COMMUNICATION SYSTEM, COMMUNICATION TERMINAL, COMMUNICATION METHOD, CHIP CLOCK GENERATION METHOD, AND ORTHOGONAL CODE GENERATION METHOD

摘要

When multiple communication terminals access a base station in CDMA in which transmission signals are spread with orthogonal codes, the orthogonal codes in CDMA signals transmitted from the communication terminals are synchronized on the communication path. The communication terminals each include an information acquirer acquiring reference time information common to the multiple communication terminals, a transmission time generator generating a chip clock on the basis of the time information, an orthogonal code generator generating orthogonal codes in time with the timing of the chip clock, a CDMA spreader spreading transmission signals with the orthogonal codes to generate code division multiple access signals, a carrier wave generator generating a carrier wave, and a BPSK modulator modulating the carrier wave generated by the carrier wave generator with the code division multiple access signals and transmitting the carrier wave.

主权项

1. A communication system, comprising:
a base station radio-transmitting to multiple communication terminals; and multiple communication terminals receiving signals transmitted from the base station and radio-transmitting to the base station, wherein the communication terminals each comprise: a time acquirer acquiring reference time information common to the multiple communication terminals; a clock generator generating a chip clock on the basis of the time information; a code generator generating orthogonal codes in time with the timing of the chip clock; a signal generator spreading transmission signals with the orthogonal codes to generate code division multiple access signals; a carrier wave generator generating a carrier wave; and a transmitter modulating the carrier wave generated by the carrier wave generator with the code division multiple access signals and transmitting the carrier wave to the base station, wherein the clock generator generates a chip clock having a chip duration of which the allowable error is larger than the time accuracy of the time information.