Point-to-multipoint digital radio frequency transport
One embodiment is directed to a system for use with a coverage area in which one or more wireless units wirelessly transmit using a wireless radio frequency spectrum. The system comprises a first unit, and a plurality of second units communicatively coupled to the first unit using at least one communication medium. Each of the plurality of second units generates respective digital RF samples indicative of a respective analog wireless signal received at that second unit. Each of the plurality of second units communicates the respective digital RF samples generated by that second unit to the first unit using the at least one communication medium. The first unit digitally sums corresponding digital RF samples received from the plurality of second units to produce summed digital RF samples. The system is configured so that an input used for base station processing is derived from the resulting summed digital RF samples.
1. A distributed antenna system comprising:
a host unit configured to convert a first signal to a transmitted digital signal, the host unit further configured to convert a received digital signal to a second signal;
a plurality of remote antenna units communicatively coupled with the host unit, each remote unit configured to transmit an analog representation of the transmitted digital signal, each remote antenna unit further configured to receive radio frequency signals from a coverage area and to convert the radio frequency signals into a digitized received spectrum; and
a summing unit communicatively coupled to the host unit and at least one remote antenna unit of the plurality of remote antenna units, the summing unit positioned downstream of and remote from the host unit and upstream of and remote from the at least one remote antenna unit, the summing unit including a digital summer configured to sum a first digitized spectrum derived from a signal received by the summing unit from the at least one remote antenna unit with a second digitized spectrum to generate a digitally summed signal, wherein the digitally summed signal is transmitted toward the host unit.
2. The distributed antenna system of claim 1 , wherein the at least one remote antenna unit includes a first remote antenna unit; and
wherein the second digitized spectrum is received by the summing unit from a second remote antenna unit of the plurality of remote antenna units.
3. The distributed antenna system of claim 2 , wherein the second remote antenna unit is remote from the summing unit.
4. The distributed antenna system of claim 1 , wherein the summing unit is a digital expansion unit.
5. The distributed antenna system of claim 1 , wherein the host unit, summing unit, and plurality of remote antenna units are communicatively coupled over at least one communication medium.
6. The distributed antenna system of claim 5 , wherein the at least one communication medium includes at least one optical communication medium;
wherein the transmitted digital signal is a transmitted digital optical signal; and
wherein the received digital optical signal is a received digital optical signal.
7. A system for digital transport of a wireless spectrum, the system comprising:
a first unit;
a second unit remotely located from the first unit and communicatively coupled to the first unit using at least a first cabled communication link;
a third unit remotely located from the first unit and communicatively coupled to the second unit;
wherein the third unit is configured to receive a first analog wireless signal comprising first wireless spectrum and any transmissions from any wireless units within a first coverage area associated with the third unit;
wherein the third unit is configured to generate first digital samples indicative of at least a first portion of the first wireless spectrum of the first analog wireless signal;
wherein the third unit is configured to communicate the first digital samples to the second unit;
wherein the second unit is configured to digitally sum the first digital samples with second digital samples indicative of at least a second portion of a second wireless spectrum of a second analog wireless signal to produce first summed digital samples;
wherein the second unit is configured to communicate the first summed digital samples to the first unit using the first cabled communication link; and
wherein the system is configured so that an input used for base station processing is derived from the first summed digital samples.
8. The system of claim 7 , wherein the third unit is remotely located from the second unit and communicatively coupled to the second unit using at least a second cabled communication link.
9. The system of claim 8 , wherein the third unit is configured to communicate the first digital samples to the second unit using the second cabled communication link.
10. The system of claim 7 , wherein the first unit is a host unit; and
wherein the third unit is remote antenna unit.
11. The system of claim 10 , wherein the second unit is a digital expansion unit.
12. The system of claim 7 , wherein the second digital samples are received at the second unit from a fourth unit remotely located from the second unit.
