Pre-coding in a faster-than-Nyquist transmission system

Patent metadata

Field	Value
Publication number	US-9838230-B2
Application number	US-201415101047-A
Country	US
Kind code	B2
Filing date	Dec 5, 2014
Priority date	Dec 9, 2013
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

The invention refers to faster than Nyquist communication system wherein a set of symbols is conveyed from a transmitter ( 21 ) to a receiver ( 23 ), wherein the transmitter ( 21 ) and the receiver ( 23 ) are coupled by means of a transmission channel ( 22 ), comprising a precoder ( 210 ) adapted for generating a set of precoded symbols from a set of input symbols by performing a matrix operation with a precoding matrix, a pulse filter ( 212 ) adapted for generating a transmission signal to be transmitted over the transmission channel ( 22 ) as a function of the precoded symbols, a receiving filter ( 230 ) adapted for generating a set of sampled symbols as a function of the transmission signal and noise added by the transmission channel, and a decoder ( 232 ) adapted for generating a set of decoded symbols as a function of the set of sampled symbols, wherein the elements of the precoding matrix are dependent on a property of the pulse filter ( 212 ), The invention further refers to a transmitter, a receiver and corresponding methods, and to a user equipment and a base station.

First claim

The invention claimed is:

1. A faster than Nyquist communication system adapted for conveying a set of symbols from a transmitter to a receiver, wherein the transmitter and the receiver are coupled by means of a transmission channel, comprising the following circuits:
a precoder configured to generate a set of precoded symbols from a set of input symbols by performing a matrix operation with a precoding matrix;
a pulse filter configured to generate a transmission signal to be transmitted over the transmission channel as a function of the precoded symbols, the transmission signal comprising a sequence of pulses having a pulse form g T , wherein the pulses are separated by a time distance ρT, wherein T is an intermediate time for orthogonal pulse transmission with respect to the pulse form g T , and ρ is an acceleration factor having a value between 0 and 1;
a receiving filter configured to generate a set of sampled symbols as a function of the transmission signal and noise added by the transmission channel;
a decoder configured to generate a set of decoded symbols as a function of the set of sampled symbols;
wherein the elements of the precoding matrix are dependent on a property of the pulse form g T .

2. The communication system of claim 1 , wherein the decoder is configured to generate the set of decoded symbols by performing a matrix operation with a decoding matrix, wherein the elements of the decoding matrix are dependent on the receiving filter.

3. The communication system of claim 1 , wherein the matrix elements of the precoding matrix are further dependent on an acceleration factor ρ, the acceleration factor being adapted to be used by the pulse filter to decrease the symbol delay time below the Nyquist delay time, wherein the acceleration factor ρ is a value between 0 and 1.

4. The communication system of claim 1 , wherein the pulse filter is configured to perform the following operation onto a number of N input symbols a n :

s
⁡

(
t
)

=

∑
n

⁢

a
n

·

ρ

⁢

g
T

⁡

(

t
-

n
⁢

⁢
ρ
⁢

⁢
T

)

.

5. The communication system of claim 4 , wherein the matrix of the precoder is derived form a matrix G, the matrix elements of the matrix G being calculated as:

G

m
,
n

=

∫

-
∞

∞

⁢

ρ

⁢

g
T

⁡

(

t
-

n
⁢

⁢
ρ
⁢

⁢
T

)

·

ρ

⁢

g
T

⁡

(

t
-

m
⁢

⁢
ρ
⁢

⁢
T

)

⁢
dt

with 1<n≦N and 1<m≦N and N being an integer value >1.

6. The communication system of claim 5 , wherein the matrix of the precoder is an inverse square root matrix G −1/2 of the matrix G.

7. The communication system of claim 6 , wherein the receiving filter is matched to the pulse filter, and wherein both the precoding matrix and the decoding matrix are inverse square root matrices G−1/2 of the matrix G.

8. The communication system of claim 7 , wherein the precoder matrix and the decoder matrix are derived from a decomposition of the matrix G with G=L L T , wherein L is a lower triangular matrix with all matrix elements above the main diagonal being zero and L T is a transpose conjugate matrix to the matrix L, wherein the precoder is adapted to apply an inverse matrix L −T of the transpose conjugate matrix L T , and the decoder is adapted to apply an inverse matrix L −1 of the lower triangular matrix L.

9. The communication system of claim 5 , wherein the matrix P of the precoder relates to the matrix G as follows:
G=PSP*
wherein P, P* and S are matrixes, wherein the matrix P* denotes the transpose conjugate to the matrix P, and the matrix S is a singular value matrix, wherein all matrix elements except the elements of the main diagonal equal zero.

10. The communication system of claim 1 , wherein the decoder is adapted to perform a matrix operation for transforming a set of n sampled symbols to a set of n decoded symbols.

11. The communication system of claim 1 , wherein a maximum-likelihood estimation

Assignees

• ERICSSON TELEFON AB L M (publ)

Inventors

• Gattami Ather
• Ringh Emil

Classifications

• H04L25/497 Primary

  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

• H04L25/03834

  using pulse shaping · CPC title