The idea of this special issue came about when I was approached by IOS Press (working on behalf ACTSLINES) and Wiley's International Journal of Adaptive Control and Signal Processing directly after the European Union (EU) Satellite Communications Workshop: ''From the Fourth to the Fifth Framework Programme,' a 2-day workshop organized with ACTS, ESPRIT and TELEMATICS Projects, 4-5 March 1999, Brussels, Belgium. This special issue has been conceived as a natural step as we were approaching the closed door of the research activities of the 4th Framework of the EU's Advanced Communications Technologies and Services (ACTS) projects. The objectives of the special issue were to highlight the achievements and research advances of ACTS projects, and to promote these results into a wider audience.
Over the last decade the world has witnessed explosive growth in the use of wireless mobile communications. Looking around we find users with mobile phones, wireless PDAs, pagers, MP3 players, and wireless headphones to connect to these devices } a small testament of the impact of wireless communications on our daily lives. In addition the burst of new technologies such as Bluetooth and other short-range wireless communications are encouraging the further development of a wide variety of distributed wireless devices.
Second generation wireless mobile communication systems (e.g. GSM, IS-136, PDC and IS-95) are mature technologies now. Radio Communications are in the process of a qualitative leap due to the technological revolution and new services that have emerged recently. In many countries more than 50% of the population own mobile phones and by the year 2003 it is predicted that there will be over 1 billion users worldwide. The technical revolution and continuing growth of mobile radio communication systems has been made possible by extraordinary advances in the related fields of digital computing, high-speed circuit technology, the Internet and, of course, digital signal processing.
Third generation (3G) and next generation wireless mobile communication systems should support a substantially wider and enhanced range of services with respect to those supported by second generation systems. These services include data, electronic mail, images and video, and interactive multimedia communications. The never-ending quest for such personal and multimedia services, however, demands technologies operating at higher data rates and broader bandwidths. This combined with the unpredictability and randomness of the mobile propagation channel has created many new technically challenging problems for which innovative, adaptive and advanced signal processing algorithms may offer new and better solutions! It was timely, therefore, to dedicate a special issue exploring recent signal processing advances in mobile radio communications. Five papers have been accepted in this special issue. The first two articles are contributions related to the ACTS European projects; these articles are invited contributions to this special issue.