SYSTEM AND METHOD FOR FREQUENCY OFFSETTING OF INFORMATION COMMUNICATED IN MIMO BASED WIRELESS NETWORKS

• US 20090117859A1
• Filed: 11/20/2008
• Published: 05/07/2009
• Est. Priority Date: 04/07/2006
• Status: Abandoned Application

• Current Assignee: Ericsson Wifi Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: BelAir Networks Inc (Telefonaktiebolaget LM Ericsson)
• Inventors: Keir, Andrew, Rayment, Stephen, Smith, Roland A., Williams, Chris
• Application Number:
  US12/274,794
• Publication Number:
  US 20090117859A1
• Time in Patent Office: Days
• US Class Current: 455/78
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0469 taking special antenna structures, e.g. cross polarized antennas into account
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/12 Frequency diversity

Abstract

A communications system includes a multiple-input/multiple-output architecture, which has a plurality of radio frequency chains. One of the plurality of radio frequency chains is configured to apply a first frequency offset to a base frequency of an output signal to generate a first transmitting frequency; and another of the plurality of radio frequency chains being configured to apply a second frequency offset to the base frequency to generate a second transmitting frequency.

Claims

1. A communications system comprising:

a multiple-input/multiple-output architecture comprising a plurality of radio frequency chains,

a first of the plurality of radio frequency chains being configured to apply a first frequency offset to a base frequency of an output signal to generate a first transmitting frequency; and

a second of the plurality of radio frequency chains being configured to apply a second frequency offset to the base frequency to generate a second transmitting frequency.

2. The communications system of claim 1, wherein the first of the plurality of radio frequency chains is configured to apply the first frequency offset to a frequency of a first received signal to generate the base frequency, and the second of the plurality of radio frequency chains is configured to apply the second frequency offset to a frequency of a second received signal to generate the base frequency.

3. The communications system of claim 1, wherein the plurality of radio frequency chains includes at least one radio frequency chain dedicated for transmitting a transmission signal and at least one radio frequency chain dedicated for receiving a reception signal.

4. The communications system of claim 1, further comprising a first local oscillator circuit operative with the first of the plurality of radio frequency chains to generate the first frequency offset.

5. The communications system of claim 4, further comprising a second local oscillator circuit operative with the second of the plurality of radio chains to generate the second frequency offset.

6. The communications system of claim 1 further comprising a zero intermediate frequency communication (ZIF) circuit, the ZIF circuit being operative at the baseband frequency.

7. The communications system of claim 1, wherein at least one of the plurality of radio frequency chains comprises one of time division duplexing and frequency division duplexing.

8. The communications system of claim 1, wherein at least one of the plurality of radio frequency chains comprises a switch for switching between a receiving mode and a transmitting mode.

9. The communications system of claim 1, wherein the first and second of the plurality of radio frequency chains comprise a heterodyne architecture to produce the first and second frequency offsets.

10. The communications system of claim 1, wherein one of the first and second transmitting frequencies comprises a frequency in the industrial, scientific, and medical radio band.

11. The communications system of claim 1, wherein the system is operative as one of the group consisting of an IEEE 802.11 radio, an IEEE 802.16d Worldwide Interoperability for Microwave Access (“

WiMAX”

), an 802.16e WiMAX;

4G, a 3rd Generation Partnership Project (“

3GPP”

), and a 3rd Generation Partnership Project 2 (“

3GPP2”

) standards based radio.

12. The communications system of claim 1 further comprising an antenna associated with at least one of the plurality of radio frequency chains, wherein the antenna is includes a first polarization.

13. The communication system of claim 1, further comprising a first antenna associated with the first of the plurality of radio frequency chains;

and a second antenna associated with the second of the plurality of radio frequency chains, wherein the first antenna includes a first polarization and the second antenna includes a second polarization, the first polarization being different from the second polarization.

14. The communication system of claim 1, further comprising a first antenna associated with the first of the plurality of radio frequency chains;

and a second antenna associated with the second of the plurality of radio frequency chains, wherein each of the first and second antennas includes a common polarization, wherein an offset frequency of one of the first and second radio frequency chains is transmitted using beam steering.

