Radio terminal

• US 20030125026A1
• Filed: 06/27/2002
• Published: 07/03/2003
• Est. Priority Date: 12/28/2001
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kuwahara, Mikio, Tsunehara, Katsuhiko
• Granted Patent: US 7,016,653 B2
• Time in Patent Office: Days
• US Class Current: 455/435.1
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A radio terminal that receives signals from a plurality of radio stations to calculate its current position has: interference canceling means for canceling each interference signal from the plurality of received signals; a plurality of delay profile generating means for generating delay profiles of the plurality of interference-canceled received signals with use of respective corresponding codes; and position calculating means for calculating its current position, which is a signal receiving point, with use of the plurality of delay profiles, whereby advantageously reducing the capacity of a memory mounted in the mobile terminal while the position calculation is speeded up

Claims

1. A radio terminal that receives signals from a plurality of radio stations to calculate its current position, comprising:

interference canceling means for canceling the interference component from among said received signals;

a plurality of delay profile generating means for generating delay profiles of said plurality of interference-canceled received signals, in parallel with use of their corresponding codes; and

position calculating means for calculating a position that is a signal receiving point with use of said delay profiles.

2. The radio terminal according to claim 1;

wherein said interference canceling means comprising;

received signal replica generating means for generating a replica of each interference signal to be cancelled from said plurality of received signals; and

calculating means for calculating said replica signal generated by said received signal replica generating means and each of said received signals to thereby cancel the interference component from among said received signals.

3. The radio terminal according to claim 1 or 2;

wherein said terminal further comprises;

delay profile retaining means for retaining delay profiles generated by said plurality of delay profile generating means; and

delay profile memory controlling means for controlling input/output of information to/from said plurality of delay profile retaining means;

wherein said delay profile retaining means is composed of a plurality of areas for retaining delay profiles generated by said plurality of delay profile generating means.

4. The radio terminal according to any of claims 1 to 3;

wherein said terminal further comprises;

received signal retaining means composed of a plurality of areas for retaining information related to said received signals; and

received signal memory controlling means for controlling input/output of information to/from said plurality of received signal retaining means;

wherein said plurality of delay profile generating means uses said information related to said received signals retained in said received signal retaining means to thereby generate delay profiles of said received signals.

5. The radio terminal according to any of claims 1 to 4;

wherein said terminal further comprises interference cancel determining means for determining each signal to be canceled as an interference one with use of said delay profiles;

wherein said received signal replica generating means generates a replica of each signal determined so as to be cancelled as an interference one by said interference cancel determining means.

6. The radio terminal according to claim 5;

wherein said interference cancel determining means calculates a delay profile power value of a delay profile at the timing of each of said delay profiles and determines an interference signal to be canceled as an interference one according to a result of a comparison between said calculated power value and a predetermined threshold value.

7. A radio terminal that receives signals from a plurality of radio stations to calculate its current position, comprising:

delay profile generating means for generating a delay profile of each received signal with use of said received signals;

delay profile retaining means for retaining delay profiles generated by said delay profile generating means;

interference canceling means for canceling the interference component from among said delay profiles; and

position calculating means for calculating a position that is a signal receiving point with use of interference-canceled delay profiles retained in said delay profile retaining means.

8. The radio terminal according to claim 7;

wherein said interference canceling means comprises;

delay profile replica generating means for generating a replica of each delay profile to be canceled as an interference one from said delay profiles; and

calculating means for calculating said replica of said delay profile generated by said delay profile replica generating means and each delay profile retained by said delay profile retaining means to thereby cancel the interference component from among said delay profiles.

9. The radio terminal according to claim 7 or 8;

wherein said terminal further includes correlation value retaining means for retaining a correlation value of each code used by said delay profile generating means; and

wherein said delay profile replica generating means uses said correlation value to generate a replica of each delay profile to be canceled as an interference one.

10. The radio terminal according to claim 9;

wherein said correlation value retaining means retains an autocorrelation value for each phase difference that is less than the half of the length of a sequence used in calculation of a correlation value by each of said delay profile generating means;

wherein said correlation value retaining means outputs an autocorrelation value of each phase difference retained by said correlation value retaining means when any of said delay profile replica generating means uses said autocorrelation value that is less than the half of the length of said sequence used in calculation of said correlation value; and

wherein said correlation value retaining means outputs a complex conjugate of said autocorrelation value corresponding to a phase difference obtained by subtracting said phase difference from said sequence length when said delay profile replica generating means uses said autocorrelation value that is greater than the half of the length of said sequence used in calculation of said correlation value.

11. The radio terminal according to any of claims 7 to 10;

wherein said terminal further includes interference cancel determining means for determining a signal to be canceled as an interference one with use of said delay profiles; and

wherein said delay profile replica generating means generates a replica of each delay profile determined so as to be canceled as an interference one by said interference cancel determining means.

