Method for identifying the beginning of a UWB pulse sequence

• US 20050031043A1
• Filed: 07/01/2004
• Published: 02/10/2005
• Est. Priority Date: 07/30/2003
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Paquelet, Stephane
• Granted Patent: US 7,535,983 B2
• Time in Patent Office: Days
• US Class Current: 375/259
• CPC Class Codes: H04B 1/7176 Data mapping, e.g. modulation
• CPC Class Codes: H04B 1/7183 Synchronisation

Abstract

The present invention relates to a method for transmitting data in the form of pulse sequences, which method includes a signal synchronization step carried out by a receiver of dataframes DF, in the course of which at least one time window ΔT(0) is scanned during a signal detection step, in search of the beginning PSB of a pulse sequence, said time window being then subdivided into a predefined number of sub-windows ΔT(1), which sub-windows are then to be scanned during further signal detection steps until the beginning PSB of the pulse sequence has been detected whithin one of said sub-windows which will then be substituted for the previous time window ΔT(0), until the width of the resulting sub-windows becomes smaller than a predetermined minimum width. The invention allows to identify the beginning of a pulse sequence without requiring an exhaustive mapping of said sequence.

Claims

1. ) A method for transmitting data in a telecommunication system including at least one transceiver and one receiver, said transmitter being intended to transmit a signal formed by at least one sequence of Np pulses over Np time windows, each pulse being enclosed within a time chip whose position whithin its relevant time window is defined by a chip number, which method includes at least one signal synchronization step in the course of which at least one time window having a predermined width is scanned during a signal detection step in search of the beginning of a pulse sequence, said time window being then subdivided into a predefined number of sub-windows if the beginning of a pulse sequence has been detected within said time window, which sub-windows are then to be scanned during further signal detection steps in search of the beginning of said pulse sequence until such a beginning has been detected whithin one of said sub-windows which will then be substituted for the previous time window, until the width of the resulting sub-windows becomes smaller than a predetermined minimum width.

2. ) A method as claimed in claim 1, according to which Np detection windows encompassing the time chips defined by the chip numbers are to be examined in search of an expected pulse sequence during each signal detection step.

3. ) A method as claimed in claim 2, according to which the examination of each detection window involves the computation of a detection value defined by a mean value over all detection windows of a correlation between the received signal and a series of Np expected pulse forms, which detection value is to be compared to a predetermined threshold value.

4. ) A method as claimed in claim 2, according to which the examination of each detection window involves the computation of a detection value defined by a mean value over all detection windows of a squared value of a correlation between the received signal and a series of Np expected pulse forms, which detection value is to be compared to a predetermined threshold value.

5. ) A method as claimed in any one of claims 3 or 4, according to which the predetermined threshold value is independent of an amplitude of the received signal.

6. ) A telecommunication system including at least one transceiver and one receiver, said transmitter being intended to transmit a signal formed by at least one sequence of Np pulses over Np time windows, each pulse being enclosed within a time chip whose position whithin its relevant time window is defined by a chip number, system in which the receiver includes signal synchronization means intended to identify at least one time window having a predermined width to be scanned by signal detection means in search of the beginning of a pulse sequence, said time window being then subdivided into a predefined number of sub-windows if the beginning of a pulse sequence has been detected within said time window, which sub-windows are then in turn to be scanned by said signal detection means in search of the beginning of said pulse sequence until such a beginning has been detected whithin one of said sub-windows which will then be substituted for the previous time window, until the width of the resulting sub-windows becomes smaller than a predetermined minimum width.

7. ) A telecommunication system as claimed in claim 6, in which the signal detection means are intended to perform an examination of Np detection windows encompassing the time chips defined by the chip numbers in search of an expected pulse sequence.

8. ) A telecommunication system as claimed in claim 7, in which the detection means include computation means for computing a detection value defined by a mean value over all detection windows of a correlation between the received signal and a series of Np expected pulse forms, and comparison means for comparing said detection value to a predetermined threshold value.

9. ) A telecommunication system as claimed in claim 7, in which the detection means include computation means for computing a detection value defined by a mean value over all detection windows of a squared value of a correlation between the received signal and a series of Np expected pulse forms, and comparison means for comparing said detection value to a predetermined threshold value.

10. ) A telecommunication system as claimed in claim 9, in which the computation means include:

a plurality of correlating modules, each of which being intended to be activated during the Np detection windows and to compute a correlation over said detection windows between a signal received by the receiver and a characteristic signal associated with said correlating module,

a plurality of accumulating modules, each of which being intended to accumulate output values delivered by one of said correlating modules,

a plurality of squaring modules, each of which being intended to produce a squared value of the contents of one of said accumulating modules, and

an additioner intended to compute a sum of output values delivered by the squaring modules in order to produce a detection value which will be compared to the predetermined threshold value.

11. ) A telecommunication system as claimed in claim 9, in which the computation means include:

at least one band-pass filter intended to be fed with a signal received by the receiver,

a sampling module intended to be activated during the detection windows and to convert a signal delivered by the band-pass filter into a series of digital samples,

memory means in which successive series of samples delivered by the sampling module are intended to be stored,

an additionner intended to deliver a series of accumulated samples, each accumulated sample resulting from a sum of all samples having a same rank among the various series of samples stored within the memory means, and

an integrator intended to compute a mean-square value over all detection windows of the accumulated samples delivered by the additionner, which mean-square value will constitute the detection value.

12. ) A device intended to receive a signal formed by at least one sequence of Np pulses over Np time windows, each pulse being enclosed within a time chip whose position whithin its relevant time window is defined by a chip number, which device includes signal synchronization means intended to identify at least one time window having a predermined width to be scanned by signal detection means in search of the beginning of a pulse sequence, said time window being then subdivided into a predefined number of sub-windows if the beginning of a pulse sequence has been detected within said time window, which sub-windows are then in turn to be scanned by said signal detection means in search of the beginning of said pulse sequence until such a beginning has been detected whithin one of said sub-windows which will then be substituted for the previous time window, until the width of the resulting sub-windows becomes smaller than a predetermined minimum width.

13. ) A device as claimed in claim 12, in which the signal detection means are intended to perform an examination of Np detection windows encompassing the time chips defined by the chip numbers in search of an expected pulse sequence.