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MIMO technology using cooperative spectrum sensing is a useful way to reduce error and improve the system gain. In this paper, this kind of scenario is used to provide better spectrum utilization in rural areas. The proposed system model is described for Nakagami-m fading model. Graphical analysis of detection probability is shown which is obtained from closed form of analytical solution. Simulation...
Phase adjusting and power adjusting input schemes of non-orthogonal Gaussian multiple access channels (GMAC) for two-user with finite input constellations have been studied. In this paper, the input scheme for multi-user is jointly optimized by both powers and phases. This scheme is deduced from the constellation constrained (CC) capacity of multi-user GMAC. Performance analysis indicates that the...
Competitive advantage of a firm is usually reflected through its superiority in production resources and performance outcomes. In order to achieve high performance (e.g., productivity) and significantly improve product quality, major US industries have promoted and implemented Robust Design (RD) techniques during the last decade. RD is a cost-effective procedure for determining the optimal settings...
We propose partial computation of Continuous Wavelet Transform (CWT) and Power Spectrum (PS) in acoustic signal detection for decrease latency caused by the repeated calculations of CWT and PS. This allows detecting growing PS peaks earlier than the full CWT and PS calculating cycle is done that important for the real time systems. Numerical simulation of the test narrowband signal detection within...
An optimal energy scheme for mobile ad hoc networks (MANETs) is developed in this paper. Four elements are considered as the most important keys that influence network performance; these four elements are transmission power, interference, link lifetime, and load balance. A load balance approach is involved to distribute the traffic over available routes to address well-known problem in energy efficient...
In multi-tier cellular/small cell networks, user performance is largely affected by the varying transmit powers, distances, and non- uniform traffic loads of different BSs in both the downlink (DL) and uplink (UL) directions of transmission. To optimize user performance in such networks, decoupled UL-DL association (DUDe) has recently been investigated. DUDe enables a user to be associated with different...
In this paper, we propose a novel method of signal-to-noise ratio (SNR) estimation for cognitive radio (CR) systems at low SNRs. By jointly exploiting the second-order moment of the received signal and the correlation of the received signal power spectrum with the a priori known primary power spectrum, we obtain the estimates of both the signal power and the noise power, and the SNR estimation is...
In this paper, we analyze moments of instantaneous signal-to-noise ratio (SNR) in a multichannel relay system with subchannel pairing (SP) over Rayleigh fading environments. With aid of order statistics, new unified expressions of moments of the SNR are derived in closed-form for three SP cases, i.e., ordered subchannel pairing (OSP), reversely ordered subchannel pairing (ROSP) and non-subchannel...
In this paper, we consider amplify-and-forward cognitive relay networks in a spectrum-sharing environment. We present the performance analysis under two different partial relay selection (PRS) schemes, namely source-relay partial relay selection (SR-PRS) and relay-destination partial relay selection (RD-PRS). Specifically, we consider interference power constraint on secondary source and relay nodes,...
Device-to-device (D2D) communications have the potential to improve spectrum efficiency and link capacity by allowing nearby devices to communicate directly with each other on the licensed frequency resource. However, the co-channel interference (CCI) among D2D pairs is the major issue that needs to be solved when they are sharing the same frequency resource. The interference alignment (IA) is an...
This paper demonstrates the effect of timing offset and carrier frequency offset (CFO) on generalized frequency division multiplexing (GFDM) systems. We provide the mathematical expressions of the received GFDM signals in condense form in the presence of timing offset and CFO using linear matrix models respectively. Furthermore, we compare the signal-to-interference ratio (SIR) performance between...
Background: In this paper, the phase modulation coding/decoding technology is discussed for the application in the high attenuation medium based on the simulation and the experiment. Methods: For the decoding perspective, the matched filter and the inverse filter are compared. An extra processing is introduced right after the matched filtering to restrain the range sidelobes. Furthermore, in the latter...
How to dynamically utilize the spectrum and efficiently enhance spectrum utilization for a variety of clients' demands is still an open issues. This paper studies the dynamic access network with database-assisted, where spectrum brokers (SBs) compete to provide service for secondary users (SUs) with different QoS demands and budget. To this end, we investigate the interactions among BSs and SUs as...
In this paper, we propose a non-cooperative, dynamic and extensive game model for routing in a wireless sensor network (WSN). We treat each sensor node as a player who has a strategy to choose from in order to find the route that meets certain objective functions. A multi-hop routing is performed concurrently between multiple source and multiple destination nodes considering signal-to-noise-interference...
Sphere Decoding (SD) algorithm was proposed to effectively find the Maximum Likelihood (ML) solution. However, the computational complexity of SD is still too high when SNR is low or the dimension of the problem is large. In this paper, we propose three improved schemes based on contraction factor to reduce the complexity of sphere decoding. In the proposed schemes, a factor was introduced for speeding...
The progressive-edge-growth (PEG) algorithm for constructing Tanner graphs with large girth by progressively establishing edges/connections between symbol nodes and check nodes in an edge-by-edge way is highly known to construct low-density parity-check (LDPC) codes at short block lengths for achieving good performance. This paper proposed an improved PEG construction for irregular codes, which heuristically...
For the low accuracy of the spectrum sensing of the single node, this paper discusses several popular cooperative spectrum sensing technology. It also proposes a clustering double threshold cooperative spectrum sensing algorithm does two threshold detection based on the double threshold cooperative spectrum sensing algorithm. This algorithm applies or data fusion rule to realize the combination of...
A new frequency estimator of sinusoid based on interpolated FFT amplitudes is proposed. The coarse frequency estimation is made by the position of the maximum DFT amplitude. Then the fine estimation is made by utilizing the amplitudes of two DFT coefficients. Simulation results show that the root mean square errors of frequency estimation of the proposed estimator and Fang's estimator are close to...
Massive multiple-input multiple-output (MIMO) using a large number of antennas at the base station (BS) is a promising technique for the next-generation 5G wireless communications. It has been shown that linear precoding schemes can achieve near-optimal performance in massive MIMO systems. However, classical linear precoding schemes such as zero- forcing (ZF) precoding suffer from high complexity...
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