Patent ID: 8489133
Filing Date: 2013-07-16
Classification: H04L

Abstract:
1. A communication system comprising a transmission device for transmitting a synchronization signal for establishing synchronization, and a reception device for establishing synchronization by detecting the synchronization signal, wherein said reception device sequentially changes intervals from long intervals to shorter intervals at which an attempt is made to detect the synchronization signal, said transmission device is set to transmit the synchronization signal at long intervals of said reception device, said synchronization is frequency synchronization, and said establishment of synchronization includes detecting an effective communication frequency, said reception device sequentially switches a preset frequency change amount from a larger value to a smaller value in stages, calculates a reception side candidate frequency for detecting the synchronization signal based on the frequency change amount, and detects the synchronization signal using the calculated reception side candidate frequency, and said transmission device calculates a transmission side candidate frequency which is a candidate for a frequency for transmitting the synchronization signal, based on the largest possible frequency change amount calculated on the basis of a system bandwidth in which said communication system communicates, and determines the transmission side candidate frequency as a synchronization signal frequency for transmitting the synchronization signal when the transmission side candidate frequency exists within the system frequency band.