Spread spectrum GMSK signals

Patent metadata

Field	Value
Publication number	US-9503153-B2
Application number	US-201514844740-A
Country	US
Kind code	B2
Filing date	Sep 3, 2015
Priority date	Sep 4, 2014
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A method for generating a spread spectrum Gaussian Minimum Shift Keying (GMSK) signal includes obtaining a sequence of data symbols for a data channel, obtaining at least one first spread spectrum code comprising a first sequence of spread spectrum chips for the data channel, obtaining at least one second spread spectrum code comprising a second sequence of spread spectrum chips for a pilot channel, and generating a sequence of pre-modulation chips by combining the sequence of data symbols for the data channel with the spread spectrum chips of the first sequence of the at least one first spread spectrum code and data symbols for the pilot channel with the spread spectrum chips of the second sequence of the at least one second spread spectrum code to a combined sequence of chips. The method further includes assigning the chips of the combined sequence of chips to the transmission channels In-Phase I and Quadrature Q of the spread spectrum GMSK signal so that not more than two consecutive pre-modulation chips generated with the same spread spectrum code are transmitted in the same transmission channel I or Q, and performing GMSK modulation using the sequence of pre-modulation chips to generate a spread spectrum GMSK signal.

First claim

What is claimed is:

1. A method for generating a spread spectrum Gaussian Minimum Shift Keying (GMSK) signal comprising the acts of:
obtaining a sequence of data symbols for a data channel;
obtaining at least one first spread spectrum code comprising a first sequence of spread spectrum chips for the data channel;
obtaining at least one second spread spectrum code comprising a second sequence of spread spectrum chips for a pilot channel;
generating a sequence of pre-modulation chips by combining the sequence of data symbols for the data channel with the spread spectrum chips of the first sequence of the at least one first spread spectrum code and data symbols for the pilot channel with the spread spectrum chips of the second sequence of the at least one second spread spectrum code to a combined sequence of chips;
assigning the chips of the combined sequence of chips to the transmission channels In-Phase I and Quadrature Q of the spread spectrum GMSK signal so that not more than two consecutive pre-modulation chips generated with the same spread spectrum code are transmitted in the same transmission channel I or Q;
performing GMSK modulation using the sequence of pre-modulation chips to generate the spread spectrum GMSK signal;
obtaining one first spread spectrum code and one second spread spectrum code;
assigning pre-modulation chips generated with the first spread spectrum code to the transmission channels In-Phase I and Quadrature Q of the spread spectrum GMSK signal so that two consecutive pre-modulation chips generated with the first spread spectrum code are transmitted in different transmission channels I or Q; and
assigning pre-modulation chips generated with the second spread spectrum code to the transmission channels In-Phase I and Quadrature Q of the spread spectrum GMSK signal so that two consecutive pre-modulation chips generated with the second spread spectrum code are transmitted in different transmission channels I or Q.

2. A method for generating a spread spectrum Gaussian Minimum Shift Keying (GMSK) signal comprising the acts of:
obtaining a sequence of data symbols for a data channel;
obtaining at least one first spread spectrum code comprising a first sequence of spread spectrum chips for the data channel;
obtaining at least one second spread spectrum code comprising a second sequence of spread spectrum chips for a pilot channel;
generating a sequence of pre-modulation chips by combining the sequence of data symbols for the data channel with the spread spectrum chips of the first sequence of the at least one first spread spectrum code and data symbols for the pilot channel with the spread spectrum chips of the second sequence of the at least one second spread spectrum code to a combined sequence of chips;
assigning the chips of the combined sequence of chips to the transmission channels In-Phase I and Quadrature Q of the spread spectrum GMSK signal so that not more than two consecutive pre-modulation chips generated with the same spread spectrum code are transmitted in the same transmission channel I or Q;
performing GMSK modulation using the sequence of pre-modulation chips to generate the spread spectrum GMSK signal;
obtaining two or more first spread spectrum codes and two or more second spread spectrum codes;
assigning pre-modulation chips generated with the first spread spectrum codes to the transmission channel In-Phase I of the spread spectrum GMSK signal by interleaving the pre-modulation chips so that not more than two consecutive pre-modulation chips generated with the same one of the first spread spectrum codes are transmitted in the transmission channel I; and
assigning pre-modulation chips generated with the second spread spectrum codes to the transmission channel Quadrature Q of the spread spectrum GMSK signal by interleaving the pre-modulation chips so that not more than two consecutive pre-modulation chips generated with the same one of the second spread spectrum codes are transmitted in the transmission channel Q.

