SDR/Cognitive Radio Front-end

Software-defined radio or cognitive radio has attracted a lot of attention in academic research in recent years. In general (at least to my limited understanding) this type of reconfigurable radio architecture demands high performance, high bandwidth analog/rf front-ends to support some proposed algorithms, such as spectrum sensing and dynamic spectrum accessing.

I am fairly interested in this field and was wondering is anyone out there doing any research in terms of development of such radio front-ends. If so, can you provide some interesting topics and even share pointers to the research papers.

Thanks