Methods and devices for interference variance estimation and interference cancellation

Patent metadata

Field	Value
Publication number	US-9794097-B2
Application number	US-201514700382-A
Country	US
Kind code	B2
Filing date	Apr 30, 2015
Priority date	Jun 24, 2014
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

An interference variance estimation method includes receiving a composite sample comprising a sample of a first OFDM transmission scheme interfered by out-of-band interference of a second OFDM transmission scheme; determining for each of the resource elements of the first transmission scheme a power estimate of the out-of-band interference; and filtering the power estimates over subcarriers corresponding to a same symbol, wherein weights of the filtering are based on a correlation property of the power estimates with respect to the subcarriers. An interference cancellation method includes: receiving the composite sample; determining a first estimate of the out-of-band interference with respect to non-data bearing subcarriers; determining a second estimate of the out-of-band interference with respect to data bearing subcarriers based on the first estimate; and cancelling the out-of-band interference based on the composite signal and the second estimate.

First claim

The invention claimed is:

1. An interference variance estimation method, comprising:
receiving a composite sample comprising a sample of a first OFDM transmission scheme interfered by an out-of-band interference of a second OFDM transmission scheme, the first OFDM transmission scheme comprising a plurality of resource elements arranged in a symbol-subcarrier grid;
determining, for each of the plurality of resource elements, a power estimate of the out-of-band interference; and
filtering the plurality of power estimates by using a filter length of 17 over a plurality of subcarriers corresponding to a same symbol of the symbol-subcarrier grid to obtain the interference variance, wherein weights of the filtering are based on a correlation property of the plurality of power estimates with respect to the plurality of subcarriers.

2. The method of claim 1 ,
wherein the first OFDM transmission scheme comprises a cellular transmission scheme; and
wherein the second OFDM transmission scheme comprises a wireless network transmission scheme.

3. The method of claim 1 , comprising:
time-averaging the interference variance of a particular subcarrier over a plurality of symbols of the symbol-subcarrier grid to obtain an estimate of the interference variance for the particular subcarrier.

4. The method of claim 3 , comprising:
time-averaging the interference variance based on a sliding window.

5. The method of claim 1 , comprising:
filtering the plurality of power estimates over a plurality of adjacent sets of subcarriers of the symbol-subcarrier grid.

6. The method of claim 1 , comprising:
determining the weights of the filtering based on an MMSE algorithm.

7. The method of claim 1 , comprising:
determining a hypothesis of the sample of the first OFDM transmission scheme based on a distance between the composite sample and a set of modulation symbols of the first OFDM transmission scheme.

8. The method of claim 7 , comprising:
determining for each of the resource elements the power estimate of the out-of-band interference based on the received composite sample, the hypothesis of the sample of the first OFDM transmission scheme and an estimated channel.

9. The method of claim 1 ,
wherein a correlation coefficient of power estimates corresponding to a predetermined subcarrier distance of 50 indicates that the power estimates are totally correlated.

10. The method of claim 1 ,
wherein a distribution of the out-of-band interference on each subcarrier of the first OFDM transmission scheme is Gaussian with zero mean.

11. An interference variance estimator, comprising:
a receiving port configured to receive a composite sample comprising a sample of a first OFDM transmission scheme interfered by an out-of-band interference of a second OFDM transmission scheme, the first OFDM transmission scheme comprising a plurality of resource elements arranged in a symbol-subcarrier grid;
a first circuit configured to determine, for each of the resource elements, a power estimate of the out-of-band interference; and
a second circuit configured to filter a plurality of power estimates by using a filter length of 17 over subcarriers corresponding to a same symbol of the symbol-subcarrier grid to obtain the interference variance, wherein weights of the filtering are based on a correlation property of the plurality of power estimates with respect to the subcarriers.

12. The interference variance estimator of claim 11 ,
wherein the second circuit comprises an MMSE filter configured to filter the power estimates.

Assignees

• Intel Ip Corp

Inventors

• Ibrahim Ahmed S
• Marzban Mohamed F
• Amin Belal S

Classifications

• H04L27/2601 Primary

  Multicarrier modulation systems · CPC title

• H04W24/08

  Testing, {supervising or monitoring} using real traffic · CPC title

• H04L5/0007

  the frequencies being orthogonal, e.g. OFDM(A) or DMT · CPC title

• H04W24/02 Primary

  Arrangements for optimising operational condition · CPC title