An interference determining method for selecting a frequency candidate resource to be allocated to a terminal during carrier aggregation performed by a network device, comprising: obtaining, by an obtaining unit of the network device, first frequency information of a first resource; obtaining, by the obtaining unit, second frequency information of a second resource, wherein a frequency indicated by the first frequency information is lower than a frequency indicated by the second frequency information and wherein the first resource is an allocated resource and the second resource is a candidate resource to be allocated to the terminal and a candidate resource of a candidate resource set comprising at least one second resource or wherein the second resource is the allocated resource and the first resource is the candidate resource to be allocated to the terminal and the candidate resource of the candidate resource set comprising at least one first resource; determining, by a determining unit of the network device, based on the first frequency information, harmonic frequency information corresponding to the first resource; wherein the harmonic frequency information comprises at least a harmonic that corresponds to the first resource including a main lobe and a side lobe; determining, by the determining unit, based on the harmonic frequency information and the second frequency information, harmonic interference information between the first resource and the second resource for at least identifying whether the second frequency information corresponds to frequencies of the main lobe, the side lobe or frequencies different from the main lobe and the side lobe of the first frequency information; modifying, by the determining unit, the quality of the candidate resource based on the identification made by the harmonic interference information by assigning the best quality to a candidate resource resulting in second frequency information corresponding to frequencies other than the main lobe or the side lobe of the first frequency information, followed by candidate resources resulting in second frequency information corresponding to frequencies of the side lobe of the first frequency information and finally candidate resources resulting in second frequency information corresponding to frequencies of the main lobe of the first frequency information; and performing, by the determining unit, resource selection or allocation for selecting or allocating a candidate resource from the candidate resource set based decreasing order of the modified quality of the candidate resources. obtaining, by an obtaining unit of the network device, first frequency information of a first resource; obtaining, by the obtaining unit, second frequency information of a second resource, wherein a frequency indicated by the first frequency information is lower than a frequency indicated by the second frequency information and wherein the first resource is an allocated resource and the second resource is a candidate resource to be allocated to the terminal and a candidate resource of a candidate resource set comprising at least one second resource or wherein the second resource is the allocated resource and the first resource is the candidate resource to be allocated to the terminal and the candidate resource of the candidate resource set comprising at least one first resource; determining, by a determining unit of the network device, based on the first frequency information, harmonic frequency information corresponding to the first resource; wherein the harmonic frequency information comprises at least a harmonic that corresponds to the first resource including a main lobe and a side lobe; determining, by the determining unit, based on the harmonic frequency information and the second frequency information, harmonic interference information between the first resource and the second resource for at least identifying whether the second frequency information corresponds to frequencies of the main lobe, the side lobe or frequencies different from the main lobe and the side lobe of the first frequency information; modifying, by the determining unit, the quality of the candidate resource based on the identification made by the harmonic interference information by assigning the best quality to a candidate resource resulting in second frequency information corresponding to frequencies other than the main lobe or the side lobe of the first frequency information, followed by candidate resources resulting in second frequency information corresponding to frequencies of the side lobe of the first frequency information and finally candidate resources resulting in second frequency information corresponding to frequencies of the main lobe of the first frequency information; and performing, by the determining unit, resource selection or allocation for selecting or allocating a candidate resource from the candidate resource set based decreasing order of the modified quality of the candidate resources.