Method and apparatus for use with a radio distributed antenna having a fiber optic link

• US 10,523,388 B2
• Filed: 04/17/2017
• Issued: 12/31/2019
• Est. Priority Date: 04/17/2017
• Status: Expired due to Fees

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Gerszberg, Irwin, Henry, Paul Shala, Barzegar, Farhad, Blandino, George, Kafka, Henry
• Primary Examiner(s): Vanderpuye, Kenneth N
• Assistant Examiner(s): Lee, Jai M
• Application Number:
  US15/489,340
• Publication Number:
  US 20180302162A1
• Time in Patent Office: 988 Days
• CPC Class Codes: H04B 10/2575 Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
• CPC Class Codes: H04B 10/25752 Optical arrangements for wireless networks
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

Aspects of the subject disclosure may include, for example, a transceiver that converts first modulated channel signals in a first spectral segment to the first modulated channel signals in a second spectral segment based on signal processing of the first modulated channel signals and without modifying the signaling protocol of the first modulated channel signals. The transceiver transmits, via a fiber optic cable, a transmission signal including a first reference signal with the first modulated channel signals in the second spectral segment to a network element of a plurality of network elements of the distributed antenna system for wireless distribution of the first modulated channel signals to mobile communication devices in the first spectral segment. The first reference signal enables the distributed antenna system to reduce a phase error during processing of the first modulated channel signals from the second spectral segment to the first spectral segment.

Claims

1. A method, comprising:

receiving, by a system including signal processing circuitry, first modulated channel signals in a first spectral segment directed to communication devices, wherein the first modulated channel signals conform to a signaling protocol;

converting, by the system, the first modulated channel signals in the first spectral segment to the first modulated channel signals in a second spectral segment based on a signal processing of the first modulated channel signals and without modifying the signaling protocol of the first modulated channel signals, wherein the converting includes mixing the first modulated channel signals with a local oscillator signal; and

transmitting, by the system and over a fiber optic cable, a transmission signal including a first reference signal with the first modulated channel signals in the second spectral segment to a network element of a plurality of network elements of a distributed antenna system, the first reference signal having a phase and a frequency of the local oscillator signal, the reference signal enabling the network element to reduce a first phase error when reconverting at least a first portion of the first modulated channel signals to the first spectral segment via the local oscillator signal, wherein the network element retransmits at least a second portion of the transmission signal to another network element of the plurality of network elements of the distributed antenna system.

2. The method of claim 1, wherein the signal processing circuitry comprises analog signal processing circuitry that facilitates analog signal processing, wherein the signal processing of the first modulated channel signals comprises the analog signal processing of the first modulated channel signals without performing digital signal processing of the first modulated channel signals, and wherein the analog signal processing does not require either an analog to digital conversion or a digital to analog conversion.

3. The method of claim 1, wherein the transmitting comprises multiplexing the first modulated channel signals in the second spectral segment with other signaling carried by the fiber optic cable.

4. The method of claim 1, wherein the second spectral segment is in an optical frequency band.

5. The method of claim 1, wherein the first modulated channel signals are generated by modulating signals in a plurality of frequency channels according to the signaling protocol to generate the first modulated channel signals in the first spectral segment.

6. The method of claim 1, wherein the signaling protocol comprises a Long-Term Evolution (LTE) wireless protocol or a fifth-generation cellular communications protocol.

7. The method of claim 1, wherein the converting by the system comprises up-converting the first modulated channel signals in the first spectral segment to the first modulated channel signals in the second spectral segment.

8. The method of claim 1, wherein the retransmitting by the network element comprises down-converting the first modulated channel signals in the second spectral segment to the first modulated channel signals in the first spectral segment and upconverting the first modulated channel signals in the first spectral segment to the first modulated channel signals in a third spectral segment for wireless transmission to another network element of the plurality of network elements of the distributed antenna system.

9. The method of claim 1, wherein the retransmitting by the network element comprises converting the first modulated channel signals in the second spectral segment to the first modulated channel signals in a third spectral segment for wireless transmission to another network element of the plurality of network elements of the distributed antenna system.

10. The method of claim 9, wherein the first spectral segment corresponds to a fourth-generation wireless frequency band and the third spectral segment corresponds to a millimeter wave frequency band.

11. The method of claim 1, further comprising receiving, by the system, a second modulated channel signal from the network element, wherein the network element converts the second modulated channel signal to a third spectral segment and transmits the second modulated channel signal in the third spectral segment and a second reference signal via the fiber optic cable.

