Precoding in faster-than-nyquist communications

Patent metadata

Field	Value
Publication number	US-2016365992-A1
Application number	US-201514423017-A
Country	US
Kind code	A1
Filing date	Feb 18, 2015
Priority date	Feb 18, 2015
Publication date	Dec 15, 2016
Grant date	—

Abstract

There is provided a method for processing a set of input symbols. The method is performed by a transmitter. The method comprises acquiring a set of input symbols. The method comprises generating a set of precoded symbols from the set of input symbols by subjecting the set of input symbols to a coding vector. The method comprises generating a transmission signal comprising a sequence of pulse forms from the set of precoded symbols by pulse shaping the set of precoded symbols. The coding vector is based on a model vector modelling intersymbol interference experienced by the pulse forms.

First claim

1 . A method for processing a set of input symbols a, the method being performed by a transmitter, the method comprising:
acquiring a set of input symbols a; generating a set of precoded symbols â from the set of input symbols a by subjecting the set of input symbols a to a coding vector g MH ; and generating a transmission signal s comprising a sequence of pulse forms gT from the set of precoded symbols â by pulse shaping the set of precoded symbols â; wherein the coding vector g MH is based on a model vector g ISI modelling intersymbol interference experienced by the pulse forms gT.

2 . The method according to claim 1 , wherein â=g MH a.

3 . The method according to claim 1 , wherein the coding vector g MH is based on the negative square root of the model vector g ISI .

4 . The method according to claim 1 , wherein the coding vector g MH is determined from the model vector g ISI according to:
g MH =IFFT(√{square root over (|FFT( g ISI ) −1 |)})
where FFT and IFFT denote Fast Fourier Transform and Inverse Fourier Transform, respectively.

5 . The method according to claim 1 , wherein the model vector g ISI is defined by the inner product of one pulse form in the sequence of pulse forms gT and coefficients of a matched filter which is matched to the sequence of pulse forms.

6 . The method according to claim 5 , wherein the inner product is calculated at integer multiples of ±ρT, where T is an intermediate time for orthogonal pulse transmission with respect to the pulse form gT, and 0<ρ<1 is a scale factor.

7 . The method according to claim 1 , wherein the model vector g ISI is defined by the center-most row vector of a Gram matrix G of the set of input symbols a.

8 . The method according to claim 7 , wherein the Gram matrix G is defined by the inner product of all pulse forms in the sequence of pulse forms gT and coefficients of a matched filter which is matched to the sequence of pulse forms.

9 . The method according to claim 1 , wherein the pulse forms in the sequence of pulse forms are separated by a time distance ρT, where T is an intermediate time for orthogonal pulse transmission with respect to the pulse form gT, and 0<ρ<1 is a scale factor.

10 . The method according to claim 9 , wherein ρ is determined such as (1+β)ρ>1, where 0.1<β<0.3.

11 . The method according to claim 10 , wherein β=0.22.

12 . The method according to claim 1 , further comprising:
transmitting the transmission signal.

13 . A method for processing a reception signal r, the method being performed by a receiver, the method comprising:
receiving a reception signal r representing a set of input symbols a, the reception signal comprising a sequence of pulse forms gT; generating a set of sampled symbols y by subjecting the reception signal r to a matched receiver filter; and generating a set of decoded symbols ŷ from the set of sampled symbols y by subjecting the set of sampled symbols y to a coding vector g MH ; wherein the coding vector g MH is based on a model vector g ISI modelling intersymbol interference experienced by the pulse forms gT.

14 . The method according to claim 13 , wherein ŷ=g MH y.

15 . The method according to claim 13 , wherein generating the set of decoded symbols ŷ further comprises:
subjecting the set of sampled symbols y, after having been subjected to the coding vector g MH , to an adaptive equalizer.

16 . The method according to claim 13 , wherein the coding vector g MH is based on the negative square root of the model vector g ISI .

17 . The method according to claim 13 , wherein the coding vector g MH is determined from the model vector g ISI according to:
g MH =IFFT(√{square root over (|FFT( g ISI ) −1 |)})
where FFT and IFFT denote Fast Fourier Transform and Inverse Fourier Transform, respectively.

18 . The method according to claim 13 , wherein the model vector g ISI is defined by the inner product of one pulse form in the sequence of pulse forms gT and coefficients of a matched filter which is matched to the sequence of pulse forms.

19 . The method according to claim 18 , wherein the inner product is calculated at integer multiples of ±ρT, where T is an intermediate time for orthogonal pulse transmission with respect to the pulse form gT, and 0<ρ<1 is a scale factor.

20 . The method according to claim 13 , wherein the pulse forms in the sequence of pulse forms are separated by a time distance ρT, where T is an intermediate time for orthogonal pulse transmission with respect to the pulse form gT, and 0<ρ<1 is a scale factor.

21 . The method according to claim 20 , wherein ρ is determined such as (1+β)ρ>1, where 0.1<β<0.3.

22 . The method according to claim 21 , wherein β=0.22.

23 . A transmitter for processing a set of input symbols a, the transmitter comprising a processing unit, the processing unit being configured to cause the transmitter to:
acquire a set of input symbols a; generate a set of precoded symbols â from the set of input symbols a by subjecting the set of input symbols a to a coding vector g MH ; and generate a transmission signal s comprising a sequence of pulse forms gT from the set of precoded symbols â by pulse shaping the set of precoded symbols â; wherein the coding vector g MH is based on a model vector g ISI modelling intersymbol interference experienced by the pulse forms gT.

24 . A receiver for processing a reception signal r, the receiver comprising a processing unit, the processing unit being configured to cause the receiver to:
receive a reception signal r representing a set of input symbols a, the reception signal comprising a sequence of pulse forms gT; generate a set of sampled symbols y by subjecting the reception signal r to a matched receiver filter; and generate a set of decoded symbols ŷ from the set of sampled symbols y by subjecting the set of sampled symbols y to a coding vector g MH ; wherein the coding vector g MH is based on a model vector g ISI modelling intersymbol interference experienced by the pulse forms gT.

25 . A computer program for processing a set of input symbols a, the computer program comprising computer code which, when run on a processing unit of a transmitter, causes the transmitter to:
acquire a set of input symbols a; generate a set of precoded symbols â from the set of input symbols a by subjecting the set of input symbols a to a coding vector g MH ; and generate a transmission signal s comprising a sequence of pulse forms gT from the set of precoded symbols â by pulse shaping the set of precoded symbols â; wherein the coding vector g MH is based on a model vector g ISI modelling intersymbol interference experienced by the pulse forms gT.

26 . A computer program for processing a reception signal r, the computer program comprising computer code which, when run on a processing unit of a receiver, causes the receiver to:
receive a reception signal r representing a set of input symbols a, the reception signal comprising a sequence of pulse forms gT; generate a set of sampled symbols y by subjecting the reception signal r to a matched receiver filter; and generate a set of decoded symbols ŷ from the set of sampled symbols y by subjecting the set of sampled symbols y to a coding vector g MH ; wherein the coding vector g MH is based on a model vector g ISI modelling intersymbol interference experienced by the pulse forms gT.

Assignees

• ERICSSON TELEFON AB L M (publ)

Inventors

• Sjödin Martin

Classifications

• H04L25/03343 Primary

  Arrangements at the transmitter end · CPC title

• H04L25/03006 Primary

  Arrangements for removing intersymbol interference · CPC title

• H04L43/028

  by filtering · CPC title

• H04B7/0456

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

• H04L25/497

  by correlative coding, e.g. partial response coding or echo modulation coding {transmitters and receivers for partial response systems (transversal equalizers at the transmitter end H04L25/03343)} · CPC title