Granting interference rights to a secondary spectrum user that has a need for spectrum access to carry out wireless communications includes receiving a spectrum access request from the secondary user and determining a primary user that has a protected use area that overlaps with a secondary use area of the secondary user. A quantified predicted amount of interference that operation of the secondary user has on the primary channel of the primary user is determined and spectrum access to a primary channel of the primary user under interference rights is authorized if the quantified predicted amount of interference has less than a predetermined amount of effect on the primary channel of the primary user. The spectrum access is communicated to the secondary user.