Patent ID: 7069025

Claim:
A mobile unit for providing location identification signals, said location identification signals useful for determining location of a mobile asset in a communication network, said mobile unit comprising: a receiver; a transmitter; and a controller; wherein said controller is responsive to wake up signals received by said receiver to operate said receiver to determine if radio frequency energy in a first channel in a first cell of a cellular network is substantially less than a predetermined threshold, and to cause said transmitter to transmit said location identification signals on said first channel if radio frequency energy in said first channel is substantially less than a predetermined threshold: wherein said controller is responsive to said receiver, if said radio frequency energy in said first channel is not substantially less than said threshold, to cause said receiver to detect the presence of radio frequency energy in a second channel in a second cell of said cellular network; and wherein said controller is responsive to said receiver, if radio frequency energy in said second channel is substantially less than a predetermined threshold, to cause said transmitter to transmit said location identification information on said second channel.