15. A communications system comprising:

a multiple-input/multiple-output architecture comprising a plurality of radio frequency chains,

a first and a second of the plurality of radio frequency chains comprising a first linked group, the first linked group being configured to apply a first frequency offset to a base frequency of a output signal to generate a first transmitting frequency; and

a third and a fourth of the plurality of radio frequency chains comprising a second linked group, the second linked group being configured to apply a second frequency offset to the base frequency of the output signal to generate a second transmitting frequency.

16. The communications system of claim 15, further comprising an antenna, the antenna including a first polarization and a second polarization, the first polarization associated with the first transmitting frequency and the second polarization associated with the second transmitting frequency.

17. The communications system of claim 16, wherein each of the first and second polarizations is selected from the group consisting of a vertical polarization, a horizontal polarization, and an orthogonal polarization.

18. The communications system of claim 15, further comprising a first antenna and a second antenna, each antenna associated with a respective one of the first and second linked groups, each antenna comprising an input for a respective one of the first and second polarizations.

19. The communications system of claim 15, wherein each of the first and second linked groups further comprises a respective local oscillator circuit for generating the respective first and second frequency offsets.

20. A communications system comprising:

a multiple-input/multiple-output architecture comprising a plurality of radio frequency chains,

at least one of the radio frequency chains comprising a plurality of filtering submodules, a first and a second of the filtering submodules being configured to apply a respective first and second frequency offset to a base frequency of an output signal to generate a respective first and second signal respectively comprising a first and second transmitting frequency.

21. The communications system of claim 20, further comprising a combiner for combining the first and second signals into a transmission signal.

22. The communications system of claim 20 wherein each of the first and second submodules comprises a respective first and second local oscillator circuit for generating the respective first and second frequency offsets.

23. The communications system of claim 20 wherein each of the first and second submodules comprises a respective first and second local oscillator circuit, and the system further comprises a common oscillator circuit operative with at least two of the plurality of radio frequency chains, the common oscillator circuit being operative with the first and second local oscillator circuit for generating the respective first and second frequency offsets.

24. A communications system comprising:

a multiple-input/multiple-output architecture comprising a plurality of radio frequency chains,

a first of the plurality of radio frequency chains being configured to apply a first frequency offset to a base frequency of an output signal to generate a first transmitting frequency; and

a second of the plurality of radio frequency chains being configured to apply a second frequency offset to a base frequency to generate a second transmitting frequency;

wherein a first and a second transmitted signal comprise respective first and second transmitting frequencies;

wherein at least two of the plurality of radio frequency chains are switchable to a receiving mode for receiving the first and second transmitted signals, each of the at least two of the plurality of radio frequency chains comprising a respective first and a second receiving-side filtering submodule for applying the first frequency offset to the first transmitting frequency and the second frequency offset to the second transmitting frequency to obtain respective signals at the base frequency.

25. The communications system of claim 24, wherein each of the plurality of radio frequency chains comprises only one receiving antenna.

26. The communications system of claim 24, wherein each of the plurality of radio frequency chains comprises only one transmitting antenna.

27. The communications system of claim 24, wherein one of the at least two of the plurality of radio frequency chains further comprises a transmission-side filtering submodule and a first local oscillator circuit, the first local oscillator circuit being operative with the respective transmission-side filtering submodule and the respective first receiving-side filtering submodule of the respective one of at least two of the plurality of radio frequency chains.

28. The communications system of claim 27, wherein the second receiving side filtering submodule comprises a second local oscillator circuit for generating the second frequency offset.

29. The communications system of claim 27, wherein the first local oscillator circuit is further operative with the second receiving-side filtering submodule of the other of the at least two of the plurality of radio frequency chains.

30. The communications system of claim 29 further comprising a first frequency gain circuit for enabling maximal ratio combining (MRC) gains, the first frequency gain circuit being operative with the first receiving-side filtering submodule of one of the at least two of the plurality of radio frequency chains and with the second of the receiving-side filtering submodule of the other of the at least two of the plurality of radio frequency chains.

