Receiver that reconfigures between zero intermediate frequency and direct sampling based on channel conditions

• US 9,037,104 B2
• Filed: 02/04/2013
• Issued: 05/19/2015
• Est. Priority Date: 02/04/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gudem, Prasad Srinivasa Siva, Fernando, Udara C
• Primary Examiner(s): Nguyen, Duc M
• Application Number:
  US13/758,846
• Publication Number:
  US 20140220920A1
• Time in Patent Office: 834 Days
• Field of Search: 455132-135, 455/277.1, 455/277.2, 455/296, 455/303, 455/334, 455/338, 455/340, 455/266, 455/254
• US Class Current: 455/230
• CPC Class Codes: H04B 1/0007 wherein the AD/DA conversion occurs at radiofrequency or intermediate frequency stage
• CPC Class Codes: H04B 1/0021 Decimation, i.e. data rate reduction techniques H04B1/0025 takes precedence
• CPC Class Codes: H04B 1/0025 using a sampling rate lower than twice the highest frequency component of the sampled signal for demodulation of angle-modulated signals H03D3/006
• CPC Class Codes: H04B 1/0028 wherein the AD/DA conversion occurs at baseband stage
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless device for receiving wireless signals based on channel conditions is described. The wireless device includes a direct sampling path used when operating in a direct sampling mode. The wireless device also includes a zero intermediate frequency path used when operating in a normal sampling mode. The wireless device further includes a first switch coupling a filter module input to an input of the direct sampling path and an input of the zero intermediate frequency path. The wireless device also includes a second coupling a filter module output to an output of the direct sampling path and an output of the zero intermediate frequency path. The first switch and the second switch are configured to switch between the direct sampling path and the zero intermediate frequency path based on a received signal power.

Claims

1. A wireless device for receiving wireless signals based on channel conditions, comprising:

a direct sampling path used for operations in a direct sampling mode, wherein the direct sampling path comprises a tunable low pass filter module;

a zero intermediate frequency path for operations in a normal sampling mode, wherein the zero intermediate frequency path comprises a mixer, an oscillator and an amplifier;

a first switch coupling a filter module input to an input of the direct sampling path and an input of the zero intermediate frequency path; and

a second switch coupling a filter module output to an output of the direct sampling path and an output of the zero intermediate frequency path, wherein the first switch and the second switch are configured to switch between the direct sampling path and the zero intermediate frequency path based on a received signal power,

wherein the wireless device is configured to operate in the direct sampling mode when the received signal power is greater than a received signal power threshold, and wherein the received signal power threshold varies according to at least one of a power capacity and a battery life of the wireless device.

2. The wireless device of claim 1, wherein the first switch and the second switch are positioned to allow a signal to pass through the direct sampling path when operating in the direct sampling mode.

3. The wireless device of claim 1, wherein the first switch and the second switch are positioned to allow a signal to pass through the zero intermediate frequency path when operating in a normal sampling mode.

4. The wireless device of claim 1, further comprising an analog-to-digital converter coupled to the second switch.

5. The wireless device of claim 4, wherein the analog-to-digital converter is configured to sample a signal at a direct sampling rate when operating in the direct sampling mode.

6. The wireless device of claim 4, wherein the analog-to-digital converter is configured to sample a signal at a normal sampling rate when operating in the normal sampling mode.

7. The wireless device of claim 1, further comprising a transceiver, wherein the direct sampling path and the zero intermediate frequency path are implemented on the transceiver.

8. The wireless device of claim 1, further comprising a first transceiver and a second transceiver, wherein the direct sampling path is implemented on the first transceiver and the zero intermediate frequency path is implemented on the second transceiver.

9. The wireless device of claim 8, wherein the first transceiver and the second transceiver are coupled to an analog-to-digital converter, wherein the analog-to-digital converter is configured to sample a signal at a direct sampling rate when operating in the direct sampling mode and at a normal sampling rate when operating in the normal sampling mode.

10. The wireless device of claim 8, wherein the first transceiver comprises a first analog-to-digital converter configured to sample a signal at a direct sampling rate, and wherein the second transceiver comprises a second analog-to-digital converter configured to sample a signal at a normal sampling rate.

11. The wireless device of claim 1, wherein the direct sampling mode comprises operating in one of an undersampling mode, a Nyquist mode and an oversampling mode.

12. The wireless device of claim 1, wherein operating in the normal sampling mode uses more battery power than the operating in the direct sampling mode.

13. A wireless device for receiving wireless signals based on channel conditions, comprising:

a direct sampling path used for operations in a direct sampling mode, wherein the direct sampling path comprises a tunable low pass filter module;

a zero intermediate frequency path for operations in a normal sampling mode, wherein the zero intermediate frequency path comprises a mixer, an oscillator and an amplifier;

a first switch coupling a filter module input to an input of the direct sampling path and an input of the zero intermediate frequency path; and

a second switch coupling a filter module output to an output of the direct sampling path and an output of the zero intermediate frequency path, wherein the first switch and the second switch are configured to switch between the direct sampling path and the zero intermediate frequency path based on a received signal power,

wherein the wireless device is configured to operate in the normal sampling mode when the received signal power is less than or equal to a received signal power threshold, and wherein the received signal power threshold varies according to at least one of a power capacity and a battery life of the wireless device.

14. A wireless device for receiving wireless signals based on channel conditions, comprising:

a direct sampling path used for operations in a direct sampling mode, wherein the direct sampling path comprises a tunable low pass filter module;

a zero intermediate frequency path for operations in a normal sampling mode, wherein the zero intermediate frequency path comprises a mixer, an oscillator and an amplifier;

a first switch coupling a filter module input to an input of the direct sampling path and an input of the zero intermediate frequency path; and

a second switch coupling a filter module output to an output of the direct sampling path and an output of the zero intermediate frequency path, wherein the first switch and the second switch are configured to switch between the direct sampling path and the zero intermediate frequency path based on a received signal power,

wherein the wireless device is configured to operate in the direct sampling mode when a carrier-to-noise ratio is greater than a carrier-to-noise ratio threshold, and wherein the carrier-to-noise ratio threshold varies according to at least one of a power capacity and a battery life of the wireless device.

