Radio communication system, terminal device, base station device, radio communication method, and integrated circuit with efficient transmission and reception through repetition

A terminal device configured to communicate with a base station device and perform a random access procedure, wherein:

• the terminal device includes:
• a processor;
• and
• a memory in electronic communication with the processor, the memory storing instructions executable by the processor to:
• receive, from the base station device, random access information including:
• (i) information for selecting a level for determining a repetition number, (ii) a first number and a last number of preambles included in a group corresponding to the level, and (iii) a number of attempts of preamble transmission configured for each level,
• select, in a MAC layer, the level based on a received downlink radio quality, and
• perform, in the MAC layer, processing of increasing the level in a case that a first counter exceeds a maximum of the number of attempts of transmission, the maximum being configured for the level.

A base station device configured to communicate with a terminal device, wherein:

• the base station device includes:
• a processor;
• and
• a memory in electronic communication with the processor, the memory storing instructions executable by the processor to:
• notify the terminal device of random access information including:
• (i) information for selecting a level for determining a repetition number, (ii) a first number and a last number of preambles included in a group corresponding to the level, and (iii) a number of attempts of preamble transmission configured for each level.

A radio communication method applied to a terminal device configured to communicate with a base station device and perform a random access procedure, the radio communication method comprising the steps of:

• receiving, from the base station device, random access information including:
• (i) information for selecting a level for determining a repetition number, (ii) a first number and a last number of preambles included in a group corresponding to the level, and (iii) a number of attempts of preamble transmission configured for each level;
• selecting the level based on a received downlink radio quality;
• and
• increasing the level by a MAC layer in the terminal device in a case that a first counter exceeds a maximum of the number of attempts of transmission, the maximum being configured for the level.