Transmit power control for physical random access channels
The invention relates to methods for adjusting the transmit power utilized by a mobile terminal for uplink transmissions, and to methods for adjusting the transmit power used by a mobile terminal for one or more RACH procedures. The invention is also providing apparatus and system for performing these methods, and computer readable media the instructions of which cause the apparatus and system to perform the methods described herein. In order to allow for adjusting the transmit power of uplink transmissions on uplink component carriers, the invention suggests introducing a power scaling for uplink PRACH transmissions performing RACH procedures on an uplink component carrier. The power scaling is proposed on the basis of a prioritization among multiple uplink transmissions or on the basis of the uplink component carriers on which RACH procedures are performed.
1. A communication apparatus comprising:
a receiver which, in operation, receives a transport block over a physical uplink shared channel (PUSCH) of a first component carrier which belongs to a first timing advance group (TAG), and receives a random access preamble transmitted over a physical random access channel (PRACH) of a second component carrier which belongs to a second TAG, the second TAG being different from the first TAG, wherein power for the PUSCH transmission is determined for each subframe at a terminal apparatus, and wherein when a total transmission power exceeds a maximum output power configured for the terminal apparatus P MAX , the power for the PUSCH transmission is adjusted at the terminal apparatus so that the adjusted total transmission power does not exceed P MAX on an overlapped portion of the PUSCH transmission on a first subframe of the first component carrier and the PRACH transmission on a second subframe of the second component carrier, the second subframe being a subframe with a time offset from the first subframe along a time axis, wherein the power for the PRACH transmission is kept unadjusted; and
a transmitter which, in operation, transmits a random access response in response to the random access preamble.
2. The communication apparatus according to claim 1 , wherein
the receiver further receives control information over a physical uplink control channel (PUCCH); and
wherein power for the PUCCH transmission is determined and at least one of the power for the PUSCH transmission and the power for the PUCCH transmission is adjusted at the terminal apparatus.
3. The communication apparatus according to claim 1 , wherein the PRACH transmission is initiated by a PDCCH order.
4. The communication apparatus according to claim 1 , wherein the power for the PUSCH transmission is adjusted per subframe.
5. The communication apparatus according to claim 1 , wherein the total transmission power is adjusted in a priority order of the PRACH, the PUCCH and the PUSCH.
6. A receiving method comprising:
receiving a transport block over a physical uplink shared channel (PUSCH) of a first component carrier which belongs to a first timing advance group (TAG), and receiving a random access preamble transmitted over a physical random access channel (PRACH) of a second component carrier which belongs to a second TAG, the second TAG being different from the first TAG, wherein power for the PUSCH transmission is determined for each subframe at a terminal apparatus, and wherein when a total transmission power exceeds a maximum output power configured for the terminal apparatus P MAX , the power for the PUSCH transmission is adjusted at the terminal apparatus so that the adjusted total transmission power does not exceed P MAX on an overlapped portion of the PUSCH transmission on a first subframe of the first component carrier and the PRACH transmission on a second subframe of the second component carrier, the second subframe being a subframe with a time offset from the first subframe along a time axis, wherein the power for PRACH transmission is kept unadjusted; and
transmitting a random access response in response to the random access preamble received from the terminal apparatus.
7. The receiving method according to claim 6 , further comprising:
receiving control information over a physical uplink control channel (PUCCH), wherein power for the PUCCH transmission is determined and at least one of the power for the PUSCH transmission and the power for the PUCCH transmission is adjusted at the terminal apparatus.
8. The receiving method according to claim 6 , wherein the PRACH transmission is initiated by a PDCCH order.
9. The receiving method according to claim 6 , wherein the power for the PUSCH transmission is adjusted per subframe.
10. The receiving method according to claim 6 , wherein the total transmission power is adjusted in a priority order of the PRACH, the PUCCH and the PUSCH.