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In this work, a relay-selection scheme is proposed for underlay cognitive radio networks, with fixed and adaptive relaying power. The relay-selection and power allocation is based on the calculation of the log-likelihood ratio (LLR) value, calculated at each of the relay nodes available in the secondary network. No interference is caused to the primary network, through the satisfaction of a low power...
In this paper, two methods to improve the secrecy of cooperative transmissions using unshared jamming are investigated in which only the source and destination nodes know the jamming signals. The jamming signals are based on unique cipher keys obtained on the high layers. In the first proposed method (SJ protocol), a source combines its secrecy signal with its jamming signal using the power allocation...
This paper investigates the ergodic capacity of a multi-input multi-output (MIMO) wireless powered communication system with partial channel state information at the power beacon (PB). Employing time splitting protocol, the PB first transmit energy-bearing signals to the energy constrained source S through beamforming, and then S uses this energy to transmit information to the destination. Unlike...
Estimation of intracranial sources, using inverse solutions methods, has been proposed as a mean to improve performance in non-invasive brain-computer interfaces. These methods estimate the activity of a large number of neural sources from a smaller number of scalp electroencephalography (EEG) channels. This is a highly undetermined problem and regularisation constraints need to be applied. In this...
We consider the scheduling problem for Aggregated ConvergeCast in wireless sensor networks with a physical interference model. Previous work consists of either heuristics without performance guarantees, or approximation algorithms which do not perform well in practice. We propose here a first scalable mathematical SINR (Signal to Interference plus Noise Ratio) model that outputs an optimal Aggregated...
Various clustering protocols for ad hoc networks have been proposed in order to optimise the networks energy efficiency. These protocols rely on the formation of highly dense clusters which resulted in a large variation of cluster size and thus suffers from a poor load balancing. This paper introduce a novel distributed clustering algorithm using fuzzy logic for the formation of uniform size clusters...
Energy efficiency has been a growing requirement in the latest development of wireless communication systems, and it has led to research on off-grid relay nodes with simultaneous wireless information and power transfer (SWIPT) capabilities. Two SWIPT protocols have been developed in the past, named power splitting and time switching. Both protocols have been theoretically proven to improve energy-constrained...
Relay communication network is a technique to obtain spatial diversity by using one or more relay terminals in order to improve the transmission performance. Amplifty-and-forward (AF) and decode-and-forward (DF) are two kinds of fixed relaying protocols and widely researched now. In this paper the performance of AF and DF in terms of the outage probability and the symbol error rate (SER) is analysed...
This study deals with the joint channel and carrier frequency offset (CFO) estimation in a Multiple Input Single Output (MISO) communications system. This problem arises in OFDM (Orthogonal Frequency Division Multiplexing) based multi-relay transmission protocols such that the geo-routing one proposed by A. Bader et al in 2012. Indeed, the outstanding performance of this multi-hop relaying scheme...
Communication system design becomes more complicated due to excessive increase of number of users. Systems need to address this load, while providing acceptable levels of Quality of Service (QoS). Additionally, user expectations, quantified via Quality of Experience (QoE), need to be addressed. QoE is calculated on the application layer, where end users interact with the system. As well as user expectations,...
Relay selection is a crucial method that can improve the spectrum efficiency and converge performance of relay assisted (RA) network. However, most of the existing research about relay selection did not consider the effect of imperfect channel state information (CSI) and the CSI obtaining cost. Few of the study about the relay selection with imperfect CSI focused mainly on the decode-and-forward (DF)...
In this paper, we analyze the outage performance of two multicarrier relay selection schemes, i.e. bulk and per-subcarrier selections, for two-hop orthogonal frequency-division multiplexing (OFDM) systems. To provide a comprehensive analysis, three forwarding protocols: decode-and-forward (DF), fixed-gain (FG) amplify-and-forward (AF) and variable-gain (VG) AF relay systems are considered. We obtain...
Cognitive heterogeneous cellular networks (CHCNs) and multi-user multiple-input multiple-output (MU-MIMO) are both promising technologies in the future network where wireless transmissions are inherently vulnerable to security breaches. Under an interference constraint set by the primary user, this study examines the impact of MU-MIMO technology on secure communication between cognitive base stations...
Information dissemination protocols for ad-hoc wireless networks frequently use a minimal subset of the available communication links, defining a rooted Broadcast Tree. In this work, we focus on the core challenge of disseminating from one layer to the next one of such tree. We call this problem Layer Dissemination. We study Layer Dissemination under a generalized model of interference, called Affectance...
In this work, we acknowledge the existence of the accumulation of the loopback self-interference when AF protocol is made used of in FDTW relaying and the channel estimation of the loopback channel is not done perfectly as will seen in the section to follow. The accumulation of the loopback self-interference comes from the functionality of FD antenna, which will bring back the transmitted signal to...
Non-orthogonal multiple access (NOMA) is a promising multiple access technique for future wireless communications as it results in high spectral efciency. In this paper, we study a NOMA based dual-hop X-relay system, where a decode-and- forward relay assists the communication between the sources and the destinations. We assume that the statistical channel state information is known to the network...
Using the minimum number of broadcasts to flood information in a vehicle network so that the maximum number of vehicles receives the information is a critical issue. Up to now, no research reports show the relationship between broadcast radius and success rate, the one-hop broadcast efficiency (i.e., the ratio of nodes that successfully received nodes to all nodes within the broadcast range). Determining...
In this paper, we consider a cooperative wireless network involving two transceiver nodes whose communication is assisted by energy-constrained two-way amplify-and-forward (AF) relay nodes. The transceiver nodes can simultaneously transmit information and energy, and the relay nodes harvest the energy from the received signal and use the harvested energy to amplify and retransmit the received signal...
We propose a decentralized multi-cell aware opportunistic random access (MA-ORA) protocol that almost achieves the optimal throughput scaling in a K-cell random access network with one access point (AP) and N users in each cell. Under our MA-ORA protocol, users opportunistically transmit with a predefined physical layer data rate in a decentralized manner if the desired signal power to the serving...
IEEE 802.11n/ac wireless local area network (WLAN) supports frame aggregation, called aggregate medium access control (MAC) protocol data unit (A-MPDU), to enhance MAC efficiency by reducing protocol overhead. However, the current channel estimation process conducted only once during the preamble reception is known to be insufficient to ensure robust delivery of long A-MPDU frames in mobile environments...
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