Adaptive communication apparatus

• US 6,115,426 A
• Filed: 11/21/1997
• Issued: 09/05/2000
• Est. Priority Date: 11/22/1996
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
• Original Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
• Inventors: Shibata, Tsutayuki, Suzuki, Noriyoshi, Endo, Chisato, Fujimoto, Mitoshi
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Ha, Dac V.
• Application Number:
  US08/976,261
• Time in Patent Office: 1,019 Days
• Field of Search: 375/267, 375/285, 375/346, 375/347, 375/349, 375/260, 370/319, 370/343, 370/344, 455/273, 455/276.1
• US Class Current: 375/260
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 27/2649 Demodulators
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2662 Symbol synchronisation

Abstract

An adaptive communication apparatus for use in a multicarrier transmission system in which data sequence to be transmitted is divided into a plurality of data sequences, and these data sequences are converted into a high-frequency signal including a plurality of carriers allocated different frequencies and radio-transmitted in parallel. In the adaptive communication apparatus, a received high-frequency signal is separated into a plurality of carriers by a wave separator. The frequency characteristic of the received high-frequency signal is corrected by a frequency characteristic compensation unit. The frequency characteristic compensation unit is controlled by a controller through use of the high-frequency signal subjected to signal processing by the frequency characteristic compensation unit and the wave separator. The high-frequency signal thus processed by the frequency characteristic compensation unit and the wave separator is demodulated by a demodulator in order to output a plurality of data sequences corresponding to the respective carriers. The original data is reproduced by a parallel-to-serial converter from the plurality of data sequences corresponding to the respective carriers.

Claims

1. An adaptive communication apparatus for use in a multicarrier transmission system in which a data sequence to be transmitted is divided into a plurality of data sequences, converted into a high-frequency signal including a plurality of carriers with different frequencies and radio-transmitted in parallel, said apparatus comprising:

a wave separator for separating a received high-frequency signal into a plurality of carriers;

a frequency characteristic compensation unit for correcting frequency characteristic of the received high-frequency signal;

a controller for controlling said frequency characteristic compensation unit through use of the high-frequency signal subjected to signal processing by said frequency characteristic compensation unit and said wave separator;

a demodulator for demodulating the high-frequency signal thus signal-processed by said frequency characteristic compensation unit and said wave separator in order to output a plurality of data sequences corresponding to the respective carriers; and

a parallel-to-series converter for producing one data sequence from the plurality of data sequences corresponding to the respective carriers;

wherein the received high-frequency signal that includes the plurality of carriers is first input to said frequency characteristic compensation unit in order to correct the frequency characteristic of the high-frequency signal;

the corrected signal is then input to said wave separator in order to obtain signals corresponding to the respective carriers; and

the obtained signals are input to said controller and said demodulator.

2. An adaptive communication apparatus according to claim 1, further comprising a plurality of antenna elements which receive signals to be output to said wave separator or said frequency characteristic compensation unit.

3. An adaptive communication apparatus according to claim 1, further comprising a plurality of antenna elements which receive the high-frequency signal including a plurality of carriers and to be output to said wave separator or said frequency characteristic compensation unit.

4. An adaptive communication apparatus according to claim 1, further comprising an antenna unit in which the high-frequency signal to be input to said wave separator or said frequency characteristic compensation unit is generated by dividing a signal received by a single antenna to obtain divided signals and delaying the divided signals by various periods of time through use of a delay unit.

5. An adaptive communication apparatus according to claim 1, wherein said frequency characteristic compensation unit comprises a weighting unit for weighting the high frequency signals received by the respective antenna elements and a combiner for combining the signals weighted by said weighting unit.

6. An adaptive communication apparatus according to claim 1, wherein said frequency characteristic compensation unit comprises a weighting unit for weighting the respective divided signals having different delay times;

and a combiner for combining together the signals weighted by said weighting unit.

7. An adaptive communication apparatus for use in a multicarrier transmission system in which a data sequence to be transmitted is divided into a plurality of data sequences, converted into a high-frequency signal including a plurality of carriers with different frequencies, and radio-transmitted in parallel, said apparatus comprising:

a wave separator for separating a received high-frequency signal into a plurality of carriers;

a frequency characteristic compensation unit for correcting high frequency characteristic of the received high-frequency signal;

a controller for controlling said frequency characteristic compensation unit based on said plurality of carriers included in said high-frequency signal subjected to signal processing by said separator so that a frequency characteristic determined by one of amplitudes and powers of said respective carriers have a predetermined characteristic;

a demodulator for demodulating the high-frequency signal signal-processed by said frequency characteristic compensation unit and said wave separator in order to output a plurality of data sequences corresponding to the respective carriers; and

a parallel-to-serial converter for reproducing one data sequence from the plurality of data sequences corresponding to the respective carriers, wherein said controller compares a reference signal periodically inserted into data to be transmitted with a reference signal provided on a reception side to obtain a difference therebetween, and controls said frequency characteristic compensation unit such that the difference is minimized.

