This article gives an overview of the European research on mobile Broadband Systems (MBS), whos e features range from WLANs type scenarios, allowing low mobility and medium data rates, up to public cellular MBS, where high mobility and high data rates are foreseen, lead to plain ubiquity. Current trends in 4G systems are described leading to the definition of the MBS concept. Owing to high transmission data rate and spectrum limitations at lower frequency bands, MBS intend also to operate at millimetrewave frequency bands, namely the 40 and 60 GHz, offering improved system capacity. THe MBS concept and the Trial Platform developed in the framework of the European ACTS-SAMBA and RACE-MBS projects are presented. Cellualr planning aspects are discussed including a comparison between the 40 GHz and 60 GHz bands, considering services and applications, tele-traffic, and MBS optimisation based on economic aspects. Field trials results on hte radio interface performance are presented, demonstrating MBS cellualr operation feasibility at millimetrewave frequency bands.