摘要:
There are disclosed a radiocommunication apparatus and a radiocommunication system. There are provided a receiving section capable of receiving a plurality of types of signals which have been spread through use of different spread code information according to a CDMA scheme in a transmitting-side radiocommunication apparatuses; and a spread demodulation section which carries out despread processing for the common signal portions of the plurality of types of signals received by the receiving section through use of a composite spread code formed from a plurality of spread codes. Accordingly, it becomes possible to significantly improve the quality of received signals.
摘要:
The present invention reduces the scale of circuitry and shortens the code phase detection time needed to achieve initial synchronization. In a correlator for calculating correlation between a received spreading code contained in a received spread-spectrum signal and a reference spreading code, a combined code generator is included. The combined code generator outputs a combined spreading code by weighting and combining a plurality of phase-shifted reference spreading codes A1–AM. Further, an arithmetic circuit calculates correlation between the received spreading code and the plurality of phase-shifted reference spreading codes simultaneously. A phase detection circuit detects the phase difference between the received spreading code and a reference spreading code, namely the phase of the received spreading code from the results of the arithmetic operation.
摘要:
A multi-carrier signal received by an antenna is converted into a signal of an IF band by an RX, and converted into an I signal and a Q signal by an quadrature detector. The I signal and the Q signal as multi-carrier signals are converted into digital signals by an A/D converter, and input to complex filters. The complex filters extract a complex signal having a specified carrier. Then, complex filters shift the center frequency of the extracted complex signal into 0 Hz. The obtained base band signal is input to a finger, and despread and demodulated. The despread and demodulated signal is RAKE synthesized by a synthesis unit, and transmitted to a signal discrimination unit.
摘要:
A code multiplexing wireless apparatus for amplifying a code-multiplexed signal and then transmitting the amplified signal includes the following to reduce output back-off, improve the efficiency of a power amplifier and suppress broadening of the frequency spectrum: (1) a code-multiplexed signal generator for multiplying each item of transmission data by a spreading code sequence and combining spread-spectrum modulated signals to generate a code-multiplexed signal, (2) a signal-peak suppressing unit for holding the envelope of the code-multiplexed signal below a set level, and (3) a power amplifier for amplifying the code-multiplexed signal and transmitting the amplified code-multiplexed signal from an antenna.
摘要:
The present invention reduces the scale of circuitry and shortens the code phase detection time needed to achieve initial synchronization. In a correlator for calculating correlation between a received spreading code contained in a received spread-spectrum signal and a reference spreading code, a combined code generator is included. The combined code generator outputs a combined spreading code by weighting and combining a plurality of phase-shifted reference spreading codes A1-AM. Further, an arithmetic circuit calculates correlation between the received spreading code and the plurality of phase-shifted reference spreading codes simultaneously. A phase detection circuit detects the phase difference between the received spreading code and a reference spreading code, namely the phase of the received spreading code from the results of the arithmetic operation.
摘要:
An m-bit shift register stores data to be sent that are generated by a data generator 1 bit at a time sequentially. An orthogonal M sequence generator generates an M sequence with the m bits of data to be sent that are stored in the shift register as an initial value, then generates an orthogonal M sequence from that M sequence. A clock signal generator generates a clock signal of frequency 2m times the data rate of the data to be sent. The orthogonal M sequence generator operates in accordance with that clock signal.
摘要:
A code multiplexing transmitting apparatus spread-spectrum modulates transmission data of a plurality of channels by spreading codes that differ from one another, combines the spread-spectrum signals of each of the channels and transmits the resultant spread-spectrum modulated signal. A spread-spectrum modulating unit for each channel includes a phase shifter for shifting, by a predetermined angle channel by channel, the phase of a position vector of the spread-spectrum modulated signal of each channel. As the result of such phase control, the phases of pilot signal portions of the spread-spectrum modulated signals of the respective channels are shifted relative to one another so that the peak values of the code-multiplexed signal can be suppressed.
摘要:
Co-channel interference may be prevented even if data having different transmission rates are concurrently multiplied to a same frequency band width with a different spreading factors. A method for generating code division multiple access data from data having different rates by a direct spread spectrum includes the steps of combining an orthogonal code and a reversed orthogonal code obtained by inverting the orthogonal code, for each of orthogonal code sequence structured by an m-sequence thereby to generate a first sequence of orthogonal codes, combing two of the orthogonal code for each of orthogonal code sequences structured by the m-sequence thereby to generate a second sequence of orthogonal codes, combining two of the reversed orthogonal code for each of orthogonal code sequences structured by the m-sequence thereby to generate a third sequence of orthogonal codes, and generating another orthogonal code having twice a code length of the orthogonal code from the first, second and third sequence of orthogonal codes; and multiplying the generated orthogonal code and a different m-sequence, together.
摘要:
A code multiplexing transmitting apparatus spread-spectrum modulates transmission data of a plurality of channels by spreading codes that differ from one another, combines the spread-spectrum signals of each of the channels and transmits the resultant spread-spectrum modulated signal. A spread-spectrum modulating unit for each channel includes a phase shifter for shifting, by a predetermined angle channel by channel, the phase of a position vector of the spread-spectrum modulated signal of each channel. As the result of such phase control, the phases of pilot signal portions of the spread-spectrum modulated signals of the respective channels are shifted relative to one another so that the peak values of the code-multiplexed signal can be suppressed.
摘要:
A radio receiver includes a plurality of demodulating units for demodulating a received radio wave received via a plurality of paths so as to produce respective demodulated signals, and combining units for executing a combination process of synchronizing and combining the demodulated signals produced by the plurality of demodulating units, the combining units correlating the demodulated signals produced by the plurality of demodulating units and excluding from a combination process a demodulated signal that meets a predetermined condition based on a predetermined algorithm.