Communication device for a secondary user in a cognitive radio network

A communication device for a secondary user in a cognitive radio network, comprising:

• an antenna array comprising a plurality of antenna elements, each antenna element of the plurality of antenna elements connected to a phase shifter;
• a transceiver coupled to the plurality of antennas, the transceiver configured to transmit communication signals to or receive communication signals from another communication device in the cognitive radio network;
• and
• a controller coupled to the transceiver and to each phase shifter, the controller controlling beamforming of the plurality of antenna elements and performing a process of local spectrum sensing using receive beamforming and energy detection and the controller controlling each phase shifter,
• wherein the controller is configured to perform the process of local spectrum sensing by deciding between two hypotheses, wherein a first hypothesis, H0, of the two hypotheses determines the absence of a primary user, based on a received plurality of co-channel interferences, beamforming weights and sensing noise, and a second hypothesis, H1, of the two hypotheses determines the presence of a primary user based on detecting a primary user signal, and the received plurality of co-channel interferences, beamforming weights and sensing noise;
• and
• wherein the controller is configured to determine a set of beamforming weights by optimizing a probability of detection and constraining a probability of false alarm,
• wherein the controller is further configured to apply a genetic algorithm with multi-parent crossover to optimize the probability of detection and constrain the probability of false alarm, wherein the genetic algorithm with multi-parent crossover includes:
• initializing a random population,
• saving best chromosomes from an initialized random population by sorting according to constraint violations of the chromosomes,
• performing a tournament selection,
• performing a multi-parent crossover operation, and
• performing a diversity operation and checking replication.