Method and base station for power allocation in wireless system

Abstract

A base station in a LTE system and a method for use in the base station ( 400 ) are provided for allocating power in downlink transmissions for a UE. A report is received, from the UE, comprising a Reference Signal Received Quality, RSRQ, indicating a current channel quality of a downlink transmission with multiple subcarriers. A fairness factor used for achieving fairness in scheduling between UEs served by the base station is retrieved, from a resource management scheduler of the base station; and a combined factor is determined based on the received RSRQ and the retrieved fairness factor, for resource blocks, RBs, related to the downlink transmissions, the RBs comprising subcarriers pertaining to resources to be allocated to the UE. Then, a power is determined for the resource RBs based on the determined combined factor; and the determined power for the downlink transmission for the UE is allocated.

The invention claimed is:  
     
       1. A method for use in a base station for allocating power in downlink transmissions for a user equipment, UE, in a Long Term Evolution, LTE, system, the method comprising:
 receiving, from the UE, a report comprising a Reference Signal Received Quality, RSRQ, indicating a current channel quality of a downlink transmission with multiple subcarriers; 
 retrieving, from a resource management scheduler of the base station, a fairness factor used for achieving a fairness in scheduling between user equipments served by the base station; 
 determining a combined factor, based on the received RSRQ and the retrieved fairness factor, for resource blocks, RBs, related to the downlink transmissions, said RBs comprising subcarriers pertaining to resources to be allocated to the UE; 
 determining a power for the resource blocks, based on the determined combined factor; and 
 allocating the determined power for the downlink transmissions for the UE. 
 
     
     
       2. The method according to  claim 1 , further comprising determining a power for subcarriers of the RBs, for determining a Modulation and Coding Scheme, MCS level to be used by the UE. 
     
     
       3. The method according to  claim 1 , wherein determining the combined factor comprises determining said combined factor by multiplying the received RSRQ and the retrieved fairness factor according to f=((RSRQ)a)*((fairness factor)b), where f is the combined factor; and a and b are modify factors with a value from 0 to 1. 
     
     
       4. The method according to  claim 1 , wherein allocating the determined power for downlink transmission for the UE comprises using a predefined water filling function. 
     
     
       5. The method according to  claim 1 , wherein the method further comprises determining a new MCS level based on the determined power for the subcarriers of the resource blocks. 
     
     
       6. A base station in a Long Term Evolution, LTE, system, adapted to allocate power in downlink transmissions for a user equipment, UE, comprising:
 a transceiver circuit configured for transmitting signals to the UE and for receiving signals from the UE; and 
 a processing circuit operatively connected to the transceiver circuit and configured to:
 receive, from the UE, a report comprising a Reference Signal Received Quality, RSRQ, indicating a current channel quality of a downlink transmission with multiple subcarriers; 
 retrieve, from a resource management scheduler of the base station, a fairness factor used for achieving a fairness in scheduling between user equipments served by the base station; 
 determine a combined factor, based on the received RSRQ and the retrieved fairness factor, for resource blocks, RBs, related to the downlink transmissions, said RBs comprising subcarriers pertaining to resources to be allocated to the UE; 
 determine a power for the RBs based on the determined combined factor; and 
 allocate the determined power for the downlink transmissions towards the UE. 
 
 
     
     
       7. The base station according to  claim 6 , wherein the processing sing circuit is configured to determine a power for subcarriers of the RBs, for determining a Modulation and Coding Scheme, MCS level to be used by the UE. 
     
     
       8. The base station according to  claim 6 , wherein the processing circuit is configured to determine the combined factor by multiplying the received RSRQ and the retrieved fairness factor according to f=((RSRQ)a)*((fairness factor)b), where f is the combined factor, and where a and b are modify factors with a value from 0 to 1. 
     
     
       9. The base station according to  claim 6 , wherein the processing circuit is configured to allocate the determined power for downlink transmission for the UE using a predefined water filling function. 
     
     
       10. The base station according to  claim 6 , wherein the processing circuit is configured to determine a new MCS level based on the determined power for the subcarriers of the resource blocks.