Granted Patent B2

US 8,781,008 · App. 13/921,665 · Granted Jul 15, 2014

Inventors: Amir Eliaz (Moshav Ben Shemen, IL); Ilan Reuven (Ganey Tikva, IL)

Assignee: MagnaCom Ltd.

Abstract

Claims (78)

1. A method performed in a first electronic device, the method comprising:

mapping, using a modulation constellation, each of C′ bit sequences to a respective one of C′ symbols, where C′ is a number greater than one;

processing said C′ symbols to generate C′ inter-carrier correlated virtual subcarrier values;

decimating said C′ virtual subcarrier values down to C physical subcarrier values, C being an number less than C′;

transmitting said C physical subcarrier values on C orthogonal frequency division multiplexed (OFDM) subcarriers;

receiving a first message from a second electronic device;

in response to said first message, ceasing transmission of data on a particular one of said OFDM subcarriers;

receiving a second message from said second electronic device; and

in response to said second message, resuming transmission of data on said particular one of said OFDM subcarriers.

2. The method of claim 1 , wherein:

said transmitting is via a channel having a significant amount of nonlinearity;

said significant amount of nonlinearity degrades a performance metric in a receiver by less than 1 dB, relative to a perfectly linear channel; and

in a full response communication system, said significant amount of nonlinearity would degrade said performance metric by 1 dB or more, relative to a perfectly linear channel.

3. The method of claim 1 , wherein said modulation constellation is an N-QAM constellation, N being an integer.

4. The method of claim 1 , wherein said bit sequences are coded according to a forward error correction algorithm.

5. The method of claim 1 , wherein said processing comprises multiplication of said C′ symbols by a C′×C′ matrix.

6. The method of claim 1 , wherein said processing comprises filtering said C′ symbols using an array of filter tap coefficients.

7. The method of claim 6 , wherein said filtering comprises cyclic convolution.

8. The method of claim 7 , wherein said filtering comprises multiplication by a circulant matrix populated with said filter tap coefficients.

9. The method of claim 6 , wherein said filter tap coefficients are selected based on signal-to-noise ratio (SNR) measurements fed back from said second electronic device that receives communications from said first electronic device.

10. The method of claim 1 , comprising:

subsequent to said receiving said first message and prior to receiving said second message, transmitting a pilot signal on said particular one of said physical subcarriers.

11. The method of claim 1 , wherein said ceasing transmission of data on said particular one of said physical subcarriers comprises one or more of:

changing a value of said number C; and

changing a value of said number C′.

12. The method of claim 1 , wherein:

an OFDM symbol period for said transmitting is approximately (C+Δ)/BW; and

each of said C OFDM subcarriers has a bandwidth of approximately BW/(C+Δ),

where BW is a bandwidth used for said transmitting, and

Δ is the number of non-data-carrying OFDM subcarriers within said bandwidth BW.

13. The method of claim 1 , comprising, prior to said transmitting, transforming said C physical subcarrier values to C+Δ+P time-domain samples using an inverse fast Fourier transform, where Δ is the number of non-data-carrying OFDM subcarriers and P is cyclic prefix size.

14. A method performed in a first electronic device, the method comprising:

mapping, using a modulation constellation, each of C′ bit sequences to a respective one of C′ symbols, where C′ is a number greater than one;

processing said C′ symbols to generate C′ inter-carrier correlated virtual subcarrier values;

decimating said C′ virtual subcarrier values down to C physical subcarrier values, where C is a number less than C′;

transmitting said C physical subcarrier values on C orthogonal frequency division multiplexed (OFDM) subcarriers, wherein:

said processing comprises multiplication of said C′ symbols by a matrix; and

row or column length of said matrix is an integer less than C′, such that said multiplication results in said decimating of said C′ symbols.

15. A method performed in a first electronic device, the method comprising:

mapping, using a modulation constellation, each of C′ bit sequences to a respective one of C′ symbols, where C′ is a number greater than one;

processing said C′ symbols to generate C′ inter-carrier correlated virtual subcarrier values;

decimating said C′ virtual subcarrier values down to C physical subcarrier values, where C is a number less than C′;

transmitting said C physical subcarrier values on C orthogonal frequency division multiplexed (OFDM) subcarriers; and

configuring said processing based on feedback indicating a symbol error rate, bit error rate, and/or packet error rate, wherein said configuring seeks to achieve a target symbol error rate, target bit error rate, and/or target packet error rate in presence of additive white Gaussian noise and a dynamic frequency selective fading channel.

