Transmission power controller

• US 6,418,321 B1
• Filed: 01/05/1999
• Issued: 07/09/2002
• Est. Priority Date: 01/05/1998
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Itoh, Katsutoshi
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): CRAVER, CHARLES R
• Application Number:
  US09/225,300
• Time in Patent Office: 1,281 Days
• Field of Search: 455/522, 455/423-425, 455/10, 455/501-506, 455/69, 455/232--25, 375/224
• US Class Current: 455/522
• CPC Class Codes: H04B 2001/0416 having gain or transmission power control
• CPC Class Codes: H04W 52/08 Closed loop power control

Abstract

A transmission power controller includes a transmission amplifier located in a first station and having an adjustable gain. The transmission amplifier controls the power transmitted from the first station to a second station in accordance with a power control information signal transmitted from the second station. The transmission power controller comprises a power control information extracting circuit, and up/down decision circuit, and a filter interposed between the up/down decision circuit and the transmission amplifier. The filter extracts low frequency band components from sequential output signals of the up/down decision circuit, generates command signals, and applies the command signals to the transmission amplifier to control the gain of the transmission amplifier.

Claims

1. A transmission power controller including a transmission amplifier located in a first station and having an adjustable gain, said transmission amplifier controlling the power transmitted from the first station to a second station in accordance with a power control information signal transmitted from the second station, comprising:

a power control information extracting circuit for receiving the power control information signal from the second station and extracting information therefrom;

an up/down decision circuit coupled to said power control information extracting circuit for generating sequential output signals in accordance with the information extracted from said power control information extracting circuit, each of the sequential signals output by said up/down decision circuit including a low frequency band component; and

a filter interposed between said up/down decision circuit and the transmission amplifier, said filter extracting the low frequency band components from the sequential output signals of said up/down decision circuit, generating command signals therefrom, and applying said command signals to the transmission amplifier to control the gain thereof.

2. A transmission power controller according to claim 1 wherein said transmission power controller further comprises:

a switch for coupling the output of said up/down decision circuit to one of the transmission amplifier and said filter; and

an estimating circuit for estimating whether the power transmitted by said transmission amplifier matches a target power level set by said second station, said switch switching the output of said up/down decision circuit to said filter when the power transmitted by said transmission amplifier matches said target power level and to said transmission amplifier when the power transmitted by said transmission amplifier does not match said target power level.

3. A transmission power controller according to claim 1 wherein said first station is a mobile station and said second station is a base station of a CDMA communication system.

4. A transmission power controller according to claim 1, wherein said power control information signal transmitted from said second station comprises binary logical values even when the power transmitted from said first station is maintained.

5. A transmission power controller according to claim 1, wherein the information extracted by said power control information extracting circuit comprises binary logical values, and wherein said up/down decision circuit accumulates said binary logical values from said power control information extracting circuit to obtain said sequential output signals.

6. A transmission power controller including a transmission amplifier located in a first station and having an adjustable gain, said transmission amplifier controlling the power transmitted from the first station to a second station in accordance with a power control information signal transmitted from the second station, comprising:

a power control information extracting circuit for receiving the power control information signal from the second station and extracting information therefrom;

an up/down decision circuit coupled to said power control information extracting circuit for generating sequential output signals in accordance with the information extracted from said power control information extracting circuit, each of the sequential signals output by said up/down decision circuit including a low frequency band component; and

a filter interposed between said up/down decision circuit and the transmission amplifier, said filter extracting the low frequency band components from the sequential output signals of said up/down decision circuit, generating command signals therefrom, and applying said command signals to the transmission amplifier to control the gain thereof;

wherein said filter includes;

an adder having first and second inputs and an output, the output of said adder being coupled to the transmission amplifier;

a first gain control element having a first filter coefficient (1-A), where (A) is between 0 and 1, said first gain control element inputting a product of a sequential output signal of said up/down decision circuit and said first filter coefficient to the first input of said adder;

a second gain control element having a second filter coefficient (A), said second gain control element being connected to the second input of said adder; and

a delay circuit interposed between the output of said adder and an input of said second gain control element, said delay circuit inputting to said second gain control element the output of said adder during the interval preceding the interval when said first gain control element inputted to the first input of said adder the product of said sequential output signal of said up/down decision circuit and said first filter coefficient, said second gain control element inputting to said adder the product of the output of said delay circuit and said second filter coefficient.