3. A method for receiving a spread spectrum Gaussian Minimum Shift Keying (GMSK) signal that was generated according to the acts of:
obtaining a sequence of data symbols for a data channel;
obtaining at least one first spread spectrum code comprising a first sequence of spread spectrum chips for the data channel;
obtaining at least one second spread spectrum code comprising a second sequence of spread spectrum chips for a pilot channel;
generating a sequence of pre-modulation chips by combining the sequence of data symbols for the data channel with the spread spectrum chips of the first sequence of the at least one first spread spectrum code and data symbols for the pilot channel with the spread spectrum chips of the second sequence of the at least one second spread spectrum code to a combined sequence of chips;
assigning the chips of the combined sequence of chips to the transmission channels In-Phase I and Quadrature Q of the spread spectrum GMSK signal so that not more than two consecutive pre-modulation chips generated with the same spread spectrum code are transmitted in the same transmission channel I or Q; and
performing GMSK modulation using the sequence of pre-modulation chips to generate the spread spectrum GMSK signal,
wherein the method for receiving the spread spectrum GMSK signal comprising the acts of:
generating a first reference signal considering that a first data symbol has been transmitted with the received spread spectrum GMSK signal;
generating a second reference signal considering that a second data symbol has been transmitted with the received spread spectrum GMSK signal;
simultaneously evaluating a first correlation function of the received spread spectrum GMSK signal and the first reference signal and a second correlation function of the received spread spectrum GMSK signal and the second reference signal;
determining the highest value among the punctual correlations of the evaluated first and second correlation function;
selecting the first reference signal or the second reference signal depending on the determined highest value; and
determining the integration time used for performing a correlation of the received spread spectrum GMSK signal with a first or second spread spectrum code depending on the selected first reference signal or second reference signal.

4. A method for receiving a spread spectrum Gaussian Minimum Shift Keying (GMSK) signal that was generated according to the acts of:
obtaining a sequence of data symbols for a data channel;
obtaining at least one first spread spectrum code comprising a first sequence of spread spectrum chips for the data channel;
obtaining at least one second spread spectrum code comprising a second sequence of spread spectrum chips for a pilot channel;
generating a sequence of pre-modulation chips by combining the sequence of data symbols for the data channel with the spread spectrum chips of the first sequence of the at least one first spread spectrum code and data symbols for the pilot channel with the spread spectrum chips of the second sequence of the at least one second spread spectrum code to a combined sequence of chips;
assigning the chips of the combined sequence of chips to the transmission channels In-Phase I and Quadrature Q of the spread spectrum GMSK signal so that not more than two consecutive pre-modulation chips generated with the same spread spectrum code are transmitted in the same transmission channel I or Q; and
performing GMSK modulation using the sequence of pre-modulation chips to generate the spread spectrum GMSK signal,
wherein the method for receiving the spread spectrum GMSK signal comprising the acts of:
generating a reference signal according to the following equation:

Assignees

• Airbus Ds Gmbh

Inventors

• Floch Jean-Jacques
• Soualle Francis
• Wendel Jan

Classifications

• H04L27/2017 Primary

  in which the phase changes are non-linear, e.g. generalized and Gaussian minimum shift keying, tamed frequency modulation (H04L27/201 takes precedence) · CPC title

• H04B1/707

  using direct sequence modulation · CPC title

• G01S19/02

  Details of the space or ground control segments · CPC title

• H04B2001/70724

  featuring pilot assisted reception · CPC title

• H04L27/364

  Arrangements for overcoming imperfections in the modulator, e.g. quadrature error or unbalanced I and Q levels · CPC title