Method of allocating resource in wireless communication system

An apparatus for wireless communication, the apparatus comprising:

• a radio frequency (RF) unit for transmitting and receiving radio signals;
• and
• a processor coupled with the RF unit and configured for:
• selecting sub-parts, wherein each of the sub-parts is selected from different physical resource blocks (PRBs) and occupies different positions in each of the PRBs, each of the PRBs comprising consecutive orthogonal frequency division multiplexing (OFDM) symbols in time domain and consecutive subcarriers in frequency domain;
• mapping the sub-parts to virtual resource blocks (VRBs), wherein N sub-parts are mapped to one VRB, where N is an integer greater than 1;
• and
• transmitting data using the VRBs,
• wherein at least one of the N sub-parts comprises a different number of reference signal-resource elements (RS-REs) compared to the remaining sub-parts among the N sub-parts, and
• the N sub-parts are selected such that each of the mapped VRBs comprises a same number of RS-REs, and
• the data is transmitted using the remaining resource elements except the RS-REs in the mapped VRBs;
• and
• when the data is transmitted by using the mapped VRBs, a same effective code rate is used for the mapped VRBs.