Patent ID: 7660524

Claim:
A method for monitoring transmissions over a unidirectional optical fiber loop coupling multiple nodes wherein a first node is a main base station unit, including processing circuitry and a central clock source, and the one or more other nodes are remote base station units including radio transceiving circuitry for communicating over a radio interface with a mobile radio terminal, comprising the steps of: measuring a round trip delay time for a signal sent from said first node to travel around the unidirectional optical fiber loop and be received at the first node; using the measured round trip delay time to account for temperature induced affects on signal transmissions over the unidirectional optical fiber loop; and wherein the mobile terminal determines one or more round trip times (RTTs), said step further comprises: the mobile terminal sending an RTT message to one of the remote base station units over the radio interface; the one remote base station unit sending the RTT message to the main base station via the unidirectional optical fiber loop; the main base station unit modifying the RTT message with a recently determined round trip delay time that accounts for temperature induced delay variations in the loop; the main base station unit sending the modified RTT message to the remote base station via the unidirectional optical fiber loop; the remote base station unit transmitting the modified RTT message to the mobile terminal over the radio interface; and the mobile terminal determining the RTT based on the modified RTT message.