Patent attributes
The disclosed subject matter relates to communicatively coupled cognitive radio systems, devices, methodologies, or combinations thereof, facilitating improved utilization of unused portions of spectral bands by secondary users generally allocated to other primary users. This improved utilization can be achieved by cooperative spectrum sensing employing ST coding and/or SF coding for transmit diversity. Further, cooperative spectrum sensing can be improved by employing relay diversity with or without algebraic coding. It is illustrated that a threshold probability of false alarm can be reduced by applying transmit diversity with space time coding and/or space frequency coding. It is further illustrated that relay diversity can be employed to compensate for reduced sensing diversity order were some nodes in a cooperative spectrum sensing system cannot report directly. It is disclosed that algebraic coding can be combined with relay diversity to decrease the threshold probability of false alarm in relay diversity systems while maintaining high levels of sensing diversity order.
