Abstract: A method and apparatus is disclosed herein for relative calibration of transceivers in a wireless communication system. In one embodiment, the method comprises transmitting multiple pilots from units in the first group; receiving, in response to the multiple pilots, a first set of pilot observations at each unit in the second group; transmitting a single pilot simultaneously from at least two units in the second group; in response to the single pilot, receiving a second set of pilot observations at each unit in the first group; and using the first and second sets of pilot observations to calibrate each of at least two units in the second group based on a reference array of transceivers in the first group of transceivers.