Power management in a cellular system

1. A method for controlling a power allocation in a base station of a cell in a cellular communications network across a plurality of sub-bands, the method comprising:

determining whether a long-term performance achieved by the cell exceeds a first threshold value; and

allocating a total transmit power across the sub-bands according to whether the long-term performance achieved by the cell exceeds the first threshold value, wherein allocating the total transmit power comprises distributing the total transmit power across the sub-bands according to an algorithm which may produce an uneven distribution of the total transmit power across the sub-bands when the long-term performance achieved by the cell is equal to or more than the first threshold value.

2. A method as claimed in claim 1 , wherein the algorithm is adapted to allocate a transmit power to a sub-band based on the frequency of the sub-band.

3. A method as claimed in claim 2 , wherein:

if the long-term performance achieved by the cell is less than the first threshold value, allocating the total transmit power comprises:

for each sub-band, determining whether a power currently allocated to the sub-band exceeds a second threshold value; and

distributing the total transmit power across the sub-bands by allocating a power to each sub-band according to whether the power currently allocated to said sub-band exceeds the second threshold value.

4. A method as claimed in 3 , wherein:

if the power currently allocated to a sub-band is greater than or equal to the second threshold value, distributing the total transmit power across the sub-bands comprises:

allocating a first power to said sub-band.

5. A method as claimed in claim 4 , wherein the first power is greater than the second threshold value.

6. A method as claimed in claim 5 , wherein:

if the power currently allocated to a sub-band is less than the second threshold value, distributing the total transmit power across the sub-bands comprises:

allocating a second power to said sub-band.

7. A method as claimed in claim 6 , wherein the second power is less than the second threshold value.

8. A method as claimed in claim 1 , wherein:

if the long-term performance achieved by the cell is less than the first threshold value, allocating the total transmit power comprises:

distributing the total transmit power evenly across the sub-bands.

9. A method as claimed in claim 1 , wherein the long-term performance is determined based on a sum of a Packet Data Convergence Protocol (PDCP) packet delay for each bearer established for the base station per delay budget for the cell.

10. A method as claimed in claim 9 , wherein the long-term performance is determined based on the sum of the Packet Data Convergence Protocol (PDCP) packet delay for each bearer established for the base station that meets a certain Quality of Service (QoS) requirement, per delay budget for the cell.

11. A method as claimed in claim 1 , wherein the long-term performance is determined based on a sum of a percentile of a Packet Data Convergence Protocol (PDCP) packet delay for each bearer established for the base station per delay budget for the cell.

12. A method as claimed in claim 11 , wherein the long-term performance is determined based on the sum of the percentile of the Packet Data Convergence Protocol (PDCP) packet delay for each bearer established for the base station that meets a certain Quality of Service (QoS) requirement, per delay budget for the cell.

13. A method as claimed in claim 12 , wherein the sum used to determine the long-term performance is a weighted sum.

14. A method as claimed in claim 1 , further comprising:

determining whether a short-term performance achieved by the cell exceeds a second threshold value; and

adapting the total transmit power according to whether the short-term performance achieved by the cell exceeds the second threshold value, wherein, if the short-term performance achieved by the cell is equal to or more than the second threshold value, adapting the total transmit power comprises decreasing the total transmit power.

15. A method as claimed in claim 14 , wherein, if the short-term performance achieved by the cell is less than the second threshold value, adapting the total transmit power comprises increasing the total transmit power.

16. A method as claimed in claim 15 , wherein the short-term performance is determined using a same measure as the long-term performance.

17. A base station configured for power allocation across a plurality of sub-bands, comprising:

a processor to:

determine whether a long-term performance achieved by a cell of the base station exceeds a first threshold value, and

allocate a total transmit power across the sub-bands according to whether the long-term performance achieved by the cell exceeds the first threshold value, wherein allocating the total transmit power comprises distributing the total transmit power across the sub-bands according to an algorithm which may produce an uneven distribution of the total transmit power across the sub-bands when the long-term performance achieved by the cell is equal to or more than the first threshold value.

18. A base station as claimed in claim 17 , wherein the long-term performance is based on an average happiness of users in the cell or a weighted average happiness of users in the cell.

19. A base station as claimed in claim 17 , wherein the long-term performance is based on a standard deviation of a happiness of users in the cell or on a percentile of the happiness of users in the cell.

20. A base station as claimed in claim 17 , wherein the long-term performance is based on a ratio of each user's average bit rate to the user's required bit rate.

21. A base station as claimed in claim 17 , further comprising a transceiver.

22. A base station as claimed in claim 17 , wherein, if the long-term performance achieved by the cell is less than the first threshold value, allocation of the total transmit power comprises distribution of the total transmit power evenly across the sub-bands.

23. One or more non-transitory computer readable media having instructions thereon that, in response to execution by one or more processors of a base station, cause the base station to:

determine whether a long-term performance achieved by a cell of the base station exceeds a first threshold value; and

allocate a total transmit power across the sub-bands according to whether the long-term performance achieved by the cell exceeds the first threshold value, wherein allocating the total transmit power comprises distributing the total transmit power across the sub-bands according to an algorithm which may produce an uneven distribution of the total transmit power across the sub-bands when the long-term performance achieved by the cell is equal to or more than the first threshold value.

24. One or more non-transitory computer readable media as claimed in claim 23 , having instructions thereon that, in response to execution by one or more processors of a base station, cause the base station to:

determine whether a short-term performance achieved by the cell exceeds a second threshold value; and

adapt the total transmit power according to whether the short-term performance achieved by the cell exceeds the second threshold value.

25. One or more non-transitory computer readable media as claimed in claim 23 , wherein, if the long-term performance achieved by the cell is less than the first threshold value, allocation of the total transmit power comprises distribution of the total transmit power evenly across the sub-bands.

26. One or more non-transitory computer readable media as claimed in claim 23 , wherein the long-term performance measure is sub-band specific.