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In this paper, a new spectrum sharing model referred to as riding on the primary (RoP) is proposed for wireless- powered IoT devices with ambient backscatter communication capabilities. The key idea of RoP is that the secondary transmitter harvests energy from the primary signal, then modulates its information bits to the primary signal, and reflects the modulated signal to the secondary receiver...
Pilot contamination has been confirmed as a major bottleneck to performance improvement of time division duplexing (TDD) massive multiple-input-multiple-output (MIMO) systems. An asynchronous pilots scheduling (APS) scheme is proposed in this paper for pilot decontamination. According to interfering levels, users are divided into cell-center users, which are generally interfered slightly, and cell-edge...
In this paper, we propose a unified framework to analyze the performance of dense small cell networks (SCNs) in terms of the coverage probability and the area spectral efficiency (ASE). In our analysis, we consider a practical path loss model that accounts for both non-line-of-sight (NLOS) and line-of-sight (LOS) transmissions. Furthermore, we adopt a generalized fading model, in which Rayleigh fading,...
This paper develops a mathematical paradigm to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). Particularly, we study the dominant intra-cell interferer problem that appears between HD users scheduled on the same FD-channel. The distribution of the dominant interference is first characterized via its distribution function, which...
In this paper, we investigate the uplink transmission performance of low-power wide-area networks (LPWANs) with regards to coexisting radio modules using LoRa as an example. In doing so we adopt a new topology to model the network where the node locations of the network of focus (LoRa) follow a Poisson cluster process (PCP) while other coexisting interfering radio modules follow a Poisson point process...
In this paper, the outage performance of two-way/one-way full-duplex/half-duplex fixed-gain amplify-and-forward (AF) relay systems are investigated over Rayleigh fading channels in the presence of residual loop-interference (LI). A unified end-to-end signal-to-interference-plus-noise expression is obtained. Then, a new unified exact outage probability expression for all fixed-gain AF relay systems...
We consider a hybrid eavesdropping wireless system, where the locations of the eavesdroppers are drawn from Poisson point process (PPP). The eavesdroppers work in a half-duplex mode with a certain probability to transfer from eavesdropping mode to jamming mode. Based on the stochastic geometry (SG) and the random matrix theory (RMT), we derive the analytic results for the secrecy outage probability...
Massive MIMO (multiple-input multiple-output) provides great improvements in spectral efficiency over legacy cellular networks, by coherent combining of the signals over a large antenna array and by spatial multiplexing of many users. Since its inception, the coherent interference caused by pilot contamination has been believed to be an impairment that does not vanish, even with an unlimited number...
Heterogeneous cellular network has become an important network architecture to improve network spectral efficiency. This paper works on a theoretical framework for analyzing outage probability and spectral efficiency in a two-tier heterogeneous network with joint processing cooperation. The heterogeneous network consists of high power nodes (HPNs) and low power nodes (LPNs). A range expansion association...
In this paper, we study the average downlink rate in Ultra-Dense Networks (UDNs) considering the idle mode capability of the base stations (BSs). Wireless networks are densified by deploying a surplus of small cells in order to provide uniform coverage and high capacity. Consequently, the density of the small cells outpaces that of the active users in UDNs. Idle mode capability permits the idle BSs,...
The application of stochastic geometry to the analysis of wireless networks is shown to be propelled by (i) a clean separation of time scales, (ii) abstraction of small-scale effects via ergodicity, and (iii) an interference model reflecting the receiver's lack of knowledge of how individual interference terms are faded. These steps render the analysis simpler and more precise, and more amenable to...
A time domain signal tracking algorithm is proposed to estimate the frequency of a chirp-type global navigation satellite system (GNSS) interference. The unknown interference frequency of GNSS in the received signal can be estimated by using the properties of the trigonometrical functions, but the thus-obtained value can have a lot of error caused by measurement noise and by the frequency change of...
In this paper, we develop and analyze a novel performance metric, called interference efficiency (IE), that shows the number of transmitted bits per unit of interference energy imposed on the primary users (PUs) in an underlay cognitive radio network (CRN). Specifically, we develop a framework to maximize the IE of a CRN with multiple secondary users (SUs) while satisfying target constraints on the...
Coherent detection requires exact knowledge of the channel state information, which is often a challenging task in demanding practical applications. Based on this, non-coherent detection of differentially modulated signals can be considered as an alternative method. The present paper investigates the effects of in-phase/quadrature-phase imbalance (IQI), which are known to degrade the performance of...
Random access protocols relying on the transmission of packet replicas in multiple slots and exploiting interference cancellation at the receiver have been shown to achieve performance competitive with that of orthogonal schemes. So far the optimization of the repetition degree profile, defining the probability for a user to transmit a given number of replicas, has mainly been performed targeting...
The max-min signal-to-interference-plus-noise ratio (SINR) problem is considered in a coordinated network wherein L base stations (BSs) each equipped with N antennas serve in total K single-antenna users that are uniformly distributed in the network. We conduct the analysis in the asymptotic regime in which N and K grow large to compute a deterministic approximation for the max-min SINR. The results...
The deployment of long term evolution (LTE) in unlicensed spectrum (LTE-U) is a promising solution to overcome the spectrum shortage. However, the interaction between LTE-U and Wi-Fi in unlicensed spectrum has not been well understood. In this paper, we use stochastic geometry to develop a framework for the co-existence between LTE-U and Wi-Fi in unlicensed spectrum. To reduce the intra-and inter-RAT...
Closed-form approximations to the expected perterminal signal-to-interference-plus-noise-ratio (SINR) and ergodic sum spectral efficiency of a large multiuser multiple-input multiple-output system are presented. Our analysis assumes correlated Ricean fading with maximum ratio combining on the uplink, where the base station (BS) is equipped with a uniform linear array (ULA) with physical size restrictions...
Cellular networks operating at millimeter wave (mmWave) frequencies are able to achieve multi-gigabit-per-second data rates due to the large bandwidth available. However, the data transmission range will be shorter and significant signal power difference will be observed between line-of-sight (LOS) and non-line-of-sight (NLOS) links. This paper considers interference management and useful signal enhancement...
We consider an energy harvesting (EH) based cooperative relaying network, where two half-duplex relays can alternatively forward source data to the destination. The power-splitting technique is implemented at each relay. That is, part of the received source signal and inter-relay interference is allocated for the EH, while the remaining part is used for the information decoding (ID). The inter-relay...
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