Distributed antenna system for wireless network systems

• US 8,346,091 B2
• Filed: 04/29/2009
• Issued: 01/01/2013
• Est. Priority Date: 04/29/2009
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Kummetz, Thomas, McAllister, Donald, Pagano, Carmine, Cleary, Dennis M., Hanson, Van, Schmalisch, Mathias, Eisenwinter, Stefan, Yan, Hongju
• Primary Examiner(s): Vanderpuye, Kenneth N
• Assistant Examiner(s): Ngo, Tanya
• Application Number:
  US12/431,872
• Publication Number:
  US 20100278530A1
• Time in Patent Office: 1,343 Days
• Field of Search: 398 15-117, 455/3.01, 455 303- 305, 455/403, 4554221-4262
• US Class Current: 398/115
• CPC Class Codes: H04B 10/2575 Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
• CPC Class Codes: H04B 10/25753 Distribution optical network, e.g. between a base station and a plurality of remote units
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

A distributed antenna system is provided for communicating with a plurality of base stations. The distributed antenna system includes a system controller and a master unit communicating with at least one of the plurality of base stations. A remote unit communicates over a high data rate media with the master unit and/or a downstream remote unit. Alternatively, the distributed antenna system includes a controller and a digital time/space crosspoint switch controlled by the controller. A digitizing transceiver is in communication with the digital time/space crosspoint switch. The crosspoint switch is configured to transmit and receive digital data through the digitizing transceiver.

Claims

1. A distributed antenna system comprising:

a master unit configured for receiving downlink signals from a plurality of base stations and for transmitting uplink signals to the plurality of base stations, the downlink signals being associated with a plurality of wireless protocols and a plurality of bands, wherein the master unit is configured to output the downlink signals as digitized downlink signals, the master unit comprising;

a first radio channel having circuitry comprising a duplexer, the circuitry being configured to (i) receive downlink signals associated with a first band of the plurality of bands from the plurality of base stations and (ii) transmit the uplink signals associated with the first band to the plurality of base stations;

a second radio channel comprising a switch configured for, responsive to transmitting the uplink signals associated with a second band to the plurality of base stations, opening and protecting an RF downconverter in the second radio channel; and

a controller configured for providing switch control timing for controlling operation of the switch;

an extension unit configured to receive the digitized downlink signals from the master unit over a first fiber optic cable; and

a remote unit configured for receiving downlink signals from the extension unit over a second fiber optic cable, wherein the remote unit is configured for wirelessly transmitting the downlink signals as radio frequency (RF) signals using the plurality of wireless protocols and in the plurality of bands.

2. The distributed antenna system of claim 1, wherein the remote unit is a first remote unit, the distributed antenna system further comprising:

a second remote unit configured for receiving at least a subset of the downlink signals from the remote unit over a third fiber optic cable, wherein the second remote is adapted to convert the subset of the downlink signals to second RF downlink signals and to wirelessly transmit the second RF downlink signals.

3. The distributed antenna system of claim 2, wherein the first remote unit is configured for receiving a second uplink signal from the second remote unit and for summing the second uplink signal with a first uplink signal generated from an RF uplink signal wirelessly received by the first remote unit to generate combined uplink signals, the first remote unit being configured to provide the combined uplink signals to the extension unit over the second fiber optic cable.

4. The distributed antenna system of claim 1, wherein the master unit comprises:

a digitally modulated optical channel configured for communicating with at least one of the first radio channel or the second radio channel and for further communicating with the remote unit;

a wavelength division multiplexer configured for being in communication with the digitally modulated optical channel, the wavelength division multiplexer being configured to combine or split the uplink and downlink signals on the digitally modulated optical channel.

5. The distributed antenna system of claim 1, wherein the master unit comprises a digitally modulated optical channel, the digitally modulated optical channel comprising:

a formatter configured to;

block, into time division multiplexed frames, the digitized downlink signals and an Ethernet signal;

convert the time division multiplexed framed downlink signals into a downlink serial stream;

phaselock to a serial stream representing the uplink signals from at least one of the remote unit or the expansion unit;

convert the serial stream to a parallel uplink digital data stream;

split the parallel uplink digital data stream into a plurality of bands comprising uplink digital signals; and

route each of the plurality of bands comprising the uplink digital signals to at least one of the first radio channel or the second radio channel; and

an electro-optical transceiver configured to;

modulate an optical transmitter using the downlink serial stream; and

convert an uplink optical signal to the serial stream representing the uplink digital signals.

6. The distributed antenna system of claim 1, wherein the master unit further comprises:

an Ethernet interface configured to transceive operation and maintenance data associated with the master unit and that is separate from the downlink signals and the uplink signals.

