This study is primarily motivated by the observation that in a wireless network, a multihop high-rate path can potentially achieve better throughput and delay than using a single-hop low-rate path for transmission. Specifically, this paper introduces a relay-aided media access (RAMA) protocol by taking advantage of the existence of such multihop high-rate links. This is demonstrated by replacing one low-rate link with two high-rate links using a relay node. One of the key novelties in the proposed RAMA protocol is that the transmission from the immediate relay node to the destination node is free of contention. Results from analysis and simulations show that RAMA can significantly improve performances in terms of both throughput and delay.     

Performance of new relay selection scheme for buffer-assisted multihop decode-and-forward networks

In this paper, a new relay selection scheme is proposed to reduce the end-to-end packet delivery delay for buffer-assisted multihop decode-and-forward cooperative networks. The proposed method selects a relay node having more packets in the associated buffer and relay's proximity to the destination node. Mathematical expressions for the outage probability and average packet delay in Rician fading are obtained by modeling the system as a Markov chain. The proposed relay selection scheme has less packet delay as compared to the max-link relay selection scheme with marginally higher outage probability. Thus, the proposed relay selection scheme is a good alternative to low latency wireless applications.     

Cooperative transmission in energy harvesting-based cognitive D2D networks

A cognitive device-to-device (D2D) network with D2D transmitters (DTs) that harvest radio-frequency energy from the primary transmitters (PTs) is investigated. A novel D2D transmitter-assisted cooperative (DTAC) protocol is proposed, in which a group of DTs that have no transmission opportunity act as potential relays to improve the communications of the primary network. The outage probability of the primary networ is characterized and used to make comparisons between the direct link and the cooperative link which adopts selection combining and maximal-ratio combining (MRC) schemes at the primary receivers. The cooperative link with MRC scheme improves the outage performance of the primary network with direct link, as much as 93%. The active probability of the DTs and the outage probability are derived, and the D2D network throughput is maximized by finding an optimal transmission power for the PTs. Simulation results are provided to validate the theoretical analysis.     

全双工协作多播业务在NOMA系统中的应用和性能

研究了多播业务在协作非正交多址接入（non-orthogonal multiple access,NOMA）系统中的应用及其性能。在一个单播和多播混合业务的场景中,多播用户组中选择某个信道状态最好的用户作为中继进行解码转发单播用户的信号,并在中继用户支持全双工的模式下,分析和推导了单播用户的中断概率和平均可达速率的闭式表达式。蒙特卡洛仿真结果和理论推导高度一致,表明提出的协作多播应用可以极大改善单播用户的中断性能,且多播用户的容量性能在中继发射功率不是很高的情况下不会受到影响。     

Outage Probability and Ergodic Capacity Analysis for Two-Way Relaying System with Different Relay Selection Protocols

The outage probability and ergodic capacity analysis for decode-and-forward two-way relaying system is investigated in this paper. First, the exact expressions (or bounds) of outage probability, ergodic capacity and average bidirectional ergodic capacity (ABEC) for max–min relay selection, random relay selection and direct transmission protocols are derived through theoretic analysis, and performance comparisons among different relay selection protocols are developed. Then a novel maximum average bidirectional mutual information (MABM) relay selection protocol is proposed and analyzed. Simulation results demonstrate that the derived analytical results fit well with Monte-Carlo simulations. The proposed MABM protocol can always achieve larger ABEC than other protocols while keeping low outage probability, and the MABM and max–min protocols in this paper can always achieve better performance than the max–min selection and max-sum selection in Krikidis (IEEE Trans Veh Technol 59(9):4620–4628, 2010). In addition, outage probability, ergodic capacity and ABEC performance of the proposed protocol become worse while distance becomes larger.     

Capacity of large hybrid erasure networks with random node distribution

The Gupta–Kumar’s nearest-neighbor multihop routing with/without infrastructure support achieves the optimal capacity scaling in a large erasure network in which n wireless nodes and m relay stations are regularly placed. In this paper, a capacity scaling law is completely characterized for an infrastructure-supported erasure network where n wireless nodes are randomly distributed, which is a more feasible scenario. We use two fundamental path-loss attenuation models (i.e., exponential and polynomial power-laws) to suitably model an erasure probability. To show our achievability result, the multihop routing via percolation highway is used and the corresponding lower bounds on the total capacity scaling are derived. Cut-set upper bounds on the capacity scaling are also derived. Our result indicates that, under the random erasure network model with infrastructure support, the achievable scheme based on the percolation highway routing is order-optimal within a polylogarithmic factor of n for all values of m.     

