Patent ID: 8654719

Claim:
An apparatus comprising: at least one processor; at least one memory including computer program code; the at least one memory and the computer program code configured, with the at least one processor, to cause the apparatus to perform at least: checking for available radio spectrum resources in a first system in a radio coverage area; sending information to a second system indicating the availability of radio spectrum resources of the first system which is usable by said second system in at least part of said radio coverage area and sending a message to said second system requesting at least one entity of said second system to transmit a reference signal on an available frequency; receiving one or more said reference signals from said second system on said available frequency; comparing one or more received reference signal power levels with a map of allowed interference limits; calculating one or more offsets to the allowed interference limits to generate an offset map; sending the offset map to one or more base stations of the second system such that, based on the offset map, the one or more base stations allocate radio resources for downlink and uplink: wherein said first system has priority over said radio spectrum resources; and wherein said apparatus is configured to determine interference information for defining an exclusion zone around an entity of said first system.