INSERTED PILOT CONSTRUCTION FOR AN ECHO CANCELLATION REPEATER

• US 20100284445A1
• Filed: 10/30/2009
• Published: 11/11/2010
• Est. Priority Date: 05/11/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gore, Dhananjay Ashok, Wang, Michael Mao, Proctor, James Arthur JR., Barriac, Gwendolyn Denise, Tian, Tao
• Granted Patent: US 9,020,009 B2
• Time in Patent Office: Days
• US Class Current: 375/211
• CPC Class Codes: H04B 7/15535 Control of relay amplifier gain amplifier gain control in general H03G3/00; gain control reducing self - or loop interference H04B7/15578
• CPC Class Codes: H04B 7/15585 by interference cancellation
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/2613 Structure of the reference signals

Abstract

In one embodiment, a device for constructing a pilot signal for use in a wireless repeater where the pilot signal is added to a transmit signal includes one or more pilot generators. Each pilot generator generates a carrier pilot signal associated with a single carrier of the transmit signal and the carrier pilot signals generated by the one or more pilot generators are summed to generate the pilot signal. Each of the one or more pilot generators includes a pilot symbol unit providing multiple data symbols having a predetermined data structure as the carrier pilot signal, a pilot scrambler, a filter, a pilot power determination unit, and a cyclic prefix insertion unit for inserting a cyclic prefix, to the carrier pilot signal. In another embodiment, the pilot symbol unit providing multiple data symbols in frequency domain as the carrier pilot signal.

Claims

1. A pilot construction device to construct a pilot signal for use in a wireless repeater, the repeater configured to add the pilot signal to a transmit signal for transmission, the device comprising:

one or more pilot generators, each pilot generator to generate a carrier pilot signal associated with a single carrier of the transmit signal, wherein the pilot construction device is configured to construct the pilot signal by summing the carrier pilot signals generated by the one or more pilot generators, wherein each of the one or more pilot generators comprises;

a pilot symbol unit to provide a plurality of data symbols having a predetermined data structure as the carrier pilot signal;

a pilot scrambler to scramble the plurality of data symbols;

a filter to shape spectral properties of the carrier pilot signal;

a pilot power determination unit to set a power level of the carrier pilot signal relative to a power level of the transmit signal; and

a cyclic prefix insertion unit to insert a cyclic prefix to the carrier pilot signal.

2. The device of claim 1, wherein the predetermined data structure comprises an OFDM data structure.

3. The device of claim 1, wherein the pilot scrambler is configured to scramble the plurality of data symbols using a scrambling sequence that imparts a unique identifier to the repeater.

4. The device of claim 1, further comprising a power measurement unit to measure the power level of each carrier in the transmit signal, the pilot power determination unit to control the power level of the carrier pilot signal relative to the measured power level of the corresponding carrier in the transmit signal so that the power level of the carrier pilot signal tracks the power level of the corresponding carrier in the transmit signal.

5. The device of claim 4, wherein the power measurement unit comprises a filter to filter the measured power level values.

6. The device of claim 4, wherein the pilot power determination unit is configured to set the power level of the carrier pilot signal to a value lower than the measured power level of the corresponding carrier in the transmit signal.

7. The device of claim 6, wherein the pilot power determination unit is configured to set the power level of the carrier pilot signal at least 20 dB lower than the measured power level of the corresponding carrier in the transmit signal.

8. The device of claim 1, wherein the filter has characteristics indicative of a transmit filter of the repeater to shape the spectral properties of the transmit signal, wherein the carrier pilot signal is generated to have the same spectral properties as the transmit signal.

9. A pilot construction device to construct a pilot signal for use in a wireless repeater, the pilot signal being added to a transmit signal for transmission on a transmitting antenna of the repeater, the device comprising:

one or more means for generating a carrier pilot signal associated with a single carrier of the transmit signal, the carrier pilot signals generated by the one or more means being summed to generate the pilot signal, wherein each of the one or more means comprises;

means for providing a plurality of data symbols having a predetermined data structure as the carrier pilot signal;

means for scrambling the plurality of data symbols;

means for shaping spectral properties of the carrier pilot signal;

means for setting a power level of the carrier pilot signal relative to a power level of the transmit signal; and

means for inserting a cyclic prefix to the carrier pilot signal.

10. A method for constructing a pilot signal for use in a wireless repeater, the pilot signal being added to a transmit signal for transmission, the method comprising:

providing a plurality of data symbols having a predetermined data structure as a carrier pilot signal;

scrambling the plurality of data symbols;

shaping spectral properties of the carrier pilot signal using a filter;

setting a power level of the carrier pilot signal relative to a power level of the transmit signal; and

inserting a cyclic prefix to the carrier pilot signal to generate the carrier pilot signal for a single carrier, the pilot signal being formed from the carrier pilot signal of at least one carrier.

11. The method of claim 10, further comprising:

generating a carrier pilot signal for each of one or more carriers of the transmit signal; and

summing the carrier pilot signals for each carrier to generate the pilot signal.

12. The method of claim 10, wherein the predetermined data structure comprises an OFDM data structure.

13. The method of claim 10, wherein scrambling the plurality of data symbols comprises scrambling the plurality of data symbols using a scrambling sequence that imparts a unique identifier to the repeater.

14. The method of claim 10, further comprising:

measuring the power level of each carrier in the transmit signal; and

controlling the power level of the carrier pilot signal relative to the measured power level of the corresponding carrier in the transmit signal so that the power level of the carrier pilot signal tracks the power level of the corresponding carrier in the transmit signal.

