Method and system for distributing multiband wireless communications signals

• US 6,801,767 B1
• Filed: 01/26/2001
• Issued: 10/05/2004
• Est. Priority Date: 01/26/2001
• Status: Expired due to Term

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: LGC Wireless Incorporated (TE Connectivity Limited)
• Inventors: Hart, David, Schwartz, Adam L., Forth, Peter, Eisenberg, John
• Primary Examiner(s): Appiah, Charles
• Assistant Examiner(s): Mehrpour, Naghmeh
• Application Number:
  US09/771,320
• Time in Patent Office: 1,348 Days
• Field of Search: 455/131, 455/132, 455/133, 455/150.1, 455/151.2, 455/151.4, 455/154.1, 455/190.1, 455/192.1, 455/73, 455/82, 455/87, 455/550.1, 455/553.1, 455/552.1, 455/554.2, 455/353, 455/355, 455/127.4, 455/168.1, 455/118, 455/426.2, 455/207, 398/115
• US Class Current: 455/426.2
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 10/25755 Ring network topology

Abstract

This invention provides a method and system for distributing multiband wireless communications signals. Downlink RF signals in a plurality of downlink frequency bands are received and then combined into a combined downlink RF signal at the main unit. The combined downlink RF signal is subsequently split into multiple downlink RF-parts, which are converted to multiple downlink optical signals and optically transmitted to the remote units. At each remote unit, a delivered downlink optical signal is first converted back to a downlink RF-part which is subsequently separated into a plurality of downlink RF-groups by frequency band. Each downlink RF-group is individually conditioned (e.g., filtered and amplified). The individual-conditioned downlink RF-groups are then combined and transmitted to a dedicated downlink antenna.

Claims

1. A method of distributing multiband radio frequency (RF) signals in a wireless communications system, comprising:

a) receiving at a main unit a plurality of downlink RF-sets in a plurality of downlink frequency bands, wherein each of said downlink RF-sets contains downlink RF signals in one of said downlink frequency bands;

b) combining said downlink RF-sets into a multiband combined downlink RF signal;

c) splitting said multiband combined downlink RF signal into multiple multiband downlink RF-parts;

d) converting said multiple multiband downlink RF-parts to multiple downlink optical signals;

e) optically transmitting said downlink optical signals to multiple remote units;

f) receiving a delivered downlink optical signal at each of said remote units;

g) converting said delivered downlink optical signal to a multiband delivered downlink RF-part;

h) separating said multiband delivered downlink RF-part into a plurality of downlink RF-groups by frequency band;

i) performing individual downlink-signal-conditioning on each of said downlink RF-groups, including one or more steps of RF-amplifying, gain-adjusting, and RF-filtering;

j) combining said individual-conditioned downlink RF groups into a multiband downlink RF transmit signal; and

k) transmitting said multiband downlink RF transmit signal to at least one dedicated downlink antenna;

wherein said at least one dedicated downlink antenna is not used for uplink reception.

2. The method of claim 1 further comprising the step of performing a first global frequency-translation on at least one of said downlink RF-sets preceding step b), whereby said downlink RF-sets are placed in disjoint frequency bands that are separated in frequency.

3. The method of claim 2 further comprising the step of performing a second global frequency-translation on at least one of said downlink RF-groups, whereby said downlink RF-groups are placed back into said downlink frequency bands.

4. The method of claim 1 further comprising the step of performing a first local frequency-translation on at least one of said downlink RF-groups following said step h) and preceding said step i), so as to place said at least one of said downlink RF-groups in an intermediate frequency band.

5. The method of claim 4 further comprising the step of performing a second local frequency-translation on said at least one of said downlink RF-groups following said step i), so as to substantially undo the effect of said first frequency-translation.

6. The method of claim 1 further comprising the step of carrying out an end-to-end gain calibration, thereby setting a prescribed gain for each of said downlink RF-groups in each of said remote units.

7. The method of claim 6 wherein a calibration-tone signal is used to carry out said end-to-end gain calibration, and wherein said calibration-tone signal is set to a frequency within a frequency band of each of said downlink RF-groups to be calibrated.

8. The method of claim 6 further comprising the step of injecting a downlink-gain-control signal to each of said downlink RF-parts, wherein said gain-control-signal is set at a frequency outside of any of said downlink frequency bands.

9. The method of claim 8 further comprising the step of detecting and thereby using said downlink-gain-control signal to maintain said prescribed gain in each of said remote units.

