Distributed antenna system interface for processing digital signals in a standardized format

• US 9,735,999 B2
• Filed: 06/11/2012
• Issued: 08/15/2017
• Est. Priority Date: 06/09/2011
• Status: Active Grant

• Current Assignee: Outdoor Wireless Networks LLC (CommScope Holding Company, Inc.)
• Original Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Inventors: Kummetz, Thomas, Ranson, Christopher G.
• Primary Examiner(s): Cadeau, Wednel
• Application Number:
  US13/493,060
• Publication Number:
  US 20120314797A1
• Time in Patent Office: 1,891 Days
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04L 27/34 Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

An interface is provided for processing digital signals in a standardized format in a distributed antenna system. One example includes a unit disposed in a distributed antenna system. The unit includes an interface section and an output section. The interface section is configured for outputting a first complex digital signal and a second complex digital signal. The first complex digital signal is generated from a digital signal in a standardized format received from a digital base station. The output section is configured for combining the first complex digital signal and the second complex digital signal into a combined digital signal. The output section is also configured for outputting the combined digital signal. The combined digital signal comprises information to be wirelessly transmitted to a wireless user device.

Claims

1. A unit of a distributed antenna system, the unit comprising:

an interface section configured for processing signals for communication between (i) a first base station configured for communicating the signals using a first standard communication protocol and a second base station configured for communicating the signals using a second standard communication protocol and (ii) a remote antenna unit that is not configured for processing the signals using the first standard communication protocol and the second standard communication protocol, wherein the interface section is configured for processing the signals by performing operations comprising;

receiving a first downlink signal comprising first packetized data that includes first carrier data and first control data formatted according to the first standard communication protocol,

receiving a second downlink signal comprising second packetized data that includes second carrier data and second control data formatted according to the second standard communication protocol, and

converting the first downlink signal and the second downlink signal from the first and second standard communication protocols into a format that allows the remote antenna unit to wirelessly transmit information from the first and second downlink signals to wireless user devices, wherein the interface section is configured for converting the first downlink signal and the second downlink signal by performing operations comprising;

extracting the first carrier data from the first packetized data and generating a first complex digital signal from the extracted first packetized data, and

extracting the second carrier data from the second packetized data generating a second complex digital signal from the extracted second packetized data; and

an output section configured for;

combining the first complex digital signal and the second complex digital signal into a combined digital downlink signal that comprises the information to be wirelessly transmitted, and

transmitting the combined digital downlink signal to the remote antenna unit in the format that allows the remote antenna unit to wirelessly transmit the information; and

wherein the interface section further comprises;

a first digital interface card for interfacing with a first digital base station and for outputting the first complex digital signal;

a second digital interface card for interfacing with a second digital base station and for outputting the second complex digital signal, the second digital base station being associated with a different frequency clock than a frequency clock associated with the first digital base station; and

a clock select device for selecting a system reference signal from a plurality of reference signals generated based on frequency clocks of the first digital base station and the second digital base station, the system reference signal being usable by components of the unit.

2. The unit of claim 1, wherein the output section is further configured for combining the first complex digital signal and the second complex digital signal into the combined digital downlink signal by summing a first plurality of digital samples from the first extracted carrier data and a second plurality of digital samples from the second extracted carrier data, wherein each of the first plurality of digital samples and the second plurality of digital samples represents a respective in-phase component and quadrature component.

3. The unit of claim 1, wherein the interface section is further configured for receiving an analog downlink signal received from an analog base station,

wherein the interface section comprises:

a digital interface device configured for transforming the first downlink signal into the first complex digital signal and transforming the second downlink signal into the second complex digital signal, and

an analog interface device configured for transforming the analog downlink signal into a third complex digital signal,

wherein the output section is further configured for combining the first complex digital signal, the second complex digital signal, and the third complex digital signal into the combined digital downlink signal.

4. The unit of claim 1, wherein the interface section further comprises:

a physical layer device configured for receiving the first downlink signal and the second downlink signal; and

a de-framer configured for;

extracting the first carrier data from the first downlink signal, and

extracting the second carrier data from the second downlink signal.

5. The unit of claim 1, wherein the first standard communication protocol comprises at least one of a Common Public Radio Interface protocol or an Open Radio Equipment Interface protocol and the second standard communication protocol comprises at least one of the Common Public Radio Interface protocol or the Open Radio Equipment Interface protocol.

6. The unit of claim 1, wherein the output section comprises a backplane configured for:

combining the first complex digital signal and the second complex digital signal into the combined digital downlink signal, and

outputting the combined digital downlink signal as serialized data over a serial link to an RF transceiver.

7. The unit of claim 1, wherein the interface section comprises a drop/add device and a decision circuit in communication with the drop/add device, wherein the decision circuit is configured for causing, based on a first clock rate for the digital base station being different from a second clock rate from an additional base station in communication with the unit, the drop/add device to perform at least one of (i) dropping bits from the first complex digital signal and (ii) adding bits to the first complex digital signal.

