Clustering for cooperative MIMO cognitive radio sensor networks under interference constraints

CRSN (Cognitive Radio Sensor Networks) have recently gained huge interest as an area of research. Naturally, due to energy limitations in WSN (Wireless Sensor Networks), grouping sensor nodes into clusters has been widely adopted by the research community to overcome the issue of limited energy budget and generally achieve high energy efficiency as well as prolonging network lifetime in large-scale WSN environments. Combining clustering of WSN with MIMO (Multiple Input Multiple Output) is a promising technique used in literature of this research area leading to what is called cooperative MIMO clustered WSN. Compared with existing work, our contributions are: i) Extension of CR (Cognitive Radio) technique to cooperative MIMO clustered WSN in a spectrum sharing sense as well as demonstrating that SISO setting isn´t always the best setting for transmission even at small distances. The shift to other settings is more favorable to guarantee not disturbing the primary user while transmitting on the same channel; and ii) Proposing a selection criterion for cooperative MIMO CRSN that chooses the minimum energy setting (SISO/SIMO/MISO/MIMO) to guarantee a proper communication for the secondary CR system under some interference constraint to the primary user as well as satisfying a specific BER requirement for CR secondary system.