Space-Frequency Coded Cooperative Scheme Among Distributed Nodes In Cognitive UWB Radio

Cooperative transmission scheme utilizing space-frequency coding (SFC) is investigated for cognitive ultra wideband (UWB) communications and networks, in the cases where multiple relaying is necessary among distributed nodes. The new scheme avoids the issue of the lack of required perfect synchronization on propagation delay and timing among the distributed nodes while using virtual multi-input multi-output (MIMO) algorithms. By computer simulations, it is shown that in the modified IEEE 802.15.3a S-V channel, the proposed SFC scheme combined with selective Rake receiver achieves almost the same BER performance compared with Alamouti´s space-time block coding (STBC) performance. The most promising perspective of this new scheme relies on its application to cognitive UWB radio and its networking in potentially providing full spatial and frequency diversity. Moreover, the proposed cooperative relaying scheme is capable of matching with the FCC emission mask while still achieving interference avoidance as well as efficient wireless transmission