10. The method of claim 1 further comprising the step of diverting a fraction of said delivered downlink RF-part to one or more additional remote units.

11. The method of claim 1 further comprising the step of transmitting a specific downlink optical signal to an expansion unit, wherein said specific downlink optical signal is amplified and further divided into multiple secondary-optical-signals, and wherein said secondary-optical-signals are transmitted to a plurality of additional remote units.

12. The method of claim 1 further comprising:

1) receiving at each of said remote units multiple multiband uplink RF signals in a plurality of uplink frequency bands from at least one dedicated uplink antenna, wherein said at least one dedicated uplink antenna is not used for downlink transmission;

2) separating said multiband uplink RF signals into a plurality of uplink RF-groups by frequency band;

3) performing individual uplink-signal-conditioning on each of said uplink RF-groups, including one or more steps selected from the group consisting of RF-amplifying, gain-adjusting, and RF-filtering;

4) combining said uplink RF-groups into a multiband uplink RF-part; and

5) converting said multiband uplink RF-part to an uplink optical signal;

whereby multiple uplink optical signals corresponding to multiple uplink RF-parts are optically transmitted from said remote units to said main unit.

13. The method of claim 12 further comprising the step of performing a first frequency-translation on at least one of said uplink RF-groups preceding said step 3), so as to place said at least one of said uplink RF-groups in an intermediate frequency band.

14. The method of claim 13 further comprising the step of performing a second frequency-translation on said at least one of said uplink RF-groups, so as to substantially undo the effect of said first frequency-translation.

15. The method of claim 12 wherein said step 4) further comprises the step of combining with said uplink RF-part additional uplink RF signals transmitted from one or more additional remote units.

16. The method of claim 12 further comprising the step of transmitting downlink RF signals in a TDD frequency band from each of said remote units to a TDD antenna and receiving at each of said remote units uplink RF signals in said TDD frequency band from said TDD antenna by actuating an RF-switching means.

17. The method of claim 16 wherein said RF-switching means is actuated according to a power level of said downlink RF signals in said TDD frequency band.

18. The method of claim 12 further comprising the step of using an RF-switching means to enable transmission of downlink RF signals in a TDD frequency band from each of said remote units to said at least one dedicated downlink antenna and to allow reception of uplink RF signals in said TDD frequency band at each of said remote units from said at least one dedicated uplink antenna.

19. The method of claim 18 wherein said RF-switching means is actuated according to a power level of said downlink RF signals in said TDD frequency band.

20. The method of claim 12 further comprising the following steps carried out at said main unit:

(1) receiving said uplink optical signals;

(2) converting said uplink optical signals to said multiband uplink RF-parts;

(3) combining said multiband uplink RF-parts into a multiband combined uplink RF signal; and

(4) transmitting said multiband combined uplink RF signal to a plurality of wireless communications networks.

21. The method of claim 12 further comprising the step of transmitting a plural number of said uplink optical signals to an expansion unit, wherein said plural number of said uplink optical signals are amplified and combined to a combined optical signal.

22. The method of claim 21 wherein said combined optical signal is transmitted to said main unit.

23. The method of claim 21 wherein said combined optical signal is transmitted to a higher-level expansion unit.

24. A multiband distributed wireless communications system comprising:

(a) a main unit comprising;

(1) a downlink-RF-interface for receiving a plurality of downlink RF-sets in a plurality of downlink frequency bands, wherein each of said downlink RF-sets contains downlink RF signals in one of said downlink frequency bands;

(2) a downlink RF-combining means for combining said downlink RF-sets into a multiband combined downlink RF signal;

(3) a downlink RF-splitting means for splitting said multiband combined downlink RF signal into multiple multiband downlink RF-parts; and

(4) multiple RF-to-optical converters for converting said multiple multiband downlink RF-parts to multiple downlink optical signals;

(b) multiple remote units optically coupled to said main unit, each comprising;

(5) a remote optical-to-RF converter for converting a delivered downlink optical signal to a multiband delivered downlink RF-part;

(6) a downlink splitting-filtering means for separating said multiband delivered downlink RF-part into a plurality of downlink RF-groups by frequency band;

(7) a plurality of downlink-signal-conditioning assemblies for performing individual downlink-signal-conditioning on each of said downlink RF-groups; and

(8) a downlink filtering-combining means for combining said individual-conditioned downlink RF-groups into a multiband downlink RF-transmit signal;

(c) multiple dedicated downlink antennae, wherein each of said remote units is in RF-communication with at least one of said dedicated downlink antennae, whereby said multiband downlink RF-transmit signal is transmitted to said at least one of said dedicated downlink antennae;

wherein said dedicated downlink antennae are not used for uplink reception.

