BI-DIRECTIONAL, COMPACT, MULTI-PATH AND FREE SPACE CHANNEL REPLICATOR

• US 20120294621A1
• Filed: 05/10/2012
• Published: 11/22/2012
• Est. Priority Date: 05/16/2011
• Status: Active Grant

• Current Assignee: Eastern Optx Inc.
• Original Assignee: Eastern Optx Inc.
• Inventors: Mazzochette, Joseph, MacMullen, Edward J., Lomurno, Jerome
• Granted Patent: US 8,755,693 B2
• Time in Patent Office: Days
• US Class Current: 398/115
• CPC Class Codes: H04B 10/2575 Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier

Abstract

An apparatus for simulating radio frequency (RF) signal propagation characteristics in a wireless communication network is disclosed. The apparatus includes a set of optical modulators in electrical communication with corresponding ones of a set of RF terminals. A set of optical demodulators is in optical communication with corresponding ones of the set of optical modulators and corresponding ones of the set of RF terminals. A set of optical delay lines may be configured to be in optical communication with the corresponding ones of the set of optical modulators and the corresponding ones of the set of optical demodulators.

Claims

1. An apparatus for simulating radio frequency (RF) signal propagation characteristics in a wireless communication network, comprising:

a plurality of optical modulators in electrical communication with corresponding ones of a plurality of RF terminals;

a plurality of optical demodulators in optical communication with corresponding ones of the plurality of optical modulators and corresponding ones of the plurality of RF terminals; and

a plurality of optical delay lines configured to be in optical communication with the corresponding ones of the plurality of optical modulators and the corresponding ones of the plurality of optical demodulators.

6. The apparatus of claim 1, further comprising a plurality of N-way optical splitter-combiners having an input and n−

1 outputs,

wherein n is at least two,

wherein an input of each of the plurality of N-way optical splitter-combiners is optically coupled to a corresponding one of the plurality of optical modulators and a corresponding one of the plurality of optical demodulators, and

wherein the n−

1 outputs of the plurality of N-way optical splitter-combiners is optically coupled to n−

1 optical delay lines of the plurality of optical delay lines.

7. The apparatus of claim 1, further comprising a plurality of N-way optical splitter-combiners having an input and n−

1 outputs,

wherein n is at least two,

wherein an input of each of the plurality of N-way optical splitter-combiners is optically coupled to a corresponding one of the plurality of optical modulators and a corresponding one of the plurality of optical demodulators, and

wherein the n−

1 outputs of the plurality of N-way optical splitter-combiners are optically coupled to n−

1 optical delay lines of the plurality of optical delay lines.

8. The apparatus of claim 1, further comprising a plurality of optical attenuators in optical communication with corresponding ones of the plurality of optical delay lines, corresponding ones of the plurality of optical modulators, and corresponding ones of the plurality of optical demodulators.

9. The apparatus of claim 8, wherein at least one of the plurality of optical attenuators is a variable optical attenuator.

10. The apparatus of claim 1, wherein at least one of the plurality of optical delay lines is an optical delay line having a fixed delay.

11. The apparatus of claim 1, wherein at least one of the plurality of optical delay lines is a variable optical delay line.

12. The apparatus of claim 11, wherein the at least one of the plurality of optical delay lines comprises:

a second plurality of optical delay lines configured in a series configuration, wherein a delay associated with each of the second plurality of optical delay lines increases progressively;

a plurality of bypass stubs each associated with a corresponding one of the second plurality of optical delay lines;

a plurality of two-position optical switches each configured to switch between one of the second plurality of optical delay lines and a corresponding one of the plurality of bypass stubs;

a global bypass stub associated with an input and an output of the second plurality of optical delay lines arranged in a series configuration; and

at least one two-position optical switch configured to switch between the global bypass stub associated with the second plurality of optical delay lines and at least one of the plurality of bypass stubs and the second plurality of optical delay lines.

