Systems and techniques for synchronization between in-coverage and out-of coverage user devices. A base station configures in-coverage and out-of coverage synchronization signals and configures user devices to recognize synchronization signals as in-coverage or out-of-coverage. An in-coverage device furnishes an in-coverage synchronization signal upon detection of an out-of coverage signal, and may continue to furnish the signal upon continued detection of an out-of-coverage signal that is not synchronized to the network. An out-of-coverage device may receive and synchronize to an in-coverage signal if available, or an out-of-coverage signal if available, or may generate and transmit its own out-of-coverage signal if no in-coverage or out-of-coverage signal is available. Signals may include rank information to indicate relay sequence information, and user devices may be configured to respond to signals based on the rank information—such as favoring a signal whose rank indicates that the signal represents a lower relay order number.