Abstract: In a radio communications system where a base station communicates with each terminal while controlling transmission power of a channel used for communication between the base station and the terminal, a magnitude of the transmission power is monitored and a communication charge rate is determined based on the magnitude of the transmission power. A communication charge for the communication is calculated using as parameters the communication charge rate and a time period during which the communication charge rate is kept.

Abstract: A receiving apparatus in a spread spectrum system includes a quadrature-demodulating section for demodulating a received signal in accordance with a clock signal to generate first and second quadrature components of an information signal and first and second quadrature components of a pilot signal and a spreading code generating section for generating a spreading code sequence which is the same as used on a transmission side, for each of the information signal first and second quadrature components and pilot signal first and second quadrature components in response to the clock signal. A despreading section despreads each of the information signal first and second quadrature components and pilot signal first and second quadrature components by use of the corresponding generated spreading code sequence.

Abstract: The object of the present invention is to provide a radio receiver, having a high reception sensitivity, that can limit cross-modulation even during the transmission of a signal that is related to frame synchronization and that has a signal strength different from that of another channel, and that can take into consideration the deterioration of a received signal caused by thermal noise. A gain controller is provided that employs the quality of received data detected by an error detector and the magnitude of a signal output by a band-pass filter in order to determine whether cross-modulation has occurred, and that controls the degree of attenuation provided by a variable gain attenuator provided at the front end of a reception unit.

Abstract: In order to provide a handy phone which enables a user of a radio telephone network to reopen automatically a communication disconnected because of communication quality degradation by way of another available radio telephone network with a simple configuration, a multi-modal handy phone (1) of the invention comprises a plurality of radio modules each prepared for accessing corresponding each of the plurality of radio telephone networks; monitoring means for monitoring communication quality; a change-over unit for selecting one of the plurality of radio modules according to result of the monitoring; a telephone number register for storing telephone number of the other party; a calling unit for calling the telephone number registered in the telephone number register 4 by way of one of the plurality of radio modules selected by said changeover unit; and a user interface unit.

Abstract: An automatic gain controller controls the gain of a variable-gain amplifier based on an error signal which is corrected by a correction controller using discrete characteristic data which are sampled from a gain control characteristic of the variable-gain amplifier in sampling steps each being set depending on a variation of the gain control characteristic. The correction controller corrects the error signal based on continuous characteristic data generated from the discrete characteristic data stored in the memory so that the gain control characteristic of the variable-gain amplifier is substantially linear with respect to the error signal.

Abstract: A de-spread code phase detection apparatus and method in an SS receiver having a RAKE synthesizing demodulation function of receiving a pilot signal and a data signal, which have undergone spread spectrum modulation, is provided. The apparatus detects a plurality of different de-spread code phases used for demodulation by: performing de-spread processing of the pilot signal, separately performing de-spread demodulation of the data signal by using the plurality of de-spread code phases, performing predetermined weighting processing for the outputs upon phase matching, synthesizing the outputs, and outputting resultant data. The apparatus includes a search correlator, a search processing control section, and a search processing section. The search correlator obtains correlation results of the pilot signal and a de-spread code while sequentially changing the phase of the de-spread code.

Abstract: A data rate detector is used for a terminal station receiver for receiving a coded signal which is transmitted at a selected one of a plurality of information data rates and whose transmission power is controlled to a predetermined ratio in accordance with the selected information data rate. The coded signal has at least one power control bit inserted in one information frame to control the transmission power in a terminal station. The detector includes a bit extractor, a comparator, and a rate determination device. The bit extractor extracts the reception power value of the power control bit and the reception power value of an information symbol other than the power control bit from a plurality of symbols constituting an information frame obtained by demodulating the received coded signal in a predetermined interval. The comparator compares the two reception power values extracted by the bit extractor.

Abstract: In a sync acquisition and tracking circuit for a DS/CDMA receiver, phase position signals are sequentially and cyclically selected at a specified rate higher than the rate at which Rayleigh fading occurs. The selected signal is used to-control the phase of PN sequences. Correlation is taken between spread pilot signals and the orthogonal PN sequences at a chip rate to produce despread pilot signals, which are integrated to produce a correlation value. A set of accumulators are provided, which are sequentially and cyclically selected at the specified rate. The correlation value is applied to the selected accumulator to produce a total sum of correlation values. The highest total sums are selected from the outputs of all accumulators, and corresponding phase position signals are identified. A set of orthogonal despreading sequences are generated corresponding to the identified phase position signals for application to the receiver.

Abstract: In a direct sequence spread spectrum receiver, spread orthogonal data signals and spread orthogonal pilot signals are correlated with orthogonal despreading sequences at a chip rate. These despread signals are integrated at a symbol rate to produce orthogonal data symbols and orthogonal pilot symbols. A predetermined number of pilot symbols of each phase component are moving-averaged. Each phase component of the orthogonal data symbols is weighted with the moving average value of the corresponding phase component of the pilot symbols, and summed with the other weighted component of the data symbols to produce an output signal of the spread spectrum receiver.

Abstract: In a direct sequence spread spectrum receiver, multiple correlators are provided for despreading a spread data signal and a spread pilot signal. During a sync acquisition mode, pilot demodulators are connected to the correlators, respectively, and during a subsequent tracking mode, data demodulators are connected to the correlators whose outputs are combined by an adder to produce an output for the receiver. Despreading codes of different phase positions are generated and supplied to the correlators, respectively. During the sync acquisition mode, the phase position of each despreading code is successively shifted and high correlation values are determined from the outputs of the pilot demodulators. During the tracking mode, the phase positions of the despreading codes are set according to the high correlation values.