Performance Analysis of Decode-and-Forward Scheme with Relay Ordering for Secondary Spectrum Access

The communication efficiency of primary networks in cognitive radio depends on wireless environments, such as obstacles (e.g. buildings), distances between transmitter and receiver, and limited transmit power. A cooperative model between primary and secondary networks has the potential to overcome these problems. In this paper, we propose and analyze the performance of a decode-and-forward scheme with relay ordering for secondary spectrum access. In this scheme, a primary transmitter communicates with a primary receiver with the help of two secondary transmitters. Each secondary transmitter relays primary signals from the primary transmitter to primary receiver, and follows an optimal order to ensure the best communication capacity of the primary network and to find opportunities to transmit its own signals. The performance of primary and secondary networks is evaluated by theoretical analysis in terms of outage probability. Monte Carlo simulations are presented to verify the theoretical analysis and to compare the performance of the proposed protocol with that of a direct transmission protocol and a decode-and-forward protocol with a relay selection scheme.     

Secrecy enhancement in two-hop DF relaying system under hardware impairment

In this paper, we investigate joint jammer selection and network coding for secrecy enhancement under transceiver hardware impairment. We propose two protocols of joint jammer selection and network coding (SCCJ-OJS and SCCJ-MiJS) to improve secrecy outage and throughput performance compared with a protocol without cooperative jamming (SCC). For performance evaluation, we derive exact closed-form expressions for the secrecy outage probability (SOP) and throughput performance of the three protocols. Our analysis is substantiated via Monte Carlo simulation. The results show that the SCC protocol is nearly in an outage state when the eavesdroppers are close to the source and/or relays, while the SCCJ-OJS and SCCJ-MiJS protocols still improve the performance compared with the SCC protocol in this strict case. In addition, transceiver hardware impairments can degrade the eavesdropping channel: the performance of the SCC protocol increases linearly with hardware impairment level, whereas SCCJ-OJS and SCCJ-MiJS protocol performance is enhanced at a low level and experience a minor decrease at a high level of hardware impairment. Finally, the theoretical results match the simulation results well.     

An opportunistic relaying‐based incremental hybrid DAF cooperative system

In this paper, an opportunistic relaying‐based incremental hybrid decode‐amplify‐forward (OR‐IHDAF) scheme that combines robust protocol switch with efficient relay selection is proposed in multi‐relay scenario to cope with the complex and variable channel environments. The proposed OR‐IHDAF scheme can improve the system performance significantly compared with the incremental hybrid decode‐amplify‐forward protocol with the increase of the possible candidate relay nodes and opportunistic relay selection. The analytical expression of the system outage probability of the OR‐IHDAF scheme is presented based on the probability density function and cumulative distribution function, which might be useful to avoid lengthy simulations. Numerical results show the correctness of our theoretical analysis and the performance improvement of the OR‐IHDAF scheme compared with the other current hybrid cooperative protocols and OR‐based cooperative schemes. The effects of the power allocation schemes on the outage probability are also provided. Copyright © 2015 John Wiley & Sons, Ltd.     

Outage of cooperative NOMA with an energy harvesting relay in an underlay cognitive radio network

This paper analyzes the performance of a cooperative nonorthogonal multiple access (NOMA) in an underlay cognitive radio network aided by an energy harvesting relay. A secondary source transmits signal for two users, where a near user acts as a relay for the far user. The far user applies the selection combining (SC) approach on the signals which were relayed by the near user and received via direct path from the secondary source. We analytically derive the outage probability (OP) of each user separately, the overall system OP, and the throughput of the system. The impact of the power allocation coefficient of NOMA and energy harvesting parameters on outage is indicated. Further, the performance of the network is investigated with imperfection in successive interference cancellation (SIC), maximal ratio combining (MRC) at relay, and Nakagami-m fading. The results derived analytically are supported by simulation in MATLAB.