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This work presents a study on the performance of a hybrid 5G RF/FSO communication system. Both transmitter and receiver communicate through two paths: the first link operates under Radio-Frequency (RF) technology, assumed to undergo a Weibull fading channel, while the second link operates under Free Space Optical (FSO) technology, subject to Málaga-M turbulence model with the presence of pointing...
Direct Device-to-Device (D2D) communication permits to offload the network, increase the capacity, and extend the cellular coverage. In D2D systems, user equipments (UEs) do not necessarily communicate via evolved Node Base station (eNB); instead, they are allowed to communicate directly with each other. This underlying communication generates interference due to reusing the same resources of the...
A digital communications receiver requires precise symbol synchronization before the transmitted information can be recovered. Gardner's algorithm is a synchronizer that can acquire and track timing with only two samples per symbol, and it does not require prior carrier synchronization. In this paper, a feed-forward, all-digital version of Gardner's algorithm is presented. It is shown that this synchronizer...
This paper investigates the energy harvesting fading multiple-access channels, where the transmitters harvest random amounts of energy from the environment and the data transmissions are subject to statistical quality of service (QoS) constraints in the form of limitations on the buffer overflow probability. With the assumption that the channel state information (CSI) and harvested energy in all time...
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...
This paper proposes an enhanced version of multicarrier differential chaos-shift keying (MC-DCSK) scheme using quadrature modulation (QM), namely QMC-DCSK. In the proposed scheme, the chaotic spreading sequence is transmitted on a predefined frequency the same as in the conventional MC-DCSK, while each of the remaining frequencies is phase-shifted an 90◦ angle in order to produce two quadrature sub-carriers...
In this paper, we propose a non-orthogonal random access (NORA) technique for the uplink 5G networks, in which user equipments (UEs) make use of the channel inversion so that their received power at the base station (BS) can satisfy a certain threshold condition. In particular, each UE opportunistically adjusts its transmit power according to its channel gain. We also mathematically analyze the system...
The existence of high multipath resolution allows Rake collectors to maximize the signal-to-noise ratio efficiently. However, previous studies show that the conventional Rake receivers do not consider the multipath effect caused by long channel response such as in ultra-wideband wireless system. In this paper, we propose a new statistical selection (SS)-Rake receiver in long multipath channel. The...
Citizen Broadband Radio Service band (3550–3700 GHz) is seen as one of the key frequency bands to enable improvements in the performance of wireless broadband and cellular systems. A careful study of interference caused by a secondary cellular communication system coexisting with an incumbent naval radar is required to establish a pragmatic protection distance, which not only protects the incumbent...
Considering a small-scale fading environment in a dense random wireless network, we investigate the impact of the carrier-sensing threshold on the link performance under the premise of a fixed carrier-sensing range. At first, we assume a close transmitter-receiver distance and model the network nodes as a homogeneous Poisson point process (PPP). Then we present a simple analysis model of the conditional...
Viswanathan has shown that the practical mobile communication system can be modeled as the finite state Markov channel (FSMC) with delayed feedback, where the receiver perfectly knows the channel state information (CSI) which undergoes a Markov process, and the receiver sends the CSI and his own channel output back to the transmitter after some time delay. Viswanathan found that the delayed feedback...
A joint radar-communication (JRC) system can provide cost-effective and spectrum-efficient platform solution with simultaneous operation, while accomplishing important tasks, sensing via radar processing and allocation of communication links. Existing modulation techniques where information embedding is achieved using sidelobe Amplitude-Shift Keying (ASK) for the JRC system are not investigated so...
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...
The Internet of Things (IoT), describing the Machine Type Communications (MTC), is in the center of many new technical studies and industrial projects. It is also a central topic for the future 5G technologies standardization. Pending the new generation of cellular networks, the 3rd Generation Partnership Project (3GPP) has already standardized in May 2016, an evolution of the 2G and 4G networks to...
Vehicle-to-vehicle channel characteristics differ significantly from those of conventional cellular channels, especially in terms of fading statistics due to varying environmental conditions, link types, vehicle types, and objects that result in complex propagation effects. Accurate modeling of the vehicular channel remains a complex challenge. In this paper, existing, common vehicular channel models...
In this paper, we present a nonuniform quantizer based on the condition of maximum information rate achieved over uncorrelated Rayleigh fading channel and when successive cancellation (SC) decoding algorithm of polar codes is applied. Based on symmetry condition of random variables, we start with theoretical model where uniform scaling factors are applied to correct soft messages at the absence of...
In this paper, we investigate the impact of the carrier-sensing range on the link performance in a dense wireless network. Considering small-scale fading effects, we fix the carrier-sensing threshold and adaptively adjust the carrier-sensing range. At first, we assume a close transmitter-receiver distance and model the network nodes as a homogeneous Poisson point process (PPP). Then we obtain the...
This paper studies an uplink simultaneous wireless information and power transfer (SWIPT) system with non-orthogonal multiple access (NOMA), consisting of two users and one energy-harvesting access point (AP). The users transmit their independent information simultaneously to the AP which harvests energy and decodes information at the same time by dynamic power splitting (DPS). We focus on the ergodic...
The Gaussian fading channel is studied, in which the channel from the transmitter to the receiver is corrupted by a multiplicative fading coefficient H and an additive Gaussian random noise. It is assumed that the channel is experiencing block fading, and the transmitter does not know the channel state information (CSI). The receiver is assumed to have full knowledge of the CSI. If the channel state...
Evolution of modern communications and radar systems have steadily increased the demand on modelling the propagation effects with real world scenarios for various signal types. The main purpose of this research is to create a flexible, generic and realistic Radio Frequency (RF) environment simulator including both radar and communication signals. Software defined radio (SDR) platform has been utilized...
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