  This letter provides a simple but efficient technique, which allows each
transmitter of an interference network, to exchange local channel state
information with the other transmitters. One salient feature of the proposed
technique is that a transmitter only needs measurements of the signal power at
its intended receiver to implement it, making direct inter-transmitter
signaling channels unnecessary. The key idea to achieve this is to use a
transient period during which the continuous power level of a transmitter is
taken to be the linear combination of the channel gains to be exchanged.