16. A method performed in a first electronic device, the method comprising:

mapping, using a modulation constellation, each of C′ bit sequences to a respective one of C′ symbols, where C′ is a number greater than one;

processing said C′ symbols to generate C′ inter-carrier correlated virtual subcarrier values, wherein said processing comprises filtering said C′ symbols using an array of filter taps;

decimating said C′ virtual subcarrier values down to C physical subcarrier values, where C is a number less than C′;

transmitting said C physical subcarrier values on C orthogonal frequency division multiplexed (OFDM) subcarriers, wherein said filtering comprises cyclic convolution; and

selecting said filter tap coefficients based on feedback indicating a symbol error rate, bit error rate, and/or packet error rate, wherein said selecting seeks to achieve one or more of: a target symbol error rate, a target bit error rate, and/or a target packet error rate in presence of one or more of: additive white Gaussian noise, dynamic frequency selective fading channel, and non-linear distortion.

17. An electronic device comprising:

a filter circuit operable to process a quantity, C′, of symbols to generate C′ virtual subcarrier values, wherein there is inter-carrier correlation among said C′ virtual subcarriers values, and C′ is a number;

a decimation circuit operable to decimate said C′ virtual subcarrier values down to C physical subcarrier values, wherein C is a number less than C′;

a transform circuit operable transform said C physical subcarrier values to C+Δ+P time-domain samples, where Δ is the number of non-data-carrying OFDM subcarriers and P is cyclic prefix size;

a front-end circuit operable to transmit said time-domain samples into a channel,

wherein:

said filter circuit is configured to perform a cyclic convolution of said C′ symbols;

said cyclic convolution comprises multiplication by a circulant matrix populated with filter tap coefficients and zeros; and

said decimation is realized by said circulant matrix having a dimension less than C′.

18. The electronic device of claim 17 , wherein each of said C′ symbols is an N-QAM symbol, N being an integer.

19. The electronic device of claim 17 , wherein said electronic device is operable to transmit tap coefficients of said filter circuit to a receiver.

20. The electronic device of claim 17 , wherein said electronic device is operable to transmit coefficients of said filter circuit such that a receiver may receive the coefficients and update its controlled combined inter-symbol correlation and/or inter-subcarrier interference (ISCI) model.

21. The electronic device of claim 17 , wherein said electronic device is operable to transmit settings of said front-end circuit that enable a receiver to determine a nonlinear distortion model.

22. An electronic device comprising:

a filter circuit operable to process a quantity, C′, of symbols to generate C′ virtual subcarrier values, wherein:

there is inter-carrier correlation among said C′ virtual subcarriers values, and C′ is a number; and

said filter circuit is operable to select said filter tap coefficients based on feedback indicating one or more of symbol error rate, bit error rate, and/or packet error rate to achieve one or more target performance metrics in presence of additive white Gaussian noise and a dynamic frequency selective fading channel;

a decimation circuit operable to decimate said C′ virtual subcarrier values down to C physical subcarrier values, where C is a number less than C′;

a transform circuit operable transform said C physical subcarrier values to C+Δ+P time-domain samples, where Δ is a number equal to the number of non-data-carrying subcarriers and P is cyclic prefix size; and

a front-end circuit operable to transmit said time-domain samples into a channel.

23. An electronic device comprising:

a filter circuit operable to process a quantity, C′, of symbols to generate C′ virtual subcarrier values, wherein there is inter-carrier correlation among said C′ virtual subcarriers values, and C′ is a number;

a decimation circuit operable to decimate said C′ virtual subcarrier values down to C physical subcarrier values, where C is a number less than C′;

a transform circuit operable transform said C physical subcarrier values to C+Δ+P time-domain samples, where Δ is the number of non-data-carrying OFDM subcarriers and P is cyclic prefix size; and

a front-end circuit operable to transmit said time-domain samples into a channel, wherein said electronic device is operable to:

in response to a first message from a second electronic device, cease transmission of data on a particular one of said OFDM subcarriers; and

in response to a second message from said second electronic device, resume transmission of data on said particular one of said OFDM subcarriers.

24. The electronic device of claim 23 , wherein said electronic device is operable to, subsequent to said cessation of transmission of data on said particular one of said physical subcarriers and prior to resuming transmission of data on said particular one of said physical subcarriers, transmit a pilot signal on said particular one of said physical subcarriers.

Assignments (4)

Continuity (8)