Guest editorial: optical wireless communications

Over the last two decades, wireless communications has gained enormous popularity, offering attractive options for many personal and organizational communication needs due to major intrinsic characteristics such as flexibility, cost effectiveness, and mobility.     

Guest editorial wireless and pervasive communications for healthcare

The 16 articles in this special issue report cutting-edge research achievements in the field of applications of Networks for Healthcare.     

Guest editorial - Equalization techniques for wireless communications theory & applications

The fifteen articles in this special issue are devoted to new equalization techniques for wireless communications, including new the latest theories and applications.     

Guest editorial peer-to-peer communications and applications

The twenty-one papers in this special issue are devoted to peer-to-peer communications and their applications. Covers such topics as: overlay networks, searching, video streaming, files and servers, and theories and applications.     

Narrowband interference suppression in time-hopping impulse radio ultra-wideband communications

Ultra-wideband (UWB) technology has been considered an innovative solution for future short-range high-speed wireless communications. Interference suppression is important for the UWB devices to operate over spectrum occupied by narrowband systems. In this paper, the use of a notch filter in time-hopping impulse radio (TH-IR) for UWB communication is considered, where a Gaussian monopulse is employed with pulse position modulation. Lognormal channel fading is assumed, and a complete analytical framework is provided for the performance evaluation of using a transversal-type notch filter to reject narrowband interference (NBI). A closed-form expression of bit-error probability is derived, and the numerical results show that the use of a notch filter can improve the system performance significantly. Furthermore, a performance comparison between TH-IR and multicarrier code-division multiple-access (MC-CDMA) UWB systems is made under the conditions of the same transmit power, the same data rate, and the same bandwidth. It is shown that in the presence of NBI, the TH-IR system and MC-CDMA system achieve similar performance when both use a notch filter.