8. An adaptive communication apparatus for use in a multicarrier transmission system in which a data sequence to be transmitted is divided into a plurality of data sequences, converted into a high-frequency signal including a plurality of carriers with different frequencies, and radio-transmitted in parallel, said apparatus comprising:

a wave separator for separating a received high-frequency signal into a plurality of carriers;

a frequency characteristic compensation unit for correcting high frequency characteristic of the received high-frequency signal;

a controller for controlling said frequency characteristic compensation unit based on said plurality of carriers included in said high-frequency signal subjected to signal processing by said separator so that a frequency characteristic determined by one of amplitudes and powers of said respective carriers have a predetermined characteristic;

a demodulator for demodulating the high-frequency signal signal-processed by said frequency characteristic compensation unit and said wave separator in order to output a plurality of data sequences corresponding to the respective carriers; and

a parallel-to-serial converter for reproducing one data sequence from the plurality of data sequences corresponding to the respective carriers, wherein said controller controls said frequency characteristic compensation unit so that all of said amplitudes or powers of said respective carriers become equal to a predetermined value.

9. An adaptive communication apparatus for use in a multicarrier transmission system in which data sequence to be transmitted is divided into a plurality of data sequences, converted into a high-frequency signal including a plurality of carriers with different frequencies, and radio-transmitted in parallel, said apparatus comprising:

a plurality of incident wave extractors each of which extracts only one of the incident wave components from a received high-frequency signal;

a phase shifter for adjusting a phase of each of the incident wave components extracted by said incoming wave extractors;

a combiner for combining together the incident wave components whose phases are adjusted by said phase shifter;

a demodulator for demodulating the incident wave components combined by said combiner in order to output a plurality of data sequences corresponding to the respective carriers; and

a parallel-to-serial converter for reproducing one data sequence from the plurality of data sequences corresponding to the respective carriers,

wherein each of said incident wave extractors comprises;

a frequency characteristic compensation unit for correcting frequency characteristic of the high-frequency signal;

a wave separator for separating the high-frequency signal into signals corresponding to the respective carriers; and

a controller for controlling the frequency characteristic compensation unit through use of the high-frequency signal processed by said frequency characteristic compensation unit and said wave separator.

10. An adaptive communication apparatus according to claim 9, wherein said high-frequency signal includes guard intervals which are formed by adding a part of data to be transmitted to the data to be transmitted.

11. An adaptive communication apparatus according to claim 9, wherein said wave separator comprises a serial-to-parallel converter for converting an input signal to a parallel signal, and a Fourier transform unit to which the parallel signal is input from said serial-to-parallel converter and which outputs said signals corresponding to the respective carriers.

12. An adaptive communication apparatus according to claim 11, wherein the serial-to-parallel converter of each of said incident wave extractors converts a corresponding signal into parallel signals at different timings within a delay time corresponding to the guard interval.

13. An adaptive communication apparatus according to claim 9, wherein said phase shifter adjusts each of said phases for the respective carriers.

14. An adaptive communication apparatus according to claim 9, further comprising a delay and phase detection unit for detecting the delay time and phase of each of the incident wave components from the received high-frequency signal and for providing said respective serial-to-parallel converter of each of said incident wave extractors with timing for conversion from the serial signal to the parallel signals based on the detected delay time and phase.

15. An adaptive communication apparatus according to claim 14, wherein said phase shifter commonly adjusts said phases with respect to said carriers.

16. An adaptive communication apparatus according to claim 14, further comprising a matching unit for compensating the delay of each of the incident wave components output from said incident wave extractors in accordance with the delay time and phase of each of said incident wave components detected by said delay and phase detection unit, and adding said incident wave components just in phase, said matching unit being an alternative to said phase shifter.

17. An adaptive communication apparatus for use in a multicarrier transmission system in which a data sequence to be transmitted is divided into a plurality of data sequences, converted into a high-frequency signal including a plurality of carriers with different frequencies, and radio-transmitted in parallel, said apparatus comprising:

a wave separator for separating a received high-frequency signal into a plurality of carriers;

a frequency characteristic compensation unit for correcting high frequency characteristic of the received high-frequency signal;

a controller for controlling said frequency characteristic compensation unit based on said plurality of carriers included in said high-frequency signal subjected to signal processing by said separator so that a frequency characteristic determined by one of amplitudes and powers of said respective carriers have a predetermined characteristic;

a demodulator for demodulating the high-frequency signal signal-processed by said frequency characteristic compensation unit and said wave separator in order to output a plurality of data sequences corresponding to the respective carriers; and

a parallel-to-serial converter for reproducing one data sequence from the plurality of data sequences corresponding to the respective carriers, wherein the received high-frequency signal that includes the plurality of carriers is first input to said wave separator in order to obtain signals corresponding to the respective carriers;

the thus-obtained signals are then input to said frequency characteristic compensation unit in order to correct the frequency characteristic; and

the corrected signals are input to said controller and said demodulator.

18. An adaptive communication apparatus according to claim 17, further comprising a plurality of antenna elements which receive signals to be output to said wave separator or said frequency characteristic compensation unit.

19. An adaptive communication apparatus according to claim 17, further comprising a plurality of antenna elements which receive the high-frequency signal including said plurality of carriers and to be output to said wave separator or said frequency characteristic compensation unit.

20. An adaptive communication apparatus according to claim 17, further comprising an antenna unit in which the high-frequency signal to be input to said wave separator or said frequency characteristic compensation unit is generated by dividing a signal received by a single antenna to obtain divided signals and delaying the divided signals by various periods of time through use of a delay.

21. An adaptive communication apparatus according to claim 17, wherein said frequency characteristic compensation unit comprises a weighting unit for weighting the high frequency signals received by the respective antenna elements and a combiner for combining the signals weighted by said weighting unit.

22. An adaptive communication apparatus according to claim 17, wherein said frequency characteristic compensation unit comprises a weighting unit for weighting the respective divided signals having different delay times;

and a combiner for combining the signals weighted by said weighting unit.