Patent ID: 8982926
Filing Date: 2015-03-17
Classification: H04B,H04J

Abstract:
1. A spectrum spread communication system comprising: a communication base unit which communicates with communication extension units, wherein: each of the communication extension units has: a spread code generator which switches and selectively outputs spread codes in each frame; and a spread modulation unit which performs spread modulation of frame-structured transmission data by using the spread codes from the spread code generator, and transmits a spread-modulated signal to a transmission line; and the communication base unit has: a reference code generating unit which generates a plurality of reference codes corresponding to the plurality of spread codes; spread demodulation units in respective spread demodulation systems, the spread demodulation units performing spread demodulation of the spread-modulated signal received via the transmission line by using the reference codes; a code phase synchronization detection unit which controls the phase of the reference codes from the reference code generating unit so that the spread-modulated signal is synchronized in phase with any one of the reference codes; a frame synchronization detection unit which outputs a frame synchronization signal on the basis of timing of switching from a state in which the spread-modulated signal is synchronous with one reference code, to a state in which the spread-modulated signal is synchronous with another reference code; and a selection unit which selectively outputs, on the basis of the frame synchronization signal, signals demodulated by the spread demodulation units.