DISTRIBUTED ANTENNA SYSTEM AND METHOD

• US 20130236180A1
• Filed: 08/17/2012
• Published: 09/12/2013
• Est. Priority Date: 03/12/2012
• Status: Active Grant

• Current Assignee: Advanced RF Technologies Incorporated
• Original Assignee: Younghoon Ko
• Inventors: Kim, Bung Chul, Ko, Younghoon
• Granted Patent: US 9,374,187 B2
• Time in Patent Office: Days
• US Class Current: 398/72
• CPC Class Codes: H04J 14/0234 using multiple wavelengths
• CPC Class Codes: H04J 14/0236 using multiple wavelengths
• CPC Class Codes: H04J 14/0246 using one wavelength per ONU
• CPC Class Codes: H04J 14/0247 Sharing one wavelength for at least a group of ONUs
• CPC Class Codes: H04J 14/025 using one wavelength per ONU, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
• CPC Class Codes: H04J 14/0252 Sharing one wavelength for at least a group of ONUs, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

A distributed antenna system includes a plurality of remote units configured to service different regions of a service area, and a head-end unit configured to process and transmit downlink signals from base stations to the remote units over optical cables, and to process and transmit uplink signals from the remote units to the base stations, wherein the remote units are configured to adjust or filter a level of downlink signals from the head-end unit and to transmit the adjusted or filtered downlink signals to mobile stations, and to process and transmit uplink signals from mobile stations to the head-end unit over the optical cables.

Claims

1. A distributed antenna system comprising:

a plurality of remote units configured to service different regions of a service area; and

a head-end unit configured to process and transmit downlink signals from base stations to the remote units over optical cables, and to process and transmit uplink signals from the remote units to the base stations;

wherein the remote units are configured to adjust or filter a level of downlink signals from the head-end unit and to transmit the adjusted or filtered downlink signals to mobile stations, and to process and transmit uplink signals from mobile stations to the head-end unit over the optical cables.

2. The distributed antenna system of claim 1, wherein the head-end unit is configured to process the downlink signals from the base stations by adjusting or filtering said downlink signals and is configured to process the uplink signals from the remote units by adjusting or filtering said uplink signals, and wherein at least one of the remote units is configured to process the uplink signals from the mobile stations by adjusting or filtering said uplink signals.

3. The distributed antenna system of claim 1, wherein the head-end unit comprises:

a plurality of head-end RF units each configured to adjust or filter the downlink signals from at least one base station and to output corresponding downlink RF signals, and to adjust or filter the uplink signals from corresponding ones of the remote units;

a plurality of E/O converters each configured to convert the downlink RF signals from a corresponding head-end RF unit into a downlink optical signal, wherein the downlink optical signals from a first one of the E/O converters has a different wavelength than the downlink optical signals from a second one of the E/O converters;

a wavelength division multiplexer configured to combine a plurality of downlink optical signals with different wavelengths from the E/O converters into a combined downlink optical signal with multiple wavelengths, and to split a combined uplink optical signal with multiple wavelengths into a plurality of uplink optical signals with different wavelengths and transmit the uplink optical signals with different wavelengths to a plurality of optical paths according to the different wavelengths;

an optical splitter configured to split the combined downlink optical signal into a plurality of downlink optical signals each having multiple wavelengths to the remote units via a corresponding optical cable for each remote unit, and to combine a plurality of uplink optical signals each having multiple wavelengths from the remote units into the combined uplink optical signal with multiple wavelengths; and

a plurality of O/E converters each configured to convert uplink optical signals from the wavelength division multiplexer via a corresponding one of the optical paths into an uplink RF signal, wherein the uplink optical signals received by a first one of the O/E converters has a different wavelength than the uplink optical signals received by a second one of the O/E converters.

4. The distributed antenna system of claim 3, wherein the wavelength division multiplexer comprises a dense wavelength division multiplexer.

5. The distributed antenna system of claim 3, wherein the wavelength division multiplexer comprises a coarse wavelength division multiplexer.

6. The distributed antenna system of claim 1, wherein the downlink signals from the head-end unit are downlink optical signals with multiple wavelengths, and wherein each of the remote units comprises:

a wavelength division multiplexer configured to split corresponding downlink optical signals with multiple wavelengths into a plurality of downlink optical signals with different wavelengths and transmit the downlink optical signals with different wavelengths to a plurality of optical paths according to the different wavelengths, and to combine a plurality of uplink optical signals with different wavelengths into an uplink optical signal with multiple wavelengths;

a plurality of O/E converters each configured to convert a corresponding downlink optical signal at one of the different wavelengths into a corresponding downlink RF signal;

at least one remote RF unit configured to adjust a level of the downlink RF signals from at least one of the O/E converters to obtain a predefined service coverage, and to adjust a level of uplink RF signals received from corresponding mobile stations; and

a plurality of E/O converters each configured to receive adjusted uplink RF signals from the remote RF unit, and to convert the adjusted uplink RF signals into one a corresponding one of the plurality of uplink optical signals to be transmitted to the wavelength division multiplexer.

