Capacitive-loaded jumper cables, shunt capacitance units and related methods for enhanced power delivery to remote radio heads
Tower systems suitable for use at cellular base stations include a tower, an antenna mounted on the tower, a remote radio head mounted on the tower and a power supply. A power cable having a power supply conductor and a return conductor is connected between the power supply and the remote radio head. A shunt capacitance unit that is separate from the remote radio head that is electrically coupled between the power supply conductor and the return conductor of the power cable.
1. A jumper cable for a cellular base station, comprising:
a cable segment including a power supply conductor and a return conductor that are enclosed within a cable jacket and electrically insulated from each other;
a first connector on a first end of the cable segment;
a second connector on a second end of the cable segment;
a shunt capacitance unit that is connected between the power supply conductor and the return conductor, the shunt capacitance unit including at least one capacitor that is coupled between the power supply conductor and the return conductor,
wherein the jumper cable is installed between a trunk cable and a remote radio head.
2. The jumper cable of claim 1 , wherein the at least one capacitor is a non-polar electrolytic capacitor.
3. The jumper cable of claim 1 , wherein the shunt capacitance unit includes a housing that has first and second apertures that the cable segment extends through, and wherein the at least one capacitor is mounted within the housing.
4. The jumper cable of claim 3 , wherein the housing is filled with epoxy that is configured to provide environmental protection to the at least one capacitor and the power supply and return conductors.
5. The jumper cable of claim 1 , further comprising a fuse circuit that is coupled in series with the at least one capacitor between the power supply conductor and the return conductor.
6. The jumper cable of claim 1 , wherein the shunt capacitance unit is included in at least one of the first connector and the second connector.
7. The jumper cable of claim 1 , wherein the shunt capacitance unit is enclosed within the cable jacket.
8. The jumper cable of claim 1 , wherein the at least one capacitor has a capacitance of at least 400 microfarads.
9. The jumper cable of claim 1 , wherein the shunt capacitance unit is configured to reduce a voltage drop at the remote radio head due to a spike in a direct current power supply signal carried by the jumper cable.
10. The jumper cable of claim 1 , further comprising at least one optical fiber within the jacket.
11. A method of operating a cellular base station, the method comprising:
outputting a direct current (“DC”) power signal from a power supply and supplying the DC power signal that is output from the power supply to a remote radio head that is mounted remotely from the power supply over a trunk cable and a jumper cable that are connected in series, the jumper cable including a power supply conductor, a return conductor and a shunt capacitance unit that is coupled between the power supply conductor and the return conductor; and
adjusting a voltage level of the DC power signal that is output from the power supply so that the DC power signal that is delivered to the remote radio head has a substantially constant voltage notwithstanding variation in a current level of the DC power signal that is output from the power supply.
12. The method of claim 11 , wherein the power supply comprises a programmable power supply, the method further comprising inputting information to the power supply from which the voltage level of the DC power signal that is output from the power supply can be determined that will provide the DC power signal at the first end of the power cable that has the substantially constant voltage.
13. The method of claim 12 , the method further comprising measuring the current level of the DC power signal that is output from the power supply, wherein the voltage level of the DC power signal that is output by the power supply is automatically adjusted in response to changes in the measured current level of the DC power signal that is output from the power supply to provide the DC power signal at the first end of the power cable that has the substantially constant voltage.
14. The method of claim 13 , further comprising determining a resistance or an impedance of the power cabling connection between the power supply and the shunt capacitance unit by transmitting an alternating current signal over the power cabling connection and through the shunt capacitance unit.
15. The method of claim 12 , wherein the substantially constant voltage comprises a voltage that exceeds a nominal power signal voltage of the remote radio head and which is less than a maximum power signal voltage of the remote radio head.
16. A shunt capacitance unit for a cellular base station, comprising:
a housing;
a first connector coupled to the housing, the first connector including a first power supply conductor and a first return conductor;
a second connector coupled to the housing, the second connector including a second power supply conductor that is electrically connected to the first power supply conductor and a second return conductor that is electrically connected to the first return conductor;
at least one capacitor electrically coupled between the first power supply conductor and the first return conductor.
17. The shunt capacitance unit of claim 16 , further comprising a fuse circuit coupled in series with the at least one capacitor between the first power supply conductor and the first return conductor.
18. The shunt capacitance unit of claim 16 , wherein the at least one capacitor is a non-polar electrolytic capacitor or at least two polar electrolytic capacitors.
19. The shunt capacitance unit of claim 16 , wherein the at least one capacitor has a capacitance of at least 400 microfarads.
20. The jumper cable of claim 1 , wherein the at least one capacitor comprises at least two polar electrolytic capacitors.