7. The distributed antenna system of claim 1, wherein the remote unit comprises:

an antenna configured to transmit and receive signals using the plurality of wireless protocols and in the plurality of bands;

a remote unit radio channel configured for communicating with the antenna; and

a remote unit controller configured to monitor and control the components of the remote unit.

8. The distributed antenna system of claim 7, wherein the remote unit radio channel comprises:

a combiner/duplexer configured for being in communication with the antenna and configured to transmit uplink signals to the extension unit and receive downlink signals from a second remote unit or the extension unit.

9. The distributed antenna system of claim 7, wherein the remote unit further comprises:

an Ethernet interface configured to communicate transceive operation and maintenance data associated with the remote unit and that is separate from the downlink signals and the uplink signals.

10. The distributed antenna system of claim 7, wherein the remote unit further comprises:

a digital to analog converter; and

a digital pre-distortion unit, the digital pre-distortion unit configured to compare a digitized uplink signal to a delayed downlink signal,

wherein the remote unit is configured to, based on a difference from the comparison in the digital pre-distortion unit, automatically adjust a gain and phase of a signal prior to conversion in the digital to analog converter.

11. The distributed antenna system of claim 1, wherein the remote unit comprises:

an antenna configured to transmit and receive signals from a mobile unit over the plurality of air interfaces and RF bands;

a remote unit radio channel configured for communicating with the antenna;

a digital switch configured for communicating with the remote unit radio channel and for further communicating with a second remote unit or the master unit; and

a remote unit controller configured to monitor and control the components of the remote unit and digital switch.

12. The distributed antenna system of claim 1, wherein the extension unit further comprises:

an Ethernet interface configured to transceive operation and maintenance data associated with the extension unit and separate from the downlink signals and the uplink signals.

13. The distributed antenna system of claim 1, wherein the master unit is a first master unit and the remote unit is a first remote unit, the distributed antenna system further comprising:

a second master unit configured for communicating with at least one of the plurality of base stations;

a second remote unit configured for communicating over a digitally modulated channel with at least one of the second master unit or a third remote unit;

a combiner; and

an antenna,

wherein the first and second master units are configured to use the combiner to transmit using a multi-band RF link over the antenna to communicate with at least one of the plurality of base stations.

14. The distributed antenna system of claim 1, wherein the master unit comprises:

at least four optical interfaces configured for coupling to fiber optic cables that are adapted to be coupled to a plurality of extension units.

15. The distributed antenna system of claim 1, wherein the remote unit is further configured to receive RF uplink signals wirelessly and convert the RF uplink signals to uplink digital signals,

wherein the extension unit is further configured to receive the uplink digital signals from the remote unit over the second fiber optic cable,

wherein the master unit is further configured to receive the uplink digital signals from the extension unit over the first fiber optic cable, convert the uplink digital signals to the uplink signals to be provided to the plurality of base stations.

16. The distributed antenna system of claim 15, wherein the first fiber optic cable comprises a first fiber optic cable for carrying downlink digital signals and a second fiber optic cable for carrying uplink digital signals.

17. The distributed antenna system of claim 1, wherein the master unit comprises a resampler configured to reduce a size of the digitized downlink signals by re-sampling the digitized downlink signals.

18. The distributed antenna system of claim 1, wherein the master unit comprises an interface that is configured to send the uplink signals to at least one of the plurality of base stations by a third fiber optic cable and to receive the downlink signals from the at least one of the plurality of base stations by a fourth fiber optic cable.

19. The distributed antenna system of claim 18, wherein a format of the uplink signals and the downlink signals comprises a Common Public Radio Interface (CPRI) or an Open Base Station Architecture Initiative (OBSAI) link.

20. The distributed antenna system of claim 1, wherein the master unit is configured to separately digitize each of the downlink signals,

wherein the master unit is configured to digitally sum uplink digital signals received from a plurality of remote units,

wherein the remote unit is configured to process signals associated with the plurality of bands.

29. The distributed antenna system of claim 1, wherein the extension unit is a switch.

21. A method, comprising:

receiving, by a master unit of a distributed antenna system, downlink signals from a plurality of base stations, the downlink signals being associated with a plurality of wireless protocols and a plurality of bands, wherein receiving downlink signals from the plurality of base stations comprises receiving, by circuitry comprising a duplexer of a first radio channel, downlink signals associated with a first band of the plurality of bands from the plurality of base stations;

outputting the downlink signals as digitized downlink signals to an extension unit over a first fiber optic cable;

transmitting uplink signals to the plurality of base stations comprising transmitting, by the circuitry, the uplink signals associated with the first band to the plurality of base stations;

responsive to transmitting the uplink signals associated with a second band to the plurality of base stations, opening and protecting, by switch of a second radio channel, an RF downconverter in the second radio channel; and

providing, by a controller, switch control timing for controlling operation of the switch.

