Abstract: A discontinuous change in a transmission timing in a time domain, which is caused by a transmission timing adjustment processing of an OFDMA uplink or the like, brings about a discontinuous rotation of a signal phase in a frequency domain, resulting in reduced communication quality. A wireless communication system of the present invention allows the signal phase of the frequency domain in a receiving station to be continuous before and after the timing adjustment processings by controlling a signal sequence in a transmission signal after conversion in the time domain in synchronization with the timing adjustment processing.

Abstract: A discontinuous change in a transmission timing in a time domain, which is caused by a transmission timing adjustment processing of an OFDMA uplink or the like, brings about a discontinuous rotation of a signal phase in a frequency domain, resulting in reduced communication quality. A wireless communication system of the present invention allows the signal phase of the frequency domain in a receiving station to be continuous before and after the timing adjustment processings by controlling a signal sequence in a transmission signal after conversion in the time domain in synchronization with the timing adjustment processing.

Abstract: A network unit for exchanging control messages with a remote network unit through a communication path to be established in a network. The network unit enables recovery of failures whether they occur in any of one way links, both-way links. The network unit also enables recovery of node failures to occur in a GMPLS network. The network decides whether or not it is possible to bypass all failure-occurred links detected in the communication path by switching the communication path to another by itself. When it is possible, the network unit detects the switching state of a downward segment that can bypass all those failure-occurred links. If the communication path is already switched or being switched in the downward segment, the network unit cancels the switching. If the communication path is not switched nor being switched in the downward segment, the network unit switches the communication path to a bypass route.