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METHODS AND SYSTEMS FOR CREST FACTOR REDUCTION IN MULTI-CARRIER MULTI-CHANNEL ARCHITECTURES

2014
Online Patent
Zugriff:
View record in USPTO Patent Applications (Volltext)

Crest factor reduction (CFR) can be performed on the various carriers of a multi-carrier multi-channel signal prior to modulation and/or beamforming operations in order to improve signal-to-noise ratios (SNRs) in the resulting wireless communication. More specifically, clipping noise is introduced into each of the individual carrier signals prior to application of the beamforming weight vectors, as well as prior to carrier modulation, thereby causing the beamforming weight vectors to be applied to both the signal and the clipping noise. As a result, variations between the signal antenna pattern and the clipping noise antenna pattern are reduced, which mitigates and/or reduces low SNR spatial locations in which the signal would have been drowned out by the clipping noise under conventional CFR.

Titel:
METHODS AND SYSTEMS FOR CREST FACTOR REDUCTION IN MULTI-CARRIER MULTI-CHANNEL ARCHITECTURES
Link:
Veröffentlichung: 2014
Medientyp: Patent
Sonstiges:
  • Nachgewiesen in: USPTO Patent Applications
  • Sprachen: English
  • Document Number: 20140269984
  • Publication Date: September 18, 2014
  • Appl. No: 13/802028
  • Application Filed: March 13, 2013
  • Assignees: FUTUREWEI TECHNOLOGIES, INC. (Plano, TX, US)
  • Claim: 1. A method for reducing a peak-to-average (PAR) ratio of a multi-carrier wireless signal, the method comprising: generating a first carrier signal and a second carrier signal; introducing clipping noise into the first carrier signal and the second carrier signal, thereby obtaining a first clipped carrier signal and a second clipped carrier signal; and modulating the first clipped carrier signal and the second clipped carrier signal to obtain a modulated carrier signal.
  • Claim: 2. The method of claim 1 further comprising: applying beamforming weights to the first clipped carrier signal and the second clipped carrier signal prior to modulating the first clipped carrier signal and the second clipped carrier signal, wherein the clipping noise is introduced into both the first carrier signal and the second carrier signal prior to application of the beamforming weights.
  • Claim: 3. The method of claim 2, wherein a different set of beamforming weights is applied to the first clipped carrier signal than is applied to the second clipped carrier signal.
  • Claim: 4. The method of claim 1, wherein introducing clipping noise into the first carrier signal and the second carrier signal comprises: introducing a first clip noise into the first carrier signal to obtain the first clipped carrier signal; and introducing a second clip noise into the second carrier signal to obtain a second clipped carrier signal.
  • Claim: 5. The method of claim 1, further comprising transmitting the modulated carrier signal over a plurality of a wireless interfaces, wherein the modulated carrier signal comprises a plurality of element signals, and wherein each of the plurality of element signals are emitted over a different one of the plurality of wireless interfaces.
  • Claim: 6. The method of claim 4, further comprising determining the first clip noise and the second clip noise by: projecting element signals prior to the modulating the step, the projected element signals corresponding to the plurality of element signals in the modulated carrier signal; identifying one of the projected element signals having a highest amplitude; determining the first clip noise and second clip noise in accordance with the estimated element signal having the highest amplitude.
  • Claim: 7. The method of claim 6, wherein determining the first clip noise and second clip noise in accordance with the projected element signal having the highest amplitude comprises: determining a difference between an amplitude of the estimated element signal and an amplitude threshold, the difference comprising a first component attributable to the first carrier signal and a second component attributable to the second carrier signal; determining the first clip noise in accordance with the first component; and determining the second clip noise in accordance with the second component.
  • Claim: 8. An apparatus for reducing a peak-to-average (PAR) ratio of a multi-carrier wireless signal, the apparatus comprising: a processor; and a computer readable storage medium storing programming for execution by the processor, the programming including instructions to: generate a first carrier signal and a second carrier signal; introduce clipping noise into the first carrier signal and the second carrier signal, thereby obtaining a first clipped carrier signal and a second clipped carrier signal; and modulate the first clipped carrier signal and the second clipped carrier signal to obtain a modulated carrier signal.
  • Claim: 9. The apparatus of claim 8, wherein the clipping noise is introduced into the first carrier signal and the second carrier signal prior to the modulating step.
  • Claim: 10. The apparatus of claim 10, wherein the programming further includes instructions to: apply beamforming weights to the first clipped carrier signal and the second clipped carrier signal prior to modulating the first clipped carrier signal and the second clipped carrier signal, wherein the clipping noise is introduced into the first carrier signal and the second carrier signal prior to application of the beamforming weights.
