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Low-density parity check (LDPC) codes are a mature coding scheme in telecommunications and the low power implementation of corresponding decoders is an issue of significant importance for receivers with stringent power budgets. This paper presents a power reduction technique for LDPC decoders that further extends their energy-proportional behavior, obtained with early-termination (ET), by predicting...
This paper presents an analyzing on the prediction of a primary signal in cognitive radio networks using a hybrid algorithm based on two parts, know as: an alpha-beta filter and a neyman-pearson (NP) detector. Today, it is important to predict a primary signal in a cluttered environment and especially when the secondary user (SU) is moving. However, the challenges of this contribution are based on...
Vehicle-to-vehicle (V2V) communication which supports ubiquitous information exchange and content sharing among vehicles with little or no human intervention becomes a key enabler for intelligent transportation industry. In this paper, we adopt a two-hop relay transmission mode to maximize the total spectrum efficiency of a device-to-device (D2D) based vehicular cooperative network while ensuring...
Considering unreliable wireless backhaul connections across transmitters, we investigate the outage performance of a finite-sized selective relaying system with M transmitters and N relays under Nakagami-m fading channels. To send the source message to the destination, the transmitter-relay pair providing the highest end-to-end signal-to-noise ratio is selected for transmission. The backhaul reliability...
The transmission structure of quadrature spatial modulation (QSM) restricts the signal constellation to be lattice style. Meanwhile, both the minimum amplitude and minimum Euclidean distance (MED) in quadrature and in-phase domain should be taken into account for the constellation design of QSM. In this paper, a non-uniform lattice constellation is designed for quadrature spatial modulation (QSM),...
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...
In this paper we consider centralized cooperative spectrum sensing (SS) techniques for cognitive radio networks using energy detector scheme. In light of the requirements imposed by centralized SS methods such as Maximum Ratio Combining (MRC), namely the estimation and transmission of the signal-to-noise ratio (SNR) on each secondary user, as well as the transmission of the exact energy level to the...
Cumulative distribution function (CDF)-based scheduling (CS) has been known as an efficient technique for cellular networks, which satisfies arbitrary channel access ratio requirements of users in a cell, while efficiently exploiting multiuser diversity (MUD). In this paper, we mathematically analyze both throughput and energy efficiency (EE) of CS in a multi-cell downlink network where the users...
Low-density parity-check (LDPC) coded massive multiple-input and multiple-output (MIMO) scheme is getting increasingly popular and sophisticated in today's wireless communication systems, since it can highly improve the spectral efficiency, data rates, and error performance. In this paper, a novel iterative detection and decoding (IDD) method for LDPC-coded massive MIMO systems is proposed. Based...
Recently, automatic modulation classification techniques using convolutional neural networks on raw IQ samples have been investigated and show promise when compared to more traditional likelihood-based or feature-based techniques. While likelihood-based and feature-based techniques are effective, making classification decisions directly on the raw IQ samples allows for reduced system complexity and...
In next generation cellular networks, small cell base stations (BSs) with ultra-dense deployments are likely to cooperate together to manage interference and provide users with high data rates. But users may still experience large drops in throughput due to lack of available resources even with high received signal strength. In this paper, we propose a congestion-aware user-centric cooperative BS...
According to the prior knowledge used in the algorithms, NMF-based speech enhancement can be categorized into supervised (NMF) one and semi-supervised (SNMF) one. In the supervised version, speech is estimated with the prior knowledge of both speech and noise. For the semi-supervised version, speech bases are learned on clean speech data in advance and adapted to different noise conditions. With the...
Distributed detection without fusion center (FC) allows each sensor node to exchange measurements with its neighbors and to reach agreement on the existence of the target using the consensus algorithm. Comparing with the centralized system, the decentralized system has better performance, in terms of robustness, scalability and invulnerability. Due to the decentralized and open properties, the security...
We present an optimal frame timing estimator for OFDM signals that utilizes both cyclic prefix (CP) and pilot-carrier-aided channel estimation. Combining the periodic nature of the embedded pilot signal information with the correlation present in the cyclic prefix allows improved frame timing estimates relative to use of either one. Following a derivation of the ML estimator, a processor diagram is...
Since at any given frequency a linear filter affects both the noise and the signal of interest proportionally, when a linear filter is used to suppress the interference outside of the passband of interest the resulting signal quality is affected only by the total power and spectral composition, but not by the type of the amplitude distribution of the interfering signal. Thus a linear filter cannot...
Increased demand for wireless services has spurred research into spectrum co-existence between radar and communication systems. The effect of an unaltered radar interference on an uncoded communication receiver has been investigated for constellations used in commercial systems. However, the constellation design — possible for a cognitive transmitter-receiver pair — that maximizes the transmission...
The main objective of this paper is to develop an efficient satellite digital beam-forming (BF) method that can provide user specific desirable signal-to-interference-plus-noise ratio (SINR) or data rate for each user in each zone. And a massive multiple-input multiple-output (MIMO) communications system model and its favorable channel propagation condition are assumed (i.e., channel independence...
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...
The Hoyt distribution can be used to characterize two types of fading in satellite communications. In this paper, the secrecy of the Hoyt-Hoyt fading channel is investigated. A set of exact formulas of the probability of strictly positive secrecy capacity are derived. Profile examples are illustrated to show the effects of secrecy capacity.
Communications survivability of mobile wireless segments in tactical military networks is and will be an enormous challenge in the present and future defence forces, which is vital to fulfill military missions in a timely manner. We have previously presented an autonomous system named OPAL, which uses distributed cooperative management solutions for enhancing communications survivability in volatile...
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