Arrangement for transforming data packets into a regular multiplex for a transmission system utilizing the TDMA principle

DETAILED DESCRIPTION OF THE INVENTION FIG.
1 proposes a frame organisation example, which, and that for a better understanding, allows a rapid recall to mind of the structure of the TDMA frame and multi-frame used in the information transmission system.
In the TDMA direction, that is to say in the direction from the sub-stations to the main station, the data transmission is effected in time slots denoted GRO to GR31 within a frame TGR.
Each time slot GR has a safety guard during which there is no transmission, which causes an uncertainty as regards the time of arrival of the data at the main staion.
To reduce the influence of the safety guard on the efficiency of the transmission rate, each time slot GR corresponds to 72 octets.
The time slot GRO is reserved for a semaphore channel which can be seized in a random manner by each one of the stations.
The time slot GR1 which mainly serves to check the delay of the stations, is seized successively by each one of the stations.
The time slots GR2 to GR31 can be seized by each of the sub-stations, under the control of the main station, to convey information.
Each slot contains a packet of 72 octets, formed as follows: 1 octet as guard time during which there is no transmission; 5 clock octets permitting to recover the clock on reception; 1 octet as preambel RDP for marking the beginning of the packet; 1 octet for channel-by-channel signalling when the packet is assigned to a speech channel; 64 information octets.
When the time slot is assigned to a speech channel these 64 octets correspond to the packetizing 8 ms speech.
As the encoding of speech of is effected at 8 kHz, this frame structure results in a rate equal to 2.
304 Mbit/s.
To permit dividing of a time slot GR between a plurality of data links, the TDMA frames are advantageously organized, for example and in a non-limitative manner, in accordance with a multi-frame MTGR which is similar to that of the multiplex frame described in CCITT recommendation X.
50.
This multiplex comprises 80 envelopes of 8 bits