Method for receiving radio frequency signal and a receiver device

• US 7,171,175 B2
• Filed: 10/16/2001
• Issued: 01/30/2007
• Est. Priority Date: 10/17/2000
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Kontola, Ilkka, Lahti, Saku
• Primary Examiner(s): Swerdlow; Daniel
• Application Number:
  US09/981,101
• Publication Number:
  US 20020045427A1
• Time in Patent Office: 1,932 Days
• Field of Search: 455/553.1, 455/562.1, 455/575.7, 455/132, 455/137, 455/139, 455/140, 455/141, 455/147, 455/154.1, 455/133, 455/161.2, 455/151, 455/167.1, 455/168.1, 455/170.1, 455/183.2, 455/196.1, 455/273, 455/276.1, 4552771-2772, 455/135, 343/444, 343/445, 343/465, 375/147, 375/148, 375/349
• US Class Current: 455/135
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: H04B 7/0822 according to predefined selection scheme
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity

Abstract

In a method (300) for receiving a radio signal, there are steps of: receiving (301, 303) first and second received signal components by use of first and second antennas having different properties; processing (305) a received signal component to produce a sampled signal component; producing (307) at least one combined signal, which is a linear combination of at least two sampled signal components; and selecting (306) at least one set of complex values for coefficients of the linear combination so that a quality of a combined signal is at least equal to the quality of that sampled signal component having the best quality. Furthermore, the antennas are alternately connected (302, 304) via a switching element to radio frequency means so that received signal components are interleaving and so that first and second parts of a certain piece of transmitted information are received with the first and second antennas, respectively. A corresponding receiver device is also presented.

Claims

1. A method for receiving a radio frequency signal, said method comprising:

receiving a first received signal component of the radio frequency signal using a first antenna having first properties, and receiving a second received signal component of the radio frequency signal using a second antenna having second properties, which are different from the first properties,

processing the first received signal component to produce a first sampled signal component having an In-phase and a Quadrature-phase component, and processing the second received signal component to produce a second sampled signal component having an In-phase and a Quadrature phase component,

producing at least one combined signal that is a linear combination of at least the first sampled signal components and the second sampled signal component, and

selecting at least one set of complex values for coefficients of the linear combination so that a quality of the combined signal corresponding to each set of coefficient values is at a certain time at least equal to a quality of the one of the first sampled signal components and the second sampled signal component having the best quality.

2. A method according to claim 1, wherein the set(s) of coefficient values is/are selected using the signal-to-noise ratio as a measure of the quality of a signal.

3. A method according to claim 1, wherein the set(s) of coefficient values is/are selected by minimizing the effect of multipath propagation.

4. A method according to claim 1, wherein the polarization properties of the combined signal are adjusted.

5. A method according to claim 1, wherein the angular properties of the combined signal are adjusted.

6. A method according to claim 1, wherein the spatial properties of the first antenna and the second antenna are different.

7. A method according to claim 1, wherein the radio signal is a narrow spectrum signal comprising a sequence of symbols and a piece of transmitted information is a symbol, said piece of transmitted information being received by alternately connecting the first antenna and the second antenna to radio frequency means such that a first part of said piece of transmitted information is received with the first antenna, and a second part of said piece of transmitted information is received with the second antenna.

8. A method according to claim 1, wherein a spread spectrum signal, corresponding to at least one sequence of data bits spread with a spreading code, is received, and said method further comprises the step of correlating the received signal components at a certain phase after the receipt of signal components with at least one local spreading code.

9. A method according to claim 8, wherein the received signal components are correlated with the local spreading code(s) before they are sampled.

10. A method according to claim 8, wherein the sampled signal components are correlated with the local spreading code(s).

11. A method according to claim 8, wherein the combined signal(s) are correlated with the local spreading code(s).

12. A method according to claim 8, wherein the spreading code consists of a certain repeated sequence of chips, which sequence lasts a certain time period shorter than half a duration of a data bit, and a piece of transmitted information comprises a first sequence of chips, which is combined with a certain data bit, and at least part of a second sequence of chips, which is combined with the same data bit, where the first sequence of chips combined with the data bit is received with the first antenna and at least part of the second sequence of chips combined with the data bit is received with the second antenna, said piece of transmitted information being received by alternately connecting the first antenna and the second antenna to radio frequency means such that a first part of said piece of transmitted information is received with the first antenna, and a second part of said piece of transmitted information is received with the second antenna.

