Code division multiple access signal receiving apparatus

• US 7,020,183 B2
• Filed: 12/04/2002
• Issued: 03/28/2006
• Est. Priority Date: 07/11/2000
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nakamura, Takaharu
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Wang, Ted M.
• Application Number:
  US10/314,268
• Publication Number:
  US 20030076877A1
• Time in Patent Office: 1,210 Days
• Field of Search: 375/150, 375/141, 375/225, 375/146, 375/142, 375/143, 375/148, 375/147, 375/149, 375/145, 375/130, 375/152, 375/343, 370/342, 370/208, 370/333, 370/335, 714/755, 341/107
• US Class Current: 375/150
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity

Abstract

In a code division multiple access signal receiving apparatus for demodulating transmit data by subjecting a receive signal to despread processing using a code sequence identical with a spreading-code sequence on a transmitting side, a cross-correlation detector calculates a cross-correlation value, on a per-symbol basis, between a spreading-code sequence for spread-spectrum modulating local-station-addressed transmit data and a spreading-code sequence for spread-spectrum modulating other-station-addressed transmit data; a discriminator discriminates whether the calculated cross-correlation value has exceeded a threshold value; and a switch halts input, to a decoder, of a portion of the receive signal that corresponds to the full interval or partial interval of a symbol where the cross-correlation value exceeds the threshold value.

Claims

1. A code division multiple access signal receiving apparatus for demodulating transmit data by subjecting a receive signal to despread processing using a code sequence identical with a spreading-code sequence on a transmitting side, comprising:

a cross-correlation detector for calculating a cross-correlation value per symbol between a spreading-code sequence for spread-spectrum modulating local-station-addressed transmit data and a spreading-code sequence for spread-spectrum modulating other-station-addressed transmit data;

a comparator for comparing the cross-correlation value with a threshold value;

a control signal output portion for outputting a control signal during a symbol interval when the cross-correlation value is larger than or equal to the threshold value; and

a switch for halting passage of a portion of the receive signal that corresponds to said symbol interval during which the control signal is output or halting despread processing of a portion of the receive signal that corresponds to said symbol interval.

2. A code division multiple access signal receiving apparatus according to claim 1, comprising:

a despreader for subjecting the receive signal to despread processing using a code sequence identical with a spreading-code sequence on the transmitting side; and

a decoder for decoding transmit data using a despread signal output from the despreader;

said switch regarding the receive signal prior to despreading thereof or a despread signal as said receive signal, and halting passage of a portion of the despread signal that corresponds to all or a part of said spreading-code sequence.

3. A code division multiple access signal receiving apparatus according to claim 2, comprising:

a delay unit for delaying said code sequence for despread processing or despread signal for a prescribed period of time;

said delay unit matching timing of the despread signal, which is input to said switch, to detection timing of the cross-correlation value by delay processing.

4. A code division multiple access signal receiving apparatus according to claim 1, wherein said cross-correlation detector calculates the cross-correlation value between said spreading-code sequences in advance and saves the position of the spreading-code sequence discriminated to be an interference interval based upon the cross-correlation value;

and

said switch halts passage of a portion of the receive signal regarding all or part of a spreading-code sequence that conforms to the position saved.

5. A code division multiple access signal receiving apparatus according to claim 1, wherein said switch outputs a signal of a predetermined level when blocking passage of part of the receive signal.

6. A code division multiple access signal receiving apparatus for demodulating transmit data by subjecting a receive signal to despread processing using a code sequence identical with a spreading-code sequence on a transmitting side, comprising:

a cross-correlation detector for calculating a cross-correlation value per symbol between spread-spectrum modulated local-station-addressed transmit data and spread-spectrum modulated other-station-addressed transmit data;

a comparator for comparing the cross-correlation value with a threshold value;

a control signal output portion for outputting a control signal during a symbol interval when the cross-correlation value is larger than or equal to the threshold value; and

a switch for halting passage of a portion of the receive signal that corresponds to said symbol interval dining which the control signal is output or halting despread processing of a portion of the receive signal that corresponds to said symbol interval.

7. A code division multiple access signal receiving apparatus for demodulating transmit data by subjecting a receive signal to despread processing using a code sequence identical with a spreading-code sequence on a transmitting side, comprising:

a cross-correlation detector for calculating a cross-correlation value per symbol between a first spreading-code sequence for spread-spectrum modulating local-station-addressed transmit data and a second spreading-code sequence for spread-spectrum modulating other-station-addressed transmit data;

a comparator for comparing the cross-correlation value with a threshold value;

a code-coincident-chip detector for detecting whether the values of the first and second spreading-code sequence coincide or not per chip;

a control signal output portion for outputting a control signal during a chip interval when the values of the first and second spreading-code sequence coincide per chip and the cross-correlation value is larger than or equal to the threshold value; and

a switch for halting passage of a portion of the receive signal that corresponds to said chip interval during which the control signal is output or halting despread processing of a portion of the receive signal that corresponds to said chip interval.

8. A code division multiple access signal receiving apparatus according to claim 7 comprising:

a despreader for subjecting a receive signal to despread processing using a code sequence identical with the spreading-code sequence on the transmitting side; and

a decoder for decoding transmit data using a despread signal output from the despreader;

said switch regarding the receive signal prior to despreading thereof or the despread signal as said receive signal, and halting passage of a portion of the despread signal that corresponds to all or a part of said spreading-code sequence on the transmitting side.

9. A code division multiple access signal receiving apparatus according to claim 8 comprising:

a delay unit for delaying said code sequence for despread processing or despread signal for a prescribed period of time;

said delay unit matching timing of the despread signal, which is input to said switch, to detection timing of the cross-correlation value by delay processing.

10. A code division multiple access signal receiving apparatus according to claim 7 wherein said cross-correlation detector calculates the cross-correlation value between said spreading-code sequence in advance and saves the position of the spreading-code sequence discriminated to be an interference interval based upon the cross-correlation value;

and

said switch halts passage of a portion of the receive signal regarding all or part of the spreading-code sequence that conforms to the position saved.

11. A code division multiple access signal receiving apparatus according to claim 7 wherein said switch outputs a signal of a predetermined level when blocking passage of part of the receive signal.

12. A code division multiple access signal receiving apparatus comprising:

a decoder for decoding transmit data;

a despreader for subjecting a receive signal to despread processing; and

a cross-correlation detector for calculating a cross-correlation value between a first spreading-code sequence for spread-spectrum modulating local-station-addressed transmit data and a second spreading-code sequence that differs from said first spreading-code sequence and for generating, based upon the result of the cross-correlation value, a control signal that prevents a portion of the result of the despread processing from inputting to said decoder.