TRANSMIT POWER CONTROL FOR PHYSICAL RANDOM ACCESS CHANNELS

• US 20130058315A1
• Filed: 04/01/2011
• Published: 03/07/2013
• Est. Priority Date: 04/01/2010
• Status: Active Grant

• Current Assignee: Sun Patent Trust
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Aoyama, Takahisa, Feuersnger, Martin, Lhr, Joachim
• Granted Patent: US 9,008,050 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/281 taking into account user or data type priority
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/327 Power control of multicast channels
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

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.

Claims

1. A method for adjusting the transmit power utilized by a mobile terminal for uplink transmissions, wherein the mobile terminal is configured with at least a first and a second uplink component carrier, the method comprising the following steps:

determining a transmit power required for transmitting a transport block P_PUSCH(i) via a physical uplink shared channel on the first uplink component carrier, and determining a transmit power required for transmitting a random access preamble P_PRACH(i) via a physical random access channel on the second uplink component carrier;

reducing the determined transmit power for the physical uplink shared channel transmission and/or the physical random access channel transmission according to a prioritization between the transmit power for the physical uplink shared channel transmission and the transmit power for the physical random access channel transmission,

transmitting the transport block on the first uplink component carrier and the random access preamble on the second uplink component carrier within a transmission time interval i, using the respective transmit powers.

2. The method according to claim 1, wherein the step of determining the transmit powers further includes determining a transmit power required for transmitting another transport block via an assigned physical uplink shared channel on a third component carrier, and the transmit powers for transmitting each transport block P_PUSCHc(i) are determined according to the corresponding uplink component carrier c, the uplink component carriers having a priority order;

wherein the step of reducing the determined transmit powers further includes reducing the determined transmit power for transmitting each transport block w_c·

P_PUSCHc(i) according to the priority order, where w_c ε

[0, . . . , 1]; and

wherein the step of transmitting includes transmitting each transport block using the respective reduced transmit power.

3. The method according to claim 2, wherein, in case the transmit power for transmitting via a physical uplink shared channel is prioritized over the transmit power for transmitting via a physical random access channel, the mobile terminal first reduces the determined transmit power P_PRACH(i) for transmitting the random access preamble via the physical random access channel and then reduces the transmit power

4. The method according to claim 1, wherein, in case the transmit power of physical random access channel transmissions is prioritized over the transmit power of physical uplink shared channel transmissions, the mobile terminal reduces the transmit power

5. The method according to claim 1, wherein the determined transmit powers are reduced such that the sum of the determined transmit powers is smaller or equal to a maximum transmit power available P_MAX to the mobile terminal for transmitting on the uplink component carriers within the transmission time interval i.

6. The method according to claim 1, wherein the step of determining the transmit powers further includes determining a transmit power required for transmitting another random access preamble via a physical random access channel on a fourth uplink component carrier within the transmission time interval i, and the transmit powers for transmitting each random access preamble P_PRACHc(i) are determined according to the corresponding uplink component carrier c, the uplink component carriers having a priority order;

wherein the step of reducing the determined transmit powers further includes reducing the determined transmit powers for transmitting each random access preamble w_c·

P_PRACHc(i) according to the priority order, where w_c ε

[0, . . . , 1]; and

wherein the step of transmitting includes transmitting each random access preamble using the respective reduced transmit power.

7. The method according to claim 6, wherein each uplink component carrier is assigned a cell index and the step of reducing the determined transmit power for transmitting each random access preamble w_c·

P_PRACH(i) is based on the priority order given by the cell indexes of the uplink component carriers.

8. The method according to claim 6, wherein one uplink component carrier is configured with the mobile terminal as the primary component carrier and any other uplink component carrier is configured with the mobile terminal as a secondary component carrier, and the step of reducing the determined transmit power for transmitting each random access preamble w_c·

P_PRACHc(i), where the primary component carrier is prioritized over any other secondary component carrier.

9. The method according to claim 6, wherein the step of reducing the transmit power for transmitting each random access preamble w_c·

P_PRACHc(i) is based on a flag for each random access preamble, the flag indicating for each random access preamble to be transmitted whether or not a request for transmitting the respective random access preamble was previously received for the corresponding uplink component carrier by the terminal.