22. The method of claim 21, further comprising:

receiving, by a remote unit, the downlink signals from the extension unit over a second fiber optic cable;

converting the downlink signals to RF downlink signals;

wirelessly transmitting the RF downlink signals;

receiving by a second remote unit at least a subset of the downlink signals from the remote unit over a third fiber optic cable;

converting the subset of the downlink signals to second RF downlink signals; and

wirelessly transmitting the second RF downlink signals.

23. The method of claim 21, further comprising:

receiving RF uplink signals wirelessly by a remote unit;

converting the RF uplink signals to uplink digital signals;

transmitting the uplink digital signals to the extension unit over a second fiber optic cable;

receiving by the master unit the uplink digital signals from the extension unit over the first fiber optic cable; and

converting the uplink digital signals to the uplink signals.

24. The method of claim 23, wherein transmitting the uplink digital signals to the extension unit over the second fiber optic cable comprises:

receiving second uplink digital signals from a second remote unit over a third fiber optic cable;

combining the second uplink digital signals with the uplink digital signals converted from the RF uplink signals received by the remote unit to generate combined uplink digital signals; and

transmitting the combined uplink digital signals to the extension unit over the second fiber optic cable,

wherein receiving by the master unit the uplink digital signals from the extension unit over the first fiber optic cable comprises receiving the combined uplink digital signals,

wherein converting the uplink digital signals to uplink signals comprises converting the combined uplink digital signals to the uplink signals.

25. The method of claim 21, further comprising:

separately digitizing each of the downlink signals to generate the digitized downlink signals;

re-sampling by the master unit the digitized downlink signals to reduce a size of the digitized downlink signals; and

digitally summing uplink digital signals received from a plurality of remote units.

26. The method of claim 21,

wherein outputting the downlink signals as the digitized downlink signals to the extension unit over the first fiber optic cable comprises:

(A) arranging, by a formatter, the digitized downlink signals and an Ethernet signal into frames;

(B) converting the framed downlink signals into a downlink serial stream; and

(C) modulating, by an electro-optical transceiver, an optical transmitter using the downlink serial stream,

wherein the method further comprises;

(A) converting, by the electro-optical transceiver, an uplink optical signal to a serial stream representing uplink digital signals from a remote unit;

(B) phaselocking to the serial stream;

(C) generating a bit clock that is phaselocked to a data rate of the serial stream;

(D) converting the serial stream to a parallel uplink digital data stream;

(E) splitting the parallel uplink digital data stream into the plurality of bands of uplink digital signals; and

(F) routing each of the plurality of bands of uplink digital signals to an appropriate one of the first radio channel or the second radio channel.

27. A distributed antenna system, comprising:

a master unit configured for sending uplink signals to a plurality of base stations, the uplink signals being associated with a plurality of wireless protocols and a plurality of bands, wherein the master unit is configured for receiving the uplink signals as digitized uplink signals from an extension unit over a first fiber optic cable;

a first remote unit configured to generate first digitized uplink signals by digitizing first RF uplink signals wirelessly received by the first remote unit, the first remote unit being configured to provide the first digitized uplink signals to the extension unit, the first remote unit comprising;

a digital to analog converter; and

a digital pre-distortion unit, the digital pre-distortion unit configured to compare the first digitized uplink signals to a delayed downlink signal, wherein the remote unit is configured to, based on a difference from the comparison in the digital pre-distortion unit, automatically adjust a gain and phase of a signal prior to conversion in the digital to analog converter; and

a second remote unit configured to generate second digitized uplink signals by digitizing second RF uplink signals wirelessly received by the second remote unit, the second remote unit being configured to provide the second digitized uplink signals to the extension unit,

the extension unit configured to generate the digitized uplink signals by summing the first digitized uplink signals and the second digitized uplink signals.

28. The distributed antenna system of claim 27, wherein the master unit comprises:

a first radio channel having circuitry comprising a duplexer, the circuitry being configured to (i) receive downlink signals associated with a first band of the plurality of bands from the plurality of base stations and (ii) transmit the uplink signals associated with the first band to the plurality of base stations;

a second radio channel comprising a switch configured for, responsive to transmitting the uplink signals associated with a second band to the plurality of base stations, opening and protecting an RF downconverter in the second radio channel; and

a controller configured for providing switch control timing for controlling operation of the switch.