Frequency sharing mobile communication system equipped with diversity receiver incorporated with shared wave canceller

• US 6,301,316 B1
• Filed: 06/24/1998
• Issued: 10/09/2001
• Est. Priority Date: 03/31/1997
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Matsumoto, Shinji, Uchida, Yoshinori
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): PHAM, BRENDA H
• Application Number:
  US09/091,732
• Time in Patent Office: 1,203 Days
• Field of Search: 370/328, 370/329, 370/342, 370/344, 370/337, 370/335, 370/336, 370/345, 375/343, 375/347
• US Class Current: 375/347
• CPC Class Codes: H04B 7/084 Equal gain combining, only phase adjustments antenna beam scanning or forming by phase or amplitude control H01Q3/26, e.g. phased arrays
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04J 4/00 Combined time-division and frequency-division multiplex systems H04J13/00 takes precedence ; data transmission H04L5/26; telemetry G08C15/00

Abstract

In a mobile communication system, FDMA/TDMA signals, CDMA signals or TD-CDMA signals have a same time-slot and one signal shares a frequency in the time-slot. The system of a time-slot sharing and a frequency sharing has diversity receivers for demodulating information of desired waves based on signals in which shared waves have already been removed at receiving of desired waves when one signal is a desired wave and there are one or more shared waves.

Claims

1. A frequency sharing mobile communication system which shares frequency spectrum with other mobile communication systems using different multiple access encoding and modulation methods, comprising:

at least one base station having a diversity receiver including multiple antennas for receiving communication signals from different transmission signal paths;

a shared wave cancellation circuit including

a plurality of correlators for obtaining shared wave signals from each diversity antenna,

a plurality of multi-path equalizers for equalizing respective shared wave signals from said plurality of correlators, a combiner for combining the shared wave signals from said equalizers to obtain shared wave information, and

a plurality of multi-path simulators, each for receiving said shared wave information and simulating the transmission path of the signal received by a respective diversity antenna to produce a simulated transmission path shared wave signal;

said simulated transmission path shared wave signals being sent to a desired wave receiver which receives signals from each diversity antenna and subtracts said simulated transmission path shared wave signals from the signals received by each diversity antenna to obtain a desired wave signal.

2. The frequency sharing mobile communication system of claim 1, wherein said shared wave cancellation circuit comprises a CDMA shared wave canceller for cancelling CDMA shared wave signals on CDMA signal channels that share frequencies with FDMA/TDMA signals on a frequency axis.

3. A frequency sharing mobile communication system as claimed in claim 2, wherein the CDMA canceller for cancelling the CDMA signals sharing with the FDMA/TDMA signals in frequency fields, comprises:

CDMA correlators whose number is equal to the number of a plurality of diversity antennas;

a correlation code generator for generating CDMA correlation codes and providing them to the CDMA correlators;

transmission path equalizers whose number is equal to the number of the plurality of diversity antennas;

an adder for adding outputs from the transmission path equalizers;

a determinator for judging the output from the adder;

a modulator for inputting the output from the determinator and for generating and outputting reproduced CDMA signals;

transmission path simulators, whose number is equal to the number of the plurality of diversity antennas, for reproducing interferences in a plurality of transmission paths based on the output from the modulator; and

a microprocessor for determining coefficients of the transmission path simulators based on equalization coefficients of the transmission path equalizers.

4. A frequency sharing mobile communication system as claimed in claim 2, wherein the desired wave receiver is a FDMA/TDMA desired wave receiver, which comprises:

delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

adders, whose number is equal to the number of the plurality of diversity antennas, for removing reproduced CDMA signals, whose number is equal to the number of the plurality of diversity antennas, output from the CDMA shared wave cancellers from the output of the delay elements by subtraction;

desired wave equalizers, whose number is equal to the number of plurality of diversity antennas, for equalizing the output from the adders;

a second adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the second adder.

5. A frequency sharing mobile communication system as claimed in claim 4, comprises a plurality of the FDMA/TDMA desired wave receivers and a plurality of CDMA shared wave cancellers, thereby a plurality of the CDMA signals are removed simultaneously.

6. A frequency sharing mobile communication system as claimed in claim 4, comprises at least one base station comprising a plurality of the CDMA shared wave cancellers and a plurality of the FDMA/TDMA desired wave receivers.

7. A frequency sharing mobile communication system as claimed in claim 2, wherein the desired wave receiver is a CDMA desired wave receiver, which comprises:

delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

adders for removing reproduced CDMA signals output from the CDMA shared wave cancellers from the output of the delay elements by subtraction;

CDMA desired wave correlators, whose number is equal to the number of the plurality of diversity antennas, for correlating the output from the adders;

a correlation mode generator for generating CDMA correlation codes and for providing them to the CDMA desired wave correlators;

desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the CDMA desired wave correlators;

an adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the adder.

