| 摘要 |
In a time division multiple access data transmission system with a multiplicity of small unattended stations, for example earth stations of a system operating with a satellite, the continuous presence of a station operating as a reference station for synchronisation and organisational tasks is intended to be avoided. In the new system, each station transmits a so-called pilot burst in the stationary condition in a frame time segment permanently allocated and known to all stations, which burst contains data for system organisation only, regardless of whether it is transmitting useful information at that time or not. Each station is thus able to define the start of the frame. Each station contains means to synchronise the burst transmission phase of its pilot burst, in stationary operating mode and during an initial access procedure, with one of the pilot bursts of the access-seeking stations, and permanently couples the transmission phase of its useful burst in stationary mode with the synchronised phase of its pilot burst. During the initial access procedure, an access-seeking station in the first instance tentatively occupies a free part of the frame with its pilot burst, which it inserts following synchronisation in the position permanently allocated to the latter. <IMAGE>
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