Abstract: A mobile device (100) includes a satellite positioning receiver (102) for determining a precise location of the device (220). The first time the precise location is determined, the satellite positioning receiver is provided with location aiding information including an approximate location and a radius of uncertainty. The approximate location is determined by acquiring the location of a present base station (202), and the locations of one or more neighbor base stations (306), and calculating the spatial center of the base stations, and adjusting the spatial center according to received signal strengths of the base stations. A radius around the approximate location is then determined. The approximate location and radius are provided to the satellite positioning receiver.

Abstract: A mobile communication device (202) outside the service area of a communications network 210 in need of satellite positioning assistance information to perform a location determination (308). The mobile communication device receives the assistance information from a peer mobile communication device (204, 206) over a direct link.

Abstract: A mobile communication device (202) and peer mobile communication devices (204, 206) are capable of direct voice and data communication. The mobile communication device has a reference oscillator (104) which is used for generating operating frequencies, and is subject to frequency errors resulting from manufacturing tolerances, heat, and other error sources. The mobile communication device receives a frequency correction message (506) from a peer mobile communication device that has calibrated its reference oscillator. The frequency correction message contain offset information which is used by the mobile communication device to determine its offset (316) from a nominal frequency (302).

Abstract: The invention concerns a method (300) and mobile unit (110) for reducing transmission collisions. The method can include—in a systemless call environment—receiving (314) at a plurality of receiving mobile units (110B, 110C) a call from an original transmitting mobile unit (110A) and in the plurality of receiving mobile units, selectively randomly delaying (316) transmissions from the receiving units to reduce the probability that such transmissions will collide with one another. The selectively randomly delaying a transmission at the receiving units step can include performing (318) a pre-transmission scan when a transmission element (112) of one of the receiving mobile units is activated or by assigning (330) a random delay to an idle mode (400) following a receive session in the receiving mobile units.