Distributed antenna system architectures
Communication system includes first unit; and second unit(s) having processing unit(s), downstream signal path(s), and upstream signal path(s). First unit communicates downstream digital transport signal (including digital representation of original downstream RF signal received at first unit) to second unit(s). Second unit uses processing unit and downstream signal path to generate downstream RF signal (for radiation from antenna) from downstream digital transport signal; and communicates upstream digital transport signal (generated from upstream RF signal received at second unit(s) using processing unit(s) and upstream signal path(s)) to first unit. Upstream digital transport signal includes digital representation of received upstream RF signal. Feedback path digitizes downstream RF signal(s) to provide digital representation(s) of downstream RF signal radiated from antenna to processing unit(s). Second unit pre-distorts input signal to downstream signal path for non-linearities in downstream signal path using digital representation of downstream RF signal radiated from antenna as received from feedback path.
1. A communication system comprising:
a first unit; and
at least one second unit that is communicatively coupled to the first unit, the at least one second unit including at least one processing unit, at least one downstream signal path, and at least one upstream signal path;
wherein the first unit is configured to communicate a downstream digital transport signal from the first unit to the second unit, wherein the downstream digital transport signal includes a digital representation of an original downstream radio frequency signal received at the first unit;
wherein the second unit to which the downstream digital transport signal is communicated uses the processing unit and the downstream signal path to generate a downstream radio frequency signal for radiation from an antenna associated with the second unit from the downstream digital transport signal;
wherein the second unit is configured to communicate an upstream digital transport signal from the second unit to the first unit;
wherein the upstream digital transport signal is generated from a received upstream radio frequency signal received at the second unit using the at least one processing unit and the at least one upstream signal path, wherein the upstream digital transport signal includes a digital representation of the received upstream radio frequency signal received at the second unit; and
a feedback path configured to digitize the downstream radio frequency signal to provide a digital representation of the downstream radio frequency signal radiated from the antenna to the at least one processing unit; and
wherein the second unit is configured to pre-distort an input signal to the downstream signal path for non-linearities in the downstream signal path using the digital representation of the downstream radio frequency signal radiated from the antenna as received from the feedback path.
2. The communication system of claim 1 , wherein at least one of the downstream digital transport signal or the upstream digital transport signal includes digital baseband data.
3. The communication system of claim 1 , wherein at least one of the downstream digital transport signal or the upstream digital transport signal includes at least of one OBSAI digital baseband data or CPRI digital baseband data.
4. The communication system of claim 1 , wherein the second unit is configured to receive the received upstream radio frequency signal using the same antenna used to radiate the downstream radio frequency signal.
5. The communication system of claim 4 , wherein the second unit further comprises at least one duplexer coupled to the antenna, wherein the at least one duplexer includes at least one of:
a low-power duplexer;
a mobile handset duplexer; or
a high-power duplexer.
6. The communication system of claim 1 , wherein:
the second unit is configured to radiate the downstream radio frequency signal from a first antenna; and
the second unit is configured to receive the received upstream radio frequency signal using a second antenna.
7. The communication system of claim 1 , wherein:
the second unit is configured to perform self-interference suppression processing in an upstream signal path by digitally subtracting the digital representation of the downstream radio frequency signal radiated from the antenna from the digital representation of the received upstream radio frequency signal as received from the feedback path.
8. An antenna unit for use in a communication system, the antenna unit comprising:
a transport interface to communicatively couple the antenna unit to a remotely located communication device included in the communication system and to receive a downstream digital transport signal from the remotely located communication device, wherein the downstream digital transport signal includes a digital representation of an original downstream radio frequency signal received at the first remotely located communication device;
a processing unit coupled to the transport interface;
at least one downstream signal path; and
at least one upstream signal path;
wherein the processing unit and downstream signal path are configured to use the downstream digital transport signal to generate a downstream radio frequency signal for radiation from an antenna associated with the antenna unit;
wherein the transport interface is configured to communicate an upstream digital transport signal from the antenna unit to the remotely located communication device, wherein the processing unit and the upstream signal path are configured to generate an upstream signal from a received upstream radio frequency signal received at the antenna unit, wherein the upstream digital transport signal includes a digital representation of the received upstream radio frequency signal, wherein the transport interface uses the upstream signal to generate the upstream digital transport signal; and
a feedback path configured to digitize the downstream radio frequency signal to provide a digital representation of the downstream radio frequency signal radiated from the antenna to the processing unit; and
wherein the processing unit is configured to pre-distort an input signal to the downstream signal path for non-linearities in the downstream signal path using the digital representation of the downstream radio frequency signal radiated from the antenna as received from the feedback path.
