Method and power control unit for supplying electric power to a radio unit

Abstract

A system in a wireless network comprising a tower, a first radio unit, a power supply unit, a supplementary power source and a power control unit arranged to supply electric power to the first radio unit. The power control unit is operative to obtain a scheduled power demand related to an amount of electric power required in the first radio unit for transmissions scheduled in an imminent time interval as a resource block or subframe. The power control unit is further operative to supply electric power to the first radio unit from the power supply unit if the power demand does not exceed a power threshold, or from the power supply unit and the supplementary power source if the power demand exceeds the power threshold.

1 . A network node system in a wireless network comprising a tower, a first radio unit, a power supply unit, a supplementary power source and a power control unit arranged to supply electric power to the first radio unit located at the top of the tower, wherein the power control unit is operative to:
 obtain a scheduled power demand related to an amount of electric power required in the first radio unit for transmissions scheduled in an imminent time interval,   supply electric power from the power supply unit, located at the bottom of the tower, to the first radio unit if the power demand does not exceed a power threshold, and   supply electric power from the power supply unit, located at the bottom of the tower, and the supplementary power source, located at the top of the tower, to the first radio unit if the power demand exceeds the power threshold.   
     
     
         2 . The network node system according to  claim 1 , wherein the imminent time interval is a resource block or a subframe in which said transmissions are scheduled to one or more wireless devices. 
     
     
         3 . The network node system according to  claim 1 , wherein the power control unit is configured to adjust the power threshold based on a ratio of usage time when electric power has been supplied from the supplementary power source. 
     
     
         4 . The network node system according to  claim 1 , wherein the power threshold does not exceed an available capacity of the power supply unit. 
     
     
         5 . The network node system according to  claim 1 , wherein the power control unit is configured to obtain the scheduled power demand from a scheduling function operative to schedule said transmissions in resource elements of each time interval. 
     
     
         6 . The network node system according to  claim 1 , wherein the power control unit is operable when the power supply unit is shared with one or more other radio units. 
     
     
         7 . The network node system according to  claim 1 , wherein the supplementary power source comprises a battery and the power control unit is configured to charge said battery during periods when electric power is not supplied from the supplementary power source. 
     
     
         8 . The network node system according to  claim 7 , wherein the power control unit is operable when the battery comprises two or more segments that can be used and charged individually. 
     
     
         9 . The network node system according to  claim 1 , wherein the power control unit is configured to control the electric power from the supplementary power source by connecting and disconnecting the supplementary power source to/from the first radio unit.