Distributed antenna system architectures
One embodiment is directed to a distributed antenna system comprising a host unit and at least one remote antenna unit that is communicatively coupled to the host unit. The host unit is configured to communicate a downstream transport signal from the host unit to the remote antenna unit. The remote antenna unit to which the downstream transport signal is communicated uses the downstream transport signal to generate a downstream radio frequency signal for radiation from an antenna associated with the remote antenna unit. The remote antenna unit is configured to communicate an upstream transport signal from the remote antenna unit to the host unit, wherein the upstream transport signal is generated from a received upstream radio frequency signal received at the remote antenna unit. The remote antenna unit is configured to perform self-interference suppression processing in an upstream signal path using, as an input thereto, a feedback signal derived from the downstream radio frequency signal radiated from the antenna. Other embodiments are disclosed.
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 transport signal from the first unit to the second unit;
wherein the second unit to which the downstream 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 transport signal;
wherein the second unit is configured to communicate an upstream transport signal from the second unit to the first unit;
wherein the upstream 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 signal includes a digital representation of the received upstream radio frequency 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 at least one processing unit;
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;
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.
2. 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.
3. The communication system of claim 2 , 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.
4. 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.
5. The communication system of claim 1 , wherein:
the downstream transport signal comprises a digitized version of an original downstream radio frequency signal received at the first unit; and
the upstream transport signal comprises a digitized version of the received upstream radio frequency signal received at the second unit.
6. The communication system of claim 1 , wherein at least one of the downstream transport signal and the upstream transport signal comprises digital baseband data.
7. The communication system of claim 1 , wherein the downstream transport signal comprises an analog version of an original downstream radio frequency signal received at the first unit and wherein the upstream transport signal comprises an analog version of the received upstream radio frequency signal received at the second unit.
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 transport signal from the 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 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 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, the upstream signal including a digital representation of the received upstream radio frequency signal, wherein the transport interface uses the upstream signal to generate the upstream 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;
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; and
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.
9. 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.
10. The antenna unit of claim 9 , wherein the antenna unit further comprises at least one of:
a low-power duplexer; and
a high-power duplexer.
11. 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.
12. The antenna unit of claim 8 , wherein the downstream transport signal comprises a digitized version of an original downstream radio frequency signal received at the remotely located communication device and wherein the upstream transport signal comprises a digitized version of the received upstream radio frequency signal received at the antenna unit.
13. The antenna unit of claim 8 , wherein at least one of the downstream transport signal and the upstream transport signal comprises digital baseband data.
14. The antenna unit of claim 13 , wherein the digital baseband data comprises at least one of OBSAI digital baseband data or CPRI digital baseband data.
15. The antenna unit of claim 8 , wherein the downstream transport signal comprises an analog version of an original downstream radio frequency signal received at the remotely located communication device and wherein the upstream 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. 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 transport signal from 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 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 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, the upstream signal including a digital representation of the received upstream radio frequency signal, wherein the transport interface uses the upstream signal to generate the upstream 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;
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; and
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. The antenna unit of claim 19 , wherein the duplexer comprises a high-power duplexer.