Distributed Antenna System Interface for Processing Digital Signals in a Standardized Format

• US 20120314797A1
• Filed: 06/11/2012
• Published: 12/13/2012
• Est. Priority Date: 06/09/2011
• Status: Active Grant

• Current Assignee: Outdoor Wireless Networks LLC (CommScope Holding Company, Inc.)
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Kummetz, Thomas, Ranson, Christopher G.
• Granted Patent: US 9,735,999 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• 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 disposed in a distributed antenna system, the unit comprising;

an interface section configured for outputting a first complex digital signal and a second complex digital signal, wherein the first complex digital signal is generated from a digital signal in a standardized format received from a digital base station; and

an output section configured for combining the first complex digital signal and the second complex digital signal into a combined digital signal and for outputting the combined digital signal, wherein the combined digital signal comprises information to be wirelessly transmitted to a wireless user device.

2. The unit of claim 1, wherein each of the first complex digital signal and the second complex digital signal comprises a plurality of digital samples representing an in-phase component and quadrature component of a signal represented by carrier data of the digital signal in the standardized format.

3. The unit of claim 1, wherein the second complex digital signal is generated from an analog signal received from an analog base station,

wherein the interface section comprises:

a digital interface device configured for transforming the digital signal in the standardized format into the first complex digital signal; and

an analog interface device configured for transforming the analog signal into the second complex digital signal.

4. The unit of claim 3, wherein the digital interface device comprises:

a physical layer device configured for receiving the digital signal in the standardized format; and

a de-framer configured for;

extracting carrier data from the digital signal in the standardized format, and

generating the first complex digital signal from the carrier data, wherein the first complex digital signal comprises a plurality of digital samples representing an in-phase component and quadrature component of a signal represented by the carrier data.

5. The unit of claim 1, wherein the standardized format comprises at least one of a Common Public Radio Interface standard format or an Open Radio Equipment Interface standard format.

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

7. The unit of claim 1, wherein the unit further comprises a base station emulator module configured for emulating a source of digital signals in a standardized format, wherein the base station emulator module is communicatively coupled to a remote radio head configured for receiving digital signals in the standardized format from a digital interface device.

8. The unit of claim 1,

wherein the interface section is further configured for outputting an additional complex digital signal, wherein the additional complex digital signal is generated from an additional digital signal in an additional standardized format different from the standardized format of the digital signal;

and

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

9. The unit of claim 1, wherein the interface section 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 frequency clock that is different 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 being usable by components of the unit.

10. The unit of claim 9, wherein the first interface card comprises:

a drop/add FIFO disposed between a framer/deframer and the output section; and

a decision circuit in communication with the drop/add FIFO,

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.

11. A digital interface device comprising:

a physical layer device configured for receiving a digital signal in a standardized format; and

a de-framer configured for;

extracting carrier data from the digital signal in the standardized format, and

generating a complex digital signal from the carrier data, wherein the complex digital signal comprises a plurality of digital samples representing an in-phase component and quadrature component of a signal represented by the carrier data.

12. The digital interface device of claim 11, wherein the carrier data comprises data to be wirelessly transmitted to a wireless user device.

13. The digital interface device of claim 11, further comprising a re-sampler configured to resample the complex digital signal.

14. The digital interface device of claim 11, further comprising a digital gain adjust device configured to apply a gain function to the complex digital signal.

15. The digital interface device of claim 11, further comprising:

a framer configured for combining a digital signal not formatted according to the standardized format into frames with control data to generate a second digital signal in the standardized format; and

wherein the physical layer device is configured for transmitting the second digital signal in the standardized format.

16. The digital interface device of claim 11, wherein the de-framer is configured to communicate with an output section of a unit, wherein the unit is configured for combining the complex digital signal and a second complex digital signal generated from an analog signal received from an analog base station into a combined digital signal and for outputting the combined digital signal, wherein the combined digital signal comprises information to be wirelessly transmitted to a wireless user device.

17. A distributed antenna system comprising;

a base station emulator module configured for emulating a source of digital signals in a standardized format;

a remote radio head configured for receiving digital signals in the standardized format from a digital interface device.

18. The distributed antenna system of claim 17, wherein the base station emulator module is configured for:

receiving a signal in a non-standardized format; and

combining the signal into frames with control data to generate a digital signal in the standardized format.

19. The distributed antenna system of claim 17, wherein the base station emulator module is disposed in a master unit.

20. The distributed antenna system of claim 17, wherein the base station emulator module is disposed in an expansion unit.

21. The distributed antenna system of claim 17, wherein the base station emulator module is disposed in a unit, the unit comprising:

an interface section configured for outputting a first complex digital signal and a second complex digital signal, wherein the first complex digital signal is generated from a digital signal in a standardized format received from a digital base station, wherein the second complex digital signal is generated from an analog signal received from an analog base station; and

an output section configured for combining the first complex digital signal and the second complex digital signal into a combined digital signal and for outputting the combined digital signal, wherein the combined digital signal comprises information to be wirelessly transmitted to a wireless user device.

22. The distributed antenna system of claim 21, further comprising a remote unit configured to transmit information from the digital signal to a first wireless user device,

wherein the remote radio head has greater signal processing power than the remote unit and is configured to transmit information from the digital signals in the standardized format to a second wireless user device,

wherein the base station emulator module is comprised in the output section,

wherein the output section is further configured for:

providing the combined digital signal to the remote unit; and

providing the digital signals in the standardized format to the remote radio head.