9. The antenna unit of claim 8 , wherein at least one of the downstream digital transport signal or the upstream digital transport signal includes digital baseband data.
10. The antenna unit of claim 8 , wherein at least one of the downstream digital transport signal or the upstream digital transport signal includes at least of one OBSAI digital baseband data or CPRI digital baseband data.
11. The antenna unit of claim 8 , wherein the antenna unit is configured to receive the received upstream radio frequency signal using the same antenna used to radiate the downstream radio frequency signal.
12. The antenna unit of claim 11 , wherein the antenna unit further comprises at least one of:
a low-power duplexer; and
a high-power duplexer.
13. The antenna unit of claim 8 , wherein the antenna unit is configured to radiate the downstream radio frequency signal from a first antenna and wherein the antenna unit is configured to receive the received upstream radio frequency signal using a second antenna.
14. The antenna unit of claim 8 , wherein the downstream digital transport signal comprises a digitized version of an original downstream radio frequency signal received at the remotely located communication device and wherein the upstream digital transport signal comprises a digitized version of the received upstream radio frequency signal received at the antenna unit.
15. The antenna unit of claim 8 , wherein the downstream digital transport signal comprises an analog version of an original downstream radio frequency signal received at the remotely located communication device and wherein the upstream digital transport signal comprises an analog version of the received upstream radio frequency signal received at the antenna unit.
16. The antenna unit of claim 8 , wherein a plurality of antennas is coupled to the antenna unit.
17. The antenna unit of claim 8 , wherein the antenna unit is configured to distribute MIMO signals.
18. The antenna unit of claim 8 , wherein the antenna unit comprises a feedback path and a switch to selectively couple either the downstream radio frequency signal or an external radio frequency signal to an input of the feedback path.
19. The antenna unit of claim 8 , wherein:
the processing unit is configured to perform self-interference suppression processing on the upstream signal by digitally subtracting the digital representation of the downstream radio frequency signal radiated from the antenna from the digital representation of the received upstream radio frequency signal as received from the feedback path.
20. An antenna unit for use in a communication system, the antenna unit comprising:
a transport interface to communicatively couple the antenna unit to a remotely located communication device included in the communication system and to receive a downstream digital transport signal from the remotely located communication device, wherein the downstream digital transport signal includes a digital representation of an original downstream radio frequency signal received at the remotely located communication device;
a processing unit coupled to the transport interface;
at least one downstream signal path;
at least one upstream signal path;
at least one duplexer between an antenna associated with the antenna unit and both of the at least one downstream signal path and the at least one upstream signal path;
wherein the processing unit and downstream signal path are configured to use the downstream digital transport signal to generate a downstream radio frequency signal for radiation from the antenna associated with the antenna unit;
wherein the transport interface is configured to communicate an upstream digital transport signal from the antenna unit to the remotely located communication device, wherein the processing unit and the upstream signal path are configured to generate an upstream signal from a received upstream radio frequency signal received at the antenna unit, wherein the upstream digital transport signal includes a digital representation of the received upstream radio frequency signal received at the antenna unit, wherein the transport interface uses the upstream signal to generate the upstream digital transport signal; and
a feedback path configured to digitize the downstream radio frequency signal to provide a digital representation of the downstream radio frequency signal radiated from the antenna to the processing unit;
a switch to selectively couple either the downstream radio frequency signal or an external radio frequency signal to an input of the feedback path; and
wherein the processing unit is configured to pre-distort an input signal to the downstream signal path for non-linearities in the downstream signal path using the digital representation of the downstream radio frequency signal radiated from the antenna as received from the feedback path.
21. The antenna unit of claim 20 , wherein:
the processing unit is configured to perform self-interference suppression processing on the upstream signal by digitally subtracting the digital representation of the downstream radio frequency signal radiated from the antenna from the digital representation of the received upstream radio frequency signal as received from the feedback path.