13. The apparatus of claim 11, wherein the at least one of the plurality of optical delay lines comprises:

a second plurality of optical delay lines configured in a parallel configuration, wherein a delay of each of the second plurality of optical delay lines increases progressively; and

at least one multi-position optical switch configured to switch among each of the second plurality of optical delay lines.

14. The apparatus of claim 1, further comprising at least one pair of a second variable optical attenuator and a second variable optical delay line coupled in series with each other and together in parallel with one of the plurality of optical attenuators operable to simulate a multi-path condition.

15. The apparatus of claim 1, wherein at least one of the plurality of optical modulators comprises:

an RF isolator;

a laser modulator in electrical communication with the RF isolator; and

a circulator in optical communication with the laser modulator.

16. The apparatus of claim 15, wherein at least one of the plurality of optical demodulators comprises:

a dispersion compensator in optical communication with the circulator;

a detector in optical communication with the dispersion compensator; and

a gain stage in optical communication with the detector and in electrical communication with the RF isolator.

17. The apparatus of claim 1, wherein at least two of the plurality of optical modulators operate at different wavelengths.

18. The apparatus of claim 1, wherein at least one of the plurality of optical modulators comprises a distributed feedback laser or a fixed laser and external modulator.

2. The apparatus of claim 2, wherein a plurality of optical modulators, the plurality of optical demodulators, and the a plurality of optical delay lines are arranged in a form of a complete graph,

wherein corresponding ones of the plurality of optical modulators and corresponding ones of the optical demodulators are coupled to a plurality of vertices of the complete graph and

wherein corresponding ones of the plurality of optical delay lines form edges between vertices of the complete graph.

3. The apparatus of claim 2, wherein the complete graph has n vertices and

4. The apparatus of claim 2, wherein the complete graph is a two-dimensional complete graph.

5. The apparatus of claim 2, wherein the complete graph is a three-dimensional complete graph.

19. A computer system for simulating radio frequency (RF) signal propagation characteristics in a wireless communication network, comprising:

a memory;

a processing device, coupled to the memory, wherein the processing device is configured to provide a graphical user interface for operating an apparatus, comprising;

a plurality of RF terminals;

a plurality of optical modulators in electrical communication with corresponding ones of the plurality of RF terminals;

a plurality of optical demodulators in optical communication with corresponding ones of the plurality of optical modulators and corresponding ones of the plurality of RF terminals; and

a plurality of optical delay lines configured to be in optical communication with each of the plurality of optical modulators and the plurality of optical demodulators.

20. The system of claim 19,

wherein the apparatus further comprises a plurality of N-way optical splitter-combiners having an input and n−

1 outputs,

wherein n is at least two,

wherein an input of each of the plurality of N-way optical splitter-combiners is optically coupled to a corresponding one of the plurality of optical modulators and a corresponding one of the plurality of optical demodulators,

wherein the n−

1 outputs of the plurality of N-way optical splitter-combiners is optically coupled to n−

1 optical delay lines of the plurality of optical delay lines, and

wherein the processing device is further configured to operate the plurality of N-way optical splitter-combiners.

21. The system of claim 19, wherein the apparatus further comprises a plurality of optical attenuators in optical communication with corresponding ones of the plurality of optical delay lines, corresponding ones of the plurality of optical modulators, and corresponding ones of the plurality of optical demodulators and

wherein the processing device is further configured to operate the plurality of optical attenuators.

22. The system of claim 19,

wherein at least one of the plurality of optical delay lines is a variable optical delay line and

wherein the processing device is further configured to vary a value of the at least one of the plurality of optical delay lines.

23. The system of claim 19, wherein the system further comprises a plurality of radios in signal communication with the plurality of RF terminals.

24. The system of claim 23, wherein the graphical user interface is configured under the control of the processing device to provide a map of radio coverage area.

25. The system of claim 24, wherein the system is operable for selecting a position on the map for each of the plurality of radios.

26. The system of claim 24, wherein the graphical user interface is configured under the control of the processing device to simulate movement of each of the plurality of radios.

27. The system of claim 26, wherein the processing device is configured to record multiple scenarios of movement of each of the plurality of radios in the memory for later recall and play on the graphical user interface.