Methods and equipment for reducing power loss in cellular systems
Methods of powering a radio that is mounted on a tower of a cellular base station are provided in which a direct current (“DC”) power signal is provided to the radio over a power cable and a voltage level of the output of the power supply is adjusted so as to provide a substantially constant voltage at a first end of the power cable that is remote from the power supply. Related cellular base stations and programmable power supplies are also provided.
1. An apparatus configured to provide direct current (DC) electrical power to a DC power input of a radio from first ends to radio ends of electrical conductors and to determine a resistance of the electrical conductors, the apparatus comprising:
an input configured to receive a first DC power signal having a first DC voltage level;
an output electrically coupled to the first ends;
a current sensor coupled to the output and configured to measure direct current drawn from the output;
first circuitry electrically coupled to the input, the output, and the current sensor;
wherein the first circuitry is configured to:
(a) convert the first DC voltage level to a second DC voltage level;
(b) provide a third DC voltage level, at the radio ends, configured to forward bias a diode electrically coupled between the electrical conductors at or after the radio ends;
(c) whilst providing the third DC voltage level, determine the resistance of the electrical conductors; and
(d) upon determining the resistance of the electrical conductors:
convert the first DC voltage level to a fourth DC voltage level, wherein the fourth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels, and wherein the fourth DC voltage level is a function of the resistance of the electrical conductors and a measurement of direct current drawn from the output;
wherein the output is further configured to receive, from the first circuitry, a second DC power signal having the second DC voltage level or the fourth DC voltage level.
2. The apparatus of claim 1 , wherein the first circuitry comprises DC voltage conversion circuitry.
3. The apparatus of claim 1 , wherein the first circuitry comprises control logic and a memory coupled to one another.
4. The apparatus of claim 1 , wherein a magnitude of the fourth DC voltage level is greater than a magnitude of the first DC voltage level.
5. The apparatus of claim 1 , wherein the first circuitry is further configured to provide a fifth DC voltage level at the radio ends, wherein a magnitude of the fifth DC voltage level is less than a maximum DC voltage rating of the radio, and wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
6. The apparatus of claim 5 , wherein the magnitude of the maximum DC voltage rating of the radio is forty eight volts.
7. The apparatus of claim 5 , wherein the magnitude of the fifth DC voltage level is within four volts of the magnitude of the maximum DC voltage rating of the radio.
8. The apparatus of claim 1 , wherein the first circuitry is further configured to provide a fifth DC voltage level at the radio ends, wherein a magnitude of the fifth DC voltage level is greater than a nominal DC power input voltage rating of the radio, and wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
9. The apparatus of claim 1 , wherein each of the electrical conductors is part of a single power cable for connecting the apparatus to the radio.
10. The apparatus of claim 1 , wherein the electrical conductors include at least two electrically connected conductive elements.
11. The apparatus of claim 10 , wherein the at least two electrically connected conductive elements are a power cable.
12. The apparatus of claim 1 , wherein the first circuitry is further configured to provide a fifth DC voltage level, at the radio ends, which is regulated despite changes in the direct current drawn from the output, wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
13. A method for providing direct current (DC) electrical power to a DC power input of a radio from first ends to radio ends of electrical conductors and to determine a resistance of the electrical conductors, the method comprising:
receiving, at an input, a first DC voltage level;
converting the first DC voltage level to a second DC voltage level provided at an output;
providing a third DC voltage level, at the radio ends, configured to forward bias a diode electrically coupled between the electrical conductors at or after the radio ends;
whilst providing the third DC voltage level, determining the resistance of the electrical conductors; and
upon determining the resistance of the electrical conductors:
measuring direct current drawn from the output; and
converting the first DC voltage level to a fourth DC voltage level, wherein the fourth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels, wherein a magnitude of the fourth DC voltage level is greater than a magnitude of the first DC voltage level, and wherein the fourth DC voltage level is a function of the resistance of the electrical conductors and the direct current drawn from the output.
