In this paper, an improved sparse-aware affine projection (AP) algorithm for sparse system identification is proposed and investigated. The proposed sparse AP algorithm is realized by integrating a non-uniform norm constraint into the cost function of the conventional AP algorithm, which can provide a zero attracting on the filter coefficients according to the value of each filter coefficient. Low complexity is obtained by using a linear function instead of the reweighting term in the modified AP algorithm to further improve the performance of the proposed sparse AP algorithm. The simulation results demonstrate that the proposed sparse AP algorithm outperforms the conventional AP and previously reported sparse-aware AP algorithms in terms of both convergence speed and steady-state error when the system is sparse.
A compact CPW-fed triple band-notched antenna for ultra-wide bandwidth (UWB) application is presented. By introducing an stepped impedance resonator-defected ground structure (SIR-DGS) and fork-shaped stubs, three sharp notches are achieved at frequencies of 3.5, 5.68 and 7.48 GHz. The proposed antenna working from 2.8 to 11.3 GHz with a voltage standing wave ratio of <2 is demonstrated, except for the selected notched bands. The main advantage of the antenna is that the frequency of the notched band can be tuned easily in a wide frequency range. A good agreement between the measurement and the simulation was achieved. The measurements confirm that the technique introduces negligible antenna radiation pattern distortion, except at the triple-notched frequencies. Introduction: The Federal Communication Commission announced permitting of 3.1-10.6 GHz for ultra-wide bandwidth (UWB) applications in 2002. Antennas, as a key component of the UWB system, have been widely investigated by many researchers. However, antenna designs still face many challenges, including impedance matching, radiation patterns and so on. On the other hand, in the designated band for UWB systems, there exist several relatively narrow frequency bands used by other wireless systems such as worldwide interoperability for microwave access (WiMAX) operating at 3.3-3.7 GHz, C-band satellite communication systems operating at 3.7-4.2 GHz, IEEE 802.11a/n operating at 5.15-5.825 GHz, the downlink of X-band satellite communication systems operating at 7.25-7.75 GHz and the Earth Exploration Satellite Service (EESS) operating at 8.025-8.4 GHz. To avoid interference, various UWB antennas with one or multiple bandnotched characteristics have recently been developed [1-5]. Nevertheless, many band-notched antenna designs in the literature cannot adjust to suit for all avoidable interferences. In this Letter, a printed UWB antenna with three band notches is presented. By introducing the stepped impedence resonator-defected ground structure (SIR-DGS) and the fork-shaped stubs, three sharp notches are achieved. The fork-shaped stubs structure on the radiation patch achieves a dual band-notched performance for the IEEE 802.11a/n and the X-band satellite communication systems, and the SIR-DGS structure inserted in the ground plane obtains the band-notched characteristic for the WiMAX. Compared with the previous antennas in [1-5], a larger adjusted range can be obtained. The details of the antennas design and the results are discussed below.
This study presents a survey of the current issues, application areas, findings, and performance challenges in wireless body area networks (WBAN). The survey discusses selected areas in WBAN signal processing, network reliability, spectrum management, security, and WBAN integration with other technologies for highly efficient future healthcare applications. The foundation of the study bases on the recent growing advances in microelectronic technology and commercialization, which ease device availability, miniaturization, and communication. The survey considers a systemic review conducted using reports, standard documents, and peer-reviewed articles. Based on the comprehensive review, we find WBANs faces several operational, standardization, and security issues, affecting performance and maintenance of user safety and privacy. We envision the increasing dependency of future healthcare on WBAN for medical and non-medical applications due to internet connectivity advances. In this view, despite the WBAN advantages in remote health monitoring, further studies need to be conducted for performance optimization. Therefore we finalize our study by proposing various current and future research directions and open issues in WBAN’s performance enhancement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.