13. The system of claim 12 , wherein the fourth unit is configured to receive the second analog wireless signal comprising the second wireless spectrum and any transmissions from any wireless units within a second coverage area associated with the fourth unit.
14. The system of claim 7 , wherein the system includes base station signal processing functionality configured to perform base station processing.
15. The system of claim 7 , wherein the system is configured to convert at least one of the summed digital samples and a signal based on the summed digital samples to a replicated analog wireless signal.
16. The system of claim 15 , wherein the system comprises a digital-to-analog converter configured to convert at least one of the summed digital samples and a signal based on the summed digital samples to the replicated analog wireless signal.
17. The system of claim 7 , wherein the third unit comprises:
a respective analog-to-digital converter configured to digitize the first analog wireless signal in order to produce the first digital samples.
18. The system of claim 7 , wherein the third unit is configured to generate the first digital samples by frequency shifting the first analog wireless signal and digitizing the frequency-shifted first analog wireless signal.
19. The system of claim 7 , wherein the third unit is configured to generate the first digital samples by down converting the first analog wireless signal and digitizing the down-converted first analog wireless signal.
20. The system of claim 7 , wherein the second portion of the second wireless spectrum overlaps in wireless spectrum with the first portion of the first wireless spectrum.
21. The system of claim 7 , wherein the second portion of the second wireless spectrum is covers the same frequency range as the first portion of the first wireless spectrum.
22. The system of claim 7 , wherein the system includes base station signal processing functionality configured to perform base station processing.
23. The system of claim 22 , wherein the base station processing functionality is at least one of: co-located with the first unit and remote from the first unit.
24. The system of claim 7 , wherein the system comprises at least a portion of a base station for performing the base station processing.
25. The system of claim 7 , wherein the system further comprises software configured to perform the base station processing using the input derived from the resulting summed digital samples.
26. The system of claim 25 , wherein the first unit comprises the software configured to perform the base station processing using the input derived from the resulting summed digital samples.
27. A first unit used in digital transport of a wireless spectrum, the first unit comprising:
a first interface configured to communicatively couple the first unit to a second upstream unit located remotely from the first unit using a first cabled communication link;
a second interface configured to communicatively couple the first unit to a third downstream unit, the second interface configured to receive first digital samples from the third downstream unit, the first digital samples indicative of at least a first portion of a first wireless spectrum of a first analog wireless signal comprising the first wireless spectrum and any transmission from any wireless units with a first coverage area associated with the third downstream unit;
a digital summer configured to digitally sum the first digital samples with second digital samples indicative of at least a second portion of a second wireless spectrum of a second analog wireless signal to produce first summed digital samples;
wherein the first interface is configured to communicate the first summed digital samples to the second upstream unit using the first cabled communication link, wherein the second upstream unit is configured so that an input used for base station processing is derived from the first summed digital samples.
28. The first unit of claim 27 , wherein the first unit is a digital expansion unit;
wherein the second upstream unit is a host unit; and
wherein the third downstream unit is remote antenna unit.
29. The first unit of claim 27 , wherein the second digital samples are received at the first unit from a fourth downstream unit remotely located from the first unit; and
wherein the fourth downstream unit is configured to receive the second analog wireless signal comprising the second wireless spectrum and any transmissions from any wireless units within a second coverage area associated with the fourth downstream unit.
30. The first unit of claim 27 , wherein the second portion of the second wireless spectrum overlaps in wireless spectrum with the first portion of the first wireless spectrum.
31. The first unit of claim 27 , wherein the second portion of the second wireless spectrum is covers the same frequency range as the first portion of the first wireless spectrum.
32. The first unit of claim 27 , wherein the base station processing is at least one of: co-located with the second unit and remote from the second unit.
33. The first unit of claim 27 , wherein the base station processing is performed by at least a portion of a base station.
34. The first unit of claim 27 , wherein the first unit further comprises software configured to perform the base station processing using the input derived from the resulting summed digital samples.