A method of an image decoding by a decoding apparatus, the method comprising: receiving information on a size of a minimum coding unit, wherein the minimum coding unit represents a smallest coding unit that can be split from a largest coding unit based on a quad-tree structure; deriving the size of the minimum coding unit based on the information on the size of the minimum coding unit; deriving a current coding unit, wherein a coding unit is split into multiple coding units (410, 420, 430) in a current picture, and the current coding unit is one of the multiple coding units and wherein intra prediction is applied on the current coding unit; checking whether a size of the current coding unit is equal to the size of the minimum coding unit; deriving one or multiple prediction units from the current coding unit based on the result of the checking, wherein if the size of the current coding unit is equal to the size of the minimum coding unit: - explicit partition information is received and the one or multiple prediction units are derived based on the explicit partition information, and if the size of the current coding unit is not equal to the size of the minimum coding unit: - the one prediction unit of a same size as the current coding unit is derived without receiving the explicit partition information, - deriving the multiple prediction units from the current coding unit is not available; and performing the intra prediction with respect to the derived one or multiple prediction units. receiving information on a size of a minimum coding unit, wherein the minimum coding unit represents a smallest coding unit that can be split from a largest coding unit based on a quad-tree structure; deriving the size of the minimum coding unit based on the information on the size of the minimum coding unit; deriving a current coding unit, wherein a coding unit is split into multiple coding units (410, 420, 430) in a current picture, and the current coding unit is one of the multiple coding units and wherein intra prediction is applied on the current coding unit; checking whether a size of the current coding unit is equal to the size of the minimum coding unit; deriving one or multiple prediction units from the current coding unit based on the result of the checking, wherein if the size of the current coding unit is equal to the size of the minimum coding unit: - explicit partition information is received and the one or multiple prediction units are derived based on the explicit partition information, and - explicit partition information is received and the one or multiple prediction units are derived based on the explicit partition information, and if the size of the current coding unit is not equal to the size of the minimum coding unit: - the one prediction unit of a same size as the current coding unit is derived without receiving the explicit partition information, - deriving the multiple prediction units from the current coding unit is not available; and - the one prediction unit of a same size as the current coding unit is derived without receiving the explicit partition information, - deriving the multiple prediction units from the current coding unit is not available; and performing the intra prediction with respect to the derived one or multiple prediction units.