Communication method and its power control method
First Claim
1. A communication system for performing code-division multiple access communications between a mobile station and a base station wherein;
- said base station comprises;
base station receiving means for receiving signals from said mobile station and outputting a first reception signal;
interference canceling means for canceling a multiple access interference signal contained in said first reception signal;
interference cancellation effect estimating means for estimating a post-interference cancellation signal-to-interference power ratio of said first reception signal which is currently being received;
control command generating means for generating a power control command by comparing said post-interference cancellation signal-to-interference power ratio determined by said interference cancellation effect estimating means with a target value for power control; and
base station transmitting means for transmitting said power control command to said mobile station; and
said mobile station comprises;
mobile station receiving means for receiving a signal from said base station and outputting a second reception signal; and
mobile station transmitting means which adjusts the power of the transmission signal transmitted to said base station based on said power control command contained in said second reception signal.
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Accused Products
Abstract
The purpose of the present invention is to offer a structure of a CDMA system having a power control method and interference cancellers which can effectively increase the system capacity and is resistant to sudden changes on the communication path, and to achieve a power control method with a fast response capable of preventing unnecessary increases in the transmission power (and multiple access interference) of the uplink by reflecting the values of the post-interference cancellation signal-to-interference power ratio in the generation of power control command information. The invention is directed to a power control method in a communication system for performing communications by code-division multiple access between a mobile station and base station, wherein a multiple access interference signal contained in a reception signal from the mobile station is cancelled, a post-interference cancellation signal-to-interference power ratio of the reception signal currently received is estimated, a power control command is generated by comparing the estimated post-interference cancellation signal-to-interference power ratio and a target value for power control, and transmitting this power control command to the mobile station to control the transmission power of the mobile station.
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Citations
18 Claims
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1. A communication system for performing code-division multiple access communications between a mobile station and a base station wherein;
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said base station comprises;
base station receiving means for receiving signals from said mobile station and outputting a first reception signal;
interference canceling means for canceling a multiple access interference signal contained in said first reception signal;
interference cancellation effect estimating means for estimating a post-interference cancellation signal-to-interference power ratio of said first reception signal which is currently being received;
control command generating means for generating a power control command by comparing said post-interference cancellation signal-to-interference power ratio determined by said interference cancellation effect estimating means with a target value for power control; and
base station transmitting means for transmitting said power control command to said mobile station; and
said mobile station comprises;
mobile station receiving means for receiving a signal from said base station and outputting a second reception signal; and
mobile station transmitting means which adjusts the power of the transmission signal transmitted to said base station based on said power control command contained in said second reception signal. - View Dependent Claims (2, 3, 4, 5)
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6. A communication system for performing code-division multiple access communications between a mobile station and a base station, wherein:
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said base station comprises;
base station receiving means for receiving signals from said mobile station and outputting a first reception signal;
interference canceling means for canceling a multiple access interference signal contained in said first reception signal;
error rate calculating means for decoding said first reception signal after interference cancellation by said interference canceling means and determining an error rate of the decoded data;
first target value setting means for determining a target value for power control based on the error rate determined by said error rate calculating means;
interference cancellation effect estimating means for estimating the effects of interference cancellation by said interference canceling means;
second target value setting means for updating said target value depending on the interference cancellation effects estimated by said interference cancellation effect estimating means;
control command generating means for generating a power control command by comparing said target value outputted from said second target value setting means with the signal-to-interference power ratio of said first reception signal which is currently being received; and
base station transmitting means for transmitting said power control command to said mobile station; and
said mobile station comprises;
mobile station receiving means for receiving a signal from said base station and outputting a second reception signal; and
mobile station transmitting means which adjusts the power of the transmission signal transmitted to said base station based on said power control command contained in said second reception signal.
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7. A base station device for a communication system for performing communications with a mobile station by code-division multiple access;
- comprising;
base station receiving means for receiving signals from said mobile station and outputting a reception signal;
interference canceling means for canceling a multiple access interference signal contained in said reception signal;
interference cancellation effect estimating means for estimating a post-interference cancellation signal-to-interference power ratio of said reception signal which is currently being received;
control command generating means for generating a power control command by comparing said post-interference cancellation signal-to-interference power ratio determined by said interference cancellation effect estimating means with a target value for power control; and
base station transmitting means for transmitting said power control command to said mobile station. - View Dependent Claims (8, 9, 10, 11, 14, 15, 16, 17)
- comprising;
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12. A base station device for a communication system for performing communications with a mobile station by code-division multiple access;
- comprising;
base station receiving means for receiving signals from said mobile station and outputting a reception signal;
interference canceling means for canceling a multiple access interference signal contained in said reception signal;
error rate calculating means for decoding said reception signal after interference cancellation by said interference canceling means and determining an error rate of the decoded data;
first target value setting means for determining a target value for power control based on the error rate determined by said error rate calculating means;
interference cancellation effect estimating means for estimating the effect of the interference cancellation by said interference canceling means;
second target value setting means for updating said target value depending on the interference cancellation effects estimated by said interference cancellation effect estimating means;
control command generating means for generating a power control command by comparing said target value outputted from said second target value setting means with the signal-to-interference power ratio of said first reception signal which is currently being received; and
base station transmitting means for transmitting said power control command to said mobile station.
- comprising;
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13. A power control method in a communication system for performing communications by code-division multiple access between a mobile station and a base station;
- comprising steps of;
canceling a multiple access interference signal contained in a reception signal from said mobile station;
estimating a post-interference cancellation signal-to-interference power ratio of said reception signal which is currently being received;
generating a power control command by comparing said estimated post-interference cancellation signal-to-interference power ratio and a target value for power control; and
controlling the transmission power of said mobile station by transmitting said power control command to said mobile station.
- comprising steps of;
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18. A power control method in a communication system for performing communications by code-division multiple access between a mobile station and a base station;
- comprising steps of;
canceling a multiple access interference signal contained in a reception signal from said mobile station;
decoding said reception signal after said interference cancellation and determining the error rate of said decoded data, determining a target value for power control based on the determined error rate, estimating the interference cancellation effect due to said interference cancellation, and updating said target value depending on said estimated interference cancellation effect;
generating a power control command based on a comparison between said target value and the signal-to-interference power ratio of said reception signal which is currently being received; and
transmitting said power control command to said mobile station to control the transmission power of said mobile station.
- comprising steps of;
Specification