POWER ALLOCATION FOR OVERLAPPING TRANSMISSION WHEN MULTIPLE TIMING ADVANCES ARE USED

• US 20130044831A1
• Filed: 08/15/2011
• Published: 02/21/2013
• Est. Priority Date: 08/15/2011
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Narasimha, Murali, Nangia, Vijay, Nory, Ravikiran, Krishnamurthy, Sandeep H.
• Granted Patent: US 9,521,632 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/365 Power headroom reporting

Abstract

A method and apparatus for power allocation for overlapping transmissions is provided herein. During operation, user equipment will determine if transmissions to a single base station, on various frequencies, will be overlapping. If so, a determination is made to back off the power for at least one transmission on one frequency.

Claims

1. A method for allocating power for overlapping transmissions when multiple timing advances are used, the method comprising the steps of:

scheduling a first transmission to a base station, during a first frame on a first frequency using a first timing advance;

scheduling a second transmission to the base station, during a second frame, using a second timing advance, wherein the second frame occurs later than the first frame and the second timing advance is greater than the first timing advance;

determining that the first transmission and the second transmission will overlap; and

decreasing power to at least the first transmission or the second transmission in response to the determination.

2. The method of claim 1 wherein the step of determining that the first transmission and the second transmission will overlap comprises the step of determining that an OFDM symbol duration of an n-th subframe on the first transmission overlaps at least partially an OFDM symbol duration on an n+1-th subframe of the second transmission.

3. The method according to claim 1 wherein the step of decreasing the power to at least the first or the second transmission in response to the determination further comprises the step of prioritizing the first or the second transmissions prior to decreasing the power of a non-prioritized transmission.

4. The method according to claim 1 further comprising the steps of transmitting control information, including an indication that a power backoff is applied to the first or the second transmission, on a frequency to which no power backoff is applied.

5. The method according to claim 1 wherein the step of decreasing the power comprises the step of decreasing the power for a first duration corresponding to a first slot of an n-th subframe of the first transmission.

6. The method according to claim 1 wherein the step of decreasing the power comprises the step of decreasing the power to zero (no transmission).

7. The method of claim 1 wherein the second base station antenna comprises an antenna that is backhauled to the base station via a wired or fiber link.

8. The method of claim 7 wherein the second antenna comprises a Radio Relay Head (RRH).

10. An apparatus for allocating power for overlapping transmissions when multiple timing advances are used, the apparatus comprising:

logic circuitry scheduling a first transmission, during a first frame to a first antenna of a base station on a first frequency using a first timing advance, scheduling a second transmission, during a second frame, to a second antenna of the base station using a second timing advance, wherein the second frame occurs later than the first frame and the second timing advance is greater than the first timing advance, the logic circuitry determining that the first transmission and the second transmission will overlap and decreasing power to at least the first transmission or the second transmission in response to the determination.

11. The apparatus of claim 11 wherein the logic circuitry determines that the first transmission and the second transmission will overlap by determining that an OFDM symbol duration of an n-th subframe on the first transmission overlaps at least partially an OFDM symbol duration on an n+1-th subframe of the second transmission.

12. The apparatus of claim 11 wherein the logic circuitry decreases the power to at least the first or the second transmission by prioritizing the first or the second transmissions prior to decreasing the power of a non-prioritized transmission.

13. The apparatus of claim 11 further comprising a transmitter transmitting control information, including an indication that a power backoff is applied to the first or the second transmission, on a frequency to which no power backoff is applied.

14. The apparatus of claim 11 wherein the logic circuitry decreases the power by decreasing the power for a first duration corresponding to a first slot of an n-th subframe of the first transmission.

15. The apparatus of claim 11 wherein the logic circuitry decreases the power by decreasing the power to zero (no transmission).

16. The apparatus of claim 11 wherein the second base station antenna comprises an antenna that is backhauled to the base station via a wired or fiber link.

17. The apparatus of claim 16 wherein the second antenna comprises a Radio Relay Head (RRH).

18. A method for computing power headroom comprising:

receiving a first resource allocation for a first transmission in a first frame on a first frequency;

receiving a second resource allocation for a second transmission in a second frame on the first frequency, wherein the second frame occurs later than the first frame;

computing a first power headroom based on the first resource allocation and a second power headroom based on the second resource allocation; and

transmitting a message including the smaller of the first and the second power head rooms.

19. The method according to claim 18 further comprising:

performing transmissions on the first frequency using a first timing advance;

performing transmission on a second frequency using a second timing advance, wherein the second timing advance is larger than the first timing advance; and

transmitting a message including a power headroom for the second frequency.

20. A method for computing power headroom reporting comprising:

receiving a first resource allocation for a first transmission in a first frame on a first frequency;

receiving a second resource allocation for a second transmission in a second frame on a second frequency, wherein the second frame occurs later than the first frame;

determining that the first transmission overlaps at least in part a first ofdm symbol of the second transmission; and

transmitting a message including a power headroom for the first ofdm symbol of the second frame on the second frequency.

21. The method according to claim 20 further comprising:

performing transmissions on the first frequency using a first timing advance; and

performing transmission on the second frequency using a second timing advance, wherein the second timing advance is larger than the first timing advance.