Method and apparatus for transmitting/receiving positioning reference signal in wireless communication system

A base station comprising:

• a processor to determine a narrow-band (NB) positioning reference signal (PRS) bitmap indicating a pattern for selecting NB PRS subframes from a plurality of subframe groups, wherein each subframe group comprises N downlink subframes, wherein the NB PRS bitmap has a size of N consecutive bits respectively corresponding to the N downlink subframes of each subframe group, and wherein each NB PRS subframe comprises an NB PRS for positioning a wireless device;
• and
• a transceiver to transmit, to the wireless device, NB PRS configuration information comprising the NB PRS bitmap,
• wherein the processor is configured to determine, based on the NB PRS bitmap, NB PRS subframes of a reference cell, and to map a first NB PRS in at least one of the NB PRS subframes of the reference cell, and
• wherein the transceiver receives, from the wireless device and in response to the first NB PRS, a reference signal time difference (RSTD) measurement.