Multiple-input, multiple-output cognitive radio

A wireless communication system and constituent wireless communication devices are provided to implement a distributed, cognitive radio approach to spectrum sharing. Under the distributed approach, individual wireless communication devices self-enforce negotiated agreements on usage of an available spectrum without intervention from a centralized authority. Particularly, individual wireless communication devices are configured to enhance information rates of their respective transmissions under predetermined constraints. The predetermined constraints can include transmit power constraints (e.g., a maximum power available to the wireless communication devices), or interference constraints (e.g., constraints on the amount, direction, and/or quality of interference generated by transmissions).