Patent ID: 7738836

Claim:
In a communication system including a first node, a second node, and a repeater that applies a known modification to a primary communication signal passing therethrough that identifies the repeater, where the first node receives a first signal from the second node either directly or via the repeater, and where the first signal includes a primary communication signal and, if the first signal is received from the repeater, also includes a signature signal that is a function of the primary communication signal and the known modification applied by the repeater, the method of determining if a signal received by the first node is received directly from the second node or indirectly through the repeater, comprising the steps of: receiving the first signal at the first node; extracting the primary communication signal from the first signal; producing a candidate signature signal as a function of the primary communication signal and the known modification applied by the repeater; and determining whether the first signal has been received from the repeater by processing of the candidate signature signal and at least a portion of the first signal.