15. The method of claim 14, further comprising:

after measuring the power level of each carrier in the transmit signal, filtering the measured power level values.

16. The method of claim 14, wherein setting a power level of the carrier pilot signal comprises setting the power level of the carrier pilot signal to a value lower than the measured power level of the corresponding carrier in the transmit signal.

17. The method of claim 16, wherein setting a power level of the carrier pilot signal comprises setting the power level of the carrier pilot signal to a value at least 20 dB lower than the measured power level of the corresponding carrier in the transmit signal.

18. The method of claim 10, wherein shaping spectral properties of the carrier pilot signal using a filter comprises shaping spectral properties of the carrier pilot signal using a filter has characteristics indicative of a transmit filter of the repeater for shaping the spectral properties of the transmit signal, the carrier pilot signal thus generated having the same spectral properties as the transmit signal.

19. A pilot signal construction unit to construct a pilot signal for use in a wireless repeater, the pilot signal to be added to a transmit signal for transmission, the device comprising:

one or more pilot generators, each pilot generator to generate a carrier pilot signal associated with a single carrier of the transmit signal, wherein the pilot signal construction unit is configured to construct the pilot signal by summing the carrier pilot signals generated by the one or more pilot generators, wherein each of the one or more pilot generators comprises;

a pilot symbol unit to provide a plurality of data symbols in frequency domain as the carrier pilot signal, one data symbol being associated with one tone;

a pilot scrambler to scramble the plurality of data symbols;

a pilot power shaper to scale the scrambled data symbols to adjust the power of the data symbols across the tones; and

an IFFT filter to transform the plurality of data symbol into the time domain;

a pilot power determination unit to set an average power level of the carrier pilot signal and a power level of the carrier pilot signal across the tones relative to a power level of the transmit signal; and

a cyclic prefix insertion unit to insert a cycle prefix to the carrier pilot signal.

20. The device of claim 19, wherein the pilot scrambler is configured to scramble the plurality of data symbols using a scrambling sequence that imparts a unique identifier to the repeater.

21. The device of claim 19, further comprising a power measurement unit to measure the power level of each carrier in the transmit signal, the pilot power determination unit configured to control the power level of the carrier pilot signal relative to the measured power level of the corresponding carrier in the transmit signal so that the power level of the carrier pilot signal tracks the power level of the corresponding carrier in the transmit signal.

22. The device of claim 21, wherein the power measurement unit comprises a filter to filter the measured power level values.

23. The device of claim 21, wherein the pilot power determination unit is configured to set the power level of the carrier pilot signal to a value lower than the measured power level of the corresponding carrier in the transmit signal.

24. The device of claim 23, wherein the pilot power determination unit is configured to set the power level of the carrier pilot signal at least 20 dB lower than the measured power level of the corresponding carrier in the transmit signal.

25. A pilot construction device to construct a pilot signal for use in a wireless repeater, the pilot signal being added to a transmit signal for transmission, the device comprising:

one or more means for generating a carrier pilot signal associated with a single carrier of the transmit signal, the carrier pilot signals generated by the one or more means being summed to generate the pilot signal, wherein each of the one or more means comprises;

means for providing a plurality of data symbols in frequency domain as the carrier pilot signal, one data symbol being associated with one tone;

means for scrambling the plurality of data symbols;

means for scaling the scrambled data symbols to adjust the power of the data symbols across the tones;

means for performing IFFT to transform the plurality of data symbol into the time domain;

means for setting an average power level of the carrier pilot signal and a power level of the carrier pilot signal across the tones relative to a power level of the transmit signal; and

means for inserting a cyclic prefix to the carrier pilot signal.

26. A method for constructing a pilot signal for use in a wireless repeater, the pilot signal being added to a transmit signal for transmission, the method comprising:

providing a plurality of data symbols in frequency domain as the carrier pilot signal, one data symbol being associated with one tone;

scrambling the plurality of data symbols;

scaling the scrambled data symbols to adjust the power of the data symbols across the tones;

performing IFFT to transform the plurality of data symbol into the time domain;

setting an average power level of the carrier pilot signal and a power level of the carrier pilot signal across the tones relative to a power level of the transmit signal; and

inserting a cyclic prefix to the carrier pilot signal to generate the carrier pilot signal for a single carrier, the pilot signal being formed from the carrier pilot signal of at least one carrier.

27. The method of claim 26, further comprising:

generating a carrier pilot signal for each of one or more carriers of the transmit signal; and

summing the carrier pilot signals for each carrier to generate the pilot signal.

28. The method of claim 26, wherein scrambling the plurality of data symbols comprises scrambling the plurality of data symbols using a scrambling sequence that imparts a unique identifier to the repeater.

29. The method of claim 26, further comprising:

measuring the power level of each carrier in the transmit signal; and

controlling the average power level and the power level of the carrier pilot signal relative to the measured power level of the corresponding carrier in the transmit signal so that the power level of the carrier pilot signal tracks the power level of the corresponding carrier in the transmit signal.

30. The method of claim 29, further comprising:

after measuring the power level of each carrier in the transmit signal, filtering the measured power level values.

31. The method of claim 29, wherein setting a power level of the carrier pilot signal comprises setting the power level of the carrier pilot signal to a value lower than the measured power level of the corresponding carrier in the transmit signal.

32. The method of claim 31, wherein setting a power level of the carrier pilot signal comprises setting the power level of the carrier pilot signal to a value at least 20 dB lower than the measured power level of the corresponding carrier in the transmit signal.