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Characterization of Aggregate Interference in ArbitrarilyShaped Underlay Cognitive Networks
 PROCEEDINGS OF IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM
, 2014
"... This paper characterizes the aggregate interference at the primary user (PU) due to M secondary users (SUs) in an underlay cognitive network, where appropriate SU activity protocols are employed in order to limit the interference generated by the SUs. Different from prior works, we assume that the ..."
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This paper characterizes the aggregate interference at the primary user (PU) due to M secondary users (SUs) in an underlay cognitive network, where appropriate SU activity protocols are employed in order to limit the interference generated by the SUs. Different from prior works, we assume that the PU can be located anywhere inside an arbitrarilyshaped convex network region. Using the moment generating function (MGF) of the interference from a random SU, we derive general expressions for the nth moment and the nth cumulant of the aggregate interference for guard zone and multiplethreshold SU activity protocols. Using the cumulants, we study the convergence of the distribution of the aggregate interference to a Gaussian distribution. In addition, we compare the wellknown closedform distributions in the literature to approximate the complementary cumulative distribution function (CCDF) of the aggregate interference. Our results show that care must be undertaken in approximating the aggregate interference as a Gaussian distribution, even for a large number of SUs, since the convergence is not monotonic in general. In addition, the shifted lognormal distribution provides the overall best CCDF approximation, especially in the distribution tail region, for arbitrarilyshaped network regions.
On the Feasibility of Indoor Broadband Secondary Access to 9601215 MHz Aeronautical Spectrum
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1Interference Model for Spectrum Sensing with Power Control
"... Abstract—This paper analyzes the aggregate interference in a cognitive radio network. We consider a model in which the secondary transmitters are geographically distributed according to a Poisson point process in a wireless environment subject to shadowing noise and path loss. The secondary transmit ..."
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Abstract—This paper analyzes the aggregate interference in a cognitive radio network. We consider a model in which the secondary transmitters are geographically distributed according to a Poisson point process in a wireless environment subject to shadowing noise and path loss. The secondary transmitters may transmit simultaneously and consequently incur an aggregate interference level on the primary system. We derive the moment generating function and the expectation of the aggregate interference for this model using properties of the Poisson point process. Based on the interference analysis, a scheme is proposed to estimate the maximum transmission power for each of the active secondary transmitters so as to satisfy a constraint on the aggregate interference. Our numerical results show a significant gain in the achievable capacity for the secondary system relative to an earlier scheme in which only a single secondary transmitter was permitted to transmit at any given time.1
Energy Efficient Mechanisms for Heterogeneous Cellular Networks
"... CEA–LETI Grenoble, CoEncadrant de thèse Wireless communication proliferates into nearly each aspect of the human society, driving to the exponential growth in number of permanently connected devices. Powerful smartphones and tablets, ubiquitous wireless broadband access, and machinetomachine co ..."
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CEA–LETI Grenoble, CoEncadrant de thèse Wireless communication proliferates into nearly each aspect of the human society, driving to the exponential growth in number of permanently connected devices. Powerful smartphones and tablets, ubiquitous wireless broadband access, and machinetomachine communications generate volumes of data traffic that were unpredictable few years back. In this novel paradigm, the telecommunication industry has to simultaneously guarantee the economical sustainability of broadband wireless communications and users ’ quality of experience. Additionally, there is a strong social incentive to reduce the carbon footprint due to mobile communications, which has notably increased in the last decade. In this context, the integration of femtocells in cellular networks is a lowpower, lowcost solution to offer high data rates to indoor customers and simultaneously offload the macrocell network. However, the massive and unplanned deployment of femtocell access points and their uncoordinated operations may result in harmful cochannel interference. Moreover, a high number of lightly loaded cells increases the network energy consumption.
1Uplink Performance Characterization and Analysis of TwoTier Femtocell Networks
"... This paper provides a crosslayer analysis of uplink performance in femtocell networks. It characterizes the uplink physical interference in femtocell networks and studies its impact on the delay and data loss rate of constantbitrate (CBR) traffic, as well as on the maximum achievable femtouser t ..."
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This paper provides a crosslayer analysis of uplink performance in femtocell networks. It characterizes the uplink physical interference in femtocell networks and studies its impact on the delay and data loss rate of constantbitrate (CBR) traffic, as well as on the maximum achievable femtouser throughput. Our work derives datalink layer QoS performances as a function of physical layer parameters, thereby establishing key crosslayer relationships that can be useful for designing efficient resource allocation techniques for FC networks. Index Terms—Uplink Interference, Outage Probability, Link Delay and Capacity, Femtocell Networks. I.
A MultipleRing Model for Cognitive Radio Aggregate Interference
"... AbstractThis paper proposes a new, flexible, multiple ring model for the aggregate interference analysis of a Poisson field of cognitive radio transmitters distributed over an annular region. For Rayleigh fading or composite Rayleigh fading and Gamma shadowing environments, the moment generating f ..."
