Patent ID: 7616556

Claim:
A method for communication between unsynchronized nodes in a multi-carrier system, utilizing a set of carriers and having a predetermined symbol length, the method comprising the steps of: reserving a sub-set of carriers for communication between unsynchronized nodes, at least one respective carrier of said sub-set of carriers being assigned to nodes in the multi-carrier system to create a relation between node identity of said nodes and said at least one carrier; transmitting from a first node a phase-continuous sinusoidal signal on said at least one carrier of the sub-set of carriers assigned to the first node during a predetermined transmission period, the predetermined transmission period corresponding to the duration of n consecutive ones of the predetermined symbol length, where n is an integer larger than 1, receiving the transmitted sinusoidal signal in a second node that is unsynchronized with the first node; and the second node interpreting the received sinusoidal signal including associating at least a frequency of the received sinusoidal signal with information about the identity of the first node from which the existence of the first node within radio communication distance is determined even though the second node is unsynchronized with the first node.