US 8,804,876 B2Granted

Enhanced modulation detection

AssigneeQUALCOMM Incorporated

InventorsDivaydeep Sikri, Nico De Laurentiis, Hassan Rafique, Lukasz Bednarz, Philip Children

Life of this patent

Estimating the term…

Loading patent…

Abstract

An apparatus is provided for demodulating a block, the block including a plurality of bursts. The apparatus comprises a demodulator configured to demodulate the plurality of bursts and a modulation detector configured to detect a modulation scheme for a current burst in the plurality of bursts and to determine whether there is a high probability that the detected modulation scheme is correct. The modulation detector instructs the demodulator to demodulate each burst subsequent to the current burst in the plurality of bursts based on the detected modulation scheme when the modulation detector determines a high probability that the modulation scheme is correct.

Claims31

Dependent claims

A method for demodulating a block at a receiver, the block including a plurality of bursts, the method comprising:

detecting a modulation scheme for a current burst in the plurality of bursts, wherein a burst comprises a data symbol portion and a training sequence portion;
determining whether there is a high probability that the detected modulation scheme is correct, wherein the determining whether there is a high probability that the detected modulation scheme is correct comprises:
demodulating the current burst based on the detected modulation scheme;
estimating a burst signal-to-noise ratio (SNR), wherein estimating the burst SNR comprises:
estimating data symbols of the current burst based on the demodulated current burst;
computing first reconstructed samples by convolving the data symbol estimates with channel estimates;
computing second reconstructed samples by convolving the training sequence portion with the channel estimates;
estimating a noise power by subtracting the first reconstructed samples from the data symbol portion of the current burst and subtracting the second reconstructed samples from the training sequence portion of the demodulated current burst;
and
estimating the burst SNR based on the noise power estimate;
and
determining a high probability that the detected modulation scheme is correct if the burst SNR estimate is above a threshold;
and
demodulating each burst subsequent to the current burst in the plurality of bursts based on the detected modulation scheme when there is a high probability that the detected modulation scheme is correct.

11 more elements

An apparatus for demodulating a block, the block including a plurality of bursts, comprising:

a demodulator configured to demodulate the plurality of bursts, wherein a burst comprises a data symbol portion and a training sequence portion;
a modulation detector configured to:
detect a modulation scheme for a current burst in the plurality of bursts;
determine whether there is a high probability that the detected modulation scheme is correct;
and
instruct the demodulator to demodulate each burst subsequent to the current burst in the plurality of bursts based on the detected modulation scheme when the modulation detector determines a high probability that the detected modulation scheme is correct;
a burst signal-to-noise ratio (SNR) estimator configured to:
receive a demodulation of the current burst based on the detected modulation scheme from the demodulator;
estimate data symbols for the current burst based on the demodulation of the current burst;
compute first reconstructed samples by convolving the data symbol estimates with channel estimates;
compute second reconstructed samples by convolving the training sequence portion with the channel estimates;
estimate a noise power by subtracting the first reconstructed samples from the data symbol portion of the current burst and subtracting the second reconstructed samples from the training sequence portion of the received demodulated current burst;
and
estimating the burst SNR based on the noise power estimate;
and
a processing unit configured to:
compare the burst SNR estimate to a threshold;
and
determine a high probability that the detected modulation scheme is correct when the burst SNR estimate is above the threshold.

16 more elements

An apparatus for demodulating a block at a receiver, the block including a plurality of bursts, comprising:

means for detecting a modulation scheme for a current burst in the plurality of bursts, wherein a burst comprises a data symbol portion and a training sequence portion;
means for demodulating the plurality of bursts;
and
means for determining whether there is a high probability that the detected modulation scheme is correct, wherein:
the means for demodulating is configured to demodulate each burst subsequent to the current burst in the plurality of bursts based on the detected modulation scheme when the means for determining determines a high probability that the detected modulation scheme is correct, and
the means for determining whether there is a high probability that the detected modulation scheme is correct comprises:
means for receiving a demodulated current burst based on the detected modulation scheme from the means for demodulating;
means for estimating a burst signal-to-noise ratio (SNR), wherein the means for estimating the burst SNR comprises:
means for estimating data symbols of the demodulated current burst;
means for computing first reconstructed samples by convolving the data symbol estimates with channel estimates,
means for computing second reconstructed samples by convolving the training sequence portion with the channel estimates;
the current burst, and the training sequence portion of the demodulated current burst;
means for estimating a noise power by subtracting the first reconstructed samples from the data symbol portion of the current burst and subtracting the second reconstructed samples from the training sequence portion of the demodulated current burst;
and
means for estimating the burst SNR based on the noise power estimate;
means for comparing the burst SNR estimate to a threshold;
and
means for determining a high probability that the detected modulation scheme is correct if the burst SNR estimate is above the threshold.

15 more elements

A non-transitory machine-readable medium having instructions stored thereon, the instructions being executable by one or more processors and the instructions comprising code for:

detecting a modulation scheme for a current burst in the plurality of bursts of a block, wherein a burst comprises a data symbol portion and a training sequence portion;
determining whether there is a high probability that the detected modulation scheme is correct;
and
demodulating each burst subsequent to the current burst in the plurality of bursts based on the detected modulation scheme when there is a high probability that the detected modulation scheme is correct, wherein
determining whether there is a high probability that the detected modulation scheme is correct comprises:
demodulating the current burst based on the detected modulation scheme, estimating a burst signal-to-noise ratio (SNR);
comparing the burst SNR estimate to a threshold;
and
determining a high probability that the detected modulation scheme is correct if the burst SNR estimate is above the threshold, wherein the code for estimating the burst SNR comprises code for:
estimating data symbols of the current burst based on the demodulated current burst;
computing first reconstructed samples by convolving the data symbol estimates with channel estimates;
computing second reconstructed samples by convolving the training sequence portion with the channel estimates;
estimating a noise power by subtracting the first reconstructed samples from the data symbol portion of the current burst and subtracting the second reconstructed samples from the training sequence portion of the demodulated current burst;
and
estimating the burst SNR based on the noise power estimate.

12 more elements

An apparatus for demodulating a block, the block including a plurality of bursts, comprising:

at least one processor configured to:
detect a modulation scheme for a current burst in the plurality of bursts, wherein a burst comprises a data symbol portion and a training sequence portion,
instruct a demodulator to demodulate the current burst based on the detected modulation scheme,
estimate data symbols of the current burst based on the demodulated current burst;
compute first reconstructed samples by convolving the data symbol estimates with channel estimates;
compute second reconstructed samples by convolving the training sequence portion with the channel estimates;
estimate a noise power by subtracting the first reconstructed samples from the data symbol portion of the current burst and subtracting the second reconstructed samples from the training sequence portion of the demodulated current burst;
estimate a burst signal-to-noise ratio (SNR) based on the noise power estimate;
compare the burst SNR estimate to a threshold;
determine whether there is a high probability that the detected modulation scheme is correct if the burst SNR estimate is above the threshold, and
instruct the demodulator to demodulate each burst subsequent to the current burst in the plurality of bursts based on the detected modulation scheme when the at least one processor determines a high probability that the detected modulation scheme is correct.

8 more elements

Dependencies are inferred from the claim text.