Spread spectrum communication system

摘要

The present invention defines a combined channel or a composite channel which is to be transformed into a plurality of element channels. The composite channel may be either shared by a plurality of communication stations on time division multiplex basis, or used by a single communication station. In a transmit side, serial data information which is called a composite channel is transformed (2) to parallel form associated with a plurality of element channels, each of which is spread by using a single common PN code (5). The spread element channels are frequency converted to radio frequency so that the center carrier frequency is offset from that of adjacent element channel by an integer multiple of information transmission rate of each element channel, and frequency band occupied by spread element channels overlap with one another. The element channels thus spread and frequency converted are combined (13) on frequency axis, and transmitted to a receive side. Thus, all the element channels are synchronized with one another because of the use of a single common PN code, and receive level of signal of each element channel is uniform, irrespective of the number of communication stations, and therefore, high quality communication with no interference is obtained in relatively narrow frequency band.