25. The multiband distributed wireless communications system of claim 24 further comprising a frequency-translation means.

26. The multiband distributed wireless communications system of claim 25 wherein said frequency-translation means performs a first frequency-translation on at least one of said downlink RF-sets, whereby said downlink RF-sets are placed in disjoint frequency bands that are separated in frequency.

27. The multiband distributed wireless communications system of claim 26 wherein said frequency-translation means comprises a central global-tone mixer coupled to a global-tone generator, in RF-communication with said downlink-RF-interface and said downlink RF-combining means.

28. The multiband distributed wireless communications system of claim 26 wherein said frequency-translation means further performs a second frequency-translation on at least one of said downlink RF-groups in each of said remote units, whereby said downlink RF-groups are placed back into said downlink frequency bands.

29. The multiband distributed wireless communications system of claim 28 wherein said frequency-translation means further comprises multiple remote global-tone mixers coupled to one or more global-tone generators, and wherein there is at least one of said remote global-tone mixers in each of said remote units, in RF-communication with at least one of said downlink-signal-conditioning assemblies.

30. The multiband distributed wireless communications system of claim 25 wherein said frequency-translation means performs a first frequency-translation on at least one of said downlink RF-groups, so as to place said at least one of said downlink RF-groups in an intermediate frequency band.

31. The multiband distributed wireless communications system of claim 30 wherein said frequency-translation means performs a second frequency-translation on said at least one of said downlink RF-groups, so as to substantially undo the effect of said first frequency-translation.

32. The multiband distributed wireless communications system of claim 30 wherein said frequency-translation means comprises multiple local-tone mixers coupled to one or more local-tone generators, and wherein there is at least one of said local-tone mixers in each of said remote units, in RF-communication with at least one of said downlink-signal-conditioning assemblies.

33. The multiband distributed wireless communications system of claim 24 further comprising a gain-calibration means for performing an end-to-end gain calibration throughout said multiband distributed wireless communications system, thereby setting a prescribed gain for each of said downlink RF-groups.

34. The multiband distributed wireless communications system of claim 33 wherein said gain-calibration means comprises a calibration-tone generator, coupled to said downlink RF-combining means and said downlink RF-splitting means by way of an RF-switch.

35. The multiband distributed wireless communications system of claim 33 further comprising a downlink gain-control-signal combiner, for injecting a downlink gain-control signal to each of said downlink RF-parts, wherein said gain-control-signal is set to a frequency outside of any of said downlink frequency bands.

36. The multiband distributed wireless communications system of claim 35 wherein each of said remote units further comprises a downlink RF-splitting element coupled to a downlink-gain-control element, for detecting and thereby using said downlink-gain-control signal to maintain said prescribed gain.

37. The multiband distributed wireless communications system of claim 35 wherein said gain-control-signal is selected from the group consisting of Frequency-Shift-Key (FSK) signals, pilot signals, and constant-envelope signals.

38. The multiband distributed wireless communications system of claim 24 wherein each of said downlink-signal-conditioning assemblies comprises one or more elements selected from the group consisting of RF-amplifiers, gain-control elements, and RF-filters.

39. The multiband distributed wireless communications system of claim 24 wherein each of said remote units further comprises a downlink RF-splitting element coupled to said remote optical-to-RF converter, whereby a fraction of said delivered downlink RF-part is diverted to an auxiliary RF-to-optical converter.

40. The multiband distributed wireless communications system of claim 24 further comprising multiple dedicated uplink antennae, such that each of said remote units is in RF-communication with at least one of said dedicated uplink antennae, wherein each of said remote units further comprises:

(9) an uplink splitting-filtering means for separating multiple uplink RF signals in a plurality of uplink frequency bands into a plurality of uplink RF-groups by frequency band, wherein said uplink RF signals are transmitted from said at least one of said dedicated uplink antennae;

(10) a plurality of uplink-signal-conditioning assemblies for performing individual uplink-signal-conditioning on each of said uplink RF-groups;

(11) an uplink filtering-combining means for combining said uplink RF-groups into an multiband uplink RF-part; and

(12) a remote RF-to-optical converter for converting said multiband uplink RF-part to an uplink optical signal;

wherein said dedicated uplink antennae are not used for downlink transmission.

