Cooperative techniques, unlike coexistence methods, do not require that both sensing and communications systems treat each other as sources of interference and both systems share some knowledge or information. Cooperative methods exploit this joint knowledge to enable both systems to effectively perform interference mitigation and subsequently improve their performance. Systems willingly share necessary information with each other in order to facilitate mutual interference mitigation. Cooperative methods are the first step toward designing joint systems and achieving RF convergence as an effective solution to the spectral congestion problem..