User device, radio base station, and radio communication method

A radio base station that transmits to a user device notification information repeatedly transmitted at a predetermined cycle, the radio base station comprising:

• a notification information transmitting unit that transmits to the user device the notification information, wherein
• the notification information includes
• a first frame having a plurality of first slots to which system information of a same type used to perform radio communication is assigned;
• and
• a second frame that is transmitted after the first frame and has a plurality of second slots to which the system information is assigned, wherein,
• the first frame and the second frame are transmitted at the predetermined cycle, and
• the system information includes a predetermined number of spare bits, wherein
• the spare bits assigned to the first slot are used for a first purpose, and
• the spare bits assigned to the second slot are used for a second purpose that is different from the first purpose.

A radio communication method used in a radio communication system that includes a user device and a radio base station, the radio communication method comprising:

• transmitting in which the radio base station repeatedly transmits notification information at a predetermined cycle;
• and
• receiving in which the user device receives the notification information, wherein
• the notification information includes
• a first frame having a plurality of first slots to which system information of a same type used to perform radio communication is assigned;
• and
• a second frame that is transmitted after the first frame, and has a plurality of second slots to which the system information has been assigned, wherein
• the first frame and the second frame are transmitted at the predetermined cycle, and
• the system information includes a predetermined number of spare bits, wherein
• the spare bits assigned to the first slot are used for a first purpose, and
• the spare bits assigned to the second slot are used for a second purpose which is different from the first purpose.