Method for transmitting uplink and wireless device using same
A method for uplink transmission in a wireless communication system. A user equipment (UE) determines whether to transmit or drop a sounding reference signal (SRS) on a last symbol in a i th subframe. The SRS is dropped if multiple timing advance groups (TAGs) are configured, if a portion of the last symbol of the i th subframe for transmitting the SRS toward a first serving cell in a first TAG is overlapped with an (i+1) th subframe for transmitting an uplink channel toward a second serving cell in a second TAG and if a total power of the SRS and the uplink channel exceeds a maximum value on the overlapped portion of the last symbol.
1. A method for uplink transmission in a wireless communication system, the method performed by a user equipment (UE) and comprising:
determining whether to drop a sounding reference signal (SRS) on a last symbol in a i th subframe,
wherein the SRS is dropped if multiple timing advance groups (TAGs) are configured, if a portion of the last symbol of the i th subframe for transmitting the SRS toward a first serving cell in a first TAG is overlapped with an (i+1) th subframe for transmitting an uplink channel toward a second serving cell in a second TAG and if a total power of the SRS and the unlink channel exceeds a maximum value on the overlapped portion of the last symbol.
2. The method of claim 1 , further comprising:
determining, by the UE, a power for transmitting the SRS toward the first serving cell in the first TAG; and
determining, by the UE, a power for transmitting the uplink channel toward the second serving cell in the second TAG.
3. The method of claim 1 , further comprising:
starting a first time alignment timer for the TAG; and
starting a second time alignment timer for the second TAG.
4. The method of claim wherein the uplink channel includes at least one of a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH) and a random access channel.
5. The method of claim 1 , further comprising:
receiving a periodic configuration indicating a SRS periodicity and a SRS subframe offset,
wherein the i th subframe is determined bused on the periodic configuration.
6. The method of claim 1 , further comprising:
receiving a request for the SRS transmission.
7. A user equipment (UE) for uplink transmission in a wireless communication system, the UE comprising:
a transceiver configured to transmit and receive radio signals; and
a processor operatively coupled with the transceiver and configured to:
determine whether to drop a sounding reference signal (SRS) on a last symbol in a i th subframe,
wherein the SRS is dropped if multiple timing advance groups (TAGs) are configured, if a portion of the last symbol of the i th subframe for transmitting the SRS toward a first serving cell in a first TAG is overlapped with an (i+1) th subframe for transmitting an uplink channel toward a second serving cell in a second TAG and if a total power of the SRS and the uplink channel exceeds a maximum value on the overlapped portion of the last symbol.
8. The UE of claim 7 , wherein the processor is further configured to:
determine a power for transmitting the SRS toward the first serving cell in the first TAG; and
determine a power for transmitting the uplink channel toward the second serving cell in the second TAG.
9. The UE of claim 7 , wherein the processor is father configured to:
start a first time alignment timer for the first TAG; and
start a second time, alignment timer for the second TAG.
10. The UE of claim 7 , wherein the uplink channel includes at least one of a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH) and a random access channel.
11. The UE of claim 7 , wherein the processor is further configured to:
receive a periodic configuration indicating a SRS periodicity and a SRS sub frame offset,
wherein the subframe i th is determined based on the periodic configuration.
12. The UE of claim 7 , wherein the processor is further configured to receive a request for the SRS transmission.