The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
To meet 1000x wireless traffic volume increment in the next decade, a larger number of small base stations (SBSs) have to be densely deployed for 5G cellular networks. Analyzing the optimal density of small base station from the perspective of energy efficiency is very meaningful for green 5G mobile networks. In this paper, we analyze the SBS density for energy efficiency in ultra-dense heterogeneous...
Cognitive Radio is a promising technology to improve the spectrum exploitation and spectrum sensing is one of the key functionality for cognitive radio (CR) systems to operate in the available spectrum holes. To guard the primary users present in any spectrum from any interference, the CR should be able enough detect incumbent signals even at very low signal-to-noise ratio (SNR). In this paper, different...
In Cognitive Radio scenario achieving maximum secondary user capacity has always been a challenging task along with high detectability of primary user. Detection of primary user signal in presence of noise and channel fading condition is very conveniently carried out by energy detection scheme due to its less complexity in its structure. Further, for improving system performance under limited bandwidth...
Accurate spectrum sensing plays a decisive role in determining the performance of any cognitive radio network (CRN). Spectrum sensing enables the unlicensed secondary users (SUs) to operate in the licensed band until the primary user (PU) is detected. By allowing SUs in the same band to cooperate, we can reduce the detection time and increase overall agility and this forms the basis of cooperative...
Microwave assisted magnetic recording has been proposed as a next generation recording technology, which utilizes a spin torque oscillator (STO) imbedded between write pole and trailing shield for generating high frequency ac field [1] [2].
Non-local means (NLM) filtering of fMRI can reduce noise while preserving spatial structure. We have developed a variant called temporal-NLM (tNLM) which uses similarity in time-series between voxels as the basis for computing the weights in the filter. Using tNLM, dynamic fMRI data can be denoised while spatial boundaries between functionally distinct areas in the brain tend to be preserved. The...
In this paper, a cooperative device to device (D2D) communication system is studied while two transmitting devices communicate with one destination device in the presence of a passive eavesdropper. The second transmitting device cooperates with the first transmitting device and hence the transmission takes place is two phases. In the first phase, the first device transmits its signal to the second...
This paper investigates setup optimization of Spatial Modulation (SM) systems. Specifically, the optimal pair of the number of the transmit antennas and the modulation order, for a given spectral efficiency, that minimizes the error rate at the receiver has been discussed. Interesting results regarding the behavior of bit error rate and symbol error rate versus different transmitter setups under different...
Based on the tapped delay-lines (TDL) wideband model, the response variation (RV) constraint is applied to improve the frequency response consistency of the wideband beamforming. The optimization criterion of the proposed algorithm is minimizing the designed sidelobe level utmost and the constraints of the sidelobe level, interference suppression and the response variation while making the direction...
This paper investigates the physical layer security in a multibeam satellite communication system, where each legitimate user is surrounded by one eavesdropper. First of all, an optimization problem is formulated to maximize the sum of achievable secrecy rate, while satisfying the on-board satellite transmit power constraint. Then, two transmit beamforming(BF) schemes, namely, the zero-forcing (ZF)...
Neighbouring cells deteriorates the performance of Orthogonal Frequency Division Multiplexing Access (OFDMA) cellular networks particularly for edge users due to Inter Cell Interference (ICI). In this paper, subcarrier integration with suitable links is proposed for minimizing ICI after Self Organized Resource Allocation (SORA) and Link Grouping Algorithm (LGA) is used to selects the satisfactory...
The ultra-wide band (UWB) technology can be used for low cost and low power applications such as body area networks, IoT based applications, wireless sensor networks and high data rate short range wireless communications. In the UWB literature, non-coherent energy detector (ED) receiver is proposed to reduce receiver implementation complexity by avoiding the complex channel estimation process and...
In this paper, the comparison of several optimization methods for solving the optimal multiuser detection problem exactly or approximately are discussed. The purpose of using these algorithms is to provide complexity constraint alternatives to solving this nondeterministic polynomial-time (NP)-hard problem. An approximate solution is found firefly based optimization which is used to provide an exact...
This paper focuses on an average robust transmit beamforming optimization problem for the multiuser multiple-input-single-output (MISO) downlink scenario. In this problem, the channels are modeled as Gaussian variables with mean zero and with known covariance at the transmitter. The design criterion is to maximize the sum of the users' average rates with respect to the channels, subject to the total...
Owing to the rapidly increasing traffic demands on satellite connectivity, the current exclusive frequency allocation is becoming obsolete. Instead, aggressive frequency reuse and interference mitigation techniques are promising ideas that both industry and academia are investigating. This paper proposes an optimization precoding technique for dealing with the multibeam interference due to the aggressive...
This paper considers a multicell downlink channel in which multiple base stations (BSs) cooperatively serve users by jointly precoding shared data transported from a central processor over limited-capacity backhaul links. We jointly design the beamformers and BS-user link selection so as to maximize the sum rate subject to user-specific signal-to-interference-noise (SINR) requirements, per-BS backhaul...
In this paper, the estimation of a narrowband time-varying channel under the practical assumptions of finite block length and finite transmission bandwidth is investigated. It is shown that the signal after passing through a time-varying narrowband channel, under these assumptions, reveals a particular low-rank structure. The rank in this structure is governed by the number of dominant paths in the...
In this work, we study the fundamental tradeoff between integration time and scan rate in radar systems. The contrasting needs for a large probability of detection and a short scan time are carefully balanced by optimizing the detection rate, defined as the average number of detections from a target per unit of time. A closed-form solution for the optimum pulse train length is provided in the relevant...
The sequential analysis of the problem of joint signal detection and signal-to-noise ratio (SNR) estimation for a linear Gaussian observation model is considered. The problem is posed as an optimization setup where the goal is to minimize the number of samples required to achieve the desired (i) type I and type II error probabilities and (ii) mean squared error performance. This optimization problem...
The growth of wireless technology made opportunistic scheduling awidespread theme in recent research. Providing high systemthroughput without reducing fairness allocation is becoming a verychallenging task. The purpose of this work is twofold. On the onehand, we proposed a new optimization problem called SatisfactionProbability which consists in maximizing the number of satisfiedusers. On the other...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.