Communication device

• US 6,934,541 B2
• Filed: 09/20/2001
• Issued: 08/23/2005
• Est. Priority Date: 03/01/2001
• Status: Active Grant

• Current Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Original Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Inventors: Miyatani, Tetsuhiko
• Primary Examiner(s): Ramakrishnaiah, Melur
• Application Number:
  US09/955,983
• Publication Number:
  US 20020128007A1
• Time in Patent Office: 1,433 Days
• Field of Search: 455/423, 455/424, 455/67.1, 455/561, 342/174, 342/372, 342/173, 342/703, 342/708
• US Class Current: 455/423
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas

Abstract

A communication device for transmitting and/or receiving signals by using a communication antenna includes signal characteristic information detection means for detecting information regarding signal characteristics of a calibration signal which are contained in a signal received by the communication antenna, calibration means for calibrating a communication antenna chain based on the detected signal characteristic information, and cancellation signal generating means for generating a cancellation signal corresponding to a calibration signal contained in the signal received by the communication antenna based on the calibration signal. The device also includes signal cancellation-by-subtraction means for subtracting the generated cancellation signal from the signal received by the communication antenna, and receive signal processing means for processing the received signal that is diminished by the cancellation signal.

Claims

1. A communication device for transmitting and/or receiving signals by using a communication antenna, said communication device comprising:

signal characteristic information detection means for detecting information regarding signal characteristics of a calibration signal contained in a signal received by the communication antenna;

calibration means for calibrating a communication antenna chain based on the signal characteristic information detected by said signal characteristic information detection means;

calibration signal cancellation means for removing a signal identical or substantially identical to the calibration signal from the signal received by the communication antenna; and

receive signal processing means for processing the received signal which is diminished by the signal identical or substantially identical to the calibration signal.

2. A communication device according to claim 1, further comprising a calibration signal transmitting antenna for transmitting a calibration signal to the communication antenna.

3. A communication device according to claim 1, further comprising:

calibration signal transmitting means for transmitting a calibration signal from a communication antenna; and

a calibration signal receiving antenna for receiving the calibration signal transmitted from the communication antenna;

wherein said signal characteristic information detection means detects information regarding the signal characteristics of the calibration signal received by said calibration signal receiving antenna, and

said calibration means calibrates the communication antenna chain based on the signal characteristic information detected by said signal characteristic information detection means.

4. A communication device according to claim 2, further comprising:

calibration signal transmitting means for transmitting a calibration signal from a communication antenna; and

a calibration signal receiving antenna for receiving the calibration signal transmitted from the communication antenna;

wherein said signal characteristic information detection means detects information regarding the signal characteristics of the calibration signal received by said calibration signal receiving antenna, and

said calibration means calibrates the communication antenna chain based on the signal characteristic information detected by said signal characteristic information detection means.

5. A communication device according to claim 1, further comprising a signal generator for generating a signal of a prescribed frequency for converting signal frequency,

wherein a frequency signal generated by a common signal generator is supplied to multiple antenna chains including all communication antenna chains.

6. A communication device according to claim 2, further comprising a signal generator for generating a signal of a prescribed frequency for converting a signal frequency,

wherein a frequency signal generated by a common signal generator is supplied to multiple antenna chains including all communication antenna chains.

7. A communication device according to claim 3, further comprising a signal generator for generating a signal of a prescribed frequency for converting a signal frequency,

wherein a frequency signal generated by a common signal generator is supplied to multiple antenna chains including all communication antenna chains.

8. A communication device according to claim 4, further comprising a signal generator for generating a signal of a prescribed frequency for converting a signal frequency,

wherein a frequency signal generated by a common signal generator is supplied to multiple antenna chains including all communication antenna chains.

9. A communication device according claim 1, wherein the communication antenna performs transmission/reception of a calibration signal and said signal characteristic information detection means performs detection of information regarding signal characteristics of the calibration signal at intervals.

10. A communication device according claim 2, wherein the communication antenna performs transmission/reception of a calibration signal and said signal characteristic information detection means performs detection of information regarding signal characteristics of the calibration signal at intervals.

11. A communication device according claim 3, wherein the communication antenna performs transmission/reception of a calibration signal and said signal characteristic information detection means performs detection of information regarding signal characteristics of the calibration signal at intervals.

12. A communication device according claim 4, wherein the communication antenna performs transmission/reception of a calibration signal and said signal characteristic information detection means performs detection of information regarding signal characteristics of the calibration signal at intervals.

13. A communication device according claim 5, wherein the communication antenna performs transmission/reception of a calibration signal and said signal characteristic information detection means performs detection of information regarding signal characteristics of the calibration signal at intervals.

14. A communication device according claim 6, wherein the communication antenna performs transmission/reception of a calibration signal and said signal characteristic information detection means performs detection of information regarding signal characteristics of the calibration signal at intervals.

15. A communication device according claim 7, wherein the communication antenna performs transmission/reception of a calibration signal and said signal characteristic information detection means performs detection of information regarding signal characteristics of the calibration signal at intervals.

16. A communication device according claim 8, wherein the communication antenna performs transmission/reception of a calibration signal and said signal characteristic information detection means performs detection of information regarding signal characteristics of the calibration signal at intervals.

