Transmit power control of a mobile terminal in a dual connectivity mode

1. A method for controlling transmit power of a mobile terminal, the method being performed by the mobile terminal in a dual connectivity mode wherein the mobile terminal is configured to support two or more contemporaneous links, including a first link and a second link, with two or more wireless network access points, the method comprising:

independently calculating respective unscaled uplink transmission power levels for the contemporaneous links, based on corresponding link-specific values;

calculating respective scaling factors for the contemporaneous links to satisfy a total-power constraint and to allocate respective power levels to the links in proportion with values that the links have for one or more criterions;

applying the respective scaling factors to the respective unscaled uplink transmission power levels, to obtain corresponding scaled power levels; and

transmitting over the two or more contemporaneous links at the respective scaled power levels.

2. The method of claim 1 , wherein the one or more criterions comprise uplink resource allocation.

3. The method of claim 1 , wherein the one or more criterions comprise link quality.

4. The method of claim 1 , wherein the one or more criterions comprise uplink buffer state.

5. The method of claim 1 , wherein the one or more criterions comprise priority.

6. The method of claim 1 , wherein:

the two or more contemporaneous links are two contemporaneous links;

the respective unscaled uplink transmission power levels for the links comprises unscaled power levels P 1 and P 2 for the two contemporaneous links; and

the respective scaling factors for the links are corresponding scaling factors α and β related to the unscaled power levels P 1 and P 2 according to the expression αP 1 +βP 2 ≤P MAX , where P MAX is the total-power constraint.

7. The method of claim 6 , wherein the unscaled power levels P 1 and P 2 for the two contemporaneous links are related to the corresponding scaling factors α and β according to the expression αP 1 +βP 2 =P MAX .

8. The method of claim 7 , wherein:

the calculation of the respective scaling factors for the links is based on uplink resource allocation to each link such that:

α

=

R

1

R

1

+

R

2

·

P

MAX

P

1

;

and

⁢

⁢

β

=

R

2

R

1

+

R

2

·

P

MAX

P

2

;

and

R 1 and R 2 represent numbers of resource blocks allocated for uplink transmissions to the first and second links, respectively.

9. The method of claim 7 , wherein:

the calculation of the respective scaling factors for the links is based on link quality for each link such that:

α

=

PG

1

PG

1

+

PG

2

·

P

MAX

P

1

;

and

⁢

⁢

β

=

PG

2

PG

1

+

PG

2

·

P

MAX

P

2

;

and

PG 1 and PG 2 represent path gains for the first and second links, respectively.

10. The method of claim 7 , wherein:

the calculation of the respective scaling factors for the links is based on uplink buffer state for each link such that:

α

=

RG

1

RG

1

+

RG

2

;

and

β=1−α; and

RG 1 and RG 2 represent total uplink resource grants for the first and second links, respectively.

11. The method of claim 10 , further comprising receiving, from at least one of the wireless network access points, a parameter λ, and calculating the scaling factors α and β according to:

α=λ;and

β=1−λ.

12. The method of claim 11 , further comprising receiving, from at least one of the wireless network access points, the total uplink resource grants RG 1 and RG 2 for the first and second links, respectively.

13. The method of claim 7 , wherein the calculation of the respective scaling factors for the links is based on priority for each link such that:

α=1, for the link having the higher priority; and

β

=

P

MAX

-

P

1

P

2

,

for the other link.

14. A mobile terminal for controlling transmit power of the mobile terminal in dual connectivity mode wherein the mobile terminal is configured to support two or more contemporaneous links, including a first link and a second link, with two or more wireless network access points, the mobile terminal comprising:

one or more processing circuits configured to:

independently calculate respective unscaled uplink transmission power levels for the contemporaneous links, based on corresponding link-specific values;

calculate respective scaling factors for the contemporaneous links to satisfy a total-power constraint and to allocate respective power levels to the links in proportion with values that the links have for one or more criterions;

apply the respective scaling factors to the respective unscaled uplink transmission power levels, to obtain corresponding scaled power levels; and

a transmit circuit configured to transmit over the two or more contemporaneous links at the respective scaled power levels.

15. The mobile terminal of claim 14 , wherein the one or more criterions comprise uplink resource allocation.

16. The mobile terminal of claim 14 , wherein the one or more criterions comprise link quality.

17. The mobile terminal of claim 14 , wherein the one or more criterions comprise uplink buffer state.

18. The mobile terminal of claim 14 , wherein the one or more criterions comprise priority.

19. The mobile terminal of claim 14 , wherein:

the two or more contemporaneous links are two contemporaneous links;

the respective unscaled uplink transmission power levels for the links comprises unscaled power levels P 1 and P 2 for the two contemporaneous links; and

the respective scaling factors for the links are corresponding scaling factors α and β related to the unscaled power levels P 1 and P 2 according to the expression αP 1 +βP 2 ≤P MAX , where P MAX is the total-power constraint.

