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We propose an underlay decode-and-forward cognitive (UDFC) scheme under joint effects of hardware impairments at secondary users and interference constraints at multi primary receivers. In this scheme, the transmit powers of a source node and relays are constrained by interference thresholds of primary receivers in which the best relay is selected has the highest decoding capacity from the source...
In this paper, we analyze the outage probability of multiple-input multiple-output cognitive cooperative radio networks (CCRNs) with multiple opportunistic amplify-and-forward relays. The CCRN applies underlay spectrum access accounting for the interference power constraint of a primary network and utilizes orthogonal space-time block coding to transmit multiple data streams across a number of antennas...
This paper investigates a three-node multiple-input multiple-output relay system suffering from co-channel interference (CCI) at the multi-antenna relay. Contrary to the conventional relay networks, we consider the scenario that the relay is an energy harvesting (EH) node and has no embedded energy supply. But it is equipped with a rechargeable battery such that it can harvest and accumulate the harvested...
In this paper, we use dual-hop relaying to overcome the signal blockage problem that occurs for millimeter waves (mmWaves) due to obstacles located in the propagation environment. Using device-to-device communication, a device in the neighborhood of the transmitter and the receiver can play the role of a relay by amplifying the signal from the source device and forwarding it to the destination device...
We study the physical-layer performance of a wideband multihop system in which a long chain of amplify-and-forward relays is used for routing orthogonal frequency division multiplexing (OFDM) symbols from a source to a destination. Especially, the symbols are modulated in the source and demodulated in the destination while the relays simply forward respective waveforms with scalar amplification. We...
We address secure communications over energy-harvesting based OFDMA cooperative cognitive radio networks, where one primary user (PU) cooperates with several secondary users (SUs) in terms of both information transmission and energy harvesting. To improve spectrum utilization and ensure that SU transmitters can harvest as much energy as possible, we suppose that SUs are equipped with orthogonally...
Wireless energy harvesting (EH) is regarded as a promising energy supply alternative for energy-constrained wireless networks. In this paper, a new wireless EH protocol is proposed for an underlay cognitive radio (CR) network with multiple transceivers in a primary network (PN). Utilizing two-way amplify-and-forward (AF) relaying system as a secondary network (SN), both end-sources can harvest energy...
We address secure communication for energy-harvesting (EH) based cooperative cognitive radio networks (CRNs), in which several EH secondary users (SUs) cooperate with one primary user (PU) for both data transmission and energy harvesting. To increase the amount of energy harvested by SUs while improving spectrum utilization, we suppose that SUs are equipped with orthogonally dual-polarized antennas...
Channel selection in multichannel cognitive radio system and relay selection in multi-relay cooperative system are well studied problems in separate branches. In this study, we consider a joint channel and relay selection problem which is very important to realize multi-relay cooperative transmission in multichannel cognitive radio networks. A joint channel and relay selection algorithm is proposed...
This paper analyzes the performance of energy beamforming in spatially correlated multiple-input multiple-output (MIMO) relaying systems, where the source and destination nodes are equipped with multiple spatially correlated antennas and communicating via a dual-hop amplify-and-forward (AF) single antenna energy-constrained relay. To maximize the overall harvested energy so as to enable long-distance...
Energy-harvesting (EH) and wireless power transfer in cooperative relaying networks have recently attracted a considerable amount of research attention. Most of the existing work on this topic however focuses on Rayleigh fading channels which represents outdoor environments. Unlike these studies, in this paper we analyze the performance of wireless power transfer in two-hop decode-and- forward (DF)...
In this paper, we analyze the performance of an OFDM based amplify and forward (AF) cooperative system for multiple relay with relay selection over independent but not necessarily identically distributed (i.n.i.d.) frequency selective Nakagami-m fading channels. In the proposed work, lower-bound expression for the outage probability is derived, and the effect of nonlinearity of PA is highlighted for...
In this paper, we consider a cognitive two-way relay system with multiple relay nodes and multiple primary receivers over Nakagami-m fading channels. Relay nodes process signal following selective decode-and-forward (DF) relay technique. The opportunistic relay selection is used to choose the best relay. We derive the exact closed-form expression of the overall outage probability over Nakagami-m fading...
In this paper, we consider an incremental cooperative relaying network (IR-CRN), where a relay node harvests the radio energy from the source signal using the time-switching mechanism. Specif cally, we propose a scheme named as IR-CRN which enhances spatial diversity gain by utilizing the incremental relaying protocol. The destination node of the IR-CRN scheme employs maximal ratio combining (MRC)...
In this paper, a novel two-way relaying technique based on network coding is proposed to improve the throughput of dual-hop mixed free-space optics (FSO)/radio-frequency (RF) communication systems. We investigate the performance of the proposed systems over Gamma-Gamma atmospheric turbulence and Rice/Rayleigh channels. The effect of pointing error on FSO link is also considered in our analysis. Closed-form...
This paper analyzes the outage probability, energy efficiency, energy efficiency-spectral efficiency trade-off, through-put performance, energy efficiency-throughput gain trade-off and derives the optimal transmission power of Single-hop, Multi-hop, Decode-and-Forward (DF) and Incremental Decode-and-Forward (IDF) schemes in order to find out what extent collaborative communication can save energy...
In this paper, the multi-pair two-way relaying multi-input multiple-output system is considered, in which K-pair users exchange information within communication pair, by a shared amplify-and-forward relay station equipped with N antennas, N ≫ 2K. Considering two kinds of receiver, i.e., maximum-ratio combining receiver and zero-forcing receiver, we investigate the achievable rate performance in Ricean...
In this paper a cognitive radio network is considered where a licensed primary user and an energy harvesting secondary (cognitive) user co-exist, and relaying protocols are proposed where the cognitive user acts as a relay for the primary signal in return for spectrum access. We analyze two relaying paradigms, namely, time-splitting cooperative spectrum sharing (TS-CSS) relaying and power sharing...
In this paper, we investigate the outage performance of a decode-and-forward (DF) underlay cognitive two-way relay system with direct link using time division broadcast protocol in the presence of primary user's interference. Herein, relying on the practicability and low-complexity of statistical channel state information (CSI), the secondary transmissions satisfy the fading-averaged interference...
Cooperative cognitive radio (CCR) is a novel paradigm for improving both radio spectrum efficiency and communication quality. However, for the CCR networks with energy harvesting, how to achieve specific relay selection is still an open issue. In this paper, we consider a CCR network with energy harvesting in which multiple secondary transmitters are able to harvest energy from the received signals...
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