31. The communications system of claim 28 further comprising a first frequency gain circuit for enabling maximal ratio combining (MRC) gains, the first gain circuit being operative with the first receiving-side filtering submodule of one of the at least two of the plurality of radio frequency chains and with the second of the receiving-side filtering submodule of the other of the at least two of the plurality of radio frequency chains.

32. A communications system comprising:

a zero intermediate frequency (ZIF) circuit for producing a first and a second output signal, the first and second output signals comprising a respective first and second frequency, the ZIF circuit comprising

a plurality of radio frequency chains integrated in the ZIF circuit;

a first of the plurality of radio frequency chains being configured to generate a first transmitting frequency; and

a second of the plurality of radio frequency chains being configured to generate a second transmitting frequency.

33. The communications system of claim 32 further comprising a common frequency synthesizer integrated in the ZIF circuit, the common frequency synthesizer being operative with the first and second of the plurality of radio frequency chains to generate the respective first and second transmitting frequencies.

34. The communications system of claim 32 further comprising a first and second frequency synthesizer integrated in the ZIF circuit, the first and second frequency synthesizers being operative with the respective first and second of the plurality of radio frequency chains to generate the respective first and second transmitting frequencies.

35. A method of communicating information using a communications system comprising a multiple-input/multiple-output architecture, the architecture comprising a first and a second radio frequency chain, the method comprising the steps of:

a) receiving at least one output signal from the first radio frequency chain and at least one output signal from the second radio frequency chain, each output signal comprising a base frequency;

b) applying a first frequency offset to the base frequency of the at least one output signal received from the first radio frequency chain to generate a first offset transmission signal;

c) applying a second frequency offset to the base frequency of the at least one output signal from the first radio frequency chain to generate a second offset transmission signal; and

d) transmitting the first and second offset transmission signals.

36. The method of communicating information of claim 35, wherein step b) further comprises the step of generating the first frequency offset using a first local oscillator circuit, and wherein step c) further comprises the step of generating the second frequency offset using a second local oscillator circuit.

37. The method of communicating information of claim 35, wherein step b) further comprises the step of generating the first frequency offset using a first local oscillator circuit in combination with a common oscillator, and wherein step c) further comprises the step of generating the second frequency offset using a second local oscillator circuit in combination with the common oscillator.

38. The method of communicating information of claim 35, the method further comprising the steps of:

e) receiving at least one output signal from a third radio frequency chain, the at least one output signal from the third radio frequency chain comprising a base frequency; and

f) transmitting the at least one output signal from the third radio frequency chain without applying a frequency offset.

39. A method of communicating information using a communications system comprising a multiple-input/multiple-output architecture, the architecture comprising a first radio frequency chain and a second radio frequency chain, and the method comprising the steps of:

a) receiving a first offset transmission signal comprising a first frequency offset from a base frequency and a second offset transmission signal comprising a second frequency offset from the base frequency;

b) applying the first frequency offset by the first radio frequency chain to obtain a first signal at a base frequency of a controller; and

c) applying the second frequency offset by the second radio frequency chain to obtain a second signal at the base frequency of the controller.

*goes to MIMO receiving.

40. A method of communicating information using a communications system comprising a multiple-input/multiple-output architecture, the architecture comprising a first linked group and a second linked group wherein the first linked group comprises a first radio frequency chain and a second radio frequency chain and the second linked group comprises a third radio frequency chain and a fourth radio frequency chain, and the method comprising the steps of:

a) receiving a first output signal from the first radio frequency chain and a second output signal from the second radio frequency chain and a third output signal from the third radio frequency chain and a fourth output signal from the fourth radio frequency chain, each output signal comprising a base frequency;

b) applying a first frequency offset to the base frequency of the first output signal to generate a first offset transmission signal;

c) applying the first frequency offset to the base frequency of the second output signal to generate a second offset transmission signal;

d) applying a second frequency offset to the base frequency of the third output signal to generate a third offset transmission signal;

e) applying the second frequency offset to the base frequency of the fourth output signal to generate a fourth offset transmission signal; and

f) transmitting the first, second, third, and fourth offset transmission signals,

wherein the first and second transmission signals comprise a first transmission frequency and the third and fourth transmission signals comprise a second transmission frequency.