15. The wireless device of claim 14, wherein operating in the normal sampling mode uses more battery power than the operating in the direct sampling mode.

16. A wireless device for receiving wireless signals based on channel conditions, comprising:

a direct sampling path used for operations in a direct sampling mode, wherein the direct sampling path comprises a tunable low pass filter module;

a zero intermediate frequency path for operations in a normal sampling mode, wherein the zero intermediate frequency path comprises a mixer, an oscillator and an amplifier;

a first switch coupling a filter module input to an input of the direct sampling path and an input of the zero intermediate frequency path; and

a second switch coupling a filter module output to an output of the direct sampling path and an output of the zero intermediate frequency path, wherein the first switch and the second switch are configured to switch between the direct sampling path and the zero intermediate frequency path based on a received signal power,

wherein the wireless device is configured to operate in the normal sampling mode when a carrier-to-noise ratio is less than or equal to a carrier-to-noise ratio threshold, and wherein the carrier-to-noise ratio threshold varies according to at least one of a power capacity and a battery life of the wireless device.

17. A method for receiving a received signal based on channel conditions, comprising:

receiving a received signal using an antenna;

determining whether a received signal power is greater than a received signal power threshold; and

switching between a direct sampling mode and a normal sampling mode based on the determination, wherein the direct sampling mode includes operating a tunable low pass filter module, and wherein the normal sampling mode includes operating a mixer, an oscillator and an amplifier,

wherein the received signal power is determined to be greater than the received signal power threshold, wherein the received signal power threshold varies according to at least one of a power capacity and a battery life of a wireless device, and wherein the method further comprises switching to the direct sampling mode.

18. The method of claim 17, wherein switching to the direct sampling mode comprises:

adjusting a first switch to couple an input of the tunable low pass filter module to an input of a direct sampling path; and

adjusting a second switch to couple an output of the tunable low pass filter module to an analog-to-digital converter.

19. The method of claim 18, further comprising:

filtering a signal using the tunable low pass filter module on the direct sampling path; and

providing a filtered signal to the analog-to-digital converter.

20. The method of claim 19, further comprising sampling the filtered signal at a direct sampling rate using the analog-to-digital converter.

21. The method of claim 17, further comprising:

determining whether a carrier-to-noise ratio of the received signal is greater than a carrier-to-noise ratio threshold; and

switching between the direct sampling mode and the normal sampling mode based on whether the carrier-to-noise ratio of the received signal is greater than the carrier-to-noise ratio threshold.

22. The method of claim 17, wherein the direct sampling mode comprises operating in one of an undersampling mode, a Nyquist mode and an oversampling mode.

23. A method for receiving a received signal based on channel conditions, comprising:

receiving a received signal using an antenna;

determining whether a received signal power is greater than a received signal power threshold; and

switching between a direct sampling mode and a normal sampling mode based on the determination, wherein the direct sampling mode includes operating a tunable low pass filter module, and wherein the normal sampling mode includes operating a mixer, an oscillator and an amplifier,

wherein the received signal power is determined to be less than or equal to the received signal power threshold, wherein the received signal power threshold varies according to at least one of a power capacity and a battery life of a wireless device, and wherein the method further comprises switching to the normal sampling mode.

24. The method of claim 23, wherein switching to the normal sampling mode comprises:

adjusting a first switch to couple an input of the mixer to a zero intermediate frequency path; and

adjusting a second switch to couple an output of the amplifier to an analog-to-digital converter.

25. The method of claim 24, further comprising:

filtering a signal using the zero intermediate frequency path; and

providing a filtered signal to the analog-to-digital converter.

26. The method of claim 25, further comprising sampling the filtered signal at a normal sampling rate using the analog-to-digital converter.

27. An apparatus for receiving wireless signals based on channel conditions, comprising:

means for receiving a received signal;

means for determining whether a received signal power is greater than a received signal power threshold; and

means for switching between a direct sampling mode and a normal sampling mode based on the determination, wherein the direct sampling mode includes operating a tunable low pass filter module, and wherein the normal sampling mode includes operating a mixer, an oscillator and an amplifier,

wherein the received signal power is determined to be greater than the received signal power threshold, wherein the received signal power threshold varies according to at least one of a power capacity and a battery life of a wireless device, and further comprising means for switching to the direct sampling mode.

28. The apparatus of claim 27, further comprising:

means for filtering a signal using a direct sampling path, wherein the means for filtering includes the tunable low pass filter module; and

means for sampling the filtered signal at a direct sampling rate.

29. An apparatus for receiving wireless signals based on channel conditions, comprising:

means for receiving a received signal;

means for determining whether a received signal power is greater than a received signal power threshold; and

means for switching between a direct sampling mode and a normal sampling mode based on the determination, wherein the direct sampling mode includes operating a tunable low pass filter module, and wherein the normal sampling mode includes operating a mixer, an oscillator and an amplifier,

wherein the received signal power is determined to be less than or equal to the received signal power threshold, wherein the received signal power threshold varies according to at least one of a power capacity and a battery life of a wireless device, and further comprising means for switching to the normal sampling mode.

30. The apparatus of claim 29, further comprising:

means for filtering a signal using a zero intermediate frequency path, wherein the means for filtering includes the mixer, the oscillator and the amplifier; and

means for sampling the filtered signal at a normal sampling rate using an analog-to-digital converter.