Mutual wlan and wan interference mitigation in unlicensed spectrum

Patent metadata

Field	Value
Publication number	US-2016182134-A1
Application number	US-201414574281-A
Country	US
Kind code	A1
Filing date	Dec 17, 2014
Priority date	Dec 17, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

The disclosure provides for interference mitigation for wireless signals in unlicensed spectrum. A wireless device may receive a combined signal including a first radio access technology (RAT) signal and a second RAT signal. The wireless device may generate, using a first RAT receiver in a first processing path, a channel estimate for the first RAT signal based on a previously decoded signal of the first RAT. The wireless device may reduce interference to the second RAT signal caused by the first RAT signal, in a second processing path, using the channel estimate. The wireless device may further decode the second RAT signal. The wireless device may remodulate the decoded signal using a transmitter to generate a remodulated second RAT signal. The remodulated second RAT signal may be canceled from the combined signal. The wireless device may decode a remaining portion of the combined signal including the first RAT signal.

First claim

What is claimed is:

1 . A method for interference mitigation for wireless signals, the method comprising:
receiving a combined signal including a first radio access technology (RAT) signal and a second RAT signal; generating, by a first RAT receiver in a first processing path, a channel estimate for the first RAT signal based on a previously decoded signal of the first RAT; and reducing interference to the second RAT signal caused by the first RAT signal, in a second processing path, using the channel estimate.

2 . The method of claim 1 , wherein the first RAT signal is a long-term evolution (LTE) signal in unlicensed spectrum and the second RAT signal is a Wi-Fi signal in unlicensed spectrum.

3 . The method of claim 1 , wherein reducing interference to the second RAT signal includes:
configuring a space-time filter in the second processing path based on the channel estimate; and filtering a plurality of streams of the combined signal to null the first RAT signal.

4 . The method of claim 3 , wherein the space-time filter is configured based on an orthogonal projection operation on the channel estimate.

5 . The method of claim 1 , wherein reducing interference to the second RAT signal includes:
weighting each stream of a plurality of streams of the combined signal using a covariance matrix based on the channel estimate; and combining, by a second RAT receiver in the second processing path, the plurality of streams using the weighting.

6 . The method of claim 5 , wherein weighting each stream of the plurality of streams of the combined signal includes determining zero-forcing coefficients using the covariance matrix, the zero-forcing coefficients weighting respective streams of the plurality of streams for a maximal ratio combining equalizer.

7 . The method of claim 5 , wherein weighting each stream of the plurality of streams of the combined signal includes generating an equalization matrix using the covariance matrix, the equalization matrix weighting each stream of the plurality of streams for minimum mean square error combining.

8 . The method of claim 5 , wherein weighting each stream of the plurality of streams of the combined signal includes minimizing a maximum likelihood metric based on the covariance matrix, a channel estimate of the second RAT signal, and the plurality of streams of the combined signal.

9 . The method of claim 1 , further comprising:
decoding, by a second RAT receiver in the second processing path, the second RAT signal after reducing the interference caused by the first RAT signal; remodulating, by a second RAT transmitter, the decoded second RAT signal to generate a remodulated second RAT signal; canceling the remodulated second RAT signal from the combined signal to generate a remaining portion including the first RAT signal; and decoding, by the first RAT receiver, the remaining portion.

10 . The method of claim 9 , further comprising delaying the combined signal from entering the first RAT receiver until the remodulated second RAT signal is canceled from the combined signal.

11 . The method of claim 9 , further comprising:
generating, by the second RAT receiver, a second channel estimate for the second RAT signal; and filtering, in the first processing path, the remaining portion of the combined signal based on the second channel estimate prior to decoding, the remaining portion of the combined signal.

12 . The method of claim 9 , further comprising:
remodulating, by a first RAT transmitter, the decoded first RAT signal to generate a remodulated first RAT signal; canceling, in the second processing path, the remodulated first RAT signal from the combined signal; and decoding, by the second receiver, a second remaining portion of the combined signal including a portion of the second RAT signal.

13 . The method of claim 1 , wherein the channel estimate includes timing information for the first RAT signal.

14 . An apparatus for interference mitigation for wireless signals, the apparatus comprising:
means for receiving a combined signal including a first radio access technology (RAT) signal and a second RAT signal; means for generating, in a first processing path, a channel estimate for the first RAT signal based on a previously decoded signal of the first RAT; and means for reducing, in a second processing path, interference to the second RAT signal caused by the first RAT signal using the channel estimate.

15 . The apparatus of claim 14 , wherein the means for reducing interference to the second RAT signal include a space-time filter in the second processing path configured based on the channel estimate to filter a plurality of streams of the combined signal to null the first RAT signal.

16 . The apparatus of claim 14 , wherein the means for reducing interference to the second RAT signal are configured to:
weight each stream of a plurality of streams of the combined signal using a covariance matrix based on the channel estimate; and combine the plurality of streams using the weighting.

17 . The apparatus of claim 14 , further comprising:
means for decoding, in the second processing path, the second RAT signal after reducing the interference caused by the first RAT signal; means for remodulating the decoded second RAT signal to generate a remodulated second RAT signal; means for canceling the remodulated second RAT signal from the combined signal in the first processing path to generate a remaining portion including the first RAT signal; and means for decoding the remaining portion.

18 . The apparatus of claim 17 , further comprising:
means for remodulating, by a first RAT transmitter, the decoded first RAT signal to generate a remodulated first RAT signal; means for canceling the remodulated first RAT signal from the combined signal; means for decoding a second remaining portion of the combined signal including a portion of the second RAT signal; and means for decoding the second remaining portion of the combined signal.

19 . An apparatus for interference mitigation for wireless signals comprising:
a radio front-end configured to receive a combined signal including a first radio access technology (RAT) signal and a second RAT signal; a first RAT receiver, in a first processing path, configured to generate a channel estimate for the first RAT signal based on a previously decoded signal of the first RAT; and a second RAT receiver, in a second processing path, configured to use the channel estimate to improve the second RAT signal by reducing interference caused by the first RAT signal to the second RAT signal.

20 . The apparatus of claim 19 , further comprising:
a second RAT transmitter configured to remodulate, a decoded second RAT signal produced by the second RAT receiver to generate a remodulated second RAT signal; and a cancellation filter configured to cancel the remodulated first RAT signal from the combined signal to generate a remaining portion including the first RAT signal, wherein the first RAT receiver is configured to decode the remaining portion.

21 . The apparatus of claim 20 , further comprising a delay buffer, in the first processing path, configured to delay the combined signal from entering the first RAT receiver until the remodulated second RAT signal is canceled from the combined signal.

22 . The apparatus of claim 20 , wherein the second RAT receiver is further configured to generate a second channel estimate for the second RAT sig

Assignees

• Qualcomm Inc

Inventors

• Kol Boaz
• Touboul Assaf
• Klein Aaron Elazar

Classifications

• H04W72/541

  using the level of interference · CPC title

• H04B7/0456 Primary

  Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting · CPC title

• H04W72/082

  Electricity · mapped topic

• H04L25/021

  Estimation of channel covariance · CPC title

• H04J11/0023 Primary

  Interference mitigation or co-ordination (direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541) · CPC title