A control node is disclosed for operating in a network with shared spectrum. The control node may include one or more processors configured to execute program code to identify a spectrum allocation policy; implement a rejection strategy for managing contention-based access to a shared channel by one or more transmitters based on the identified spectrum allocation policy; and transmit or trigger transmission of a transmission request rejection in response to a transmission request by a first transmitter of the one or more transmitters according to the rejection strategy.