Systems, methods and devices for cellular synchronization references

A non-transitory computer program product comprising a computer-readable storage medium storing program code for causing one or more processors of a first user equipment (UE) to perform:

• determining available synchronization sources;
• selecting, based at least in part on a priority rule, a synchronization source from the available synchronization sources for proximity services communication with a second UE;
• establishing a common timing based on the selected synchronization source;
• and
• propagating a timing reference signal received from the selected synchronization source according to the common timing to a second UE for which the selected synchronization source is unavailable, wherein propagation of the timing reference signal comprises an implicit indication of the selected synchronization source as the source of the timing reference signal.

A method of a first user equipment (UE), comprising:

• determining available synchronization sources;
• selecting, based at least in part on a priority rule, a synchronization source from the available synchronization sources for proximity services communication with a second UE;
• establishing a common timing based on the selected synchronization source;
• and
• propagating a timing reference signal received from the selected synchronization source according to the common timing to a second UE for which the selected synchronization source is unavailable, wherein propagation of the timing reference signal comprises an implicit indication of the selected synchronization source as the source of the timing reference signal.