7. The distributed antenna system of claim 6, wherein the wavelength division multiplexer comprises a dense wavelength division multiplexer.

8. The distributed antenna system of claim 6, wherein the wavelength division multiplexer comprises a coarse wavelength division multiplexer.

9. The distributed antenna system of claim 6, wherein the wavelength division multiplexer of each of the remote units is configured to receive the optical signals with multiple wavelengths via a single corresponding optical cable.

10. The distributed antenna system of claim 6, wherein at least one of the remote units further comprises a sector selector configured to connect one of the remote RF units to at least two of the O/E converters and at least two of the E/O converters, the sector selector configured to dynamically select one of the downlink RF signals from a corresponding one of the O/E converters and to transmit one of the adjusted uplink RF signals from the remote RF unit to a corresponding one of the E/O converters.

11. The distributed antenna system of claim 10, wherein the sector selector comprises a downlink RF switch and an uplink RF switch.

12. The distributed antenna system of claim 6, wherein the remote RF unit is further configured to filter out-band spurious signals via a duplexer filter.

13. The distributed antenna system of claim 1, wherein the system is configured to transmit a plurality of sectorized signals.

14. The distributed antenna system of claim 1, wherein the system is configured to transmit multiple-input and multiple-output signals.

15. A method of utilizing a distributed antenna system comprising a plurality of remote units configured to service different regions of a service area and a head-end unit configured to process and transmit downlink signals from base stations to the remote units over optical cables, and to process and transmit uplink signals from the remote units to the base stations, wherein the remote units are configured to adjust or filter a level of downlink signals from the head-end unit and to transmit the adjusted or filtered downlink signals to mobile stations, and to process and transmit uplink signals from mobile stations to the head-end unit over the optical cables, the method comprising:

conveying a plurality of downlink sectorized signals from base stations to the remote units via the head-end unit; and

conveying a plurality of uplink sectorized signals from, the remote units to the base stations via the head-end unit;

wherein a wavelength division multiplexer in one of the remote units and a wavelength division multiplexer in the head-end unit are connected by a single optical cable, and wherein a plurality of optical signals are multiplexed and demultiplexed for transmission between the wavelength division multiplexers through said optical cable.

16. The method of claim 15, wherein at least one of the wavelength division multiplexers comprises a dense wavelength division multiplexer.

17. The method of claim 15, wherein at least one of the wavelength division multiplexers comprises a coarse wavelength division multiplexer.

18. A method of utilizing a distributed antenna system comprising a plurality of remote units configured to service different regions of a service area and a head-end unit configured to process and transmit downlink signals from base stations to the remote units over optical cables, and to process and transmit uplink signals from the remote units to the base stations, wherein the remote units are configured to adjust or filter a level of downlink signals from the head-end unit and to transmit the adjusted or filtered downlink signals to mobile stations, and to process and transmit uplink signals from mobile stations to the head-end unit over the optical cables, the method comprising:

conveying a plurality of downlink multiple-input and multiple-output signals from base stations to the remote units via the head-end unit; and

conveying a plurality of uplink multiple-input and multiple-output signals from the remote units to the base stations via the head-end unit;

wherein a wavelength division multiplexer in one of the remote units and a wavelength division multiplexer in the head-end unit are connected by a single optical cable, and wherein a plurality of optical signals are multiplexed and demultiplexed for transmission between the wavelength division multiplexers through said optical cable.

19. The method of claim 18, wherein at least one of the wavelength division multiplexers comprises a dense wavelength division multiplexer.

20. The method of claim 18, wherein at least one of the wavelength division multiplexers comprises a coarse wavelength division multiplexer.

21. A method of utilizing a distributed antenna system comprising a plurality of remote units configured to service different regions of a service area and a head-end unit configured to process and transmit downlink signals from base stations to the remote units over optical cables, and to process and transmit uplink signals from the remote units to the base stations, wherein the remote units are configured to adjust or filter a level of downlink signals from the head-end unit and to transmit the adjusted or filtered downlink signals to mobile stations, and to process and transmit uplink signals from mobile stations to the head-end unit over the optical cables, the method comprising:

conveying a plurality of downlink signals from base stations to the remote units via the head-end unit; and

conveying a plurality of uplink signals from the remote units to the base stations via the head-end unit;

wherein a sector selector is utilized to support dynamic sectorization;

wherein when the distributed antenna system supports a plurality of sectorized signals, the sector selector dynamically selects a specific sectorized signal from the plurality of sectorized signals, the remote unit is configured to switch to a sector based on traffic loads that vary with time or usage using the sector selector in accordance with the selected sectorized signal; and

wherein when the distributed antenna system supports a plurality of multiple-input and multiple-output (MIMO) signals, the sector selector dynamically selects a specific MIMO signal from a plurality of MIMO signals, the remote unit is configured to select a corresponding signal from the MIMO signals using the sector selector in accordance with the selected MIMO signal.