Cell Timing in a Wireless Device and Base Station
Methods, apparatuses, and systems are described for wireless communications. A transmission timing difference between a first cell group and a second cell group may be determined. If the transmission timing difference exceeds a threshold, one or more devices may stop transmitting uplink signals via one or more secondary cells and/or may not apply the timing adjustment for a cell group.
1 . A method comprising:
performing, by a wireless device and using a first timing advance, a first uplink transmission via one or more secondary cells associated with a first cell group;
based on a transmission timing difference between the first cell group and a second cell group exceeding a threshold, determining that a time alignment timer, associated with the one or more secondary cells, is expired; and
after the determining that the time alignment timer is expired, performing, using a second timing advance, a second uplink transmission via the one or more secondary cells.
2 . The method of claim 1 , further comprising determining that the one or more secondary cells are out-of-sync, wherein the performing the second uplink transmission comprises performing the second uplink transmission during a time that the one or more secondary cells are out-of-sync.
3 . The method of claim 1 , wherein the transmission timing difference comprises a difference between:
uplink transmission timing associated with the first cell group; and
uplink transmission timing associated with the second cell group.
4 . The method of claim 1 , wherein the transmission timing difference comprises a difference between:
a timing of a first synchronization signal; and
a timing of a second synchronization signal.
5 . The method of claim 1 , wherein the first timing advance is a non-zero timing advance and the second timing advance is a zero timing advance.
6 . The method of claim 1 , further comprising:
receiving a first timing advance command, wherein the first timing advance is based on the first timing advance command;
receiving a second timing advance command; and
determining, based on the second timing advance command, the transmission timing difference.
7 . The method of claim 1 , wherein the second uplink transmission comprises a random access preamble.
8 . The method of claim 1 , further comprising:
based on the transmission timing difference exceeding the threshold, preventing a third uplink transmission by the wireless device.
9 . A wireless device comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause a wireless device to:
perform, using a first timing advance, a first uplink transmission via one or more secondary cells associated with a first cell group;
based on a transmission timing difference between the first cell group and a second cell group exceeding a threshold, determine that a time alignment timer, associated with the one or more secondary cells, is expired; and
after determining that the time alignment timer is expired, perform, using a second timing advance, a second uplink transmission via the one or more secondary cells.
10 . The wireless device of claim 9 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to determine that the one or more secondary cells are out-of-sync, and to perform the second uplink transmission during a time that the one or more secondary cells are out-of-sync.
11 . The wireless device of claim 9 , wherein the transmission timing difference comprises a difference between:
uplink transmission timing associated with the first cell group; and
uplink transmission timing associated with the second cell group.
12 . The wireless device of claim 9 , wherein the transmission timing difference comprises a difference between:
a timing of a first synchronization signal; and
a timing of a second synchronization signal.
13 . The wireless device of claim 9 , wherein the first timing advance is a non-zero timing advance and the second timing advance is a zero timing advance.
14 . The wireless device of claim 9 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to:
receive a first timing advance command, wherein the first timing advance is based on the first timing advance command;
receive a second timing advance command; and
determine, based on the second timing advance command, the transmission timing difference.
15 . The wireless device of claim 9 , wherein the second uplink transmission comprises a random access preamble.
16 . The wireless device of claim 9 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to:
based on the transmission timing difference exceeding the threshold, prevent a third uplink transmission by the wireless device.
17 . A non-transitory computer-readable medium storing instructions that, when executed, configure a wireless device to:
perform, using a first timing advance, a first uplink transmission via one or more secondary cells associated with a first cell group;
based on a transmission timing difference between the first cell group and a second cell group exceeding a threshold, determine that a time alignment timer, associated with the one or more secondary cells, is expired; and
after determining that the time alignment timer is expired, perform, using a second timing advance, a second uplink transmission via the one or more secondary cells.
18 . The non-transitory computer-readable medium of claim 17 , wherein the instructions, when executed, further configure the wireless device to determine that the one or more secondary cells are out-of-sync, and to perform the second uplink transmission during a time that the one or more secondary cells are out-of-sync.
19 . The non-transitory computer-readable medium of claim 17 , wherein the transmission timing difference comprises a difference between:
uplink transmission timing associated with the first cell group; and
uplink transmission timing associated with the second cell group.
20 . The non-transitory computer-readable medium of claim 17 , wherein the transmission timing difference comprises a difference between:
a timing of a first synchronization signal; and
a timing of a second synchronization signal.
21 . The non-transitory computer-readable medium of claim 17 , wherein the first timing advance is a non-zero timing advance and the second timing advance is a zero timing advance.
22 . The non-transitory computer-readable medium of claim 17 , wherein the instructions, when executed, further configure the wireless device to:
receive a first timing advance command, wherein the first timing advance is based on the first timing advance command;
receive a second timing advance command; and
determine, based on the second timing advance command, the transmission timing difference.
23 . The non-transitory computer-readable medium of claim 17 , wherein the second uplink transmission comprises a random access preamble.
24 . The non-transitory computer-readable medium of claim 17 , wherein the instructions, when executed, further configure the wireless device to:
based on the transmission timing difference exceeding the threshold, prevent a third uplink transmission by the wireless device.