A second device receives a first synchronization signal transmitted by a first device for training synchronization between the second device and the first device. The second device then transmits one or more initial synchronization response signals to the first device. The one or more initial synchronization response signals are from among a fixed number of synchronization response signals that the second device is configured to transmit to the first device. After transmission of the one or more initial synchronization response signals, the second device receives a second synchronization signal from the first device. After receiving the second synchronization signal, the second device continues transmission of synchronization response signals to the first device until the fixed number of synchronization response signals are transmitted from the second device to the first device.