  • Claim: 11. The apparatus of claim 10, wherein a different set of beamforming weights are applied to the first clipped carrier signal than are applied to the second clipped carrier signal.
  • Claim: 12. The apparatus of claim 10, wherein the programming further includes instructions to transmit the modulated carrier signal over a plurality of a wireless interfaces, wherein each of the plurality of element signals are emitted over a different one of the plurality of wireless interfaces.
  • Claim: 13. The apparatus of claim 10, wherein the instructions to introduce clipping noise into the first carrier signal and the second carrier signal includes instructions to: introduce a first clip noise into the first carrier signal to obtain the first clipped carrier signal; and introduce a second clip noise into the second carrier signal to obtain a second clipped carrier signal.
  • Claim: 14. The apparatus of claim 13, wherein the programming further includes instructions to determine the first clip noise and the second clip noise, the instruction to determine the first clip noise and the second clip noise including instructions to: project element signals prior to the modulating the step, the projected element signals corresponding to the plurality of element signals in the modulated carrier signal; identify one of the projected element signals having a highest amplitude; determine the first clip noise and second clip noise in accordance with the estimated element signal having the highest amplitude.
  • Claim: 15. The apparatus of claim 14, wherein the instructions to determine the first clip noise and second clip noise includes instructions to: determine a difference between an amplitude of the estimated element signal and an amplitude threshold, the difference comprising a first component attributable to the first carrier signal and a second component attributable to the second carrier signal; determine the first clip noise in accordance with the first component; and determine the second clip noise in accordance with the second component.
  • Claim: 16. An apparatus comprising: a modulating module; a first carrier generating module configured to generate a first carrier signal; a second carrier generating module configured to generate a second carrier signal; a first noise clipping module positioned between the first carrier generating module and the modulating module, the first noise clipping module configured to: receive a first carrier signal; introduce a first clip noise into the first carrier signal to obtain the first clipped carrier signal; and forward the first clipped carrier signal to the modulating module; and a second noise clipping module positioned in between the second carrier generating module and the modulating module, the second noise clipping module configured to: receive the second carrier signal; introduce a second clip noise into the second carrier signal to obtain a second clipped carrier signal; and forward the second clipped carrier signal to the modulating module, wherein the modulating module is configured to combine the first clipped carrier signal with the second clipped carrier signal to obtain a modulated carrier signal.
  • Claim: 17. The apparatus of claim 16, further comprising a transmitting module coupled to the modulating module, the transmitting module configured to transmit the modulated carrier signal over a plurality of a wireless interfaces, wherein the modulated carrier signal comprises a plurality of element signals, and wherein the modulated signal is transmitted over the plurality of wireless interfaces such that each of the plurality of element signals are emitted over a different one of the plurality of wireless interfaces.
  • Claim: 18. The apparatus of claim 16 further comprising a clip noise calculation module coupled to the first clip noise module and the second clip noise module, the clip noise calculating module configured to: project element signals corresponding to the plurality of element signals in the modulated carrier signal; identify one of the projected element signals having a highest amplitude; determine the first clip noise and second clip noise in accordance with the estimated element signal having the highest amplitude; provide the first clip noise signal to the first clip noise module; and provide the second clip noise signal to the second clip noise module.
  • Claim: 19. The apparatus of claim 18, wherein determining the first clip noise and second clip noise comprises: determine a difference between an amplitude of the estimated element signal and an amplitude threshold, the difference comprising a first component attributable to the first carrier signal and a second component attributable to the second carrier signal; determine the first clip noise in accordance with the first component attributable to the first carrier signal; and determine the second clip noise in accordance with the second component attributable to the second carrier signal.
  • Claim: 20. The apparatus of claim 16, wherein the modulating module, the first noise clipping module, and the second noise clipping module are constructed using field programmable gate arrays.
  • Claim: 21. The apparatus of claim 16, wherein the modulating module, the first noise clipping module, and the second noise clipping module are constructed using application-specific integrated circuits (ASICs).
  • Current U.S. Class: 375/296
  • Current International Class: 04

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