41. The multiband distributed wireless communications system of claim 40 further comprising a frequency-translation means, wherein said frequency-translation means performs a first frequency-translation on at least one of said uplink RF-groups, so as to place said at least one of said uplink RF-groups in an intermediate frequency band.

42. The multiband distributed wireless communications system of claim 41 where in s aid frequency-translation means performs a second frequency-translation on said at least one of said uplink RF-groups, so as to substantially undo the effect of said first frequency-translation.

43. The multiband distributed wireless communications system of claim 41 wherein said frequency-translation means comprises multiple local-tone mixers coupled to one or more local-tone generators, and wherein there is at least one of said local-tone mixers in each of said remote units, in RF-communication with at least one of said uplink-signal-conditioning assemblies.

44. The multiband distributed wireless communications system of claim 40 wherein each of said remote units is in RF-communication with a dedicated TDD antenna by an RF-switching means, whereby said dedicated TDD antenna transmits downlink RF signals in a TDD frequency band and receives uplink RF signals in said TDD frequency band by way of actuating said RF-switching means.

45. The multiband distributed wireless communications system of claim 44 wherein said RF-switching means is actuated according to a power level of said downlink RF signals in said TDD frequency band.

46. The multiband distributed wireless communications system of claim 45 wherein said RF-switching means comprises an RF-switching element coupled to a downlink power-detect element, and wherein said RF-switching element is selected from the group consisting of RF Transmit/Receive switches, RF circulators, and power combiners.

47. The multiband distributed wireless communications system of claim 40 wherein each of said remote units further comprises an RF-switching means including downlink and uplink RF-switches coupled to a downlink power-detect element, and wherein said RF-switching means enables transmission of downlink RF signals in a TDD frequency band to said at least one of said dedicated downlink antennae, and allows reception of uplink RF signals in said TDD frequency band from said at least one of said dedicated uplink antennae.

48. The multiband distributed wireless communications system of claim 47 wherein said RF-switching means is actuated according to a power level of said downlink RF signals in said TDD frequency band.

49. The multiband distributed wireless communications system of claim 40 wherein each of said uplink-signal-conditioning assemblies comprises one or more elements selected from the group consisting of RF-amplifiers, gain-control elements, and RF-filters.

50. The multiband distributed wireless communications system of claim 40 wherein each of said remote units further comprises an uplink RF-combining element coupled to said remote RF-to-optical converter, such that additional uplink RF signals delivered by an auxiliary optical-to-RF converter are combined with said uplink RF-part.

51. The multiband distributed wireless communications system of claim 40 wherein said main unit further comprises:

(13) multiple optical-to-RF converters for converting said multiple uplink optical signals to said multiple multiband uplink RF-parts;

(14) an uplink RF-combining means for combining said multiband uplink RF-parts into a multiband combined uplink RF signal; and

(15) an uplink-RF-interface for transmitting said multiband combined uplink RF signal to said plurality of wireless communications networks.

52. The multiband distributed wireless communications system of claim 51 wherein said main unit further comprises at least one downlink RF-amplifier and at least one uplink RF-amplifier, whereby said downlink RF-parts and said uplink RF-parts are amplified.

53. The multiband distributed wireless communications system of claim 24 further comprising one or more expansion units, optically coupled to said main unit and said remote units, wherein each of said expansion units comprises:

(a) a downlink assembly, including a downlink optical-to-RF converter, a downlink RF-amplifier, a downlink RF-to-optical converter, and an optical-splitting means; and

(b) an uplink assembly, including an optical-combining means, an uplink optical-to-RF converter, an uplink RF-amplifier, and an uplink RF-to-optical converter.

54. The multiband distributed wireless communications system of claim 24 wherein said remote units are optically coupled to said main unit by a plurality of optical fibers.

55. The multiband distributed wireless communications system of claim 54 wherein said main unit further comprises a plurality of WDM filters optically coupled to one or more of said optical fibers.

56. The multiband distributed wireless communications system of claim 24 wherein said downlink RF-sets are received from a plurality of wireless communications networks, selected from the group consisting of paging, cellular, PCS, UMTS, GSM, CDMA, TDD, FDMA, GPS, EDGE, W-CDMA, bluetooth, WLAN (wide area data) and LAN (local area data) networks.