Patent ID: 8090004
Filing Date: 2012-01-03
Classification: H04B

Abstract:
1. A spread spectrum communication method using very weak power, in which one of a pair of high frequency radio apparatuses that communicate with each other through spread spectrum communication by use of the very weak power that is not a subject of regulation by law is set as a master unit and the other one of the pair is set as a slave unit, the spread spectrum communication method comprising the steps of: transmitting, by the slave unit, a spread code B allocated to the slave unit to the master unit at an intermittent communication timing determined in advance; detecting, by the master unit, a difference between a carrier frequency of the slave unit and a carrier frequency of the master unit by performing a frequency analysis of a signal component included in reception data when receiving the spread code B from the slave unit, correcting the carrier frequency of the master unit so that the detected difference is reduced, and transmitting, from the master unit, a spread code A to the slave unit at an intermittent communication timing determined based on a reception timing of the spread code B from the slave unit, wherein said spread code A is allocated to the master unit with the carrier whose frequency has been corrected; and judging, by each of the master unit and the slave unit, that there is a correlation when a correlation value level of the reception data at the time of reception of the spread code A and B respectively from the other one of the master unit and the slave unit is greater than a threshold value determined in advance, and establishing communication synchronization, wherein only the spread code A and B is exchanged until the communication synchronization is established between the master unit and the slave unit.