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AbstractThis paper proposes a new, flexible, multiple ring model for the aggregate interference analysis of a Poisson field of cognitive radio transmitters distributed over an annular region. For Rayleigh fading or composite Rayleigh fading and Gamma shadowing environments, the moment generating function of the aggregate interference and the exact and asymptotic analysis of the outage are derived for the model. Typically, the model is most accurate for larger guard distances and lower path loss exponents. However, its parameters can be tuned such that a required accuracy is obtained for a tradeoff in complexity. Index TermsCognitive radio, aggregate interference, outage probability, shadowing.
Interference Control for Cognitive Network with High Mobility
"... Interference control (IC) between the secondary system and the primary system is an important issue for underlay cognitive radio network (CRN). The secondary system should limit the interference power to primary system by adjusting its transmission power. Many relevant works have been done based on ..."
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Interference control (IC) between the secondary system and the primary system is an important issue for underlay cognitive radio network (CRN). The secondary system should limit the interference power to primary system by adjusting its transmission power. Many relevant works have been done based on the assumption of the quasistatic channel which is not suitable for the fast timevarying fading channel; the performance of IC in underlay CRN will become worse when the channel varies fast. This paper studies the IC issue in high mobility environment. By considering the channel state information (CSI) outdatedness, a short frame structure scheme and a mean interference power constraint scheme are proposed to reduce the influence of CSI outdatedness on IC performance. Furthermore, by considering the channel estimation error, a spherical error region model based robust IC scheme is designed as well. The proposed IC schemes of the secondary system are converted to the power allocation problems, and then they are formulated to optimization problem whose objects are to maximize the capacity of the secondary system with the interference constraints. The above optimization problems are solved by the waterfilling style method. The simulation results show that the proposed IC schemes can effectively control the interference power to the primary system.
Impact of Transmit Power Control on Aggregate Interference in Underlay Cognitive Radio Networks
"... AbstractThis paper analyzes how transmit power control affects the aggregate interference arising from a Poisson field of underlay cognitive radio (CR) transmitter nodes distributed in a finite area. We consider three peruser, location dependent power control schemes, when each CR transmitter is ..."
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AbstractThis paper analyzes how transmit power control affects the aggregate interference arising from a Poisson field of underlay cognitive radio (CR) transmitter nodes distributed in a finite area. We consider three peruser, location dependent power control schemes, when each CR transmitter is associated with the nearest CR receiver, where the CR receivers form a Poisson field in the entire 2dimensional space. The 3 schemes are based on: 1) CR transmitterreceiver distance rc 2) rc and a constant cutoff power level 3) rc and a random cutoff power level, respectively. For each of these, the exact moment generating function (MGF) and mean of aggregate interference power are derived. We also investigate the primary system outage due to aggregate interference. Rayleigh fading and exponential path loss links are assumed. MonteCarlo simulation results validate our analysis and also show that the CR power thresholds and node densities significantly affect the aggregate interference.
Aggregate Interference Analysis for Interweave Cognitive Networks
"... AbstractThis paper investigates the aggregate interference from interweave cognitive secondary nodes spatially distributed in a finite Poisson field. These secondary nodes sense an outofband beacon to initiate their transmissions, which can be concurrent with those of the primary system if a sens ..."
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AbstractThis paper investigates the aggregate interference from interweave cognitive secondary nodes spatially distributed in a finite Poisson field. These secondary nodes sense an outofband beacon to initiate their transmissions, which can be concurrent with those of the primary system if a sensing error is made. The resulting aggregate interference is analyzed in this paper. For this purpose, general Nakagamim fading and pathloss are assumed for all relevant channels. Moreover, we incorporate random secondary node transmit powers with any probability distribution. The analysis includes the exact moment generating function (MGF) of the aggregate interference along with the exact outage probability of the primary system. Furthermore, we develop a simple MGF approximation which is valid for severely fading channels and for lower beacon reception threshold to beacon transmit power ratios. Finally, we show that a lower fading severity significantly improves the diversity order of the PR due to more accurate spectrum sensing by the secondary nodes.
RbUCRP: A Novel ReputationBased Uneven Clustering Routing Protocol for Cognitive Wireless Sensor Networks
"... Energy of nodes is an important factor that affects the performance of Wireless Sensor Networks (WSNs), especially in the case of existing selfish nodes, which attracted many researchers' attention recently. In this paper, we present a reputationbased uneven clustering routing protocol (RbUC ..."
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Energy of nodes is an important factor that affects the performance of Wireless Sensor Networks (WSNs), especially in the case of existing selfish nodes, which attracted many researchers' attention recently. In this paper, we present a reputationbased uneven clustering routing protocol (RbUCRP) considering both energy saving and reputation assessment. In the cluster establishment phase, we adopt an uneven clustering mechanism which controls the competitive scope of cluster head candidates to save the energy of WSNs. In the cluster heads election phase, the residual energy and reputation value are used as the indexes to select the optimal cluster head, where the reputation mechanism is introduced to support reputation assessment. Simulation results show that the proposed RbUCRP can save node energy consumption, balance network energy distribution, and prolong network lifetime.