Chiyoung Ahn

Future of wireless communication: RadioApps and related security and radio computer framework

This article introduces a novel flexible mobile device reconfiguration classes (MDRCs) framework which is expected to be applicable to future generation mass market radio devices. This framework sets the scene for a vision of a smooth evolution of reconfigurability features in mobile devices, paving the way from current, mainly static implementation choices toward a fully flexible device platform environment. For this flexible mobile device framework, baseband interfaces are introduced as they are currently discussed in ETSI reconfigurable radio systems standardization. Furthermore, this technical solution is positioned with respect to security requirements and the basic regulatory framework which is currently under revision in Europe. Indeed, the future revised Radio Equipment and Telecommunications Terminal Equipment Directive is expected to allow for such advanced reconfiguration, enabling users to acquire and install so-called RadioApps software components which may affect the compliance of a mobile device to the essential requirements of the Directive.

Cognitive Radio in Multiple-Antenna Systems

This chapter presents an overview of the techniques used in a multiple-antenna 1 system and discusses the key issues in introducing cognitive radio (CR) technology. This discussion is followed by an explanation of the applications of the new system, which combines CR and multiple-antenna (MA) techniques. This chapter discusses the issues that combine the MA system with CR technology to increase the utilization of spectrum by sharing the spectrum among different systems as well as to improve the transmission efficiency by selecting the optimum transmission schemes under certain operational environments. It introduces the new functionalities, namely, radio environment observation and cognitive engine, in the MA system by adding cognitive capability. In such a system, besides signal detection and identification, the DOA and antenna correlation information should be obtained with the help of multiple antennas. By combining the environmental information, CE is able to select an optimum operation mode for the radio, depending on the related position between the primary units (PUs) and secondary units (SUs).