Network control

A method and network node for controlling operation of first and second wireless communication networks both operating in a predetermined frequency band. The first communication network is operable to communicate within a plurality of first network channels within the predetermined frequency band. The second communication network is operable to communicate within at least one second network channel within the predetermined frequency band. Each of the second network channels co-exist in a frequency range occupied by a plurality of the first network channels. The method comprises the steps of: determining that there may be data to be communicated within a network channel of one of the first and second wireless communication networks, transmitting a channel restriction message to another of the first and second wireless communications networks, the channel restriction message instructing prevention of communication within the another of the first and second wireless communications networks on at least one network channel in the another of the first and second wireless communications networks coexisting in a frequency range occupied by the network channel; and instructing communication within the one of said first and second wireless communication networks on said channel. Receiving an indication of quality of service of data traffic in said first and second wireless communication networks and scheduling transmission of said channel restriction message to minimize disruption to said data traffic in said first and second wireless communication networks.