A software radio platform for new generations of wireless communication systems

With the proliferation of mobile communication systems, the implementation of Software Defined Radio terminals able to reconfigure themselves to handle several different standards has become a key issue to provide universal seamless connection to the users (Software Radio is a very broad term involving several levels in the protocol stack, see e.g. [1], [2], [3] and references therein).In this context Eur´ ecom and EPFL have started a joint project whose objective is to study and implement a realtime software radio communications platform to validate advanced mobile communication signaling algorithms. Due to various practical design issues, the platform implements the essential physical layer features of the TDD transmission mode of the UMTS standard (airinterface and signal processing) although the Frequency Division Duplex (FDD) mode and even other standards could also be implemented. The platform is a realtime PC based system that gives access to, and allows experimenting with, wide band radio resources. It will be able to emulate both a powerful base station with smart antennas and a simpler mobile terminal with a single antenna. It provides functionality at three levels: hardware, DSP software, and link level software. In this paper we address the major issues related to the design of a realtime software radio system. Within this framework we provide a general description of the platform architecture and functionalities. A special emphasis will be devoted to the description of the signal processing techniques adopted to implement transmission and reception software frontends. Some indications on the demonstration setting will also be provided. Finally, near future perspectives for the platform evolution will be addressed.