The present invention provides an interference-overload-indicator generating device, a method of generating an interference overload indicator, an interference-overload-indicator generation controller, a method of controlling interference-overload-indicator generation, and a method of indicating interference overload, and a base station utilizing these methods, each of which is used in an uplink FDMA cellular communication system. The base station includes an interference-overload-indicator generation control sub-system (1000), an interference-overload-indicator generation sub-system (2000), and a transmitting/receiving sub-system (3000). The interference-overload-indicator generation control sub-system (1000) judges whether or not a condition to initiate interference indicator generation is satisfied, and activates the interference-overload-indicator generation sub-system (2000) only when the condition is satisfied. This makes it possible to reduce a signaling size of the interference indicator. For further reducing the signaling size, an interference indicator signaling is generated by a method such as differential coding, state coding, or a bitmap, and transmitted. According to the present invention, an interference overload indicator generation control mechanism is relatively simple and the signaling size of the interference indicator is small.