14. The method of claim 13 , wherein a magnitude of the fourth DC voltage level is greater than a magnitude of the first DC voltage level.
15. The method of claim 13 , further comprising providing a fifth DC voltage level at the radio ends, wherein a magnitude of the fifth DC voltage level is less than a maximum power signal DC voltage level of the radio, and wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
16. The method of claim 15 , wherein the magnitude of the maximum power signal DC voltage level of the radio is forty eight volts.
17. The method of claim 15 , wherein the magnitude of the fifth DC voltage level is within four volts of the magnitude of the maximum power signal DC voltage level of the radio.
18. The method of claim 13 , further comprising providing a fifth DC voltage level at the radio ends, wherein the magnitude of the fifth DC voltage level is greater than a nominal power signal DC voltage level of the radio, and wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
19. The method of claim 13 , further comprising providing a fifth DC voltage level, at the radio ends, which is substantially constant notwithstanding any variations in the direct current drawn from the output, wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
20. An apparatus configured to provide direct current (DC) electrical power to a DC power input of a radio from first ends to radio ends of first and second electrical conductors and to determine a resistance of the first and the second electrical conductors, the apparatus comprising:
an input configured to receive a first DC power signal having a first DC voltage level;
an output electrically coupled to the first ends;
a current sensor coupled to the output and configured to measure direct current drawn from the output;
first circuitry electrically coupled to the input, the output, and the current sensor;
wherein the first circuitry is configured to:
(a) convert the first DC voltage level to a second DC voltage level;
(b) provide a third DC voltage level at the radio ends;
(c) whilst providing the third DC voltage level, determine the resistance of the first and the second electrical conductors; and
(d) upon determining the resistance of the first and the second electrical conductors:
convert the first DC voltage level to a fourth DC voltage level, wherein the fourth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels, and wherein the fourth DC voltage level is a function of the resistance of the first and the second electrical conductors and a measurement of direct current drawn from the output;
wherein the output is further configured to receive, from the first circuitry, a second DC power signal having the second DC voltage level or the fourth DC voltage level.
21. The apparatus of claim 20 , wherein the first circuitry comprises DC voltage conversion circuitry.
22. The apparatus of claim 20 , wherein the first circuitry comprises control logic and a memory coupled to one another.
23. The apparatus of claim 20 , wherein a magnitude of the fourth DC voltage level is greater than a magnitude of the first DC voltage level.
24. The apparatus of claim 20 , wherein the first circuitry is further configured to provide a fifth DC voltage level at the radio ends, wherein a magnitude of the fifth DC voltage level is less than a maximum DC voltage rating of the radio, and wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
25. The apparatus of claim 24 , wherein the magnitude of the maximum DC voltage rating of the radio is forty eight volts.
26. The apparatus of claim 24 , wherein the magnitude of the fifth DC voltage level is within four volts of the magnitude of the maximum DC voltage rating of the radio.
27. The apparatus of claim 20 , wherein the first circuitry is further configured to provide a fifth DC voltage level at the radio ends, wherein a magnitude of the fifth DC voltage level is greater than a nominal DC power input voltage rating of the radio, and wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
28. The apparatus of claim 20 , wherein each of the first and the second electrical conductors is part of a single power cable for connecting the apparatus to the radio.
29. The apparatus of claim 20 , wherein the first and the second electrical conductors include at least two electrically connected conductive elements.
30. The apparatus of claim 29 , wherein the at least two electrically connected conductive elements are a power cable.
31. The apparatus of claim 20 , wherein the first circuitry is further configured to provide a fifth DC voltage level, at the radio ends, which is regulated despite changes in the direct current drawn from the output, wherein the fifth DC voltage level has a DC voltage polarity that is opposite a DC voltage polarity of the second and the third DC voltage levels.
32. The apparatus of claim 20 , wherein the third DC voltage level, at the radio ends, is configured to forward bias a device electrically coupled between the first and the second electrical conductors at or after the radio ends.
33. The apparatus of claim 32 , wherein the device comprises a diode.