Ren Sakata

TL;DR: In this article, a cognitive radio system includes a state detecting device that scans a frequency band allocated to another radio system than the CR system to detect a first use state of the frequency band; a first server including a first gathering unit that receives first information relating to the first use-state and a second gathering unit; a second server that stores a second use-State of the spectrum allocated to the other radio system; and a notifying unit that notifies a CR system of information of an available channel based on the first information and the second information.

TL;DR: In this article, a cognitive communication system consisting of a medium estimator 104 provided in a radio terminal 1005 for detecting whether the radio channel allocated to the other radio equipment is in use or in a free state was proposed.

TL;DR: In this paper, a base station which communicates with radio terminals through time frames for transmission by using a plurality of frequency channels, including: a reception section configured to receive communication quality information indicating communication quality of one or more frequency channels from each radio terminal, a scheduling section configuring to schedule frequency channels to be assigned to the respective radio terminals based on the communication quality received from the radio terminals, a signal generation section configured to generate assignment status signals indicating whether or not respective frequency channels are already assigned in a second time frame next to a first time frame, and a reporting section

TL;DR: In this article, a wireless communication system which transmits and receives a signal by using a plurality of wireless apparatuses, comprising of a first wireless apparatus group, having a first control signal, and a second wireless ad hoc network between the first and second control signals, is described.

TL;DR: In this article, the database device for frequency use situation management for a wireless communication system for performing cognitive radio is made into a network and hierarchized, where the first database device 2-4 is located at a lower rank of the hierarchy and the second database devices 2-3a, 2-2a and 2-1 being a higher rank.