20. The mobile terminal of claim 19 , wherein the unscaled power levels P 1 and P 2 for the two contemporaneous links are related to the corresponding scaling factors α and β according to the expression αP 1 +βP 2 =P MAX .

21. A method for controlling transmit power of a mobile terminal, the method being performed by the mobile terminal in a dual connectivity mode wherein the mobile terminal is configured to support two or more contemporaneous links with two or more wireless network access points, the method comprising:

independently calculating a first unscaled uplink transmission power level for a first link and a second unscaled uplink transmission power level for a second link, based on corresponding link-specific values, the first and second links being included in said two or more contemporaneous links;

calculating a scaling factor for the second link to satisfy a total-power constraint and to allocate the first unscaled uplink transmission power level to the first link, the first link having a higher priority than the second link;

applying the calculated scaling factor to the second unscaled uplink transmission power level, to obtain a corresponding scaled power level for the second link; and

transmitting over the first link at the first unscaled uplink transmission power level and over the second link at the corresponding scaled power level.

22. A mobile terminal for controlling transmit power of the mobile terminal in dual connectivity mode wherein the mobile terminal is configured to support two or more contemporaneous links with two or more wireless network access points, the mobile terminal comprising:

one or more processing circuits configured to:

independently calculate a first unscaled uplink transmission power level for a first link and a second unscaled uplink transmission power level for a second link, based on corresponding link-specific values, the first and second links being included in said two or more contemporaneous links;

calculate a scaling factor for the second link to satisfy a total-power constraint and to allocate the first unscaled uplink transmission power level to the first link, the first link having a higher priority than the second link;

apply the calculated scaling factor to the second unscaled uplink transmission power level, to obtain a corresponding scaled power level for the second link; and

a transmit circuit configured to transmit over the first link at the first unscaled uplink transmission power level and over the second link at the corresponding scaled power level.

23. A method for controlling transmit power of a mobile terminal, the method being performed by the mobile terminal in a dual connectivity mode wherein the mobile terminal is configured to support two or more contemporaneous links with two or more wireless network access points, the method comprising:

independently calculating a first uplink transmission power level for a first link and a second uplink transmission power level for a second link, based on corresponding link-specific values, the first and second links being included in said two or more contemporaneous links; and

when a sum of the first uplink transmission power level and the second uplink transmission power level does not satisfy a total-power constraint: determining an uplink transmission power level for the second link up to a remaining available power level to satisfy the total-power constraint while allocating the first uplink transmission power level to the first link, the first link having a higher priority than the second link; and transmitting over the first link at the first uplink transmission power level and over the second link at the determined uplink transmission power level.

24. The method of claim 23 , wherein the remaining available power level is a difference between a maximum allowed power level for the mobile terminal and the first uplink transmission power level for the first link.

25. The method of claim 23 , wherein the transmitting over the first link is based on single-carrier frequency-division multiple access (SC-FDMA).

26. The method of claim 23 , wherein the first link is used by the mobile terminal for transmitting to a Long Term Evolution (LTE) network.

27. A mobile terminal for controlling transmit power of the mobile terminal in dual connectivity mode wherein the mobile terminal is configured to support two or more contemporaneous links with two or more wireless network access points, the mobile terminal comprising:

one or more processing circuits configured to:

independently calculate a first uplink transmission power level for a first link and a second uplink transmission power level for a second link, based on corresponding link-specific values, the first and second links being included in said two or more contemporaneous links; and

when a sum of the first uplink transmission power level and the second uplink transmission power level does not satisfy a total-power constraint:

determine an uplink transmission power level for the second link up to a remaining available power level to satisfy a total-power constraint while allocating the first uplink transmission power level to the first link, the first link having a higher priority than the second link; and

a transmit circuit configured to transmit over the first link at the first unscaled uplink transmission power level and over the second link at the determined uplink transmission power level.

28. The mobile terminal of claim 27 , wherein the remaining available power level is a difference between a maximum allowed power level for the mobile terminal and the first uplink transmission power level for the first link.

29. The mobile terminal of claim 27 , wherein the transmit circuit is further configured to transmit over the first link based on single-carrier frequency-division multiple access (SC-FDMA).

30. The method of claim 27 , wherein the mobile terminal is configured to use the first link for transmitting to a Long Term Evolution (LTE) network.