Search

We propose a novel M-estimate conjugate gradient (CG) algorithm, termed Tukey’s biweight M-estimate CG (TbMCG), for system identification in impulsive noise environments. In particular, the TbMCG algorithm can achieve a faster convergence while retaining a reduced computational complexity as compared to the recursive least-squares (RLS) algorithm. Specifically, the Tukey’s biweight M-estimate incorporates a constraint into the CG filter to tackle impulsive noise environments. Moreover, the convergence behavior of the TbMCG algorithm is analyzed. Simulation results confirm the excellent performance of the proposed TbMCG algorithm for system identification and active noise control applications. [ABSTRACT FROM AUTHOR]

In order to improve the performances of recently presented improved normalised subband adaptive filter (INSAF) and proportionate INSAF algorithms for highly noisy system, this study proposes their set‐membership versions by exploiting the theory of set‐membership filtering. Apart from obtaining smaller steady‐state error, the proposed algorithms significantly reduce the overall computational complexity. In addition, to further improve the steady‐state performance for the algorithms, their smooth variants are developed by using the smoothed absolute subband output errors to update the step sizes. Simulation results in the context of acoustic echo cancellation have demonstrated the superiority of the proposed algorithms. [ABSTRACT FROM AUTHOR]

In recent years, the sport of mountaineering has become increasingly popular in many countries. Notably, during this activity, mountaineers are likely to enter into dangerous situations. In this paper, we propose a cloud-computing-based architecture to respond rapidly to an SOS emergency event requiring first aid. Our scheme constructs an aid platform based on cloud computing and, on the basis of the features of mobile devices, such as mobility and convenient communication, the injured party/patient can quickly send an SOS and summon aid. In this paper, we propose a scheme with which to accomplish the proxy authorization of the Schnorr signature from the patient. However, security is a very important issue as regards the communication. If an application suffers from a security challenge, the application is not practical. Therefore, the proposed scheme also integrates symmetric encryption technology, a message authentication code and RFC 2631 to defend against known attacks as well as performing an analysis with regards to achieving these security requirements provided by a proxy signature. Finally, we analyze the performance cost to determine whether our scheme is suitable for implementation in an emergency response and SOS system. [ABSTRACT FROM AUTHOR]

In this paper, link-adaptation schemes, where the transmit parameters are dynamically adapted to the changing channel conditions, are developed for spatial modulation (SM) transmission systems. The proposed schemes are based on the adaptive modulation (AM) and transmit-mode switching (TMS) techniques, to further exploit the spatial freedom of the multiple-input–multiple-output channel. More specifically, an optimal hybrid-SM (OH-SM) scheme that jointly uses both AM and TMS techniques is first developed to efficiently utilize the channel resources. In OH-SM, the transmit mode is jointly adapted with modulation orders according to the channel condition. Moreover, a suboptimal hybrid SM scheme, termed as a concatenated SM (C-SM) scheme, is also proposed. The C-SM scheme exploits the multistage adaptation strategy to balance the tradeoff between computational complexity and performance. The performance of the proposed schemes is evaluated by using the nearest neighbor approximations, to derive the parameter selection criterions. Simulation results show that, under the same spectral efficiency, the proposed schemes provide considerable system performance improvement compared with the conventional SM systems, particularly in correlated channel conditions. [ABSTRACT FROM PUBLISHER]

In this paper, a receiver algorithm for uplink multiuser orthogonal frequency-division multiplexing (OFDM) with a receiver-diversity system is proposed. The receiver uses a simple multiuser generalization of the maximum a posteriori probability (MAP) selection diversity combining followed by parallel interference cancellation with least-squares projection (PIC-LSP) for multiuser detection. Compared with the near-maximal-ratio-combining (near-MRC) scheme, simulation results show that the proposed approach achieves very good performance and has much lower complexity. [ABSTRACT FROM AUTHOR]

• This paper provides a FDEFLN-based nonlinear filtering scheme and its filtered-s version in a computationally efficient manner. • The stability, steady-state performance and computational complexity of the proposed frequency domain algorithms are derived and analyzed. • With applications to NSI, NAEC and NANC, the notable computational advantages of the proposed FDEFLN-based algorithms have been verified. The exponential functional link network (EFLN) filter has attracted tremendous interest due to its enhanced nonlinear modeling capability. However, the computational complexity will dramatically increase with the dimension growth of the EFLN-based filter. To improve the computational efficiency, we propose a novel frequency domain exponential functional link network (FDEFLN) filter in this paper. The idea is to organize the samples in blocks of expanded input data, transform them from time domain to frequency domain, and thus execute the filtering and adaptation procedures in frequency domain with the overlap-save method. A FDEFLN-based nonlinear active noise control (NANC) system has also been developed to form the frequency domain exponential filtered-s least mean-square (FDEFsLMS) algorithm. Moreover, the stability, steady-state performance and computational complexity of algorithms are analyzed. Finally, several numerical experiments corroborate the proposed FDEFLN-based algorithms in nonlinear system identification, acoustic echo cancellation and NANC implementations, which demonstrate much better computational efficiency. [ABSTRACT FROM AUTHOR]