An organic light emitting diode (OLED) display device, comprising: a display panel comprising blocks (B11-B33) of pixels configured to generate images, each block (B11-B33) comprising two or more subpixels; a data driver configured to: receive sense values from the blocks (B11-B33) of subpixels, wherein all subpixels of a block are configured to be sensed simultaneously through one sensing path whereby driving properties of the subpixels included in a same block are sensed as one value; and generate driving property values for each block (B11-B33) corresponding to the received sense value; and a data modulator comprising a memory configured to store a sensing value of each block (B11-B33) and a compensation value of each block (B11-B33), wherein the compensation value of a block is a value for minimizing a difference between a current-voltage characteristic of subpixels of said block based on the sensed value and an average current-voltage characteristic of subpixels of the display panel, wherein the data modulator is configured to: select a compensation value of each block (B11-B33) to be stored in the memory based on the sensing value of each block (B11-B33), modulate data (DATA) of an input image using the compensation value, and transmit the modulated data of the input image to the data driver. a display panel comprising blocks (B11-B33) of pixels configured to generate images, each block (B11-B33) comprising two or more subpixels; a data driver configured to: receive sense values from the blocks (B11-B33) of subpixels, wherein all subpixels of a block are configured to be sensed simultaneously through one sensing path whereby driving properties of the subpixels included in a same block are sensed as one value; and generate driving property values for each block (B11-B33) corresponding to the received sense value; and receive sense values from the blocks (B11-B33) of subpixels, wherein all subpixels of a block are configured to be sensed simultaneously through one sensing path whereby driving properties of the subpixels included in a same block are sensed as one value; and generate driving property values for each block (B11-B33) corresponding to the received sense value; and a data modulator comprising a memory configured to store a sensing value of each block (B11-B33) and a compensation value of each block (B11-B33), wherein the compensation value of a block is a value for minimizing a difference between a current-voltage characteristic of subpixels of said block based on the sensed value and an average current-voltage characteristic of subpixels of the display panel, wherein the data modulator is configured to: select a compensation value of each block (B11-B33) to be stored in the memory based on the sensing value of each block (B11-B33), modulate data (DATA) of an input image using the compensation value, and transmit the modulated data of the input image to the data driver. select a compensation value of each block (B11-B33) to be stored in the memory based on the sensing value of each block (B11-B33), modulate data (DATA) of an input image using the compensation value, and transmit the modulated data of the input image to the data driver.