17. A CDMA base station comprising:

n number of communication antennas constituting an adaptive array antenna, n being greater than 1;

n number of transceiver units;

n number of calibration signal cancellers, said n number of communication antennas, said n number of transceiver units, and said n number of calibration signal cancellers constituting n number of communication antenna chains; and

a user-segregated AAA signal processor and discriminator which is common to said n number of communication antenna chains, wherein;

each calibration signal canceller includes a despreader, a phase/gain error detector, a calibration signal generator, a complex multiplier and a subtracter;

each communication antenna is operable to transmit and receive spread spectrum signals to and from mobile stations by radio;

each transceiver unit is operable to conduct receive processing consisting of frequency-converting and orthogonally detecting received signals acquired from the associated communication antenna and outputting the result of the orthogonal detection to the associated calibration signal canceller, and to conduct transmit processing consisting of orthogonally modulating and frequency-converting a transmit signal received from the associated calibration signal canceller and outputting the result to the associated communication antenna;

for each calibration signal canceller,

said despreader is operable to acquire the received signal from the associated communication antenna, to despread the received signal by using a spreading code corresponding to the calibration signal, thereby detecting the calibration signal contained in the received signal, and to output the detection result to the associated phase/gain error detector, wherein

said associated phase/gain error detector is operable to detect the phase variation and gain variation of the calibration signal based on the detection result received from said despreader, to delete the phase component of the calibration signal produced on the calibration signal transmission side from the received calibration signal, and to output the result after deletion to the associated complex multiplier,

the associated calibration signal is operable to generate a signal identical to the calibration signal transmitted from the calibration signal transmission side and to output the generated signal to the associated complex multiplier,

said associated complex multiplier is operable to complex-multiply the result after deletion received from said associated phase/gain error detector and the generated signal received from said associated calibration signal generator, and to output the multiplication result to the associated subtracter as a cancellation signal,

said associated subtracter is operable to subtract the cancellation signal received from said associated complex multiplier from the received signal of the associated communication antenna chain input thereto by the associated transceiver unit, and to output the received signal after subtraction to said user-segregated AAA signal processor and discriminator; and

said user-segregated AAA signal processor and discriminator is operable to

conduct receive processing consisting of acquiring the received signals of the communication antenna chains from the calibration signal cancellers, multiplying the received signals of the communication antenna chains and receive weights which are applied to said communication antenna chains, and synthesizing the multiplication results for all communication antenna chains so as to produce a synthesis result that is a received signal of said adaptive array antenna, wherein the receive processing is performed for every mobile station,

conduct transmit processing consisting of modulating user specific data for X′

number of users, summing the modulated signals so as to produce transmit signals, and multiplying the transmit signals and transmit weights which are applied to said communication antenna chains, and

output the multiplication results for the respective communication antenna chains to said transceiver units via said calibration signal cancellers.

18. The CDMA base station according to claim 17, further comprising:

a calibration signal transmitting/receiving antenna;

a calibration signal transceiver unit; and

a calibration signal processor, wherein;

said calibration signal processor includes a calibration signal generator, a spreading code generator, a despreader, a phase/gain error detector and a controller;

said calibration signal transmitting/receiving antenna is operable to radio-transmit a calibration signal input thereto from said calibration signal transceiver unit and to output signals received by radio transmission to said calibration signal transceiver unit;

said calibration signal transceiver unit is operable to

receive the calibration signal from said calibration signal processor, orthogonally modulate and frequency-convert the received calibration signal, and output the modulated and frequency-converted calibration signal to said calibration signal transmitting/receiving antenna, and

acquire received signals from said calibration signal transmitting/receiving antenna, frequency-convert and orthogonally detect the received signals, and output the result of the orthogonal detection to said calibrating signal processor;

in a transmission system of said calibration signal processor, when performing receive calibration of a communication antenna chain, said calibrating signal generator is operable to operate under the control of said controller so as to generate a fixed spreading code as a calibration signal and to output the calibration signal to said calibration signal transceiver unit; and

in a reception system of said calibration signal processor during transmit calibration of a communication antenna chain upon reception of a calibration signal among calibration signals transmitted in turn from said communication antenna chains,

said controller is operable to instruct said spreading code generator to generate a spreading code corresponding to the received calibration signal, and said spreading code generator is operable to operate under the control of said controller so as to generate the instructed spreading code and output the generated spreading code to said despreader said calibration signal processor,

said despreader said calibration signal processor is operable to correlate the received signal acquired from said calibration signal transceiver unit and the spreading code supplied by said spreading code generator, and

said phase/gain error detector is operable to detect the phase variation and gain variation of the calibration signal based on the despreading result received from said despreader said calibration signal processor.

19. The CDMA base station according to claim 18, wherein:

a receiver unit of each communication antenna chain includes a low noise amplifier, a mixer, a band pass filter, an auto gain controller, an orthogonal detector, and low pass filters;

a transmitter unit of each communication antenna chain includes low pass filters, an orthogonal modulator, a band pass filter, a mixer, a band pass filter, and a power amplifier;

a calibration chain transmitter unit comprises low pass filters, an orthogonal modulator, a band pass filter, a mixer and a band pass filter;

a calibration chain receiver unit comprises a mixer, a band pass filter, an orthogonal detector, and low pass filters;

said mixers of said receiver units of said communication antenna chains and said mixer of said calibration chain transmitter unit are supplied with a receive side first local frequency signal generated by a common first signal generator, and said orthogonal detectors of said receiver units of said communication antenna chains and said orthogonal modulator of said calibration chain transmitter unit are supplied with a receive side second local frequency signal generated by a common second signal generator; and

said orthogonal modulators of said transmitter units of said communication antenna chains and said orthogonal detector of said calibration chain receiver unit are supplied with a transmit side first local frequency signal generated by a common third signal generator, and said mixers of said transmitter unit of said communication antenna chains and said mixer of said calibration chain receiver unit are supplied with a transmit side second local frequency signal generated by a common fourth signal generator.