A first wireless node of a wireless communication system is associated with a first cell having a first cell identity. The first wireless node obtains information relating to a set of wireless nodes which use at least one overlapping communication resource that is also used by at least one second node in the first cell. The first wireless node generates a preamble containing: a first data field designating the first cell identity, and a second data field reflecting a respective identity of the wireless nodes in the set of wireless nodes which use the at least one overlapping communication resource. The first wireless node transmits a preamble signal containing the preamble, over a predefined set of resources in a shared resource structure of the wireless communication system thus informing about the wireless nodes that use overlapping communication resources.