12. The radio terminal according to claim 11;

wherein said interference cancel determining means calculates a delay profile power value of each delay profile retained by said delay profile retaining means to determine a signal to be canceled as an interference one according to a result of comparison between said calculated delay profile power value and a predetermined threshold value.

13. A radio terminal that receives signals from a plurality of radio stations to calculate its current position, comprising:

a plurality of delay profile generating means for generating delay profiles of said signals received from said plurality of radio stations in parallel;

interference canceling means for canceling the interference component from among said delay profiles; and

position calculating means for calculating a signal receiving point with use of said interference-canceled delay profiles.

14. The radio terminal according to claim 13;

wherein said interference canceling means comprises;

delay profile replica generating means for generating a replica of each delay profile to be canceled as an interference one from said delay profiles; and

calculating means for calculating a replica of each delay profile generated by said delay profile replica generating means and a delay profile generated by said delay profile generating means to cancel the interference component from among said delay profiles.

15. The radio terminal according to claim 13 or 14;

wherein said terminal further includes correlation value retaining means for retaining a correlation value of each code used by said delay profile generating means; and

wherein said delay profile replica generating means uses said correlation value to generate a replica of each delay profile to be canceled as an interference one.

16. The radio terminal according to any of claims 13 to 15;

wherein said correlation value retaining means retains an autocorrelation value corresponding to each phase difference that is less than the half of the length of a sequence used in calculation of said correlation value by said delay profile generating means;

wherein said correlation value retaining means outputs an autocorrelation value of said phase difference retained by said correlation value retaining means when said delay profile replica generating means uses said autocorrelation value of a phase difference that is less than the half of the length of a sequence used in calculation of said correlation value; and

wherein said correlation value retaining means outputs a complex conjugate of an autocorrelation value corresponding to a phase difference obtained by subtracting said phase difference from the length of said sequence when said delay profile replica generating means uses an autocorrelation value of a phase difference that is greater than the half of the length of a sequence used in calculation of said correlation value.

17. The radio terminal according to any of claims 13 to 16;

wherein said terminal further comprises;

delay profile retaining means for retaining delay profiles generated by said plurality of delay profile generating means; and

delay profile memory controlling means for controlling input/output of information to/from said plurality of delay profile retaining means;

wherein said delay profile retaining means is composed of a plurality of areas, each retaining a delay profile generated by each of said plurality of delay profile generating means.

18. The radio terminal according to any of claims 13 to 17;

wherein said terminal further includes interference cancel determining means for determining each signal to be canceled as an interference one with use of said delay profile; and

wherein said delay profile replica generating means generates a replica of each delay profile determined so as to be canceled as an interference one by said interference cancel determining means.

19. The radio terminal according to claim 18;

wherein said interference cancel determining means calculates a delay profile power value of each delay profile retained in said delay profile retaining means to determine a signal to be canceled as an interference one according to a result of a comparison between said delay profile power value and a predetermined threshold value.

20. A semiconductor device used for a radio terminal that receives signals from a plurality of radio stations to calculate its current position, comprising:

received signal replica generating means for generating a replica of each signal to be canceled as an interference one from said plurality of received signals;

calculating means for calculating said replica signal generated by said received signal replica generating means and each of said plurality of received signals to be canceled as an interference one from said plurality of received signals;

a plurality of delay profile generating means, each generating a delay profile of each of said plurality of interference-canceled received signals with use of its corresponding code; and

position calculating means for calculating a position that is a signal receiving point with use of said delay profiles.

21. A semiconductor device used for a radio terminal that receives signals from a plurality of radio stations to calculate its current position, comprising:

delay profile generating means for generating a delay profile of each of said received signals with use of said received signals;

delay profile retaining means for retaining delay profiles generated by said plurality of delay profile generating means;

delay profile replica generating means for generating a replica of each delay profile to be canceled as an interference one from said delay profiles;

calculating means for calculating a replica of each delay profile generated by each of said delay profile replica generating means with use of delay profiles retained in said delay profile retaining means to cancel the interference component from among said delay profiles; and

position calculating means for calculating a position that is a signal receiving point with use of interference-canceled delay profiles retained in said delay profile retaining means.

22. A semiconductor device used for a radio terminal that receives signals from a plurality of radio stations to calculate its current position, comprising:

a plurality of delay profile generating means for generating delay profiles of signals received from said plurality of radio stations in parallel with use of their corresponding codes;

delay profile replica generating means for generating a replica of each delay profile to be canceled as an interference one from said plurality of delay profiles;

calculating means for calculating a replica of each delay profile generated by said delay profile replica generating means and a delay profile generated by said delay profile generating means to cancel the interference component from among said plurality of delay profiles; and

position calculating means for calculating a position that is a signal receiving point with use of interference-canceled delay profile.