Distributed antenna system for MIMO technologies

• US 9,130,613 B2
• Filed: 08/29/2012
• Issued: 09/08/2015
• Est. Priority Date: 12/19/2006
• Status: Active Grant

• Current Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Original Assignee: Corning Optical Communications Wireless Ltd. (Corning Incorporated)
• Inventors: Oren, Yair, Berlin, Igor, Saban, Ofer, Shapira, Isaac, Reuven, Rami
• Primary Examiner(s): SMARTH, GERALD A
• Application Number:
  US13/598,078
• Publication Number:
  US 20120321314A1
• Time in Patent Office: 1,105 Days
• Field of Search: 370/328
• US Class Current: 1/1
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 10/271 Combination of different networks, e.g. star and ring configuration in the same network or two ring networks interconnected
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0602 using antenna switching H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24

Abstract

The invention is directed to a method and system for supporting MIMO technologies which can require the transport of multiple spatial streams on a traditional Distributed Antenna System (DAS). According to the invention, at one end of the DAS, each spatial stream is shifted in frequency to a pre-assigned band (such as a band at a frequency lower than the native frequency) that does not overlap the band assigned to other spatial streams (or the band of any other services being carried by the DAS). Each of the spatial streams can be combined and transmitted as a combined signal over a common coaxial cable. At the other “end” of the DAS, the different streams are shifted back to their original (overlapping) frequencies but retain their individual “identities” by being radiated through physically separate antenna elements.

Claims

1. A distributed antenna system for distributing MIMO signals for at least one MIMO service in a distributed antenna system (DAS), comprising:

a) a remote unit configured to receive and distribute non-overlapping frequency MIMO downlink signals of at least one MIMO service;

b) at least one antenna unit configured to receive the non-overlapping frequency MIMO downlink signals of the at least one MIMO service and frequency shift the non-overlapping frequency MIMO downlink signals into native frequency MIMO downlink signals;

c) a single coaxial cable used to carry the non-overlapping frequency MIMO downlink signals of the at least one MIMO service between the remote unit and the at least one antenna unit;

wherein the at least one antenna unit is operatively coupled to at least two MIMO antennas, the at least one antenna unit is configured to transmit the native frequency MIMO downlink signals via the at least two MIMO antennas.

2. The distributed antenna system of claim 1, further comprising a radio interface unit configured to receive native frequency MIMO downlink signals and communicate the non-overlapping frequency MIMO downlink signals to the remote unit.

3. The distributed antenna system of claim 2, wherein non-overlapping frequency MIMO downlink signals are comprised of non-overlapping frequency MIMO downlink electrical signals.

4. The distributed antenna system of claim 3, wherein the radio interface unit is further configured to convert the non-overlapping frequency MIMO downlink electrical signals into non-overlapping frequency MIMO downlink optical signals to be communicated to the remote unit.

5. The distributed antenna system of claim 4, wherein the radio interface unit is comprised of a radio interface unit downlink converter configured to convert the non-overlapping frequency MIMO downlink electrical signals into non-overlapping frequency MIMO downlink optical signals to be communicated to the remote unit.

6. The distributed antenna system of claim 4, further comprising at least one fiber optic link for carrying the non-overlapping frequency MIMO downlink optical signals between the radio interface unit and the remote unit.

7. The distributed antenna system of claim 6, wherein the at least one fiber optic link is comprised of at least one multi-mode fiber optic link.

8. The distributed antenna system of claim 4, wherein the remote unit further comprises a downlink converter configured to convert the non-overlapping frequency MIMO downlink optical signals back to the non-overlapping frequency MIMO downlink electrical signals.

9. The distributed antenna system of claim 2, wherein the radio interface unit further comprises at least two radio interface unit downlink frequency shifters configured to frequency shift the native frequency MIMO downlink signals to the non-overlapping frequency MIMO downlink signals.

10. The distributed antenna system of claim 9, wherein the at least two radio interface unit downlink frequency shifters are comprised of a first radio interface unit downlink frequency shifter configured to frequency shift a first native frequency MIMO downlink signal among the native frequency MIMO downlink signals from the native frequency to a first non-overlapping frequency MIMO downlink signal.

