Transceiving system using a joined linear orthogonal modulation

Patent metadata

Field	Value
Publication number	US-10374858-B2
Application number	US-201815914137-A
Country	US
Kind code	B2
Filing date	Mar 7, 2018
Priority date	Mar 9, 2017
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

A transceiving system using a joined modulation alphabet A having a size M the symbols of which are distributed on a plurality N of orthogonal dimensions, the symbols carried by a dimension belonging to a linear sub-alphabet An having a size P, with M=NP. The transmitter performs a turbocoding of a block of information bits, the code words provided by the turbocoder being mapped to symbols of the joined modulation alphabet before modulating the signal to be transmitted. The receiver performs turbodecoding from the projection of the symbols received on the orthogonal dimensions of the alphabet.

First claim

The invention claimed is:

1. A transmitter for transmitting a block of Q bits, said transmitter comprising a turbocoder receiving said block and providing K code words having m bits, the turbocoder comprising K branches, each branch receiving said block and comprising a first interleaver for interleaving the bits of the block, followed by an elementary coder coding each word having r bits at an output of the first interleaver into a code word having m=r+c bits where c is a non-null integer, the turbocoder being followed by a modulator mapping each code word having m bits at an output of the turbocoder into a symbol of a modulation alphabet A having a size M=2 m , the symbols of the modulation alphabet provided by the modulator that modulates the symbols to a signal to be transmitted, wherein the symbols of the modulation alphabet A are distributed on a plurality N of orthogonal dimensions, the symbols carried by a dimension belonging to a linear sub-alphabet A n , having a size P>1, with M=NP, wherein m, O, M, N, and P are integer values.

2. The transmitter according to claim 1 , wherein the elementary coder comprises a convolutional coder with a rate

r
+
1

m

,

the elementary coder receiving a word with r bits, calculating a parity bit of said word and concatenating the parity bit to the received word to provide a word with r+1 bits, the convolutional coder coding said word having r+1 bits into a code word having m bits.

3. The transmitter according to claim 1 , wherein the code words having m=r+c bits provided by the elementary coder are interleaved by a second interleaver for interleaving the code words.

4. The transmitter according to claim 3 , wherein the second interleaver provides the interleaved code words to a puncturer, all puncturers of the different branches performing a word puncturing of the code words with a predetermined puncturing rate R punc >1.

5. The transmitter according to claim 1 , wherein the modulation symbols of the modulation alphabet A are defined by x k =z p f x , k∈{0, . . . , NP−1}, where f n =(f 0 n , f 1 n , . . . , f N−1 n ) T is a vector having a size N representing a symbol of an orthogonal modulation alphabet and z p ∈{z 0 , . . . , z P−1 } is a symbol of a linear modulation alphabet.

6. The transmitter according to claim 5 , wherein the orthogonal modulation alphabet consists of FSK (Frequency Shift Keying) modulation symbols having a size N.

7. The transmitter according to claim 5 , wherein the orthogonal modulation alphabet consists of Hadamard sequences having a size N.

8. The transmitter according to claim 6 , wherein the linear modulation alphabet consists of PSK (Phase Shift Keying) symbols having a size P.

9. A receiver for receiving a signal transmitted by the transmitter according to claim 1 , the signal received by the receiver being base-band demodulated to provide a block of successive received symbols, the receiver comprising a series-parallel converter receiving the successive received symbols and providing them to a plurality K of parallel branches, the receiver being characterised in that each branch (l) comprises detection circuitry adapted to project a symbol (y l ) received on this branch onto the N orthogonal dimensions of the modulation alphabet A to obtain a vector having N components (Y 0 1 , Y 1 1 , . . . , Y N−1 1 ) and deduce therefrom as a word having N×P soft values a logarithm of observation probabilities (log[p(y l |x k )]) of the received symbol assuming that different symbols of the modulation alphabet have been transmitted, the detection circuitry providing the words thus obtained to an elementary decoder, the elementary decoders of different branches being chained together so as to perform turbodecoding, the turbodecoding providing probability logarithmic ratios (LR), called LR values, for the different information bits of the block, the information bits of the block being estimated by a hard decision on the LR values thus obtained.

10. The receiver according to claim 9 , wherein, for a given branch, the words provided by the detection circuitry are depunctured by depuncturing circuitry, the block of words thus depunctured being deinterleaved in word deinterleaving circuitry performing an inverse of the word interleaving performed in the corresponding branch of the transmitter.

11. The receiver according to claim 9 , wherein the detection circuitry of a branch l calculates the NP soft values corresponding to a symbol y l received from

-

N

2
⁢

σ
2

⁢



z
p



2

+

1

σ
2

⁢

Re
⁡

(

Y
n
|

⁢

z
_

p

)

,

n=0, . . . , N−1, p=0, . . . , P−1, where Y n l is a component of the received symbol y l , on an n th dimension of the modulation alphabet, z p is a linear modulation symbol carried by the n th dimension of the modulation alphabet, z p , is a conjugate of z p , and σ 2 is a noise power received.

12. The receiver according to claim 11 , wherein the orthogonal modulation is a FSK (Frequency Shift Keying) modulation and in that the components Y n l of the received symbol y l are obtained by correlating the received symbol with different rows of a DFT (Discrete Fourier Transform) matrix having a size N×N.

13. The receiver according to claim 11 , wherein the orthogonal modulation is a Hadamard modulation and in that the components Y n l of the received symbol y l are obtained by correlating the received symbol with different rows of a Hadamard matrix having a size N×N.

14. The receiver according to claim 11 , wherein the elementary decoder of a branch l comprises a summing block performing the sum of the NP soft values

-

N

2

Assignees

• Commissariat Energie Atomique

Inventors

• Roth Yoann
• Berg Vincent
• Dore Jean-Baptiste
• Ros Laurent

Classifications

• H04L25/4902

  Pulse width modulation; Pulse position modulation · CPC title

• H04L1/006

  Trellis-coded modulation · CPC title

• H04L27/02

  Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation (H04L27/32 takes precedence) · CPC title

• H04L1/0071

  Use of interleaving (interleaving per se H03M13/27) · CPC title

• H04L27/10

  Frequency-modulated carrier systems, i.e. using frequency-shift keying (H04L27/32 takes precedence) · CPC title