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We outline guiding principles for choosing the subband bandwidth of a multicarrier system with multiple antennas. Initially, we review considerations for the choice of bandwidth in fast-fading doubly dispersive channels. We append to these considerations those relevant to the use of multiple antennas for intereference rejection in the wideband regime. To weigh the benefits of narrow subbands, which...
Electromagnetic interference can cause severe performance degradation on wireless communication systems. In modern military platforms there are many closely located electronic systems, which could potentially cause interference. The performance degradation is largely affected by the characteristics of the interference. With knowledge of the actual interference environment, radio receivers can be adapted...
In this paper, we propose a systematic design approach of polar codes for multicolor visible light communication (VLC). Owing to the mixed ratio of multicolor light intensities and the interference between different colors, the channel polarization over a multicolor VLC system is markedly different from that over a uniform channel. Our scheme quantifies these different color channels and constructs...
Dynamic Spectrum Access (DSA) based Cognitive Radio (CR) allows a secondary user (SU) to use spectrum in an opportunistic manner when the primary user (PU) of that spectrum is not transmitting. Conventional dynamic spectrum allocation methods deal with acquiring spectrum as fixed width channels. In this paper, we propose a novel technique where a node inside a network can dynamically access the spectrum...
In this article, we present a target speaker dependent speech enhancement system, to enhance a specific target talker in presence of real life background noises. The proposed system uses a multi-channel processing stage to produce a noise reference signal. This noise reference signal is further used, to not only compute the residual noise statistics from the multichannel stage output, but also to...
This paper describes an approach to address the challenges currently found in the management, provisioning, and troubleshooting of deployed SATCOM Terminals. We believe the proposed solution will address a major capabilities gap in the DOD's ability to maintain reliable and resilient network communications flows required for mission success in a dynamic net-centric battlefield. The proposed solution...
In this paper, we propose a novel m-th best average biased received power (ABRP) user association (UA) scheme for K-tier heterogeneous networks (HetNets), where a user is associated with the base station (BS) having the m-th strongest ABRP. For this novel scheme, by using stochastic geometry and modeling the positions of network elements in each tier as a homogeneous Poisson point process (PPP), we...
This paper investigates the resource allocation problem in heterogeneous cognitive radio networks (HCRNs). In this paper, two types of users, i.e., multi-homing and single-network cognitive radio users (CRUs), are considered to coexist in HCRNs. Multi-homing CRUs can access multiple networks simultaneously, while single-network CRUs can be served by only one network at a time. With the aim of maximizing...
This paper investigates physical layer security of non-orthogonal multiple access (NOMA) in cognitive radio (CR) networks. The techniques of NOMA and CR have improved the spectrum efficiency greatly in the traditional networks. Because of the difference in principles of spectrum improving, NOMA and CR can be combined together, i.e. CR NOMA network, and have great potential to improving the spectrum...
RF self-interference cancellation for Full-Duplex communication with a microwave photonic technique is proposed and demonstrated experimentally. It is based on an integrated dual-parallel Mach-Zehnder modulator (DP-MZM), where the sub-MZMs (MZM1 and MZM2) are biased at the quadrature point and the minimum point, respectively. It avoids the optical interference at the combining Y branch waveguide....
The actual meshing state of Planetary Roller Screw will change, then the pre-setting meshing state could not be ensured and backlash or pre-tightening will appear, when the sizes of the tooth figure vary with the manufacture error. Therefore, a vector method is proposed to quantify meshing state of planetary roller screw, in order to precisely describe the meshing state. Using the relative position...
In cellular mobile wireless networks, nonlinear channel fading is always a critical factor which will scientifically deteriorate the Quality of Service (QoS) for the users. However, it is difficult to describe the nonlinear channel fading by precise mathematical model because of its complexity. So, the control of wireless networks becomes an especial tough work. In this paper, a power and rate control...
In the digital communication system, the intersymbol interference (ISI) at the receiver is usually produced due to the multiple path interference and noise in the channel. Generally, the equalizer at the receiver is employed to compensate the channel and overcome the ISI. The equalizer increases the complexity of communication system. Furthermore, the performances of the equalizer are not ideal for...
Aimed at the inapplicability of LEACH protocol for large-scale sensor network and uneven energy consumption, a Distributed Self-organizing Clustering Routing protocol (DSCR) for large-scale sensor network is proposed. Based on clustering, the network routing is divided into two levels: parent cluster and cluster. The cluster structure is formed by the back-off mechanism related to the residual energy...
According to the interference of the ocular artifacts in the measurement process of EEG, a method combined independent component analysis (ICA) and empirical mode decomposition (EMD) is proposed. Firstly, ICA is applied to the mixed signal including EEG and EOG so as to obtain the independent components. Secondly, EMD threshold denoising is used to remove the ocular artifacts which have larger amplitude...
A fiber optic sensor for simultaneous measurement of temperature and strain is demonstrated, based on a few-mode solid-core photonic crystal fiber. In the core of the few-mode fiber, the fundamental mode and the first higher order mode are co-excited, when coupling light from a collapsed end, through a single-mode fiber. Mach-Zehnder interferences between the two core modes and one possible cladding...
The database-driven CRN has emerged as a promising solution for the spectrum scarcity issue. However, it also raises severe privacy concerns. Although there are some existing works on this topic, they are far from practical due to their restrict on particular database structures or extremely heavy computation and communication overhead. To address these issues, in this paper we develop two practical...
The interference attack or better known as jamming attacks are very easy to implement affecting the service of any wireless communication system given the vulnerability of data sent to the user. This attack by denying the normal operation of the service detracts from the purpose of these systems. In general, a jamming attack is difficult to detect given the little experimental data provided by the...
To mitigate performance anomalies due to different transmission rates and to improve throughput performance in ad-hoc networks, a previous work has proposed a new method called user cooperative mobility. It also showed that the method achieved good improvement when users appropriately move. However, it only employed theoretical evaluation which does not include detailed behavior such as capture effect...
Penetration of multimedia communications with mobile Wi-Fi and tethering requires wireless LANs (WLANs) to guarantee a specific bandwidth in densely deployed WLANs. IEEE802.11e (HCCA) with 802.11aa could use inefficiently radio frequency as well as fail to provide each WLAN with enough CFP period in which sending opportunity of a terminal is guaranteed. To guarantee a specific bandwidth even in densely...
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