Roaming of mobile radio units in a multicast digital network
OwnerRex Nisbetinventor
Life of this patent
Estimating the term…
Abstract
During idle periods in a non trunked mobile radio network, the base stations periodically transmit a channel-marking signal. While the channel-marking signal is being transmitted base stations in the same “channel”, with adjacent coverage areas, announce information about the base station sending the channel-marking signal. Following the base station announcements, each mobile station checks the transmit frequency of the adjacent base station. If the signal from the adjacent base station is stronger than the signal from the base station to which the mobile was previously tuned, the mobile remains tuned to the new transmit frequency. Otherwise the mobile re-tunes to the original frequency.
Claims17
A method of assisting movement of a mobile unit in a radio network, including:
- transmitting a first assist signal from a first base station in the network,
- transmitting a second assist signal from a second base station adjacent the first station, containing information about the first base station,
- assessing the first and second assist signals at a mobile unit that is served by the second station, and
- continuing service for the mobile unit without change of base station, or changing service for the unit from the second to the first station, in accord with the assessment.
A method of moving a mobile unit between base sites during a group call in a radio network, including:
- receiving an assist signal from a base station at a base site currently serving the mobile unit,
- determining from the assist signal another base station in a base site adjacent to the site currently serving the mobile unit, receiving an assist signal from the other base station in the adjacent base site, and comparing the assist signals to determine whether or not to continue service from the current base site or to switch service to the adjacent base site.
A radio network including:
- a plurality of base stations each located at a respective base site, and
- a central controller that coordinates multicast group calls among mobile units that are served by the stations, and assists movement of the units between base sites during calls, wherein the controller monitors radio traffic flows at each base station serving a common group call,
- instructs transmission of a first assist signal by a first base station that serves the call, and instructs transmission of one or more second assist signals by respective second stations that serve the call and are in sites adjacent the first station.
A base site in a radio network, including:
- a base station that provides group call services to mobile units located within the site, and
- a controller that monitors traffic flow through the base station and assists movement of mobile units into the site during a group call,
- wherein the controller instructs the base station to transmit a first assist signal when the station becomes idle, and
- instructs base stations serving the call at adjacent base sites to transmit respective second assist signals simultaneously with the first assist signal.
Dependencies are inferred from the claim text.