13. A method according to claim 12, wherein the received signal comprises Global Positioning System signals, the local spreading codes are Coarse Acquisition codes and the duration of a repeated sequence of chips is an Epoch.

14. A method according to claim 8, wherein a piece of transmitted information is a chip, said piece of transmitted information being received by alternately connecting the first antenna and the second antenna to radio frequency means such that a first part of said piece of transmitted information is received with the first antenna, and a second part of said piece of transmitted information is received with the second antenna.

15. A method according to claim 1, wherein, said first antenna and said second antenna are alternately connected via a switching element to radio frequency means so that the first and the second received signal components are interleaving each other with respect to time, said switching elements being operative based on a duration of a parameter of the first and the second received signal components received with said antennas, wherein said parameter is one of the following:

a bit, an epoch, a symbol or a chip sequence, and wherein a switching time of the first and the second antennas enables reception of a single symbol by both of said first and said second antennas to compensate for changes in polarization of a received signal.

16. A receiver device comprising:

at least a first antenna having certain first properties, which is arranged to receive a first signal component, and a second antenna having certain second properties, which second properties are different from the first properties, and which second antenna is arranged to receive a second signal component,

a processing element arranged to process the first signal component received with the first antenna to produce a first sampled signal component having an In-phase and a Quadrature-phase component, and to process the second signal component received with the second antenna to produce a second sampled signal component having an In-phase and a Quadrature-phase component,

a combination element arranged to produce at least one combined signal that is a linear combination of at least the first sampled signal components and the second sampled signal component and

a selection element arranged to select at least one set of complex values for coefficients of the linear combination so that a quality of the combined signal corresponding to each set of coefficient values is at a certain time at least equal to a quality of the one of the first or the second sampled signal components having the better quality.

17. A receiver device according to claim 16, wherein the selection element is arranged to select the set of complex values based on the quality of the received signal components during a connection of one of the antennas to the processing element for a certain period of time.

18. A receiver device according to claim 16, wherein the polarization properties of the first antenna and the second antenna are different.

19. A receiver device according to claim 18, wherein the first antenna is right hand circularly polarized antenna and the second antenna is a left hand circularly polarized antenna.

20. A receiver device according to claim 19, wherein the first antenna and the second antenna are arranged as a single dual sense antenna having a first feed for right hand circularly polarized operation and a second feed for left hand polarized operation.

21. A receiver device according to claim 20, wherein the dual sense antenna is a dual sense patch antenna.

22. A receiver device according to claim 18, wherein the first antenna is a first linearly polarized antenna and the second antenna is a second linearly polarized antenna.

23. A receiver according to claim 22, wherein the first antenna and the second antenna are arranged as a single dual polarized antenna having a first feed for the first linearly polarized operation and a second feed for the second linearly polarized operation, which is different from the first linearly polarized operation.

24. A receiver device according to claim 22, wherein the dual polarized antenna is a dual polarized patch antenna.

25. A receiver device according to claim 22, wherein the first antenna is a first planar inverted F antenna and the second antenna is a second planar inverted F antenna, whose direction is different from the direction of the first antenna.

26. A receiver device according to claim 22, wherein the first linearly polarized antenna is arranged to have polarization properties which are substantially orthogonal to the polarization properties of the second linearly polarized antenna.

27. A receiver device according to claim 16, wherein the angular properties of the first antenna and the second antenna are different.

28. A receiver device according to claim 16, wherein the spatial properties of the first antenna and the second antenna are different.

29. A receiver device according to claim 16, further comprising correlation means arranged to correlate at least one local spreading code with at least one of the following:

the combined signal, the first sampled signal component, and the second sampled signal component.

30. A receiver device according to claim 29, wherein said receiver device is a Global Positioning System receiver device.

31. A receiver device according to claim 16, wherein said receiver device is a mobile station arranged to receive Global Positioning System signals using the first and second antennas.

32. A receiver device according to claim 16, comprisng a switching element to switch continually between said first antenna and said second antenna based on the duration of a parameter of the first and the second received signal components received by said antennas, such that said first antenna and said second antenna are alternately connected via said switching element to radio frequency means so that the first and the second received signal components are interleaving each other with respect to time, wherein said parameter is one of the following:

a bit, an epoch, a symbol or a chip sequence, and wherein a switching time of the first and the second antennas enables reception of a single symbol by both of said first and said second antennas to compensate for changes in polarization of a received signal.