12. The method of claim 11, further comprising:

converting, by the system, the second modulated channel signal in the third spectral segment to the second modulated channel signal in the first spectral segment utilizing the second reference signal to reduce a second phase error of the second modulated channel signal in the first spectral segment; and

sending, by the system, the second modulated channel signal in the first spectral segment to a base station for processing.

13. The method of claim 12, wherein the second spectral segment differs from the third spectral segment.

14. The method of claim 1, wherein the signal processing comprises analog signal processing that does not require either an analog to digital conversion or a digital to analog conversion.

15. A device, comprising:

a base station interface configured to receive, from a base station, first modulated channel signals in a first spectral segment for transmission to communication devices via a distributed antenna system, wherein the first modulated channel signals conform to a signaling protocol; and

a transceiver configured to convert the first modulated channel signals in the first spectral segment to the first modulated channel signals in a second spectral segment based on a signal processing of the first modulated channel signals and without modifying the signaling protocol of the first modulated channel signals, wherein conversion of the first modulated channel signals in the first spectral segment to the first modulated channel signals in the second spectral segment includes mixing the first modulated channel signals with a local oscillator signal, wherein the transceiver is further configured to transmit, via a fiber optic cable, a transmission signal including a first reference signal with the first modulated channel signals in the second spectral segment to a network element of a plurality of network elements of the distributed antenna system for wireless distribution of the first modulated channel signals to mobile communication devices in the first spectral segment, the first reference signal having a phase and a frequency of the local oscillator signal, the first reference signal enabling the distributed antenna system to reduce a phase error during processing of the first modulated channel signals from the second spectral segment to the first spectral segment via the local oscillator signal, and the distributed antenna system retransmitting at least a portion of the transmission signal from the network element to another network element of the plurality of network elements of the distributed antenna system.

16. The device of claim 15, wherein the signal processing comprises analog signal processing that does not require either an analog to digital conversion or a digital to analog conversion, and wherein the second spectral segment is outside a frequency range of the first spectral segment.

17. The device of claim 15, wherein the transceiver receives, via the fiber optic cable, second modulated channel signals in a third spectral segment and a second reference signal from the network element, wherein the communication devices generate the second modulated channel signals in the first spectral segment, and wherein the network element converts the second modulated channel signals in the first spectral segment to the second modulated channel signals in the third spectral segment for transmission via the fiber optic cable.

18. The device of claim 15, wherein the transceiver receives, via the fiber optic cable, a second modulated signal in a third spectral segment and a second reference signal from the network element, wherein the network element receives the second modulated signal in a fourth spectral segment from another network element of the plurality of network elements of the distributed antenna system, and wherein the network element converts the second modulated signal in the fourth spectral segment to the second modulated signal in the third spectral segment for transmission via the fiber optic cable to the transceiver.

19. A method, comprising:

receiving, by a system including signal processing circuitry, first modulated channel signals in a first spectral segment directed to communication devices, wherein the first modulated channel signals conform to a signaling protocol;

converting, by the system, the first modulated channel signals in the first spectral segment to the first modulated channel signals in a second spectral segment based on a signal processing of the first modulated channel signals and without modifying the signaling protocol of the first modulated channel signals, wherein the second spectral segment differs from the first spectral segment, wherein the converting includes mixing the first modulated channel signals with a local oscillator signal;

generating a transmission signal that includes the first modulated channel signals in the second spectral segment and a reference signal; and

multiplexing the transmission signal with other signaling carried by a fiber optic cable for transmission via the fiber optic cable to a distributed antenna system that provides wireless access to the communication devices;

wherein the distributed antenna system retransmits the transmission signal among a plurality of network elements of the distributed antenna system for wireless transmission to the communication devices via selected ones of the plurality of network elements, the reference signal having a phase and a frequency of the local oscillator signal, the reference signal enabling the distributed antenna system to reduce a phase error when reconverting the first modulated channel signals to the first spectral segment via the local oscillator signal for transmission to the communication devices via the selected ones of the plurality of network elements.

20. The method of claim 19, wherein the signal processing circuitry comprises analog signal processing circuitry that facilitates analog signal processing, wherein the signal processing of the first modulated channel signals comprises the analog signal processing of the first modulated signal without performing digital signal processing of the first modulated channel signals, and wherein the analog signal processing does not require either an analog to digital conversion or a digital to analog conversion.