LTE-NR relative timing indication
Two or more base stations may share relative timing information. For example, a first cell may determining a cell level system frame number (SFN) and frame timing difference (SFTD) between the first cell and a second cell. At least one user equipment (UE) can be configured with dual connectivity with the first cell and the second cell. The first cell may send an indication of the cell level SFTD to the second cell via a backhaul with the second cell. The indication of the cell level SFTD may be the determined SFTD or a SFN reference time. In some implementations, the first cell may send a the SFTD measurement result and assistance information to the second cell via a backhaul to the second cell. The second cell may determine the cell level SFTD. In some implementations, a positioning network entity may determine the cell level SFTD.
1 . A method of wireless communication, comprising:
determining, by a first cell, a cell level system frame number (SFN) and frame timing difference (SFTD) between the first cell and a second cell; and
communicating, via a backhaul with the second cell, a message including an indication of the cell level SFTD, wherein the message is a setup request message, a setup response message, or a dual connectivity configuration update message, wherein the indication comprises an information element, and wherein:
the setup request message is an EN-DC X2 SETUP REQUEST message or an XN REQUEST message,
the setup response message is an EN-DC X2 SETUP RESPONSE message or an XN SETUP RESPONSE message, or
the dual connectivity configuration update message is an EN-DC CONFIGURATION UPDATE message or an XN CONFIGURATION UPDATE message.
2 . The method of claim 1 , wherein the indication of the cell level SFTD is the determined cell level SFTD.
3 . The method of claim 1 , wherein determining the cell level SFTD between the first cell and the second cell is based on a SFN reference time for the second cell.
4 . The method of claim 1 , wherein determining the cell level SFTD between the first cell and the second cell comprises receiving a SFTD measurement result between the first cell and the second cell from the at least one UE.
5 . The method of claim 1 , further comprising coordinating one or more of:
measurement gap configuration, handover, resource coordination, or position determination based on the cell level SFTD between the first cell and the second cell.
6 . A first cell for wireless communication, comprising:
a processing system configured to:
determine a cell level system frame number (SFN) reference time; and
communicate, via a backhaul with a second cell, a message including an indication of the cell level SFN reference time, wherein the message is a setup request message, wherein the indication comprises an information element, and wherein the setup request message is an EN-DC X2 SETUP REQUEST message or an XN REQUEST message.
7 . The first cell of claim 6 , wherein, to determine the cell level SFN reference time, the processing system is configured to determine the cell level SFN reference time based, at least in part, on a common synchronization source of the first cell and the second cell.
8 . The apparatus of claim 7 , wherein the common synchronization source is a satellite-based navigation system.
9 . The first cell of claim 7 , wherein the cell level SFN reference time is relative to a common reference time.
10 . The first cell of claim 6 , wherein the processing system is configured to determine a SFN and frame timing difference (SFTD) between the first cell and the second cell based on the cell level SFN reference time.
11 . The first cell of claim 6 , wherein the processing system is configured to coordinate one or more of: measurement gap configuration, handover, resource coordination, or position determination based on a cell level SFN and frame timing difference (SFTD) between the first cell and the second cell.
12 . The first cell of claim 6 , wherein the setup request message is the EN-DC X2 SETUP REQUEST message.
13 . The first cell of claim 6 , wherein the setup request message is the XN REQUEST message.
14 . A first cell for wireless communication, comprising:
a processing system configured to:
determine a cell level system frame number (SFN) reference time; and
communicate, via a backhaul with a second cell, a message including an indication of the cell level SFN reference time, wherein the message is a setup response message, wherein the indication comprises an information element, and wherein the setup response message is an EN-DC X2 SETUP RESPONSE message or an XN SETUP RESPONSE message.
15 . The first cell of claim 14 , wherein the setup response message is the EN-DC X2 SETUP RESPONSE message.
16 . The first cell of claim 14 , wherein the setup response message is the XN SETUP RESPONSE message.
17 . A first cell for wireless communication, comprising:
a processing system configured to:
determine a cell level system frame number (SFN) reference time; and
communicate, via a backhaul with a second cell, a message including an indication of the cell level SFN reference time, wherein the message is a dual connectivity configuration update message, wherein the indication comprises an information element, and wherein the dual connectivity configuration update message is an EN-DC CONFIGURATION UPDATE message or an XN CONFIGURATION UPDATE message.
18 . The first cell of claim 17 , wherein the dual connectivity configuration update message is the EN-DC CONFIGURATION UPDATE message.
19 . The first cell of claim 17 , wherein the dual connectivity configuration update message is the XN CONFIGURATION UPDATE message.
20 . The first cell of claim 6 , wherein, to communicate the message, the processing system is configured to receive the message.
21 . The first cell of claim 6 , wherein, to communicate the message, the processing system is configured to transmit the message.
22 . A first cell for wireless communication, comprising:
a processing system configured to:
determine a cell level system frame number (SFN) reference time; and
communicate, via a backhaul with a second cell, a message including an indication of the cell level SFN reference time, wherein the message is a setup request message, a setup response message, or a dual connectivity configuration update message, and wherein the cell level SFN reference time is an offset between an SFN 0 and a common reference time of 1980-01-06 T00: 00:19 in international atomic time (TAI).
23 . A first cell for wireless communication, comprising:
a processing system configured to:
determine a cell level system frame number (SFN) reference time, wherein the cell level SFN reference time is an offset between an SFN 0 and a common reference time of 1980-01-06 T00: 00:19 in international atomic time (TAI); and
communicate, via a backhaul with a second cell, a setup request message including an information element that indicates the cell level SFN reference time.
24 . The first cell of claim 23 , wherein the setup request message is an EN-DC X2 SETUP REQUEST message.
25 . The first cell of claim 23 , and wherein the setup request message is an XN REQUEST message.
26 . A first cell for wireless communication, comprising:
a processing system configured to:
determine a cell level system frame number (SFN) reference time, wherein the cell level SFN reference time is an offset between an SFN 0 and a common reference time of 1980-01-06 T00: 00:19 in international atomic time (TAI); and
communicate, via a backhaul with a second cell, a setup response message including an information element that indicates the cell level SFN reference time.
27 . The first cell of claim 26 , wherein the setup response message is an EN-DC X2 SETUP RESPONSE message.
28 . The first cell of claim 26 , wherein the setup response message is an XN SETUP RESPONSE message.