Cellular radiotelephone signal which enables synchronisation at an entity of a supplementary channel by means of symbol numbering, and corresponding method, terminal and base station

Cellular radiotelephony signal comprising:

• a main symmetric two-directional channel comprising a main uplink and a main downlink, particularly transmitting signalling and control data and information at low or medium speed;
• at least one supplementary channel assigned to the down direction only, particularly for high speed data transmission, using a multi-carrier technique for distribution of data in the time/frequency space, and with a structure in predefined entities each including a predetermined number of symbols,
• wherein at least one symbol of each entity of the supplementary channel comprises a position identifier used to identify the position of said symbol in said entity, such that a terminal can read the position identifier of said symbol and use it to deduce the beginning of the next entity, thus obtaining synchronisation of the supplementary channel at the level of the entity considered,
• and wherein said predefined entities are sub-frames or frames of the supplementary channel.

Method for synchronisation of a supplementary channel associated with a symmetric two-directional main channel,

• said symmetric two-directional main channel comprising a main uplink and a main downlink, particularly for transmission of signalling and control data and information at low or medium speed,
• said supplementary channel being assigned to the down direction only, particularly for transmission of high speed data using a multi-carrier technique for distribution of data in the time/frequency space, and with a structure in predefined entities each including a predetermined number of symbols, the method comprising:
• synchronizing the supplementary channel at a level of the entity considered, wherein synchronizing comprises:
• detecting and reading a position identifier of a current symbol on the supplementary channel, said position identifier being used to identify the position of said symbol in the entity to which it belongs;
• and
• deducing the beginning of the next entity as a function of the position identifier of the current symbol,
• and wherein said predefined entities are sub-frames or frames of the supplementary channel.

Terminal in a cellular radiotelephony system, comprising:

• a transmitter, which transmits a main uplink, a receiver, which receives a main downlink and a receiver, which receives at least one supplementary channel, said main uplink and said main downlink forming a symmetric two-directional main channel, particularly for low or medium speed transmission of signalling and control data and information, said supplementary channel being assigned to the down direction only, particularly for transmission of high speed data, using a multi-carrier technique for distribution of data in the time/frequency space, and with a structure in predefined entities each including a predetermined number of symbols,
• a synchronizer, which synchronizes the supplementary channel at a level of the entity considered, wherein the synchronizer comprises:
• elements that detect and read a position identifier of a current symbol on the supplementary channel, said position identifier being used to identify the position of said symbol in the entity to which it belongs;
• and
• elements that deduce the beginning of the next entity as a function of the position identifier of the current symbol,
• and wherein said predefined entities are sub-frames or frames of the supplementary channel.