8. A frequency sharing mobile communication system as claimed in claim 7, comprises the CDMA desired wave receiver and a plurality of the CDMA shared wave cancellers, thereby a plurality of the CDMA signals are removed simultaneously.

9. A frequency sharing mobile communication system as claimed in claim 7, comprises at least one base station comprising a plurality of the CDMA shared wave cancellers and a plurality of the CDMA desired wave receivers.

10. The frequency sharing mobile communication system of claim 1, wherein said shared wave cancellation circuit comprises a TD-CDMA shared wave canceller for cancelling TD-CDMA shared wave signals that share frequencies with FDMA/TDMA signals on a frequency axis.

11. A frequency sharing mobile communication system as claimed in claim 10, wherein the TD-CDMA canceller for cancelling the TD-CDMA signals sharing with the FDMA/TDMA signals in frequency fields, which comprises:

TD-CDMA correlators whose number is equal to the number of a plurality of diversity antennas;

a correlation code generator for generating TD-CDMA correlation codes and providing them to the TD-CDMA correlators;

transmission path equalizers whose number is equal to the number of the plurality of diversity antennas;

an adder for adding outputs from the transmission path equalizers;

a determinator for judging the output from the adder;

a modulator for generating and outputting reproduced TD-CDMA signals based on the output from the determinater;

transmission path simulators, whose number is equal to the number of the plurality of diversity antennas, for reproducing interferences in a plurality of transmission paths based on the output from the modulator; and

a microprocessor for determining coefficients of the transmission path simulators based on equalization coefficients of the transmission path equalizers.

12. A frequency sharing mobile communication system as claimed in claim 10, wherein the desired wave receiver is a FDMA/TDMA desired wave receiver, which comprises:

delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

adders, whose number is equal to the number of the plurality of diversity antennas, for removing reproduced TD-CDMA signals output from the TD-CDMA shared wave cancellers from the output of the delay elements by subtraction;

desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the adders;

a second adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the second adder.

13. A frequency sharing mobile communication system as claimed in claim 10, wherein the desired wave receiver is a TD-CDMA desired wave receiver, which comprises:

delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

adders for removing reproduced TD-CDMA signals output from the TD-CDMA shared wave cancellers from the output from the delay elements by subtraction;

TD-CDMA desired wave correlators, whose number is equal to the number of the plurality of diversity antennas, for correlating the output from the adders;

a correlation code generator for generating TD-CDMA correlation codes and for providing them to the TD-CDMA desired wave correlators;

desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the TD-CDMA desired wave correlators;

an adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the adder.

14. A frequency sharing mobile communication system as claimed in claim 10, wherein the desired wave receiver is a CDMA desired wave receiver, which comprises:

delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

adders for removing reproduced TD-CDMA signals output from the TD-CDMA shared wave cancellers from the output of the delay elements by subtraction;

CDMA desired wave correlators, whose number is equal to the number of the plurality of diversity antennas, for correlating the output from the adders;

a correlation code generator for generating CDMA correlation codes and for providing them to the CDMA desired wave correlators;

desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the CDMA desired wave correlators;

an adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the adder.

15. A frequency sharing mobile communication system as claimed in claim 10, wherein the desired wave receiver is a TD-CDMA desired wave receiver, which comprises:

delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

adders for removing reproduced CDMA signals output from the CDMA shared wave cancellers from the output from the delay elements by subtraction in order to cancel the CDMA signals that share in the frequency field on the frequency axis with the FDMA/1-DMA signals;

TD-CDMA desired wave correlators, whose number is equal to the number of the plurality of diversity antennas, for correlating the output from the adders;

a correlation code generator for generating TD-CDMA correlation codes and for providing them to the TD-CDMA desired wave correlators;

desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the TD-CDMA desired wave correlators;

an adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the adder.

16. A frequency sharing mobile communication system which shares frequency spectrum with other mobile communication systems using different multiple access encoding and modulation methods, comprising:

at least one base station having a diversity receiver including multiple antennas for receiving communication signals from different transmission signal paths;

a shared wave cancellation circuit comprising a FDMA/TDMA shared wave canceller for cancelling shared wave signals on FDMA/TDMA signal channels that share frequencies with CDMA signals on a frequency axis or with TD-CDMA signals in a time slot, said cancellation circuit including

a plurality of multi-path equalizers for equalizing respective shared wave signals received from respective ones of said multiple antennas, a combiner for combining the shared wave signals from said equalizers to obtain shared wave information, and

a plurality of multi-path simulators, each for receiving said shared wave information and simulating the transmission path of the signal received by a respective diversity antenna to produce a simulated transmission path shared wave signal;

said simulated transmission path shared wave signals being sent to a desired wave receiver which receives signals from each diversity antenna and subtracts said simulated transmission path shared wave signals from the signals received by each diversity antenna to obtain a desired wave signal.

