Systems, methods and devices for cellular synchronization references
Cellular (e.g., LTE or UMTS) and global navigation satellite system (GNSS) based technologies can provide ubiquitous and seamless synchronization solution for LTE-based vehicle to everything (V2X) or Proximity Services synchronization (ProSe) services. For example, by using joint GNSS timing references and LTE cellular network timing references for V2X or ProSe system synchronization benefits of using GNSS technologies to improve synchronization procedure for LTE based V2X or ProSe services can be enabled, including: (1) accurate and stable timing, (2) availability of a global and stable timing reference and (3) ability to propagate GNSS timing by user equipment having sufficient GNSS signal quality.
1. A system for wireless transmissions using a prioritized timing reference comprising:
a global navigation satellite system (GNSS) receiver;
a wireless transceiver configured to communicate with a first device;
a processor configured to:
receive a prioritized list of synchronization sources including GNSS and evolved Node B (eNB);
select a timing reference based at least in part on a ranking system of the synchronization sources; and
synchronize transmission timing to the timing reference of the synchronization source.
2. The system of claim 1 , wherein to receive a prioritized list of synchronization sources further comprises to receive the prioritized list from an eNB.
3. The system of claim 1 , wherein to receive a prioritized list of synchronization sources further comprises to use a pre-defined list of synchronization sources.
4. The system of claim 1 , wherein the processor is further configured to propagate timing information for devices without GNSS synchronization.
5. The system of claim 1 , wherein an in-coverage device uses GNSS based on an evolved Node B (eNB) priority message.
6. The system of claim 1 , wherein transmission timing further comprises transmissions that are frame mapped to coordinated universal time (UTC).
7. The system of claim 6 , wherein transmission timing further comprises a separate offset indicator for timing below one microsecond.
8. The system of claim 1 , wherein the prioritized list of synchronization sources further comprises data indicating signaling of the timing offset in a granularity of less than cyclic prefix duration relative to global coordinated universal time (UTC).
9. The system of claim 1 , wherein the timing reference between a network system timing, GNSS system timing and proximity services (ProSe) system timing is related to a common global timing reference.
10. The system of claim 1 , wherein the processor is further configured to receive GNSS assistance information broadcasted by the eNB in system information blocks (SIB).
11. The system of claim 1 , wherein GNSS assistance information in long term evolution positioning protocol (LPP) is reused.
12. The system of claim 11 , wherein GNSS-ReferenceTime data element is reused for a relationship between GNSS system time and network air-interface timing of the eNB transmission in a reference cell.
13. The system of claim 11 , wherein GNSS-ReferenceLocation data element is reused to provide knowledge of a location to improve GNSS receiver performance.
14. The system of claim 1 , wherein the processor is further configured to receive a synchronization signal or synchronization channel that carries information about a type of the synchronization source.
15. The system of any of claim 1 , wherein eNB and GNSS timing is aligned and associated with common resource allocation, unambiguously defining a physical structure of resource pool configuration for data and control, once a UE acquires timing information.
16. The system of claim 1 , wherein the processor is a baseband processor.