7. A transmission power controller including a transmission amplifier located in a first station and having an adjustable gain, said transmission amplifier controlling the power transmitted from the first station to a second station in accordance with a power control information signal transmitted from the second station, comprising:

a power control information extracting circuit for receiving the power control information signal from the second station and extracting information therefrom;

an up/down decision circuit coupled to said power control information extracting circuit for generating sequential output signals in accordance with the information extracted from said power control information extracting circuit, each of the sequential signals output by said up/down decision circuit including a low frequency band component; and

a filter interposed between said up/down decision circuit and the transmission amplifier, said filter extracting the low frequency band components from the sequential output signals of said up/down decision circuit, generating command signals therefrom, and applying said command signals to the transmission amplifier to control the gain thereof;

wherein said estimating circuit comprises;

a received sequence register for storing the sequential output signals of said up/down decision circuit for a predetermined period;

a basic sequence register for storing a predetermined basic sequence indicating alternatively power up and power down operations; and

a correlator coupled to said switch for comparing the outputs of said received and basic sequence registers and estimating a correlation therebetween, said correlator controlling said switch to switch the output of said up/down decision circuit to said filter when the power transmitted by said transmission amplifier matches said target power level and to said transmission amplifier when the power transmitted by said transmission amplifier does not match said target power level.

8. A transmission power controller including a transmission amplifier located in a first station and having an adjustable gain, said transmission amplifier controlling the power transmitted from the first station to a second station in accordance with a power control information signal transmitted from the second station, comprising:

a power control information extracting circuit for receiving the power control information signal from the second station and extracting information therefrom;

an up/down decision circuit coupled to said power control information extracting circuit for generating sequential output signals in accordance with the information extracted from said power control information extracting circuit, each of the sequential signals output by said up/down decision circuit including a low frequency band component;

a filter, having a filter coefficient, interposed between said up/down decision circuit and the transmission amplifier, said filter extracting the low frequency band components from the sequential output signals of said up/down decision circuit, generating command signals therefrom, and applying said command signals to the transmission amplifier to control the gain thereof; and

a filter coefficients renewal circuit coupled to the output of said up/down decision circuit and to the input of said filter, said filter coefficient renewal circuit comprising

a received sequence register for storing the sequential output signals of said up/down decision circuit for a predetermined period;

a basic sequence register for storing a predetermined basic sequence indicating alternatively power up and power down operations;

a correlator for comparing the outputs of said received and basic sequence registers; and

a filter coefficient set-up circuit interposed between said correlator and said filter for selecting a filter coefficient in accordance with the output of said correlator.

9. A transmission power controller having a transmission amplifier for adjusting transmission power based on a power control information signal transmitted from a base station comprising:

a power control information extracting means for extracting said power control information signal,

an up/down decision means for producing a command signal to control a gain of said transmission amplifier in response to said power control information signal, said command signal comprising sequential signals based on said power control information signal extracted by said power control information extracting means,

a filter coefficient renewal means for estimating a matching status between actual transmission power of said transmission amplifier and target power level that said base station requires, and for renewing a filter coefficient based on said matching status, and

a filtering means for extracting a predetermined frequency band signal from said command signal based on said filter coefficient and for controlling a gain of said transmission amplifier based on said extracted predetermined frequency band signal.

10. A transmission power controller according to claim 9, wherein said matching status in said filter coefficient renewal means is estimated by a correlation between a received sequence of said power control information signal and a predetermined basic sequence indicating alternatively a power up operation and a power down operation.

11. A transmission power controller as in claim 9, wherein said power control information signal transmitted from said base station comprises binary logical values even when the power transmitted to said base station is maintained.

12. A transmission power controller according to claim 9, wherein the power control information signal extracted by said power control information extracting means comprises binary logical values, and wherein said up/down decision means accumulates said binary logical values from said power control information signal to obtain said sequential signals.

13. A transmission power controller having a transmission amplifier for adjusting transmission power based on a power control information signal transmitted from a base station comprising:

a power control information extracting means for extracting said power control information signal,

an up/down decision means for producing a command signal to control a gain of said transmission amplifier in response to said power control information signal, said command signal comprising sequential signals based on said power control information signal extracted by said control information extracting means, and

soft-decision output means for estimating a matching status between actual transmission power and target power level that said base station requires, and for suppressing said command signal with a predetermined changing range based on said matching status,

wherein said matching status in said soft-decision output means is estimated by a correlation between a received sequence of said power control information signal and a predetermined basic sequence indicating alternatively a power up operation and a power down operation.