17. A frequency sharing mobile communication system as claimed in claim 16, wherein the FDMA/TDMA shared wave canceller comprises:

transmission path equalizers whose number is equal to the number of the plurality of diversity antennas;

an adder for adding outputs from the transmission path equalizers;

a determinator for judging the output from the adder;

a modulator for inputting the output from the determinator and for generating and outputting reproduced FDMA/TDMA signals;

transmission path simulators, whose number is equal to the number of the plurality of diversity antennas, for reproducing interferences in the transmission path based on the output from the modulator; and

a microprocessor for determining coefficients of the transmission path simulators based on equalization coefficients of the transmission path equalizers.

18. A frequency sharing mobile communication system as claimed in claim 16, wherein the desired wave receiver is a CDMA desired wave receiver, which comprises:

delay elements, whose number is equal to the number of a plurality of diversity antennas, for delaying each of signals received by the plurality of diversity antennas, independently;

adders, whose number is equal to the number of the plurality of diversity antennas, for removing reproduced FDMA/TDMA signals output from the FDMA/TDMA shared wave cancellers from the output of the delay elements by subtraction;

CDMA desired wave correlators, whose number is equal to the number of the plurality of diversity antennas, for correlating the output from the adders;

a correlation code generator for generating CDMA correlation codes and for providing them to the CDMA desired wave correlators;

desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the CDMA desired wave correlators;

an adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the adder.

19. A frequency sharing mobile communication system as claimed in claim 16, wherein the desired wave receiver is a TD-CDMA desired wave receiver, which comprises:

delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

adders, whose number is equal to the number of the plurality of diversity antennas, for removing reproduced FDMA/TDMA signals output from the FDMA/TDMA shared wave cancellers from TD-CDMA signals designated by a time slot that being equal to the time slot of the shared waves output from the delay elements;

TD-CDMA desired wave correlators, whose number is equal to the number of the plurality of diversity antennas, for correlating the output having no shared wave signals provided from the adders;

a correlation code generator for generating TD-CDMA correlation codes and for providing them to the TD-CDMA desired wave correlators;

desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the TD-CDMA desired wave correlators;

an adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the adder.

20. A frequency sharing mobile communication system as claimed in claim 16, which comprises a plurality of the FDMA/TDMA shared wave cancellers and a plurality of the CDMA or TD-CDMA desired wave receivers, thereby, a plurality of the FDMA/TDMA shared wave signals are removed simultaneously.

21. A frequency sharing mobile communication system having at least one base station comprising:

a plurality of CDMA shared wave cancellers for canceling shared waves on channels of CDMA signals that share frequencies with FDMA/TDMA signals on a frequency axis;

a plurality of TD-CDMA shared wave cancellers for canceling TD-CDMA signals that share frequencies with said FDMA/TDMA signals;

a plurality of FDMA/TDMA shared wave cancellers for canceling shared waves on FDMA/TDMA signal channels that share frequencies with CDMA signals on a frequency axis or share frequencies with TD-CDMA signals in a same time slot;

a plurality of desired FDMA/TDMA wave receivers comprising;

delay elements for delaying each of signals received by a plurality of diversity antennas, independently;

a plurality of adders, whose number is equal to the number of the plurality of diversity antennas, for removing reproduced CDMA signals, whose number is equal to the number of the plurality of diversity antennas, outputted by the CDMA shared wave cancellers from the output of the delay elements by subtraction;

a plurality of desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the adders;

a second adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the second adder;

a plurality of CDMA desired wave receivers, which comprises;

a plurality of delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

a plurality of adders for removing reproduced CDMA signals outputted from the CDMA shared wave cancellers from the output of the delay elements by subtraction;

a plurality of CDMA desired wave correlators, whose number is equal to the number of the plurality of diversity antennas, for correlating the output from the adders;

a correlation code generator for generating CDMA correlation codes and for providing them to the CDMA desired wave correlators;

a plurality of desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the CDMA desired wave correlators;

an adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the adder; and

a plurality of TD-CDMA desired wave receivers, which comprises;

a plurality of delay elements for delaying each of signals received by the plurality of diversity antennas, independently;

a plurality of adders for removing reproduced TD-CDMA signals output from the TD-CDMA shared wave cancellers from the output from the delay elements by subtraction;

a plurality of TD-CDMA desired wave correlators, whose number is equal to the number of the plurality of diversity antennas, for correlating the output from the adders;

a correlation code generator for generating TD-CDMA correlation codes and for providing them to the TD-CDMA desired wave correlators;

a plurality of desired wave equalizers, whose number is equal to the number of the plurality of diversity antennas, for equalizing the output from the TD-CDMA desired wave correlators;

an adder for adding the outputs from the desired wave equalizers; and

a desired wave demodulator for outputting a desired wave based on the output from the adder.