11. The distributed antenna system of claim 10, wherein the at least two radio interface unit downlink frequency shifters are further comprised of a second radio interface unit downlink frequency shifter configured to frequency shift a second native frequency MIMO downlink signal among the native frequency MIMO downlink signals from the native frequency to a second non-overlapping frequency MIMO downlink signal having a different frequency from the first non-overlapping frequency.

12. The distributed antenna system of claim 9, wherein the at least two radio interface unit downlink frequency shifters are configured to frequency shift the native frequency MIMO downlink signals to non-overlapping frequency MIMO downlink signals having non-overlapping frequencies in a frequency range of 320 MHz to 520 MHz.

13. The distributed antenna system of claim 9, wherein the at least one antenna unit comprises at least two antenna unit downlink frequency shifters configured to frequency shift the non-overlapping frequency MIMO downlink signals to the native frequency MIMO downlink signals.

14. The distributed antenna system of claim 13, wherein the at least two antenna unit downlink frequency shifters are comprised of a first antenna unit downlink frequency shifter configured to frequency shift a first non-overlapping frequency MIMO downlink signal among the non-overlapping frequency MIMO downlink signals to a first native frequency MIMO downlink signal.

15. The distributed antenna system of claim 14, wherein the at least two antenna unit downlink frequency shifters are further comprised of a second antenna unit downlink frequency shifter configured to frequency shift a second non-overlapping frequency MIMO downlink signal among the non-overlapping frequency MIMO downlink signals to a second native frequency MIMO downlink signal.

16. The distributed antenna system of claim 15, wherein the at least one antenna unit further comprises an antenna unit downlink splitter configured to split the non-overlapping frequency MIMO downlink signals into the first non-overlapping frequency MIMO downlink signal and the second non-overlapping frequency MIMO downlink signal.

17. The distributed antenna system of claim 15, wherein the at least one antenna unit is further configured to communicate the first native frequency MIMO downlink signal to a first MIMO antenna among the at least two MIMO antennas, and communicate the second native frequency MIMO downlink signal to a second MIMO antenna among the at least two MIMO antennas.

18. The distributed antenna system of claim 2, wherein the radio interface unit further comprises a splitter configured to split the non-overlapping frequency MIMO downlink signals into multiple non-overlapping frequency MIMO downlink signals to be communicated to each of a plurality of the remote units.

19. The distributed antenna system of claim 1, wherein the remote unit further comprises a splitter configured to split the received non-overlapping frequency MIMO downlink signals into a plurality of the non-overlapping frequency MIMO downlink signals to be communicated to the at least one antenna unit.

20. The distributed antenna system of claim 1, wherein the at least one MIMO service operates in a MIMO frequency domain division (FDD).

21. The distributed antenna system of claim 1, wherein the at least one antenna unit is comprised of a plurality of antenna units, and

wherein the remote unit is configured to distribute the non-overlapping frequency MIMO downlink signals over dedicated single coaxial cables to the plurality of antenna units.

22. The distributed antenna system of claim 1, wherein the at least one MIMO service comprises at least one WiMAX service.

23. The distributed antenna system of claim 22, wherein the at least one WiMAX service includes the native frequency MIMO downlink signals in the 2.5-2.7 GHz frequency band.

24. The distributed antenna system of claim 1, wherein the at least one MIMO service comprises at least one CDMA service.

25. The distributed antenna system of claim 24, wherein the at least one CDMA service includes the native frequency MIMO downlink signals in the 1.9 GHz PCS band.

26. The distributed antenna system of claim 1, wherein the at least one MIMO service comprises at least one iDEN-based service.

27. The distributed antenna system of claim 26, wherein the at least one iDEN-based service includes the native frequency MIMO downlink signals in the 800-900 MHz frequency bands.

28. The distributed antenna system of claim 26, wherein the at least one iDEN-based service includes the native frequency MIMO downlink signals in the 900-1000 MHz frequency bands.

29. The distributed antenna system of claim 1, wherein the at least one MIMO service comprises a WiMAX service and a CDMA service.

30. The distributed antenna system of claim 1, wherein the at least one MIMO service comprises a WiMAX service and an iDEN-based service.