Techniques for determining a position of a mobile device are provided. A method according to these techniques includes obtaining assistance data comprising information for cells associated with a plurality of wireless transmitters of a wireless communications network based on the coarse location of the mobile device, selecting a plurality of the cells from the assistance data, wherein selecting the plurality of cells includes identifying sets of colocated cells and selecting one cell from each of the colocated sets of cells; measuring signals from the plurality of cells to generate positioning signal measurements; and sending the positioning signal measurements to a location server. A colocated set of cells may include a narrowband cell and a non-narrowband cell, and the narrowband wireless cell may comprise a narrowband Internet of Things (NB-IoT) cell and a non-narrowband cell colocated with the NB-IoT cell at an Evolved Node B (eNodeB).