41. The method of communicating information of claim 40, wherein step f) further comprises transmitting the first offset transmission signal by using a first antenna polarization and transmitting the second offset transmission signal by using a second antenna polarization, wherein the first antenna polarization is different from the second antenna polarization.

42. The method of communicating information of claim 41, wherein step f) further comprises transmitting the third offset transmission signal by using a third antenna polarization and transmitting the fourth offset transmission signal by using a fourth antenna polarization, wherein the third antenna polarization is different from the fourth antenna polarization.

43. The method of communicating information of claim 40, wherein each of steps b) and c) further comprises the step of generating the first frequency offset using a first local oscillator circuit, and each of steps d) and e) further comprises the step of generating the second frequency offset using a second local oscillator circuit.

44. A method of communicating information using a communications system comprising a multiple-input/multiple-output architecture, the architecture comprising a plurality of radio frequency chains, at least a first radio frequency chain comprising a first transmitting-side filtering submodule and a second transmitting-side filtering submodule, and the method comprising the steps of:

a) receiving at least one output signal from the first radio frequency chain, the at least one output signal comprising a base frequency;

b) using the first transmitting-side filtering submodule to apply a first frequency offset to the base frequency of the received output signal to generate a first offset signal;

c) using the second transmitting-side filtering submodule to apply a second frequency offset to the base frequency of the received output signal to generate a second offset signal;

d) combining the first and second offset signals into an offset transmission signal; and

e) transmitting the offset transmission signal.

45. The method of communicating information of claim 44, wherein step b) further comprises the step of generating the first frequency offset using a first local oscillator circuit, and step c) further comprises the step of generating the second frequency offset using a second local oscillator circuit.

46. The method of communicating information of claim 44, wherein step b) further comprises the step of generating the first frequency offset using a first local oscillator circuit in combination with a common oscillator, and step c) further comprises the step of generating the second frequency offset using a second local oscillator circuit in combination with the common oscillator.

47. The method of communicating information of claim 44, wherein step a) is performed by using only one transmitting antenna.

48. A method of communicating information using a communications system comprising a multiple-input/multiple-output architecture, the architecture comprising a first radio frequency chain and a second radio frequency chain, the first radio frequency chain including a first receiving-side filtering submodule, and the second radio frequency chain including a second receiving-side filtering submodule, and the method comprising the steps of:

a) receiving a first offset transmission signal comprising a first frequency offset;

b) receiving a second offset transmission signal comprising a second frequency offset;

c) using the first receiving-side filtering submodule to apply the first frequency offset to the received first offset transmission signal to obtain a first signal at a base frequency of a controller; and

d) using the second receiving-side filtering submodule to apply the second frequency offset to the received second offset transmission signal to obtain a second signal at the base frequency of the controller.

49. The method of communicating information of claim 48, wherein step c) further comprises the step of generating the first frequency offset using a first local oscillator circuit, and step d) further comprises the step of generating the second frequency offset using a second local oscillator circuit.

50. The method of communicating information of claim 48, wherein step c) further comprises the step of generating the first frequency offset using a first local oscillator circuit in combination with a common oscillator, and step d) further comprises the step of generating the second frequency offset using a second local oscillator circuit in combination with the common oscillator.

51. The method of communicating information of claim 48, wherein steps a) and b) are performed by using only one receiving antenna.

52. A communications system comprising:

a multiple-input/multiple-output architecture comprising a plurality of radio frequency chains, at least two radio frequency chains applying a first and second frequency offset to a base frequency; and

a control system for selecting at least two transmission frequencies that minimize interference, the control system being configured to determine a first frequency offset and a second frequency offset.

53. A method of communicating information in a communications system, the communications system comprising a multiple-input/multiple-output architecture comprising a plurality of radio frequency chains, at least two radio frequency chains applying a first and second frequency offset to a base frequency, and the method comprising the steps of:

a) determining at least two transmission frequencies that minimize interference; and

b) determining the first and second frequency offsets to be applied to the base frequency to yield the at least two transmission frequencies.