8. The unit of claim 1, wherein at least one of the first carrier data and the second carrier data comprises voice data from a digital base station to be outputted by the wireless user device and at least one of the first control data and the second control data comprises data for coordinating communication between the digital base station and a device receiving according to at least one of the first standard communication protocol and the second standard communication protocol.

9. The unit of claim 1, wherein the first standard communication protocol and the second standard communication protocol are the same standard communication protocol.

10. The unit of claim 1, wherein the first standard communication protocol and the second standard communication protocol are different standard communication protocols;

and

wherein the second standard communication protocol is incompatible with the first standard communication protocol, preventing the first carrier data from being combined with the second carrier data.

11. The unit of claim 7, wherein the drop/add device comprises a drop/add FIFO disposed between the output section and a framer/deframer configured for extracting at least one of the first carrier data and the second carrier data, wherein the decision circuit is configured for (i) causing the drop/add FIFO to drop bits of the first complex digital signal in response to the drop/add FIFO reaching a first depth threshold and (ii) causing the drop/add FIFO to add bits to the first complex digital signal in response to the drop/add FIFO reaching a second depth threshold.

12. The unit of claim 8, wherein the unit is configured to generate a system reference clock rate for the distributed antenna system based on a reference clock obtained from the digital base station.

13. A method comprising:

processing, by a unit of a distributed antenna system, signals for communication between (i) a first base station that communicates the signals using a first standard communication protocol and a second base station that communicates the signals using a second standard communication protocol and (ii) a remote antenna unit that does not communicate the signals using the first standard communication protocol or the second standard communication protocol, wherein processing the signals for communication between (i) the first base station and the second base station and (ii) the remote antenna unit comprises;

receiving a first downlink signal comprising first packetized data that includes first carrier data and first control data formatted according to the first standard communication protocol,

receiving a second downlink signal comprising second packetized data that includes second carrier data and second control data formatted according to the second standard communication protocol, wherein the first downlink signal being formatted according to the first standard communication protocol and the second downlink signal being formatted according to the second standard communication protocol prevents the remote antenna unit from correctly transmitting information that is included in the first carrier data and the second carrier data, and

converting the first downlink signal and the second downlink signal into a format that allows the remote antenna unit to wirelessly transmit the information to wireless user devices, wherein converting the first downlink signal and the second downlink signal comprises;

extracting the first carrier data from the first packetized data and generating a first complex digital signal from the extracted first packetized data, and

extracting the second carrier data from the second packetized data and generating a second complex digital signal from the extracted second packetized data;

combining the first complex digital signal and the second complex digital signal into a combined digital downlink signal comprising the information to be wirelessly transmitted; and

transmitting the combined digital downlink signal to the remote antenna unit in the format that allows the remote antenna unit to wirelessly transmit the information;

wherein the second digital base station is associated with a different frequency than a frequency clock associated with the first digital base station; and

selecting a system reference signal from a plurality of reference signals generated based on frequency clocks of the first digital base station and the second digital base station, the system reference signal being usable by components of the unit.

14. The method of claim 13, wherein combining the first complex digital signal and the second complex digital signal into the combined digital downlink signal comprises summing a first plurality of digital samples from the first extracted carrier data and a second plurality of digital samples from the second extracted carrier data, wherein each of the first plurality of digital samples and the second plurality of digital samples represents a respective in-phase component and quadrature component.

15. The method of claim 13, further comprising:

receiving an analog downlink signal received from an analog base station; and

transforming the analog downlink signal into a third complex digital signal, wherein the first complex digital signal, the second complex digital signal, and the third complex digital signal are combined into the combined digital downlink signal.

16. The method of claim 13, wherein the first standard communication protocol comprises at least one of a Common Public Radio Interface protocol or an Open Radio Equipment Interface protocol and the second standard communication protocol comprises at least one of the Common Public Radio Interface protocol or the Open Radio Equipment Interface protocol.

17. The method of claim 13, further comprising causing, based on a first clock rate for the first digital base station being different from a second clock rate for the second digital base station, performing at least one of (i) dropping bits from the first complex digital signal and (ii) adding bits to the first complex digital signal.

18. The method of claim 13, wherein processing the signals for communication between the base station and the remote antenna unit further comprises:

receiving an uplink signal from the remote antenna unit, and

formatting the received uplink signal according to the first standard communication protocol or the second standard communication protocol for transmission to the base station, wherein formatting the uplink signal comprises;

generating uplink control data using at least one of the first control data and the second control data,

generating uplink carrier data from the received uplink signal, and

outputting uplink packetized data having the uplink control data and the uplink carrier data.

19. The method of claim 13, wherein the first standard communication protocol and the second standard communication protocol are the same standard communication protocol.

20. The method of claim 13, wherein the first standard communication protocol and the second standard communication protocol are different standard communication protocols;

and

wherein the second standard communication protocol is incompatible with the first standard communication protocol, preventing the first carrier data from being combined with the second carrier data.