Patent ID: 8903379

Claim:
A telecommunication system comprising at least one control center and at least one mobile unit moving along a track, said at least one control center connected in a network with a plurals of wireless access points distributed along the track, said at least one mobile unit and said at least one control center conducting a broad band bi-directional communication of data/signal with roaming between said mobile unit and the plurality of wireless access points, each of said at least one mobile unit comprising onboard receiving-transmitting means for connection with said wireless access points, the each of said at least one mobile unit running a control application for continuously controlling the communication between the at least one mobile unit and a presently detected one of the access points, wherein the instructions cause the each the at least one mobile unit to perform the following method steps: setting a bandwidth decision threshold under which the bandwidth obtainable with the channel in transmission triggers a roaming, said bandwidth obtainable being based on the consideration of a measurement of a received signal/noise ratio; setting a signal decision threshold under which the signal level received triggers a roaming; setting a time between two subsequent comparisons of the signal level received and the bandwidth in transmission with said respective signal decision threshold and bandwidth decision threshold, during which the presently detected one of the access points is deemed valid; evaluating the signal level and bandwidth of the channel in transmission and the time during which the presently detected one of the access points is deemed valid, and triggering a roaming step when said signal level is under the signal decision threshold, said bandwidth is under said bandwidth decision threshold, or when said set time for deeming valid the presently detected one of the access points is lapsed; the roaming step comprising scanning a predetermined and programmable list of channels a determined time lapsing between the scan of a channel and the scan of a subsequent one, said channels including only frequencies preliminarily detected in order to attain the maximum bandwidth available, the selected channels being stored for speeding up a successive scan; updating a list of the valid access points based on the scanning step; and reassociating the communication from said present access point to a new access point in said list, when the signal level of the new access point exceeds the signal level of the present access point by a value corresponding to an established hysteresis threshold determined as a function of the mobile unit speed.