10. The method according to claim 6, wherein the transmit power for transmitting a random access preamble via a random access channel on each of the second and the fourth component carrier is determined by utilizing a first offset P_0—

_PRACH, in case the uplink component carrier to be time aligned and uplink component carriers already time aligned belong to a same timing advance group; and

a second, different offset P<sub>0—

PRACHmultiple</sub>, in case the uplink component carrier to be time aligned and uplink component carriers already time aligned belong to more than one timing advance groups.

11. The method according to claim 10, wherein the first offset P_0—

_PRACH and the second offset P<sub>0—

PRACHmultiple</sub> are signaled to the mobile terminal by a base station.

12. The method according to claim 10, wherein the step of determining the transmit power for transmitting a random access preamble via a physical random access channel on an uplink component carrier to be time aligned includes re-utilizing a previously determined power ramping step for the corresponding uplink component carrier or re-utilizing a different, previously determined power ramping step for a different uplink component carrier, the power ramping step N_c and being used for ramping the transmit power of consecutive transmissions of the random access preamble.

13. The method according to claim 12, wherein the transmit power for transmitting a random access preamble via a physical random access channel on an uplink component carrier is determined by:

P_PRACHc(i)=min{P<sub>0—

PRACH</sub>−

PL(i)+(N−

1)Δ

_RACH+Δ

_Preamble,P_MAX}

where N ε

{N_c,}, in case the uplink component carrier to be time aligned and uplink component carriers already time aligned belong to a same timing advance group; and

P_PRACHc(i)=min{P<sub>0—

PRACHmultiple</sub>−

PL(i)+(N−

1)Δ

_RACH+Δ

_Preamble,P_MAX}

where N ε

{N_c,}, in case the uplink component carrier to be time aligned and uplink component carriers already time aligned belong to more than one timing advance groups.

14. The method according to claim 1, wherein the step of determining the transmit powers includes adding a base station dependent pre-scaling offset Δ

offset_c that has been received by the mobile terminal from a base station for an uplink component carrier c to adjust the transmit power for transmitting random access preambles on the respective uplink component carrier.

15. The method according to claim 14, wherein the transmit power for transmitting a random access preamble via a physical random access channel on an uplink component carrier is determined by:

P_PRACHc(i)=min{P<sub>0—

PRACH</sub>−

PL(i)+(N−

1)Δ

_RACH+Δ

_Preamble+Δ

offset_c,P_MAX}

where N ε

{N_c,}, in case the uplink component carrier to be time aligned and uplink component carriers already time aligned belong to a same timing advance group, and

P_PRACHc(i)=min{P<sub>0—

PRACHmultiple</sub>−

PL(i)+(N−

1)Δ

_RACH+Δ

_Preamble+Δ

offset_c,P_MAX}

where N ε

{N_c, }, in case the uplink component carrier to be time aligned and uplink component carriers already time aligned belong to more than one timing advance groups.

27. The mobile terminal according to claim 26 further comprising means for performing the steps according to claim 2.

16-25. -25. (canceled)

26. A mobile terminal for controlling the transmit power for uplink transmissions, wherein the mobile terminal is configured with at least a first and a second uplink component carrier, the mobile terminal comprising:

a processing unit for determining a transmit power required for transmitting a transport block P_PUSCH(i) via a physical uplink shared channel on the first uplink component carrier, and for determining a transmit power required for transmitting a random access preamble P_PRACH(i) via a physical random access channel on the second uplink component carrier;

a power control unit for reducing the determined transmit power for the physical uplink shared channel transmission and/or the physical random access channel transmission according to a prioritization between the transmit power for the physical uplink shared channel transmission and the transmit power for the physical random access channel transmission, and

a transmitter for transmitting the transport block on the first uplink component carrier and the random access preamble on the second uplink component carrier within a transmission time interval i, using the respective transmit power.

28. The mobile terminal according to claim 26, wherein:

the processing unit is adapted to determine a transmit power required for transmitting another random access preamble via a physical random access channel on a fourth uplink component carrier within the transmission time interval i, and the transmit powers for transmitting each random access preamble P_PRACHc(i) are determined according to the corresponding uplink component carrier c, the uplink component carriers having a priority order;

the power control unit adapted to reduce the determined transmit powers further includes reducing the determined transmit powers for transmitting each random access preamble w_c·

P_PRACHc(i) according to the priority order, where w_c ε

[0, . . . , 1]; and

wherein the transmitter is adapted to transmit each random access preamble using the respective reduced transmit power.

29. The mobile terminal according to claim 26, further comprising means for performing the steps according to claim 7.

30-40. -40. (canceled)