초록 ▼

The invention provides a variable rate CDMA spread circuit which can obtain a sufficient number of spread codes (i.e., channels) orthogonal to each other in a mobile communication system which employs the CDMA scheme and has a plurality of channels of different bit rates. The variable rate CDMA spre

The invention provides a variable rate CDMA spread circuit which can obtain a sufficient number of spread codes (i.e., channels) orthogonal to each other in a mobile communication system which employs the CDMA scheme and has a plurality of channels of different bit rates. The variable rate CDMA spread circuit includes channel transmission processing units. An adder adds transmission signals output from the plurality of channel transmission processing units. A spread code generator generates a spread code (long code) having a long period and assigned in units of base stations. A spreader spreads the synthesized transmission signal with the spread code (long code). A modulator modulates the transmission signal spread by the spread means to convert it into a radio signal and outputs the radio signal to an antenna.

대표청구항 ▼

[ What is claimed is:] [1.] A variable rate CDMA spread circuit in a mobile communication system using direct spread code division multiplex access and having channels which transmit data at a plurality of bit rates, saia first spread code generator which generates a first spread code at a basic rat

[ What is claimed is:] [1.] A variable rate CDMA spread circuit in a mobile communication system using direct spread code division multiplex access and having channels which transmit data at a plurality of bit rates, saia first spread code generator which generates a first spread code at a basic rate, said first spread code being used by all channels in said spread circuit;second spread code generator which generates second spread codes, each second spread code being unique for each channel in said spread circuit;wherein subrate channels which transmit data at a subrate corresponding to 1/M of said basic rate, are discriminated from one another by spreading data of said subrate channels in accordance with a respective second spread code which has a code length M; andall of said second spread codes are orthogonal to each other.