Uplink signal transmission in a wireless device
A wireless device receives a message comprising at least one information element (IE) associated with a timing advance group (TAG). The at least one IE at least indicates one of a value of the time alignment timer (TAT) IE or a TAT of the TAG is disabled. The wireless device transmits uplink signals on a secondary cell in the TAG only after receiving a timing advance command (TAC) if the IE indicates the value of the TAT IE. The wireless device transmits uplink signals on the secondary cell regardless of receiving the TAC if the IE indicates that the TAT is disabled.
1. A method comprising:
receiving, by a wireless device, at least one message comprising configuration parameters of a plurality of cells grouped into a plurality of timing advance groups (TAGs) comprising:
a primary TAG comprising a primary cell;
a secondary TAG comprising a secondary cell, wherein a time alignment timer (TAT) information element (IE) is associated with the secondary TAG and a value of the TAT IE is selected from a finite set of predetermined values comprising: a first value; and a second value;
receiving an activation command indicating activation of the secondary cell in the secondary TAG;
determining that the value of the TAT IE indicates the second value; and
based on the determining, transmitting uplink data via the secondary cell in response to the activation of the secondary cell and before receiving an initial timing advance command (TAC) for the secondary TAG.
2. The method of claim 1 , wherein the first value relates to subframes.
3. The method of claim 1 , wherein the initial TAC comprises a TAG index and a timing advance value.
4. The method of claim 1 , further comprising transmitting uplink signals employing a stored value of a timing advance when a TAT of the secondary TAG is disabled.
5. The method of claim 1 , further comprising considering a TAT of the secondary TAG disabled based on the TAT IE indicating the second value.
6. The method of claim 1 , wherein the at least one message further comprises a TAG index IE identifying the secondary TAG.
7. The method of claim 1 , wherein a random access response comprises the initial TAC.
8. The method of claim 1 , wherein the secondary cell is a licensed assisted access (LAA) cell.
9. The method of claim 1 , wherein the transmitting the uplink data further comprises transmitting the uplink data via a physical uplink shared channel of the secondary cell.
10. The method of claim 1 , wherein the activation command is a first activation command received by the wireless device for the secondary cell after configuration of the secondary cell.
11. The method of claim 1 , wherein the initial TAC starts a TAT of the secondary TAG.
12. A method comprising:
receiving, by a wireless device, at least one message comprising at least one information element (IE) associated with a secondary timing advance group (TAG), the at least one IE associated with the secondary TAG indicating at least one of: a value of a time alignment timer (TAT) IE; or a TAT of the secondary TAG is disabled;
receiving an activation command indicating activation of a secondary cell in the secondary TAG;
determining that the at least one IE associated with the secondary TAG indicates the TAT of the secondary TAG is disabled; and
based on the determining, transmitting uplink data via the secondary cell in response to the activation of the secondary cell and before receiving an initial timing advance command (TAC) for the secondary TAG.
13. The method of claim 12 , wherein the at least one message further comprises a TAG index IE identifying the secondary TAG.
14. The method of claim 12 , further comprising receiving a random access response comprising the initial TAC.
15. The method of claim 12 , further comprising transmitting uplink signals employing a stored value of a timing advance when the TAT of the secondary TAG is disabled.
16. The method of claim 12 , wherein the value of the TAT IE relates to subframes.
17. The method of claim 12 , wherein the initial TAC comprises a TAG index and a timing advance value.
18. The method of claim 12 , wherein the secondary cell is a licensed assisted access (LAA) cell.
19. The method of claim 12 , wherein the transmitting the uplink data further comprises transmitting the uplink data via a physical uplink shared channel of the secondary cell.
20. The method of claim 12 , wherein the activation command is a first activation command received by the wireless device for the secondary cell after configuration of the secondary cell.