A vehicle wide-angle rearview mirror frame has a storage box pivotally connected at a lower front edge to a lower rear edge of the rearview mirror frame, so that the storage box could be opened or closed by turning the rearview mirror frame away from or toward a front opening of the storage box. During an exchange of sounding signals, a first station can monitor the quality of the signals to select a second station that is qualified to participate in a calibration procedure. The particular node selects the relay node from among those nodes which have transmitted the detection response signals each having the actual parameter equal to or larger than the optimum parameter.