Method for generating a filter bank for receiving a signal modulated by continuous phase modulation, and method for receiving said signal

Patent metadata

Field	Value
Publication number	US-9401829-B2
Application number	US-201514844961-A
Country	US
Kind code	B2
Filing date	Sep 3, 2015
Priority date	Sep 3, 2014
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

A method for generating a filter bank for receiving a signal modulated by continuous phase modulation, the modulated signal being able to be broken down as a sum of a plurality of amplitude-modulated signals, each amplitude-modulated signal being expressed by a product between a complex pseudo-symbol and a temporal component with a waveform predefined according to the parameters of the modulation, includes: evaluating, over a duration (T) that is equal to the duration of a symbol, all waveforms of the signal from the parameters of the continuous phase modulation and the breakdown in the form of a sum of a plurality of amplitude-modulated signals, retaining all evaluated waveforms that are different from one another, constructing a filter bank made up of a plurality of filters whose temporal responses are equal to the retained waveforms, which are limited to a duration equal to the duration of a symbol.

First claim

The invention claimed is:

1. A method for receiving a signal that is transmitted after being modulated by a continuous phase modulation, said modulated signal being able to be broken down in a form of a sum of a plurality of amplitude-modulated signals, each amplitude-modulated signal being able to be expressed in a form of a product between a complex pseudo-symbol and a temporal component with a waveform predefined according to parameters of the continuous phase modulation, said method comprising a step of:
implementing, at a receiver, a filter bank, the filter bank being generated with the steps of:
evaluating, over a duration (T) that is equal to a duration of a symbol, all waveforms of the modulated signal from the parameters of the continuous phase modulation and a breakdown in the form of the sum of the plurality of amplitude-modulated signals, the evaluating including at least determining all values of the complex pseudo-symbols,
retaining all the evaluated waveforms that are different from one another, and
constructing the filter bank made up of a plurality of filters whose temporal responses are equal to the retained waveforms, said retained waveforms being limited to a duration equal to the duration of the symbol; and
demodulating, at the receiver, the modulated signal upon filtering by the filter bank.

2. The method according to claim 1 , wherein the waveforms of the modulated signal are evaluated by a representation of states of the modulated signal in the form of a trellis, by computing, over all transitions of any section of the trellis, the value of said complex pseudo-symbols for all of temporal components considered, a state (σ i ) of the trellis associated with an instant in time of index n being defined by L information symbols of the signal to be transmitted that are prior to the instant n and the (n−L) th pseudo-symbol associated with a first temporal component, L being a length of a memory associated with the continuous phase modulation.

3. The method according to claim 2 , further comprising, for each transition of any section of the trellis, the evaluating of the modulated signal, the evaluating being computed from the temporal components of the breakdown of the modulated signal and the determined values of said complex pseudo-symbols.

4. The method according to claim 1 , wherein the waveforms of the modulated signal are evaluated for a reduced number of components in the breakdown of the modulated signal in the form of the sum of the plurality of amplitude-modulated signals.

5. A method for receiving a signal modulated by a continuous phase modulation, comprising the following steps:
filtering the modulated signal by a filter bank determined by performing a method for generating the filter bank for receiving the modulated signal, said modulated signal being able to be broken down in a form of a sum of a plurality of amplitude-modulated signals, each amplitude-modulated signal being able to be expressed in a form of a product between a complex pseudo-symbol and a temporal component with a waveform predefined according to parameters of the continuous phase modulation, said method for generating including:
evaluating, over a duration (T) that is equal to a duration of a symbol, all waveforms of the modulated signal from the parameters of the continuous phase modulation and a breakdown in the form of the sum of the plurality of amplitude-modulated signals, the evaluating including at least determining all values of the complex pseudo-symbols,
retaining all evaluated waveforms that are different from one another, constructing the filter bank that is made up of a plurality of filters whose temporal responses are equal to the retained waveforms, said retained waveforms being limited to a duration equal to the duration of the symbol,
sampling outputs of symbols of the filter bank, and

demodulating the sampled outputs of the symbols by executing a trellis based algorithm, a Viterbi algorithm or a Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm.

6. A receiver for receiving a signal modulated by a continuous phase modulation, comprising:
a filter bank determined by performing a method for generating the filter bank for receiving the signal modulated by continuous phase modulation, said modulated signal being able to be broken down in a form of a sum of a plurality of amplitude modulated signals, each amplitude-modulated signal being able to be expressed in a form of a product between a complex pseudo-symbol and a temporal component with a waveform predefined according to parameters of the continuous phase modulation, said method for generating including:
evaluating, over a duration (T) that is equal to a duration of a symbol, all waveforms of the modulated signal from the parameters of the continuous phase modulation and a breakdown in the form of the sum of the plurality of amplitude-modulated signals, the evaluating including at least determining all values of the complex pseudo-symbols,
retaining all evaluated waveforms that are different from one another, constructing the filter bank that is made up of a plurality of filters whose temporal responses are equal to the retained waveforms, said retained waveforms being limited to a duration equal to the duration of the symbol,
a sampler configured to sample outputs of symbols of the filter bank, and a demodulator configured to execute, on the sampled outputs of the symbols, a trellis based algorithm for a demodulation, a Viterbi algorithm or a Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm.

7. A device storing a computer program product having instructions stored on a tangible non-transitory storage medium for executing, by a processor, a method for receiving a signal that is transmitted after being modulated by a continuous phase modulation, said modulated signal being able to be broken down in a form of a sum of a plurality of amplitude-modulated signals, each amplitude-modulated signal being able to be expressed in a form of a product between a complex pseudo-symbol and a temporal component with a waveform predefined according to parameters of the continuous phase modulation, said method when executed by the processor cause the processor to carry out steps comprising:
evaluating, over a duration (T) that is equal to a duration of a symbol, all waveforms of the modulated signal from the parameters of the continuous phase modulation and a breakdown in the form of the sum of the plurality of amplitude-modulated signals, the evaluating including at least determining all values of the complex pseudo-symbols,
retaining all evaluated waveforms that are different from one another,
constructing the filter bank that is made up of a plurality of filters whose temporal responses are equal to the retained waveforms, said retained waveforms being limited to a duration equal to the duration of the symbol, and
demodulating the modulated signal upon filtering by the filter bank.

8. A tangible non-transitory processor-readable recording medium, on which is recorded a program having processor executable instructions for executing a method for receiving a signal that is transmitted after being modulated by a continuous phase modulation, said modulated signal being able to be broken down in a form of a sum of a plurality of amplitude modulated signals, each amplitude-modulated signal being able to be expressed in a form of a product between a complex pseudo-symbol and a temporal component with a waveform predefined according to parameters of the continuous phase modulation, said method comprising:
evaluating, over a duration (T) that is equal to a duration of a symbol, all waveforms of the modulated signal from the parameters of the continuous phase modulation and a breakdown in the form of the sum of the plurality

Assignees

• Thales Sa
• Centre Nat D'Etudes Spatiales

Inventors

• Benaddi Tarik
• Gadat Benjamin
• Poulliat Charly
• Boucheret Marie-Laure

Classifications

• H04L25/03203

  Trellis search techniques · CPC title

• H04L25/03006 Primary

  Arrangements for removing intersymbol interference · CPC title

• H04L27/22 Primary

  Demodulator circuits; Receiver circuits · CPC title

• H04L1/0054

  Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms · CPC title