CDMA COMMUNICATION SYSTEM AND METHOD
First Claim
1. A base station for communicating with a plurality of terminal stations, comprising:
- an antenna for receiving uplink signals from said plurality of terminal stations and transmitting downlink signals to said plurality of terminal stations;
a modulator-demodulator for despreading signals received from said plurality of terminal stations, and for spreading signals to be transmitted to said plurality of terminal stations; and
a phase synchronization controller for generating a phase control signal for controlling a phase of an uplink signal transmitted from one of said plurality of terminal stations,wherein said modulator-demodulator detects a phase difference between a phase of a spreading code of a signal received from said terminal station and a reference phase, andsaid phase synchronization controller generates, in an acquisition searching mode, a first phase control signal, and, in a phase tracking control mode, a second phase control signal, based on said detected phase difference.
1 Assignment
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Accused Products
Abstract
In CDMA communications, a base station detects a difference between a reference phase of a spreading code and a phase of a received signal of each terminal station, and feeds a phase jump signal PJ-i representative of the phase difference back to each terminal station. After timing acquisition, the reception operation is performed using the reference phase, and a shift amount between the phase of a received signal and the reference phase is fed back to each terminal station as phase synchronization control information PC-i. Each terminal station coarsely adjusts the phase of the spreading code in accordance with the phase jump signal PJ-i, and thereafter finely adjusts the phase of its transmitting signal in accordance with the phase synchronization control information PC-i. It is therefore possible to synchronize the phases of the signals transmitted from terminal stations and received at the base station. Accordingly, an orthogonal code is used for spreading on the reverse links.
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Citations
1 Claim
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1. A base station for communicating with a plurality of terminal stations, comprising:
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an antenna for receiving uplink signals from said plurality of terminal stations and transmitting downlink signals to said plurality of terminal stations; a modulator-demodulator for despreading signals received from said plurality of terminal stations, and for spreading signals to be transmitted to said plurality of terminal stations; and a phase synchronization controller for generating a phase control signal for controlling a phase of an uplink signal transmitted from one of said plurality of terminal stations, wherein said modulator-demodulator detects a phase difference between a phase of a spreading code of a signal received from said terminal station and a reference phase, and said phase synchronization controller generates, in an acquisition searching mode, a first phase control signal, and, in a phase tracking control mode, a second phase control signal, based on said detected phase difference.
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Specification