Certain aspects of the disclosure relate to combining uplink and downlink location technologies into a single location-service system, to obtain the benefits offered by both of technologies while eliminating many of their individual shortcomings. Mobile devices that support downlink can then be located using the downlink mode, and mobile devices that do not support downlink can be located using the uplink mode. A mobile device may even be located based on a combination of uplink measurements and downlink measurements. Other aspects of the disclosure relate to providing a single location-service system to locate mobile devices that communicate using a plurality of different communication protocols.